Merge github.com:grpc/grpc into epexinf

.gitmodules

@@ -24,3 +24,6 @@
 	path = third_party/cares/cares
 	url = https://github.com/c-ares/c-ares.git
 	branch = cares-1_12_0
+[submodule "third_party/bloaty"]
+	path = third_party/bloaty
+	url = https://github.com/google/bloaty.git

BUILD

@@ -34,11 +34,11 @@ load(
 )
 
 # This should be updated along with build.yaml
-g_stands_for = "gambit"
+g_stands_for = "generous"
 
-core_version = "4.0.0-dev"
+core_version = "5.0.0-dev"
 
-version = "1.7.0-dev"
+version = "1.8.0-dev"
 
 GPR_PUBLIC_HDRS = [
     "include/grpc/support/alloc.h",
@@ -574,6 +574,8 @@ grpc_cc_library(
         "src/core/lib/compression/compression.c",
         "src/core/lib/compression/message_compress.c",
         "src/core/lib/compression/stream_compression.c",
+        "src/core/lib/compression/stream_compression_gzip.c",
+        "src/core/lib/compression/stream_compression_identity.c",
         "src/core/lib/debug/stats.c",
         "src/core/lib/debug/stats_data.c",
         "src/core/lib/http/format_request.c",
@@ -705,6 +707,8 @@ grpc_cc_library(
         "src/core/lib/compression/algorithm_metadata.h",
         "src/core/lib/compression/message_compress.h",
         "src/core/lib/compression/stream_compression.h",
+        "src/core/lib/compression/stream_compression_gzip.h",
+        "src/core/lib/compression/stream_compression_identity.h",
         "src/core/lib/debug/stats.h",
         "src/core/lib/debug/stats_data.h",
         "src/core/lib/http/format_request.h",

CMakeLists.txt

@@ -24,7 +24,7 @@
 cmake_minimum_required(VERSION 2.8)
 
 set(PACKAGE_NAME      "grpc")
-set(PACKAGE_VERSION   "1.7.0-dev")
+set(PACKAGE_VERSION   "1.8.0-dev")
 set(PACKAGE_STRING    "${PACKAGE_NAME} ${PACKAGE_VERSION}")
 set(PACKAGE_TARNAME   "${PACKAGE_NAME}-${PACKAGE_VERSION}")
 set(PACKAGE_BUGREPORT "https://github.com/grpc/grpc/issues/")
@@ -965,6 +965,8 @@ add_library(grpc
   src/core/lib/compression/compression.c
   src/core/lib/compression/message_compress.c
   src/core/lib/compression/stream_compression.c
+  src/core/lib/compression/stream_compression_gzip.c
+  src/core/lib/compression/stream_compression_identity.c
   src/core/lib/debug/stats.c
   src/core/lib/debug/stats_data.c
   src/core/lib/http/format_request.c
@@ -1314,6 +1316,8 @@ add_library(grpc_cronet
   src/core/lib/compression/compression.c
   src/core/lib/compression/message_compress.c
   src/core/lib/compression/stream_compression.c
+  src/core/lib/compression/stream_compression_gzip.c
+  src/core/lib/compression/stream_compression_identity.c
   src/core/lib/debug/stats.c
   src/core/lib/debug/stats_data.c
   src/core/lib/http/format_request.c
@@ -1631,6 +1635,8 @@ add_library(grpc_test_util
   src/core/lib/compression/compression.c
   src/core/lib/compression/message_compress.c
   src/core/lib/compression/stream_compression.c
+  src/core/lib/compression/stream_compression_gzip.c
+  src/core/lib/compression/stream_compression_identity.c
   src/core/lib/debug/stats.c
   src/core/lib/debug/stats_data.c
   src/core/lib/http/format_request.c
@@ -1892,6 +1898,8 @@ add_library(grpc_test_util_unsecure
   src/core/lib/compression/compression.c
   src/core/lib/compression/message_compress.c
   src/core/lib/compression/stream_compression.c
+  src/core/lib/compression/stream_compression_gzip.c
+  src/core/lib/compression/stream_compression_identity.c
   src/core/lib/debug/stats.c
   src/core/lib/debug/stats_data.c
   src/core/lib/http/format_request.c
@@ -2139,6 +2147,8 @@ add_library(grpc_unsecure
   src/core/lib/compression/compression.c
   src/core/lib/compression/message_compress.c
   src/core/lib/compression/stream_compression.c
+  src/core/lib/compression/stream_compression_gzip.c
+  src/core/lib/compression/stream_compression_identity.c
   src/core/lib/debug/stats.c
   src/core/lib/debug/stats_data.c
   src/core/lib/http/format_request.c
@@ -2894,6 +2904,8 @@ add_library(grpc++_cronet
   src/core/lib/compression/compression.c
   src/core/lib/compression/message_compress.c
   src/core/lib/compression/stream_compression.c
+  src/core/lib/compression/stream_compression_gzip.c
+  src/core/lib/compression/stream_compression_identity.c
   src/core/lib/debug/stats.c
   src/core/lib/debug/stats_data.c
   src/core/lib/http/format_request.c

Makefile

@@ -187,7 +187,7 @@ CXX_gcov = g++
 LD_gcov = gcc
 LDXX_gcov = g++
 CPPFLAGS_gcov = -O0 -fprofile-arcs -ftest-coverage -Wno-return-type
-LDFLAGS_gcov = -fprofile-arcs -ftest-coverage -rdynamic
+LDFLAGS_gcov = -fprofile-arcs -ftest-coverage -rdynamic -lstdc++
 DEFINES_gcov = _DEBUG DEBUG GPR_GCOV
 
 VALID_CONFIG_memcheck = 1
@@ -411,8 +411,8 @@ Q = @
 endif
 
 CORE_VERSION = 5.0.0-dev
-CPP_VERSION = 1.7.0-dev
-CSHARP_VERSION = 1.7.0-dev
+CPP_VERSION = 1.8.0-dev
+CSHARP_VERSION = 1.8.0-dev
 
 CPPFLAGS_NO_ARCH += $(addprefix -I, $(INCLUDES)) $(addprefix -D, $(DEFINES))
 CPPFLAGS += $(CPPFLAGS_NO_ARCH) $(ARCH_FLAGS)
@@ -2956,6 +2956,8 @@ LIBGRPC_SRC = \
     src/core/lib/compression/compression.c \
     src/core/lib/compression/message_compress.c \
     src/core/lib/compression/stream_compression.c \
+    src/core/lib/compression/stream_compression_gzip.c \
+    src/core/lib/compression/stream_compression_identity.c \
     src/core/lib/debug/stats.c \
     src/core/lib/debug/stats_data.c \
     src/core/lib/http/format_request.c \
@@ -3305,6 +3307,8 @@ LIBGRPC_CRONET_SRC = \
     src/core/lib/compression/compression.c \
     src/core/lib/compression/message_compress.c \
     src/core/lib/compression/stream_compression.c \
+    src/core/lib/compression/stream_compression_gzip.c \
+    src/core/lib/compression/stream_compression_identity.c \
     src/core/lib/debug/stats.c \
     src/core/lib/debug/stats_data.c \
     src/core/lib/http/format_request.c \
@@ -3621,6 +3625,8 @@ LIBGRPC_TEST_UTIL_SRC = \
     src/core/lib/compression/compression.c \
     src/core/lib/compression/message_compress.c \
     src/core/lib/compression/stream_compression.c \
+    src/core/lib/compression/stream_compression_gzip.c \
+    src/core/lib/compression/stream_compression_identity.c \
     src/core/lib/debug/stats.c \
     src/core/lib/debug/stats_data.c \
     src/core/lib/http/format_request.c \
@@ -3873,6 +3879,8 @@ LIBGRPC_TEST_UTIL_UNSECURE_SRC = \
     src/core/lib/compression/compression.c \
     src/core/lib/compression/message_compress.c \
     src/core/lib/compression/stream_compression.c \
+    src/core/lib/compression/stream_compression_gzip.c \
+    src/core/lib/compression/stream_compression_identity.c \
     src/core/lib/debug/stats.c \
     src/core/lib/debug/stats_data.c \
     src/core/lib/http/format_request.c \
@@ -4098,6 +4106,8 @@ LIBGRPC_UNSECURE_SRC = \
     src/core/lib/compression/compression.c \
     src/core/lib/compression/message_compress.c \
     src/core/lib/compression/stream_compression.c \
+    src/core/lib/compression/stream_compression_gzip.c \
+    src/core/lib/compression/stream_compression_identity.c \
     src/core/lib/debug/stats.c \
     src/core/lib/debug/stats_data.c \
     src/core/lib/http/format_request.c \
@@ -4836,6 +4846,8 @@ LIBGRPC++_CRONET_SRC = \
     src/core/lib/compression/compression.c \
     src/core/lib/compression/message_compress.c \
     src/core/lib/compression/stream_compression.c \
+    src/core/lib/compression/stream_compression_gzip.c \
+    src/core/lib/compression/stream_compression_identity.c \
     src/core/lib/debug/stats.c \
     src/core/lib/debug/stats_data.c \
     src/core/lib/http/format_request.c \

binding.gyp

@@ -101,6 +101,7 @@
             '-fprofile-arcs',
             '-ftest-coverage',
             '-rdynamic',
+            '-lstdc++',
         ],
       }],
       ['grpc_alpine=="true"', {
@@ -667,6 +668,8 @@
         'src/core/lib/compression/compression.c',
         'src/core/lib/compression/message_compress.c',
         'src/core/lib/compression/stream_compression.c',
+        'src/core/lib/compression/stream_compression_gzip.c',
+        'src/core/lib/compression/stream_compression_identity.c',
         'src/core/lib/debug/stats.c',
         'src/core/lib/debug/stats_data.c',
         'src/core/lib/http/format_request.c',

build.yaml

@@ -13,8 +13,8 @@ settings:
   '#09': Per-language overrides are possible with (eg) ruby_version tag here
   '#10': See the expand_version.py for all the quirks here
   core_version: 5.0.0-dev
-  g_stands_for: gambit
-  version: 1.7.0-dev
+  g_stands_for: generous
+  version: 1.8.0-dev
 filegroups:
 - name: census
   public_headers:
@@ -195,6 +195,8 @@ filegroups:
   - src/core/lib/compression/compression.c
   - src/core/lib/compression/message_compress.c
   - src/core/lib/compression/stream_compression.c
+  - src/core/lib/compression/stream_compression_gzip.c
+  - src/core/lib/compression/stream_compression_identity.c
   - src/core/lib/debug/stats.c
   - src/core/lib/debug/stats_data.c
   - src/core/lib/http/format_request.c
@@ -346,6 +348,8 @@ filegroups:
   - src/core/lib/compression/algorithm_metadata.h
   - src/core/lib/compression/message_compress.h
   - src/core/lib/compression/stream_compression.h
+  - src/core/lib/compression/stream_compression_gzip.h
+  - src/core/lib/compression/stream_compression_identity.h
   - src/core/lib/debug/stats.h
   - src/core/lib/debug/stats_data.h
   - src/core/lib/http/format_request.h
@@ -4780,7 +4784,7 @@ configs:
     CXX: g++
     DEFINES: _DEBUG DEBUG GPR_GCOV
     LD: gcc
-    LDFLAGS: -fprofile-arcs -ftest-coverage -rdynamic
+    LDFLAGS: -fprofile-arcs -ftest-coverage -rdynamic -lstdc++
     LDXX: g++
   helgrind:
     CPPFLAGS: -O0

config.m4

@@ -96,6 +96,8 @@ if test "$PHP_GRPC" != "no"; then
     src/core/lib/compression/compression.c \
     src/core/lib/compression/message_compress.c \
     src/core/lib/compression/stream_compression.c \
+    src/core/lib/compression/stream_compression_gzip.c \
+    src/core/lib/compression/stream_compression_identity.c \
     src/core/lib/debug/stats.c \
     src/core/lib/debug/stats_data.c \
     src/core/lib/http/format_request.c \

config.w32

@@ -73,6 +73,8 @@ if (PHP_GRPC != "no") {
     "src\\core\\lib\\compression\\compression.c " +
     "src\\core\\lib\\compression\\message_compress.c " +
     "src\\core\\lib\\compression\\stream_compression.c " +
+    "src\\core\\lib\\compression\\stream_compression_gzip.c " +
+    "src\\core\\lib\\compression\\stream_compression_identity.c " +
     "src\\core\\lib\\debug\\stats.c " +
     "src\\core\\lib\\debug\\stats_data.c " +
     "src\\core\\lib\\http\\format_request.c " +

doc/environment_variables.md

@@ -58,6 +58,7 @@ some configuration as environment variables that can be set.
     completion queue
   - round_robin - traces the round_robin load balancing policy
   - pick_first - traces the pick first load balancing policy
+  - plugin_credentials - traces plugin credentials
   - resource_quota - trace resource quota objects internals
   - glb - traces the grpclb load balancer
   - queue_pluck

doc/g_stands_for.md

@@ -11,3 +11,4 @@ future), and the corresponding version numbers that used them:
 - 1.4 'g' stands for 'gregarious'
 - 1.6 'g' stands for 'garcia'
 - 1.7 'g' stands for 'gambit'
+- 1.8 'g' stands for 'generous'

examples/node/dynamic_codegen/greeter_server.js

@@ -34,7 +34,7 @@ function sayHello(call, callback) {
  */
 function main() {
   var server = new grpc.Server();
-  server.addProtoService(hello_proto.Greeter.service, {sayHello: sayHello});
+  server.addService(hello_proto.Greeter.service, {sayHello: sayHello});
   server.bind('0.0.0.0:50051', grpc.ServerCredentials.createInsecure());
   server.start();
 }

gRPC-Core.podspec

@@ -22,7 +22,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-Core'
-  version = '1.7.0-dev'
+  version = '1.8.0-dev'
   s.version  = version
   s.summary  = 'Core cross-platform gRPC library, written in C'
   s.homepage = 'https://grpc.io'
@@ -105,8 +105,6 @@ Pod::Spec.new do |s|
     ss.source_files = 'include/grpc/support/alloc.h',
                       'include/grpc/support/atm.h',
                       'include/grpc/support/atm_gcc_atomic.h',
-                      'include/grpc/support/atm_gcc_sync.h',
-                      'include/grpc/support/atm_windows.h',
                       'include/grpc/support/avl.h',
                       'include/grpc/support/cmdline.h',
                       'include/grpc/support/cpu.h',
@@ -121,18 +119,13 @@ Pod::Spec.new do |s|
                       'include/grpc/support/sync_custom.h',
                       'include/grpc/support/sync_generic.h',
                       'include/grpc/support/sync_posix.h',
-                      'include/grpc/support/sync_windows.h',
                       'include/grpc/support/thd.h',
                       'include/grpc/support/time.h',
                       'include/grpc/support/tls.h',
-                      'include/grpc/support/tls_gcc.h',
-                      'include/grpc/support/tls_msvc.h',
                       'include/grpc/support/tls_pthread.h',
                       'include/grpc/support/useful.h',
                       'include/grpc/impl/codegen/atm.h',
                       'include/grpc/impl/codegen/atm_gcc_atomic.h',
-                      'include/grpc/impl/codegen/atm_gcc_sync.h',
-                      'include/grpc/impl/codegen/atm_windows.h',
                       'include/grpc/impl/codegen/gpr_slice.h',
                       'include/grpc/impl/codegen/gpr_types.h',
                       'include/grpc/impl/codegen/port_platform.h',
@@ -140,7 +133,6 @@ Pod::Spec.new do |s|
                       'include/grpc/impl/codegen/sync_custom.h',
                       'include/grpc/impl/codegen/sync_generic.h',
                       'include/grpc/impl/codegen/sync_posix.h',
-                      'include/grpc/impl/codegen/sync_windows.h',
                       'include/grpc/impl/codegen/byte_buffer.h',
                       'include/grpc/impl/codegen/byte_buffer_reader.h',
                       'include/grpc/impl/codegen/compression_types.h',
@@ -152,8 +144,6 @@ Pod::Spec.new do |s|
                       'include/grpc/impl/codegen/status.h',
                       'include/grpc/impl/codegen/atm.h',
                       'include/grpc/impl/codegen/atm_gcc_atomic.h',
-                      'include/grpc/impl/codegen/atm_gcc_sync.h',
-                      'include/grpc/impl/codegen/atm_windows.h',
                       'include/grpc/impl/codegen/gpr_slice.h',
                       'include/grpc/impl/codegen/gpr_types.h',
                       'include/grpc/impl/codegen/port_platform.h',
@@ -161,7 +151,6 @@ Pod::Spec.new do |s|
                       'include/grpc/impl/codegen/sync_custom.h',
                       'include/grpc/impl/codegen/sync_generic.h',
                       'include/grpc/impl/codegen/sync_posix.h',
-                      'include/grpc/impl/codegen/sync_windows.h',
                       'include/grpc/grpc_security.h',
                       'include/grpc/byte_buffer.h',
                       'include/grpc/byte_buffer_reader.h',
@@ -330,6 +319,8 @@ Pod::Spec.new do |s|
                       'src/core/lib/compression/algorithm_metadata.h',
                       'src/core/lib/compression/message_compress.h',
                       'src/core/lib/compression/stream_compression.h',
+                      'src/core/lib/compression/stream_compression_gzip.h',
+                      'src/core/lib/compression/stream_compression_identity.h',
                       'src/core/lib/debug/stats.h',
                       'src/core/lib/debug/stats_data.h',
                       'src/core/lib/http/format_request.h',
@@ -479,6 +470,8 @@ Pod::Spec.new do |s|
                       'src/core/lib/compression/compression.c',
                       'src/core/lib/compression/message_compress.c',
                       'src/core/lib/compression/stream_compression.c',
+                      'src/core/lib/compression/stream_compression_gzip.c',
+                      'src/core/lib/compression/stream_compression_identity.c',
                       'src/core/lib/debug/stats.c',
                       'src/core/lib/debug/stats_data.c',
                       'src/core/lib/http/format_request.c',
@@ -825,6 +818,8 @@ Pod::Spec.new do |s|
                               'src/core/lib/compression/algorithm_metadata.h',
                               'src/core/lib/compression/message_compress.h',
                               'src/core/lib/compression/stream_compression.h',
+                              'src/core/lib/compression/stream_compression_gzip.h',
+                              'src/core/lib/compression/stream_compression_identity.h',
                               'src/core/lib/debug/stats.h',
                               'src/core/lib/debug/stats_data.h',
                               'src/core/lib/http/format_request.h',

gRPC-ProtoRPC.podspec

@@ -21,7 +21,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-ProtoRPC'
-  version = '1.7.0-dev'
+  version = '1.8.0-dev'
   s.version  = version
   s.summary  = 'RPC library for Protocol Buffers, based on gRPC'
   s.homepage = 'https://grpc.io'

gRPC-RxLibrary.podspec

@@ -21,7 +21,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC-RxLibrary'
-  version = '1.7.0-dev'
+  version = '1.8.0-dev'
   s.version  = version
   s.summary  = 'Reactive Extensions library for iOS/OSX.'
   s.homepage = 'https://grpc.io'

gRPC.podspec

@@ -20,7 +20,7 @@
 
 Pod::Spec.new do |s|
   s.name     = 'gRPC'
-  version = '1.7.0-dev'
+  version = '1.8.0-dev'
   s.version  = version
   s.summary  = 'gRPC client library for iOS/OSX'
   s.homepage = 'https://grpc.io'

grpc.gemspec

@@ -263,6 +263,8 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/compression/algorithm_metadata.h )
   s.files += %w( src/core/lib/compression/message_compress.h )
   s.files += %w( src/core/lib/compression/stream_compression.h )
+  s.files += %w( src/core/lib/compression/stream_compression_gzip.h )
+  s.files += %w( src/core/lib/compression/stream_compression_identity.h )
   s.files += %w( src/core/lib/debug/stats.h )
   s.files += %w( src/core/lib/debug/stats_data.h )
   s.files += %w( src/core/lib/http/format_request.h )
@@ -416,6 +418,8 @@ Gem::Specification.new do |s|
   s.files += %w( src/core/lib/compression/compression.c )
   s.files += %w( src/core/lib/compression/message_compress.c )
   s.files += %w( src/core/lib/compression/stream_compression.c )
+  s.files += %w( src/core/lib/compression/stream_compression_gzip.c )
+  s.files += %w( src/core/lib/compression/stream_compression_identity.c )
   s.files += %w( src/core/lib/debug/stats.c )
   s.files += %w( src/core/lib/debug/stats_data.c )
   s.files += %w( src/core/lib/http/format_request.c )

grpc.gyp

@@ -98,6 +98,7 @@
           '-fprofile-arcs',
           '-ftest-coverage',
           '-rdynamic',
+          '-lstdc++',
         ],
       }],
       ['grpc_alpine=="true"', {
@@ -233,6 +234,8 @@
         'src/core/lib/compression/compression.c',
         'src/core/lib/compression/message_compress.c',
         'src/core/lib/compression/stream_compression.c',
+        'src/core/lib/compression/stream_compression_gzip.c',
+        'src/core/lib/compression/stream_compression_identity.c',
         'src/core/lib/debug/stats.c',
         'src/core/lib/debug/stats_data.c',
         'src/core/lib/http/format_request.c',
@@ -532,6 +535,8 @@
         'src/core/lib/compression/compression.c',
         'src/core/lib/compression/message_compress.c',
         'src/core/lib/compression/stream_compression.c',
+        'src/core/lib/compression/stream_compression_gzip.c',
+        'src/core/lib/compression/stream_compression_identity.c',
         'src/core/lib/debug/stats.c',
         'src/core/lib/debug/stats_data.c',
         'src/core/lib/http/format_request.c',
@@ -736,6 +741,8 @@
         'src/core/lib/compression/compression.c',
         'src/core/lib/compression/message_compress.c',
         'src/core/lib/compression/stream_compression.c',
+        'src/core/lib/compression/stream_compression_gzip.c',
+        'src/core/lib/compression/stream_compression_identity.c',
         'src/core/lib/debug/stats.c',
         'src/core/lib/debug/stats_data.c',
         'src/core/lib/http/format_request.c',
@@ -925,6 +932,8 @@
         'src/core/lib/compression/compression.c',
         'src/core/lib/compression/message_compress.c',
         'src/core/lib/compression/stream_compression.c',
+        'src/core/lib/compression/stream_compression_gzip.c',
+        'src/core/lib/compression/stream_compression_identity.c',
         'src/core/lib/debug/stats.c',
         'src/core/lib/debug/stats_data.c',
         'src/core/lib/http/format_request.c',

include/grpc++/generic/generic_stub.h

@@ -20,6 +20,7 @@
 #define GRPCXX_GENERIC_GENERIC_STUB_H
 
 #include <grpc++/support/async_stream.h>
+#include <grpc++/support/async_unary_call.h>
 #include <grpc++/support/byte_buffer.h>
 
 namespace grpc {
@@ -27,6 +28,7 @@ namespace grpc {
 class CompletionQueue;
 typedef ClientAsyncReaderWriter<ByteBuffer, ByteBuffer>
     GenericClientAsyncReaderWriter;
+typedef ClientAsyncResponseReader<ByteBuffer> GenericClientAsyncResponseReader;
 
 /// Generic stubs provide a type-unsafe interface to call gRPC methods
 /// by name.
@@ -51,6 +53,14 @@ class GenericStub final {
   std::unique_ptr<GenericClientAsyncReaderWriter> PrepareCall(
       ClientContext* context, const grpc::string& method, CompletionQueue* cq);
 
+  /// Setup a unary call to a named method \a method using \a context, and don't
+  /// start it. Let it be started explicitly with StartCall.
+  /// The return value only indicates whether or not registration of the call
+  /// succeeded (i.e. the call won't proceed if the return value is nullptr).
+  std::unique_ptr<GenericClientAsyncResponseReader> PrepareUnaryCall(
+      ClientContext* context, const grpc::string& method,
+      const ByteBuffer& request, CompletionQueue* cq);
+
  private:
   std::shared_ptr<ChannelInterface> channel_;
 };

include/grpc++/support/channel_arguments.h

@@ -64,6 +64,12 @@ class ChannelArguments {
   /// Set the compression algorithm for the channel.
   void SetCompressionAlgorithm(grpc_compression_algorithm algorithm);
 
+  /// Set the grpclb fallback timeout (in ms) for the channel. If this amount
+  /// of time has passed but we have not gotten any non-empty \a serverlist from
+  /// the balancer, we will fall back to use the backend address(es) returned by
+  /// the resolver.
+  void SetGrpclbFallbackTimeout(int fallback_timeout);
+
   /// Set the socket mutator for the channel.
   void SetSocketMutator(grpc_socket_mutator* mutator);
 

include/grpc/grpc.h

@@ -313,7 +313,7 @@ GRPCAPI grpc_call_error grpc_call_cancel_with_status(grpc_call *call,
                                                      void *reserved);
 
 /** Ref a call.
-    THREAD SAFETY: grpc_call_unref is thread-compatible */
+    THREAD SAFETY: grpc_call_ref is thread-compatible */
 GRPCAPI void grpc_call_ref(grpc_call *call);
 
 /** Unref a call.

include/grpc/grpc_security.h

@@ -249,19 +249,40 @@ typedef struct {
   void *reserved;
 } grpc_auth_metadata_context;
 
+/** Maximum number of metadata entries returnable by a credentials plugin via
+    a synchronous return. */
+#define GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX 4
+
 /** grpc_metadata_credentials plugin is an API user provided structure used to
    create grpc_credentials objects that can be set on a channel (composed) or
    a call. See grpc_credentials_metadata_create_from_plugin below.
    The grpc client stack will call the get_metadata method of the plugin for
    every call in scope for the credentials created from it. */
 typedef struct {
-  /** The implementation of this method has to be non-blocking.
-     - context is the information that can be used by the plugin to create auth
-       metadata.
-     - cb is the callback that needs to be called when the metadata is ready.
-     - user_data needs to be passed as the first parameter of the callback. */
-  void (*get_metadata)(void *state, grpc_auth_metadata_context context,
-                       grpc_credentials_plugin_metadata_cb cb, void *user_data);
+  /** The implementation of this method has to be non-blocking, but can
+     be performed synchronously or asynchronously.
+
+     If processing occurs synchronously, returns non-zero and populates
+     creds_md, num_creds_md, status, and error_details.  In this case,
+     the caller takes ownership of the entries in creds_md and of
+     error_details.  Note that if the plugin needs to return more than
+     GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX entries in creds_md, it must
+     return asynchronously.
+
+     If processing occurs asynchronously, returns zero and invokes \a cb
+     when processing is completed.  \a user_data will be passed as the
+     first parameter of the callback.  NOTE: \a cb MUST be invoked in a
+     different thread, not from the thread in which \a get_metadata() is
+     invoked.
+
+     \a context is the information that can be used by the plugin to create
+     auth metadata. */
+  int (*get_metadata)(
+      void *state, grpc_auth_metadata_context context,
+      grpc_credentials_plugin_metadata_cb cb, void *user_data,
+      grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+      size_t *num_creds_md, grpc_status_code *status,
+      const char **error_details);
 
   /** Destroys the plugin state. */
   void (*destroy)(void *state);

include/grpc/impl/codegen/grpc_types.h

@@ -288,7 +288,11 @@ typedef struct {
   "grpc.experimental.tcp_max_read_chunk_size"
 /* Timeout in milliseconds to use for calls to the grpclb load balancer.
    If 0 or unset, the balancer calls will have no deadline. */
-#define GRPC_ARG_GRPCLB_CALL_TIMEOUT_MS "grpc.grpclb_timeout_ms"
+#define GRPC_ARG_GRPCLB_CALL_TIMEOUT_MS "grpc.grpclb_call_timeout_ms"
+/* Timeout in milliseconds to wait for the serverlist from the grpclb load
+   balancer before using fallback backend addresses from the resolver.
+   If 0, fallback will never be used. */
+#define GRPC_ARG_GRPCLB_FALLBACK_TIMEOUT_MS "grpc.grpclb_fallback_timeout_ms"
 /** If non-zero, grpc server's cronet compression workaround will be enabled */
 #define GRPC_ARG_WORKAROUND_CRONET_COMPRESSION \
   "grpc.workaround.cronet_compression"

include/grpc/impl/codegen/port_platform.h

@@ -183,7 +183,6 @@
 #define _BSD_SOURCE
 #endif
 #if TARGET_OS_IPHONE
-#define GPR_FORBID_UNREACHABLE_CODE 1
 #define GPR_PLATFORM_STRING "ios"
 #define GPR_CPU_IPHONE 1
 #define GPR_PTHREAD_TLS 1
@@ -292,10 +291,6 @@
 #endif
 
 #ifdef _MSC_VER
-#ifdef _PYTHON_MSVC
-// The Python 3.5 Windows runtime is missing InetNtop
-#define GPR_WIN_INET_NTOP
-#endif  // _PYTHON_MSVC
 #if _MSC_VER < 1700
 typedef __int8 int8_t;
 typedef __int16 int16_t;

include/grpc/module.modulemap

@@ -1,12 +1,69 @@
+
 framework module grpc {
   umbrella header "grpc.h"
 
-  header "byte_buffer_reader.h"
-  header "grpc_security.h"
-  header "grpc_security_constants.h"
   header "support/alloc.h"
+  header "support/atm.h"
+  header "support/atm_gcc_atomic.h"
+  header "support/avl.h"
+  header "support/cmdline.h"
+  header "support/cpu.h"
+  header "support/histogram.h"
+  header "support/host_port.h"
+  header "support/log.h"
+  header "support/log_windows.h"
   header "support/port_platform.h"
   header "support/string_util.h"
+  header "support/subprocess.h"
+  header "support/sync.h"
+  header "support/sync_custom.h"
+  header "support/sync_generic.h"
+  header "support/sync_posix.h"
+  header "support/thd.h"
+  header "support/time.h"
+  header "support/tls.h"
+  header "support/tls_pthread.h"
+  header "support/useful.h"
+  header "impl/codegen/atm.h"
+  header "impl/codegen/atm_gcc_atomic.h"
+  header "impl/codegen/gpr_slice.h"
+  header "impl/codegen/gpr_types.h"
+  header "impl/codegen/port_platform.h"
+  header "impl/codegen/sync.h"
+  header "impl/codegen/sync_custom.h"
+  header "impl/codegen/sync_generic.h"
+  header "impl/codegen/sync_posix.h"
+  header "impl/codegen/byte_buffer.h"
+  header "impl/codegen/byte_buffer_reader.h"
+  header "impl/codegen/compression_types.h"
+  header "impl/codegen/connectivity_state.h"
+  header "impl/codegen/exec_ctx_fwd.h"
+  header "impl/codegen/grpc_types.h"
+  header "impl/codegen/propagation_bits.h"
+  header "impl/codegen/slice.h"
+  header "impl/codegen/status.h"
+  header "impl/codegen/atm.h"
+  header "impl/codegen/atm_gcc_atomic.h"
+  header "impl/codegen/gpr_slice.h"
+  header "impl/codegen/gpr_types.h"
+  header "impl/codegen/port_platform.h"
+  header "impl/codegen/sync.h"
+  header "impl/codegen/sync_custom.h"
+  header "impl/codegen/sync_generic.h"
+  header "impl/codegen/sync_posix.h"
+  header "grpc_security.h"
+  header "byte_buffer.h"
+  header "byte_buffer_reader.h"
+  header "compression.h"
+  header "grpc.h"
+  header "grpc_posix.h"
+  header "grpc_security_constants.h"
+  header "load_reporting.h"
+  header "slice.h"
+  header "slice_buffer.h"
+  header "status.h"
+  header "support/workaround_list.h"
+  header "census.h"
 
   export *
   module * { export * }

package.json

@@ -1,6 +1,6 @@
 {
   "name": "grpc",
-  "version": "1.7.0-dev",
+  "version": "1.8.0-dev",
   "author": "Google Inc.",
   "description": "gRPC Library for Node",
   "homepage": "https://grpc.io/",

package.xml

@@ -13,8 +13,8 @@
  <date>2017-08-24</date>
  <time>16:06:07</time>
  <version>
-  <release>1.7.0dev</release>
-  <api>1.7.0dev</api>
+  <release>1.8.0dev</release>
+  <api>1.8.0dev</api>
  </version>
  <stability>
   <release>beta</release>
@@ -275,6 +275,8 @@
     <file baseinstalldir="/" name="src/core/lib/compression/algorithm_metadata.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/compression/message_compress.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/compression/stream_compression.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/compression/stream_compression_gzip.h" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/compression/stream_compression_identity.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/debug/stats.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/debug/stats_data.h" role="src" />
     <file baseinstalldir="/" name="src/core/lib/http/format_request.h" role="src" />
@@ -428,6 +430,8 @@
     <file baseinstalldir="/" name="src/core/lib/compression/compression.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/compression/message_compress.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/compression/stream_compression.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/compression/stream_compression_gzip.c" role="src" />
+    <file baseinstalldir="/" name="src/core/lib/compression/stream_compression_identity.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/debug/stats.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/debug/stats_data.c" role="src" />
     <file baseinstalldir="/" name="src/core/lib/http/format_request.c" role="src" />

setup.py

@@ -110,8 +110,6 @@ if EXTRA_ENV_COMPILE_ARGS is None:
       EXTRA_ENV_COMPILE_ARGS += ' -D_ftime=_ftime32 -D_timeb=__timeb32 -D_ftime_s=_ftime32_s'
     else:
       EXTRA_ENV_COMPILE_ARGS += ' -D_ftime=_ftime64 -D_timeb=__timeb64'
-  elif 'win32' in sys.platform:
-    EXTRA_ENV_COMPILE_ARGS += ' -D_PYTHON_MSVC'
   elif "linux" in sys.platform:
     EXTRA_ENV_COMPILE_ARGS += ' -std=c++11 -std=gnu99 -fvisibility=hidden -fno-wrapv -fno-exceptions'
   elif "darwin" in sys.platform:
@@ -163,7 +161,7 @@ if "win32" in sys.platform:
   # TODO(zyc): Re-enble c-ares on x64 and x86 windows after fixing the
   # ares_library_init compilation issue
   DEFINE_MACROS += (('WIN32_LEAN_AND_MEAN', 1), ('CARES_STATICLIB', 1),
-                    ('GRPC_ARES', 0),)
+                    ('GRPC_ARES', 0), ('NTDDI_VERSION', 0x06000000),)
   if '64bit' in platform.architecture()[0]:
     DEFINE_MACROS += (('MS_WIN64', 1),)
   elif sys.version_info >= (3, 5):

src/core/ext/filters/client_channel/http_proxy.c

@@ -91,6 +91,7 @@ static bool proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
   char* user_cred = NULL;
   *name_to_resolve = get_http_proxy_server(exec_ctx, &user_cred);
   if (*name_to_resolve == NULL) return false;
+  char* no_proxy_str = NULL;
   grpc_uri* uri =
       grpc_uri_parse(exec_ctx, server_uri, false /* suppress_errors */);
   if (uri == NULL || uri->path[0] == '\0') {
@@ -98,20 +99,14 @@ static bool proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
             "'http_proxy' environment variable set, but cannot "
             "parse server URI '%s' -- not using proxy",
             server_uri);
-    if (uri != NULL) {
-      gpr_free(user_cred);
-      grpc_uri_destroy(uri);
-    }
-    return false;
+    goto no_use_proxy;
   }
   if (strcmp(uri->scheme, "unix") == 0) {
     gpr_log(GPR_INFO, "not using proxy for Unix domain socket '%s'",
             server_uri);
-    gpr_free(user_cred);
-    grpc_uri_destroy(uri);
-    return false;
+    goto no_use_proxy;
   }
-  char* no_proxy_str = gpr_getenv("no_proxy");
+  no_proxy_str = gpr_getenv("no_proxy");
   if (no_proxy_str != NULL) {
     static const char* NO_PROXY_SEPARATOR = ",";
     bool use_proxy = true;
@@ -147,12 +142,7 @@ static bool proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
       gpr_free(no_proxy_hosts);
       gpr_free(server_host);
       gpr_free(server_port);
-      if (!use_proxy) {
-        grpc_uri_destroy(uri);
-        gpr_free(*name_to_resolve);
-        *name_to_resolve = NULL;
-        return false;
-      }
+      if (!use_proxy) goto no_use_proxy;
     }
   }
   grpc_arg args_to_add[2];
@@ -173,9 +163,15 @@ static bool proxy_mapper_map_name(grpc_exec_ctx* exec_ctx,
   } else {
     *new_args = grpc_channel_args_copy_and_add(args, args_to_add, 1);
   }
-  gpr_free(user_cred);
   grpc_uri_destroy(uri);
+  gpr_free(user_cred);
   return true;
+no_use_proxy:
+  if (uri != NULL) grpc_uri_destroy(uri);
+  gpr_free(*name_to_resolve);
+  *name_to_resolve = NULL;
+  gpr_free(user_cred);
+  return false;
 }
 
 static bool proxy_mapper_map_address(grpc_exec_ctx* exec_ctx,

src/core/ext/filters/client_channel/lb_policy/grpclb/grpclb.c

@@ -123,6 +123,7 @@
 #define GRPC_GRPCLB_RECONNECT_BACKOFF_MULTIPLIER 1.6
 #define GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS 120
 #define GRPC_GRPCLB_RECONNECT_JITTER 0.2
+#define GRPC_GRPCLB_DEFAULT_FALLBACK_TIMEOUT_MS 10000
 
 grpc_tracer_flag grpc_lb_glb_trace = GRPC_TRACER_INITIALIZER(false, "glb");
 
@@ -299,6 +300,10 @@ typedef struct glb_lb_policy {
   /** timeout in milliseconds for the LB call. 0 means no deadline. */
   int lb_call_timeout_ms;
 
+  /** timeout in milliseconds for before using fallback backend addresses.
+   * 0 means not using fallback. */
+  int lb_fallback_timeout_ms;
+
   /** for communicating with the LB server */
   grpc_channel *lb_channel;
 
@@ -325,6 +330,9 @@ typedef struct glb_lb_policy {
    * Otherwise, we delegate to the RR policy. */
   size_t serverlist_index;
 
+  /** stores the backend addresses from the resolver */
+  grpc_lb_addresses *fallback_backend_addresses;
+
   /** list of picks that are waiting on RR's policy connectivity */
   pending_pick *pending_picks;
 
@@ -345,6 +353,9 @@ typedef struct glb_lb_policy {
   /** is \a lb_call_retry_timer active? */
   bool retry_timer_active;
 
+  /** is \a lb_fallback_timer active? */
+  bool fallback_timer_active;
+
   /** called upon changes to the LB channel's connectivity. */
   grpc_closure lb_channel_on_connectivity_changed;
 
@@ -354,9 +365,6 @@ typedef struct glb_lb_policy {
   /************************************************************/
   /*  client data associated with the LB server communication */
   /************************************************************/
-  /* Finished sending initial request. */
-  grpc_closure lb_on_sent_initial_request;
-
   /* Status from the LB server has been received. This signals the end of the LB
    * call. */
   grpc_closure lb_on_server_status_received;
@@ -367,6 +375,9 @@ typedef struct glb_lb_policy {
   /* LB call retry timer callback. */
   grpc_closure lb_on_call_retry;
 
+  /* LB fallback timer callback. */
+  grpc_closure lb_on_fallback;
+
   grpc_call *lb_call; /* streaming call to the LB server, */
 
   grpc_metadata_array lb_initial_metadata_recv; /* initial MD from LB server */
@@ -390,7 +401,9 @@ typedef struct glb_lb_policy {
   /** LB call retry timer */
   grpc_timer lb_call_retry_timer;
 
-  bool initial_request_sent;
+  /** LB fallback timer */
+  grpc_timer lb_fallback_timer;
+
   bool seen_initial_response;
 
   /* Stats for client-side load reporting. Should be unreffed and
@@ -536,6 +549,32 @@ static grpc_lb_addresses *process_serverlist_locked(
   return lb_addresses;
 }
 
+/* Returns the backend addresses extracted from the given addresses */
+static grpc_lb_addresses *extract_backend_addresses_locked(
+    grpc_exec_ctx *exec_ctx, const grpc_lb_addresses *addresses) {
+  /* first pass: count the number of backend addresses */
+  size_t num_backends = 0;
+  for (size_t i = 0; i < addresses->num_addresses; ++i) {
+    if (!addresses->addresses[i].is_balancer) {
+      ++num_backends;
+    }
+  }
+  /* second pass: actually populate the addresses and (empty) LB tokens */
+  grpc_lb_addresses *backend_addresses =
+      grpc_lb_addresses_create(num_backends, &lb_token_vtable);
+  size_t num_copied = 0;
+  for (size_t i = 0; i < addresses->num_addresses; ++i) {
+    if (addresses->addresses[i].is_balancer) continue;
+    const grpc_resolved_address *addr = &addresses->addresses[i].address;
+    grpc_lb_addresses_set_address(backend_addresses, num_copied, &addr->addr,
+                                  addr->len, false /* is_balancer */,
+                                  NULL /* balancer_name */,
+                                  (void *)GRPC_MDELEM_LB_TOKEN_EMPTY.payload);
+    ++num_copied;
+  }
+  return backend_addresses;
+}
+
 static void update_lb_connectivity_status_locked(
     grpc_exec_ctx *exec_ctx, glb_lb_policy *glb_policy,
     grpc_connectivity_state rr_state, grpc_error *rr_state_error) {
@@ -603,35 +642,38 @@ static bool pick_from_internal_rr_locked(
     grpc_exec_ctx *exec_ctx, glb_lb_policy *glb_policy,
     const grpc_lb_policy_pick_args *pick_args, bool force_async,
     grpc_connected_subchannel **target, wrapped_rr_closure_arg *wc_arg) {
-  // Look at the index into the serverlist to see if we should drop this call.
-  grpc_grpclb_server *server =
-      glb_policy->serverlist->servers[glb_policy->serverlist_index++];
-  if (glb_policy->serverlist_index == glb_policy->serverlist->num_servers) {
-    glb_policy->serverlist_index = 0;  // Wrap-around.
-  }
-  if (server->drop) {
-    // Not using the RR policy, so unref it.
-    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-      gpr_log(GPR_INFO, "Unreffing RR for drop (0x%" PRIxPTR ")",
-              (intptr_t)wc_arg->rr_policy);
+  // Check for drops if we are not using fallback backend addresses.
+  if (glb_policy->serverlist != NULL) {
+    // Look at the index into the serverlist to see if we should drop this call.
+    grpc_grpclb_server *server =
+        glb_policy->serverlist->servers[glb_policy->serverlist_index++];
+    if (glb_policy->serverlist_index == glb_policy->serverlist->num_servers) {
+      glb_policy->serverlist_index = 0;  // Wrap-around.
     }
-    GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->rr_policy, "glb_pick_sync");
-    // Update client load reporting stats to indicate the number of
-    // dropped calls.  Note that we have to do this here instead of in
-    // the client_load_reporting filter, because we do not create a
-    // subchannel call (and therefore no client_load_reporting filter)
-    // for dropped calls.
-    grpc_grpclb_client_stats_add_call_dropped_locked(server->load_balance_token,
-                                                     wc_arg->client_stats);
-    grpc_grpclb_client_stats_unref(wc_arg->client_stats);
-    if (force_async) {
-      GPR_ASSERT(wc_arg->wrapped_closure != NULL);
-      GRPC_CLOSURE_SCHED(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_NONE);
+    if (server->drop) {
+      // Not using the RR policy, so unref it.
+      if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+        gpr_log(GPR_INFO, "Unreffing RR for drop (0x%" PRIxPTR ")",
+                (intptr_t)wc_arg->rr_policy);
+      }
+      GRPC_LB_POLICY_UNREF(exec_ctx, wc_arg->rr_policy, "glb_pick_sync");
+      // Update client load reporting stats to indicate the number of
+      // dropped calls.  Note that we have to do this here instead of in
+      // the client_load_reporting filter, because we do not create a
+      // subchannel call (and therefore no client_load_reporting filter)
+      // for dropped calls.
+      grpc_grpclb_client_stats_add_call_dropped_locked(
+          server->load_balance_token, wc_arg->client_stats);
+      grpc_grpclb_client_stats_unref(wc_arg->client_stats);
+      if (force_async) {
+        GPR_ASSERT(wc_arg->wrapped_closure != NULL);
+        GRPC_CLOSURE_SCHED(exec_ctx, wc_arg->wrapped_closure, GRPC_ERROR_NONE);
+        gpr_free(wc_arg->free_when_done);
+        return false;
+      }
       gpr_free(wc_arg->free_when_done);
-      return false;
+      return true;
     }
-    gpr_free(wc_arg->free_when_done);
-    return true;
   }
   // Pick via the RR policy.
   const bool pick_done = grpc_lb_policy_pick_locked(
@@ -669,8 +711,18 @@ static bool pick_from_internal_rr_locked(
 
 static grpc_lb_policy_args *lb_policy_args_create(grpc_exec_ctx *exec_ctx,
                                                   glb_lb_policy *glb_policy) {
-  grpc_lb_addresses *addresses =
-      process_serverlist_locked(exec_ctx, glb_policy->serverlist);
+  grpc_lb_addresses *addresses;
+  if (glb_policy->serverlist != NULL) {
+    GPR_ASSERT(glb_policy->serverlist->num_servers > 0);
+    addresses = process_serverlist_locked(exec_ctx, glb_policy->serverlist);
+  } else {
+    // If rr_handover_locked() is invoked when we haven't received any
+    // serverlist from the balancer, we use the fallback backends returned by
+    // the resolver. Note that the fallback backend list may be empty, in which
+    // case the new round_robin policy will keep the requested picks pending.
+    GPR_ASSERT(glb_policy->fallback_backend_addresses != NULL);
+    addresses = grpc_lb_addresses_copy(glb_policy->fallback_backend_addresses);
+  }
   GPR_ASSERT(addresses != NULL);
   grpc_lb_policy_args *args = (grpc_lb_policy_args *)gpr_zalloc(sizeof(*args));
   args->client_channel_factory = glb_policy->cc_factory;
@@ -776,8 +828,6 @@ static void create_rr_locked(grpc_exec_ctx *exec_ctx, glb_lb_policy *glb_policy,
 /* glb_policy->rr_policy may be NULL (initial handover) */
 static void rr_handover_locked(grpc_exec_ctx *exec_ctx,
                                glb_lb_policy *glb_policy) {
-  GPR_ASSERT(glb_policy->serverlist != NULL &&
-             glb_policy->serverlist->num_servers > 0);
   if (glb_policy->shutting_down) return;
   grpc_lb_policy_args *args = lb_policy_args_create(exec_ctx, glb_policy);
   GPR_ASSERT(args != NULL);
@@ -926,6 +976,9 @@ static void glb_destroy(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   if (glb_policy->serverlist != NULL) {
     grpc_grpclb_destroy_serverlist(glb_policy->serverlist);
   }
+  if (glb_policy->fallback_backend_addresses != NULL) {
+    grpc_lb_addresses_destroy(exec_ctx, glb_policy->fallback_backend_addresses);
+  }
   grpc_fake_resolver_response_generator_unref(glb_policy->response_generator);
   grpc_subchannel_index_unref();
   if (glb_policy->pending_update_args != NULL) {
@@ -1067,10 +1120,28 @@ static void glb_cancel_picks_locked(grpc_exec_ctx *exec_ctx,
   GRPC_ERROR_UNREF(error);
 }
 
+static void lb_on_fallback_timer_locked(grpc_exec_ctx *exec_ctx, void *arg,
+                                        grpc_error *error);
 static void query_for_backends_locked(grpc_exec_ctx *exec_ctx,
                                       glb_lb_policy *glb_policy);
 static void start_picking_locked(grpc_exec_ctx *exec_ctx,
                                  glb_lb_policy *glb_policy) {
+  /* start a timer to fall back */
+  if (glb_policy->lb_fallback_timeout_ms > 0 &&
+      glb_policy->serverlist == NULL && !glb_policy->fallback_timer_active) {
+    gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+    gpr_timespec deadline = gpr_time_add(
+        now,
+        gpr_time_from_millis(glb_policy->lb_fallback_timeout_ms, GPR_TIMESPAN));
+    GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "grpclb_fallback_timer");
+    GRPC_CLOSURE_INIT(&glb_policy->lb_on_fallback, lb_on_fallback_timer_locked,
+                      glb_policy,
+                      grpc_combiner_scheduler(glb_policy->base.combiner));
+    glb_policy->fallback_timer_active = true;
+    grpc_timer_init(exec_ctx, &glb_policy->lb_fallback_timer, deadline,
+                    &glb_policy->lb_on_fallback, now);
+  }
+
   glb_policy->started_picking = true;
   gpr_backoff_reset(&glb_policy->lb_call_backoff_state);
   query_for_backends_locked(exec_ctx, glb_policy);
@@ -1173,6 +1244,58 @@ static void glb_notify_on_state_change_locked(grpc_exec_ctx *exec_ctx,
       exec_ctx, &glb_policy->state_tracker, current, notify);
 }
 
+static void lb_call_on_retry_timer_locked(grpc_exec_ctx *exec_ctx, void *arg,
+                                          grpc_error *error) {
+  glb_lb_policy *glb_policy = (glb_lb_policy *)arg;
+  glb_policy->retry_timer_active = false;
+  if (!glb_policy->shutting_down && error == GRPC_ERROR_NONE) {
+    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+      gpr_log(GPR_INFO, "Restaring call to LB server (grpclb %p)",
+              (void *)glb_policy);
+    }
+    GPR_ASSERT(glb_policy->lb_call == NULL);
+    query_for_backends_locked(exec_ctx, glb_policy);
+  }
+  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base, "grpclb_retry_timer");
+}
+
+static void maybe_restart_lb_call(grpc_exec_ctx *exec_ctx,
+                                  glb_lb_policy *glb_policy) {
+  if (glb_policy->started_picking && glb_policy->updating_lb_call) {
+    if (glb_policy->retry_timer_active) {
+      grpc_timer_cancel(exec_ctx, &glb_policy->lb_call_retry_timer);
+    }
+    if (!glb_policy->shutting_down) start_picking_locked(exec_ctx, glb_policy);
+    glb_policy->updating_lb_call = false;
+  } else if (!glb_policy->shutting_down) {
+    /* if we aren't shutting down, restart the LB client call after some time */
+    gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+    gpr_timespec next_try =
+        gpr_backoff_step(&glb_policy->lb_call_backoff_state, now);
+    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+      gpr_log(GPR_DEBUG, "Connection to LB server lost (grpclb: %p)...",
+              (void *)glb_policy);
+      gpr_timespec timeout = gpr_time_sub(next_try, now);
+      if (gpr_time_cmp(timeout, gpr_time_0(timeout.clock_type)) > 0) {
+        gpr_log(GPR_DEBUG,
+                "... retry_timer_active in %" PRId64 ".%09d seconds.",
+                timeout.tv_sec, timeout.tv_nsec);
+      } else {
+        gpr_log(GPR_DEBUG, "... retry_timer_active immediately.");
+      }
+    }
+    GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "grpclb_retry_timer");
+    GRPC_CLOSURE_INIT(&glb_policy->lb_on_call_retry,
+                      lb_call_on_retry_timer_locked, glb_policy,
+                      grpc_combiner_scheduler(glb_policy->base.combiner));
+    glb_policy->retry_timer_active = true;
+    grpc_timer_init(exec_ctx, &glb_policy->lb_call_retry_timer, next_try,
+                    &glb_policy->lb_on_call_retry, now);
+  }
+  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base,
+                            "lb_on_server_status_received_locked");
+}
+
 static void send_client_load_report_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                            grpc_error *error);
 
@@ -1203,21 +1326,6 @@ static void client_load_report_done_locked(grpc_exec_ctx *exec_ctx, void *arg,
   schedule_next_client_load_report(exec_ctx, glb_policy);
 }
 
-static void do_send_client_load_report_locked(grpc_exec_ctx *exec_ctx,
-                                              glb_lb_policy *glb_policy) {
-  grpc_op op;
-  memset(&op, 0, sizeof(op));
-  op.op = GRPC_OP_SEND_MESSAGE;
-  op.data.send_message.send_message = glb_policy->client_load_report_payload;
-  GRPC_CLOSURE_INIT(&glb_policy->client_load_report_closure,
-                    client_load_report_done_locked, glb_policy,
-                    grpc_combiner_scheduler(glb_policy->base.combiner));
-  grpc_call_error call_error = grpc_call_start_batch_and_execute(
-      exec_ctx, glb_policy->lb_call, &op, 1,
-      &glb_policy->client_load_report_closure);
-  GPR_ASSERT(GRPC_CALL_OK == call_error);
-}
-
 static bool load_report_counters_are_zero(grpc_grpclb_request *request) {
   grpc_grpclb_dropped_call_counts *drop_entries =
       (grpc_grpclb_dropped_call_counts *)
@@ -1237,6 +1345,9 @@ static void send_client_load_report_locked(grpc_exec_ctx *exec_ctx, void *arg,
     glb_policy->client_load_report_timer_pending = false;
     GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base,
                               "client_load_report");
+    if (glb_policy->lb_call == NULL) {
+      maybe_restart_lb_call(exec_ctx, glb_policy);
+    }
     return;
   }
   // Construct message payload.
@@ -1260,17 +1371,23 @@ static void send_client_load_report_locked(grpc_exec_ctx *exec_ctx, void *arg,
       grpc_raw_byte_buffer_create(&request_payload_slice, 1);
   grpc_slice_unref_internal(exec_ctx, request_payload_slice);
   grpc_grpclb_request_destroy(request);
-  // If we've already sent the initial request, then we can go ahead and
-  // sent the load report.  Otherwise, we need to wait until the initial
-  // request has been sent to send this
-  // (see lb_on_sent_initial_request_locked() below).
-  if (glb_policy->initial_request_sent) {
-    do_send_client_load_report_locked(exec_ctx, glb_policy);
+  // Send load report message.
+  grpc_op op;
+  memset(&op, 0, sizeof(op));
+  op.op = GRPC_OP_SEND_MESSAGE;
+  op.data.send_message.send_message = glb_policy->client_load_report_payload;
+  GRPC_CLOSURE_INIT(&glb_policy->client_load_report_closure,
+                    client_load_report_done_locked, glb_policy,
+                    grpc_combiner_scheduler(glb_policy->base.combiner));
+  grpc_call_error call_error = grpc_call_start_batch_and_execute(
+      exec_ctx, glb_policy->lb_call, &op, 1,
+      &glb_policy->client_load_report_closure);
+  if (call_error != GRPC_CALL_OK) {
+    gpr_log(GPR_ERROR, "call_error=%d", call_error);
+    GPR_ASSERT(GRPC_CALL_OK == call_error);
   }
 }
 
-static void lb_on_sent_initial_request_locked(grpc_exec_ctx *exec_ctx,
-                                              void *arg, grpc_error *error);
 static void lb_on_server_status_received_locked(grpc_exec_ctx *exec_ctx,
                                                 void *arg, grpc_error *error);
 static void lb_on_response_received_locked(grpc_exec_ctx *exec_ctx, void *arg,
@@ -1315,9 +1432,6 @@ static void lb_call_init_locked(grpc_exec_ctx *exec_ctx,
   grpc_slice_unref_internal(exec_ctx, request_payload_slice);
   grpc_grpclb_request_destroy(request);
 
-  GRPC_CLOSURE_INIT(&glb_policy->lb_on_sent_initial_request,
-                    lb_on_sent_initial_request_locked, glb_policy,
-                    grpc_combiner_scheduler(glb_policy->base.combiner));
   GRPC_CLOSURE_INIT(&glb_policy->lb_on_server_status_received,
                     lb_on_server_status_received_locked, glb_policy,
                     grpc_combiner_scheduler(glb_policy->base.combiner));
@@ -1332,7 +1446,6 @@ static void lb_call_init_locked(grpc_exec_ctx *exec_ctx,
                    GRPC_GRPCLB_MIN_CONNECT_TIMEOUT_SECONDS * 1000,
                    GRPC_GRPCLB_RECONNECT_MAX_BACKOFF_SECONDS * 1000);
 
-  glb_policy->initial_request_sent = false;
   glb_policy->seen_initial_response = false;
   glb_policy->last_client_load_report_counters_were_zero = false;
 }
@@ -1349,7 +1462,7 @@ static void lb_call_destroy_locked(grpc_exec_ctx *exec_ctx,
   grpc_byte_buffer_destroy(glb_policy->lb_request_payload);
   grpc_slice_unref_internal(exec_ctx, glb_policy->lb_call_status_details);
 
-  if (!glb_policy->client_load_report_timer_pending) {
+  if (glb_policy->client_load_report_timer_pending) {
     grpc_timer_cancel(exec_ctx, &glb_policy->client_load_report_timer);
   }
 }
@@ -1373,7 +1486,7 @@ static void query_for_backends_locked(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(glb_policy->lb_call != NULL);
 
   grpc_call_error call_error;
-  grpc_op ops[4];
+  grpc_op ops[3];
   memset(ops, 0, sizeof(ops));
 
   grpc_op *op = ops;
@@ -1394,13 +1507,8 @@ static void query_for_backends_locked(grpc_exec_ctx *exec_ctx,
   op->flags = 0;
   op->reserved = NULL;
   op++;
-  /* take a weak ref (won't prevent calling of \a glb_shutdown if the strong ref
-   * count goes to zero) to be unref'd in lb_on_sent_initial_request_locked() */
-  GRPC_LB_POLICY_WEAK_REF(&glb_policy->base,
-                          "lb_on_sent_initial_request_locked");
-  call_error = grpc_call_start_batch_and_execute(
-      exec_ctx, glb_policy->lb_call, ops, (size_t)(op - ops),
-      &glb_policy->lb_on_sent_initial_request);
+  call_error = grpc_call_start_batch_and_execute(exec_ctx, glb_policy->lb_call,
+                                                 ops, (size_t)(op - ops), NULL);
   GPR_ASSERT(GRPC_CALL_OK == call_error);
 
   op = ops;
@@ -1437,19 +1545,6 @@ static void query_for_backends_locked(grpc_exec_ctx *exec_ctx,
   GPR_ASSERT(GRPC_CALL_OK == call_error);
 }
 
-static void lb_on_sent_initial_request_locked(grpc_exec_ctx *exec_ctx,
-                                              void *arg, grpc_error *error) {
-  glb_lb_policy *glb_policy = (glb_lb_policy *)arg;
-  glb_policy->initial_request_sent = true;
-  // If we attempted to send a client load report before the initial
-  // request was sent, send the load report now.
-  if (glb_policy->client_load_report_payload != NULL) {
-    do_send_client_load_report_locked(exec_ctx, glb_policy);
-  }
-  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base,
-                            "lb_on_sent_initial_request_locked");
-}
-
 static void lb_on_response_received_locked(grpc_exec_ctx *exec_ctx, void *arg,
                                            grpc_error *error) {
   glb_lb_policy *glb_policy = (glb_lb_policy *)arg;
@@ -1525,6 +1620,15 @@ static void lb_on_response_received_locked(grpc_exec_ctx *exec_ctx, void *arg,
             if (glb_policy->serverlist != NULL) {
               /* dispose of the old serverlist */
               grpc_grpclb_destroy_serverlist(glb_policy->serverlist);
+            } else {
+              /* or dispose of the fallback */
+              grpc_lb_addresses_destroy(exec_ctx,
+                                        glb_policy->fallback_backend_addresses);
+              glb_policy->fallback_backend_addresses = NULL;
+              if (glb_policy->fallback_timer_active) {
+                grpc_timer_cancel(exec_ctx, &glb_policy->lb_fallback_timer);
+                glb_policy->fallback_timer_active = false;
+              }
             }
             /* and update the copy in the glb_lb_policy instance. This
              * serverlist instance will be destroyed either upon the next
@@ -1535,9 +1639,7 @@ static void lb_on_response_received_locked(grpc_exec_ctx *exec_ctx, void *arg,
           }
         } else {
           if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-            gpr_log(GPR_INFO,
-                    "Received empty server list. Picks will stay pending until "
-                    "a response with > 0 servers is received");
+            gpr_log(GPR_INFO, "Received empty server list, ignoring.");
           }
           grpc_grpclb_destroy_serverlist(serverlist);
         }
@@ -1572,19 +1674,25 @@ static void lb_on_response_received_locked(grpc_exec_ctx *exec_ctx, void *arg,
   }
 }
 
-static void lb_call_on_retry_timer_locked(grpc_exec_ctx *exec_ctx, void *arg,
-                                          grpc_error *error) {
+static void lb_on_fallback_timer_locked(grpc_exec_ctx *exec_ctx, void *arg,
+                                        grpc_error *error) {
   glb_lb_policy *glb_policy = (glb_lb_policy *)arg;
-  glb_policy->retry_timer_active = false;
-  if (!glb_policy->shutting_down && error == GRPC_ERROR_NONE) {
-    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-      gpr_log(GPR_INFO, "Restaring call to LB server (grpclb %p)",
-              (void *)glb_policy);
+  glb_policy->fallback_timer_active = false;
+  /* If we receive a serverlist after the timer fires but before this callback
+   * actually runs, don't fall back. */
+  if (glb_policy->serverlist == NULL) {
+    if (!glb_policy->shutting_down && error == GRPC_ERROR_NONE) {
+      if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+        gpr_log(GPR_INFO,
+                "Falling back to use backends from resolver (grpclb %p)",
+                (void *)glb_policy);
+      }
+      GPR_ASSERT(glb_policy->fallback_backend_addresses != NULL);
+      rr_handover_locked(exec_ctx, glb_policy);
     }
-    GPR_ASSERT(glb_policy->lb_call == NULL);
-    query_for_backends_locked(exec_ctx, glb_policy);
   }
-  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base, "grpclb_retry_timer");
+  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base,
+                            "grpclb_fallback_timer");
 }
 
 static void lb_on_server_status_received_locked(grpc_exec_ctx *exec_ctx,
@@ -1603,66 +1711,30 @@ static void lb_on_server_status_received_locked(grpc_exec_ctx *exec_ctx,
   }
   /* We need to perform cleanups no matter what. */
   lb_call_destroy_locked(exec_ctx, glb_policy);
-  if (glb_policy->started_picking && glb_policy->updating_lb_call) {
-    if (glb_policy->retry_timer_active) {
-      grpc_timer_cancel(exec_ctx, &glb_policy->lb_call_retry_timer);
-    }
-    if (!glb_policy->shutting_down) start_picking_locked(exec_ctx, glb_policy);
-    glb_policy->updating_lb_call = false;
-  } else if (!glb_policy->shutting_down) {
-    /* if we aren't shutting down, restart the LB client call after some time */
-    gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
-    gpr_timespec next_try =
-        gpr_backoff_step(&glb_policy->lb_call_backoff_state, now);
-    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-      gpr_log(GPR_DEBUG, "Connection to LB server lost (grpclb: %p)...",
-              (void *)glb_policy);
-      gpr_timespec timeout = gpr_time_sub(next_try, now);
-      if (gpr_time_cmp(timeout, gpr_time_0(timeout.clock_type)) > 0) {
-        gpr_log(GPR_DEBUG,
-                "... retry_timer_active in %" PRId64 ".%09d seconds.",
-                timeout.tv_sec, timeout.tv_nsec);
-      } else {
-        gpr_log(GPR_DEBUG, "... retry_timer_active immediately.");
-      }
-    }
-    GRPC_LB_POLICY_WEAK_REF(&glb_policy->base, "grpclb_retry_timer");
-    GRPC_CLOSURE_INIT(&glb_policy->lb_on_call_retry,
-                      lb_call_on_retry_timer_locked, glb_policy,
-                      grpc_combiner_scheduler(glb_policy->base.combiner));
-    glb_policy->retry_timer_active = true;
-    grpc_timer_init(exec_ctx, &glb_policy->lb_call_retry_timer, next_try,
-                    &glb_policy->lb_on_call_retry, now);
+  // If the load report timer is still pending, we wait for it to be
+  // called before restarting the call.  Otherwise, we restart the call
+  // here.
+  if (!glb_policy->client_load_report_timer_pending) {
+    maybe_restart_lb_call(exec_ctx, glb_policy);
+  }
+}
+
+static void fallback_update_locked(grpc_exec_ctx *exec_ctx,
+                                   glb_lb_policy *glb_policy,
+                                   const grpc_lb_addresses *addresses) {
+  GPR_ASSERT(glb_policy->fallback_backend_addresses != NULL);
+  grpc_lb_addresses_destroy(exec_ctx, glb_policy->fallback_backend_addresses);
+  glb_policy->fallback_backend_addresses =
+      extract_backend_addresses_locked(exec_ctx, addresses);
+  if (glb_policy->lb_fallback_timeout_ms > 0 &&
+      !glb_policy->fallback_timer_active) {
+    rr_handover_locked(exec_ctx, glb_policy);
   }
-  GRPC_LB_POLICY_WEAK_UNREF(exec_ctx, &glb_policy->base,
-                            "lb_on_server_status_received_locked");
 }
 
 static void glb_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
                               const grpc_lb_policy_args *args) {
   glb_lb_policy *glb_policy = (glb_lb_policy *)policy;
-  if (glb_policy->updating_lb_channel) {
-    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
-      gpr_log(GPR_INFO,
-              "Update already in progress for grpclb %p. Deferring update.",
-              (void *)glb_policy);
-    }
-    if (glb_policy->pending_update_args != NULL) {
-      grpc_channel_args_destroy(exec_ctx,
-                                glb_policy->pending_update_args->args);
-      gpr_free(glb_policy->pending_update_args);
-    }
-    glb_policy->pending_update_args = (grpc_lb_policy_args *)gpr_zalloc(
-        sizeof(*glb_policy->pending_update_args));
-    glb_policy->pending_update_args->client_channel_factory =
-        args->client_channel_factory;
-    glb_policy->pending_update_args->args = grpc_channel_args_copy(args->args);
-    glb_policy->pending_update_args->combiner = args->combiner;
-    return;
-  }
-
-  glb_policy->updating_lb_channel = true;
-  // Propagate update to lb_channel (pick first).
   const grpc_arg *arg =
       grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
   if (arg == NULL || arg->type != GRPC_ARG_POINTER) {
@@ -1680,13 +1752,43 @@ static void glb_update_locked(grpc_exec_ctx *exec_ctx, grpc_lb_policy *policy,
               "ignoring.",
               (void *)glb_policy);
     }
+    return;
   }
   const grpc_lb_addresses *addresses =
       (const grpc_lb_addresses *)arg->value.pointer.p;
+
+  if (glb_policy->serverlist == NULL) {
+    // If a non-empty serverlist hasn't been received from the balancer,
+    // propagate the update to fallback_backend_addresses.
+    fallback_update_locked(exec_ctx, glb_policy, addresses);
+  } else if (glb_policy->updating_lb_channel) {
+    // If we have recieved serverlist from the balancer, we need to defer update
+    // when there is an in-progress one.
+    if (GRPC_TRACER_ON(grpc_lb_glb_trace)) {
+      gpr_log(GPR_INFO,
+              "Update already in progress for grpclb %p. Deferring update.",
+              (void *)glb_policy);
+    }
+    if (glb_policy->pending_update_args != NULL) {
+      grpc_channel_args_destroy(exec_ctx,
+                                glb_policy->pending_update_args->args);
+      gpr_free(glb_policy->pending_update_args);
+    }
+    glb_policy->pending_update_args = (grpc_lb_policy_args *)gpr_zalloc(
+        sizeof(*glb_policy->pending_update_args));
+    glb_policy->pending_update_args->client_channel_factory =
+        args->client_channel_factory;
+    glb_policy->pending_update_args->args = grpc_channel_args_copy(args->args);
+    glb_policy->pending_update_args->combiner = args->combiner;
+    return;
+  }
+
+  glb_policy->updating_lb_channel = true;
   GPR_ASSERT(glb_policy->lb_channel != NULL);
   grpc_channel_args *lb_channel_args = build_lb_channel_args(
       exec_ctx, addresses, glb_policy->response_generator, args->args);
-  /* Propagate updates to the LB channel through the fake resolver */
+  /* Propagate updates to the LB channel (pick first) through the fake resolver
+   */
   grpc_fake_resolver_response_generator_set_response(
       exec_ctx, glb_policy->response_generator, lb_channel_args);
   grpc_channel_args_destroy(exec_ctx, lb_channel_args);
@@ -1789,13 +1891,7 @@ static const grpc_lb_policy_vtable glb_lb_policy_vtable = {
 static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
                                   grpc_lb_policy_factory *factory,
                                   grpc_lb_policy_args *args) {
-  /* Count the number of gRPC-LB addresses. There must be at least one.
-   * TODO(roth): For now, we ignore non-balancer addresses, but in the
-   * future, we may change the behavior such that we fall back to using
-   * the non-balancer addresses if we cannot reach any balancers. In the
-   * fallback case, we should use the LB policy indicated by
-   * GRPC_ARG_LB_POLICY_NAME (although if that specifies grpclb or is
-   * unset, we should default to pick_first). */
+  /* Count the number of gRPC-LB addresses. There must be at least one. */
   const grpc_arg *arg =
       grpc_channel_args_find(args->args, GRPC_ARG_LB_ADDRESSES);
   if (arg == NULL || arg->type != GRPC_ARG_POINTER) {
@@ -1831,6 +1927,11 @@ static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
   glb_policy->lb_call_timeout_ms =
       grpc_channel_arg_get_integer(arg, (grpc_integer_options){0, 0, INT_MAX});
 
+  arg = grpc_channel_args_find(args->args, GRPC_ARG_GRPCLB_FALLBACK_TIMEOUT_MS);
+  glb_policy->lb_fallback_timeout_ms = grpc_channel_arg_get_integer(
+      arg, (grpc_integer_options){GRPC_GRPCLB_DEFAULT_FALLBACK_TIMEOUT_MS, 0,
+                                  INT_MAX});
+
   // Make sure that GRPC_ARG_LB_POLICY_NAME is set in channel args,
   // since we use this to trigger the client_load_reporting filter.
   grpc_arg new_arg = grpc_channel_arg_string_create(
@@ -1839,6 +1940,11 @@ static grpc_lb_policy *glb_create(grpc_exec_ctx *exec_ctx,
   glb_policy->args = grpc_channel_args_copy_and_add_and_remove(
       args->args, args_to_remove, GPR_ARRAY_SIZE(args_to_remove), &new_arg, 1);
 
+  /* Extract the backend addresses (may be empty) from the resolver for
+   * fallback. */
+  glb_policy->fallback_backend_addresses =
+      extract_backend_addresses_locked(exec_ctx, addresses);
+
   /* Create a client channel over them to communicate with a LB service */
   glb_policy->response_generator =
       grpc_fake_resolver_response_generator_create();

src/core/ext/filters/client_channel/lb_policy_factory.c

@@ -56,7 +56,7 @@ grpc_lb_addresses* grpc_lb_addresses_copy(const grpc_lb_addresses* addresses) {
 }
 
 void grpc_lb_addresses_set_address(grpc_lb_addresses* addresses, size_t index,
-                                   void* address, size_t address_len,
+                                   const void* address, size_t address_len,
                                    bool is_balancer, const char* balancer_name,
                                    void* user_data) {
   GPR_ASSERT(index < addresses->num_addresses);

src/core/ext/filters/client_channel/lb_policy_factory.h

@@ -73,7 +73,7 @@ grpc_lb_addresses *grpc_lb_addresses_copy(const grpc_lb_addresses *addresses);
  * \a address is a socket address of length \a address_len.
  * Takes ownership of \a balancer_name. */
 void grpc_lb_addresses_set_address(grpc_lb_addresses *addresses, size_t index,
-                                   void *address, size_t address_len,
+                                   const void *address, size_t address_len,
                                    bool is_balancer, const char *balancer_name,
                                    void *user_data);
 

src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver_posix.c

@@ -20,6 +20,7 @@
 #if GRPC_ARES == 1 && defined(GRPC_POSIX_SOCKET)
 
 #include <ares.h>
+#include <sys/ioctl.h>
 
 #include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_ev_driver.h"
 
@@ -37,8 +38,6 @@
 typedef struct fd_node {
   /** the owner of this fd node */
   grpc_ares_ev_driver *ev_driver;
-  /** the grpc_fd owned by this fd node */
-  grpc_fd *fd;
   /** a closure wrapping on_readable_cb, which should be invoked when the
       grpc_fd in this node becomes readable. */
   grpc_closure read_closure;
@@ -50,10 +49,14 @@ typedef struct fd_node {
 
   /** mutex guarding the rest of the state */
   gpr_mu mu;
+  /** the grpc_fd owned by this fd node */
+  grpc_fd *fd;
   /** if the readable closure has been registered */
   bool readable_registered;
   /** if the writable closure has been registered */
   bool writable_registered;
+  /** if the fd is being shut down */
+  bool shutting_down;
 } fd_node;
 
 struct grpc_ares_ev_driver {
@@ -100,7 +103,6 @@ static void fd_node_destroy(grpc_exec_ctx *exec_ctx, fd_node *fdn) {
   GPR_ASSERT(!fdn->readable_registered);
   GPR_ASSERT(!fdn->writable_registered);
   gpr_mu_destroy(&fdn->mu);
-  grpc_pollset_set_del_fd(exec_ctx, fdn->ev_driver->pollset_set, fdn->fd);
   /* c-ares library has closed the fd inside grpc_fd. This fd may be picked up
      immediately by another thread, and should not be closed by the following
      grpc_fd_orphan. */
@@ -109,6 +111,19 @@ static void fd_node_destroy(grpc_exec_ctx *exec_ctx, fd_node *fdn) {
   gpr_free(fdn);
 }
 
+static void fd_node_shutdown(grpc_exec_ctx *exec_ctx, fd_node *fdn) {
+  gpr_mu_lock(&fdn->mu);
+  fdn->shutting_down = true;
+  if (!fdn->readable_registered && !fdn->writable_registered) {
+    gpr_mu_unlock(&fdn->mu);
+    fd_node_destroy(exec_ctx, fdn);
+  } else {
+    grpc_fd_shutdown(exec_ctx, fdn->fd, GRPC_ERROR_CREATE_FROM_STATIC_STRING(
+                                            "c-ares fd shutdown"));
+    gpr_mu_unlock(&fdn->mu);
+  }
+}
+
 grpc_error *grpc_ares_ev_driver_create(grpc_ares_ev_driver **ev_driver,
                                        grpc_pollset_set *pollset_set) {
   *ev_driver = (grpc_ares_ev_driver *)gpr_malloc(sizeof(grpc_ares_ev_driver));
@@ -175,18 +190,33 @@ static fd_node *pop_fd_node(fd_node **head, int fd) {
   return NULL;
 }
 
+/* Check if \a fd is still readable */
+static bool grpc_ares_is_fd_still_readable(grpc_ares_ev_driver *ev_driver,
+                                           int fd) {
+  size_t bytes_available = 0;
+  return ioctl(fd, FIONREAD, &bytes_available) == 0 && bytes_available > 0;
+}
+
 static void on_readable_cb(grpc_exec_ctx *exec_ctx, void *arg,
                            grpc_error *error) {
   fd_node *fdn = (fd_node *)arg;
   grpc_ares_ev_driver *ev_driver = fdn->ev_driver;
   gpr_mu_lock(&fdn->mu);
+  const int fd = grpc_fd_wrapped_fd(fdn->fd);
   fdn->readable_registered = false;
+  if (fdn->shutting_down && !fdn->writable_registered) {
+    gpr_mu_unlock(&fdn->mu);
+    fd_node_destroy(exec_ctx, fdn);
+    grpc_ares_ev_driver_unref(ev_driver);
+    return;
+  }
   gpr_mu_unlock(&fdn->mu);
 
-  gpr_log(GPR_DEBUG, "readable on %d", grpc_fd_wrapped_fd(fdn->fd));
+  gpr_log(GPR_DEBUG, "readable on %d", fd);
   if (error == GRPC_ERROR_NONE) {
-    ares_process_fd(ev_driver->channel, grpc_fd_wrapped_fd(fdn->fd),
-                    ARES_SOCKET_BAD);
+    do {
+      ares_process_fd(ev_driver->channel, fd, ARES_SOCKET_BAD);
+    } while (grpc_ares_is_fd_still_readable(ev_driver, fd));
   } else {
     // If error is not GRPC_ERROR_NONE, it means the fd has been shutdown or
     // timed out. The pending lookups made on this ev_driver will be cancelled
@@ -207,13 +237,19 @@ static void on_writable_cb(grpc_exec_ctx *exec_ctx, void *arg,
   fd_node *fdn = (fd_node *)arg;
   grpc_ares_ev_driver *ev_driver = fdn->ev_driver;
   gpr_mu_lock(&fdn->mu);
+  const int fd = grpc_fd_wrapped_fd(fdn->fd);
   fdn->writable_registered = false;
+  if (fdn->shutting_down && !fdn->readable_registered) {
+    gpr_mu_unlock(&fdn->mu);
+    fd_node_destroy(exec_ctx, fdn);
+    grpc_ares_ev_driver_unref(ev_driver);
+    return;
+  }
   gpr_mu_unlock(&fdn->mu);
 
-  gpr_log(GPR_DEBUG, "writable on %d", grpc_fd_wrapped_fd(fdn->fd));
+  gpr_log(GPR_DEBUG, "writable on %d", fd);
   if (error == GRPC_ERROR_NONE) {
-    ares_process_fd(ev_driver->channel, ARES_SOCKET_BAD,
-                    grpc_fd_wrapped_fd(fdn->fd));
+    ares_process_fd(ev_driver->channel, ARES_SOCKET_BAD, fd);
   } else {
     // If error is not GRPC_ERROR_NONE, it means the fd has been shutdown or
     // timed out. The pending lookups made on this ev_driver will be cancelled
@@ -256,6 +292,7 @@ static void grpc_ares_notify_on_event_locked(grpc_exec_ctx *exec_ctx,
           fdn->ev_driver = ev_driver;
           fdn->readable_registered = false;
           fdn->writable_registered = false;
+          fdn->shutting_down = false;
           gpr_mu_init(&fdn->mu);
           GRPC_CLOSURE_INIT(&fdn->read_closure, on_readable_cb, fdn,
                             grpc_schedule_on_exec_ctx);
@@ -296,7 +333,7 @@ static void grpc_ares_notify_on_event_locked(grpc_exec_ctx *exec_ctx,
   while (ev_driver->fds != NULL) {
     fd_node *cur = ev_driver->fds;
     ev_driver->fds = ev_driver->fds->next;
-    fd_node_destroy(exec_ctx, cur);
+    fd_node_shutdown(exec_ctx, cur);
   }
   ev_driver->fds = new_list;
   // If the ev driver has no working fd, all the tasks are done.

src/core/ext/transport/chttp2/transport/chttp2_transport.c

@@ -706,7 +706,10 @@ static int init_stream(grpc_exec_ctx *exec_ctx, grpc_transport *gt,
                     grpc_schedule_on_exec_ctx);
   grpc_slice_buffer_init(&s->unprocessed_incoming_frames_buffer);
   grpc_slice_buffer_init(&s->frame_storage);
+  grpc_slice_buffer_init(&s->compressed_data_buffer);
+  grpc_slice_buffer_init(&s->decompressed_data_buffer);
   s->pending_byte_stream = false;
+  s->decompressed_header_bytes = 0;
   GRPC_CLOSURE_INIT(&s->reset_byte_stream, reset_byte_stream, s,
                     grpc_combiner_scheduler(t->combiner));
 
@@ -740,14 +743,8 @@ static void destroy_stream_locked(grpc_exec_ctx *exec_ctx, void *sp,
   grpc_slice_buffer_destroy_internal(exec_ctx,
                                      &s->unprocessed_incoming_frames_buffer);
   grpc_slice_buffer_destroy_internal(exec_ctx, &s->frame_storage);
-  if (s->compressed_data_buffer) {
-    grpc_slice_buffer_destroy_internal(exec_ctx, s->compressed_data_buffer);
-    gpr_free(s->compressed_data_buffer);
-  }
-  if (s->decompressed_data_buffer) {
-    grpc_slice_buffer_destroy_internal(exec_ctx, s->decompressed_data_buffer);
-    gpr_free(s->decompressed_data_buffer);
-  }
+  grpc_slice_buffer_destroy_internal(exec_ctx, &s->compressed_data_buffer);
+  grpc_slice_buffer_destroy_internal(exec_ctx, &s->decompressed_data_buffer);
 
   grpc_chttp2_list_remove_stalled_by_transport(t, s);
   grpc_chttp2_list_remove_stalled_by_stream(t, s);
@@ -1448,12 +1445,14 @@ static void perform_stream_op_locked(grpc_exec_ctx *exec_ctx, void *stream_op,
     on_complete->next_data.scratch |= CLOSURE_BARRIER_MAY_COVER_WRITE;
 
     /* Identify stream compression */
-    if ((s->stream_compression_send_enabled =
-             (op_payload->send_initial_metadata.send_initial_metadata->idx.named
-                  .content_encoding != NULL)) == true) {
-      s->compressed_data_buffer =
-          (grpc_slice_buffer *)gpr_malloc(sizeof(grpc_slice_buffer));
-      grpc_slice_buffer_init(s->compressed_data_buffer);
+    if (op_payload->send_initial_metadata.send_initial_metadata->idx.named
+                .content_encoding == NULL ||
+        grpc_stream_compression_method_parse(
+            GRPC_MDVALUE(
+                op_payload->send_initial_metadata.send_initial_metadata->idx
+                    .named.content_encoding->md),
+            true, &s->stream_compression_method) == 0) {
+      s->stream_compression_method = GRPC_STREAM_COMPRESSION_IDENTITY_COMPRESS;
     }
 
     s->send_initial_metadata_finished = add_closure_barrier(on_complete);
@@ -1902,20 +1901,20 @@ void grpc_chttp2_maybe_complete_recv_message(grpc_exec_ctx *exec_ctx,
                                  &s->frame_storage);
           s->unprocessed_incoming_frames_decompressed = false;
         }
-        if (s->stream_compression_recv_enabled &&
-            !s->unprocessed_incoming_frames_decompressed) {
-          GPR_ASSERT(s->decompressed_data_buffer->length == 0);
+        if (!s->unprocessed_incoming_frames_decompressed) {
+          GPR_ASSERT(s->decompressed_data_buffer.length == 0);
           bool end_of_context;
           if (!s->stream_decompression_ctx) {
             s->stream_decompression_ctx =
                 grpc_stream_compression_context_create(
-                    GRPC_STREAM_COMPRESSION_DECOMPRESS);
+                    s->stream_decompression_method);
           }
-          if (!grpc_stream_decompress(s->stream_decompression_ctx,
-                                      &s->unprocessed_incoming_frames_buffer,
-                                      s->decompressed_data_buffer, NULL,
-                                      GRPC_HEADER_SIZE_IN_BYTES,
-                                      &end_of_context)) {
+          if (!grpc_stream_decompress(
+                  s->stream_decompression_ctx,
+                  &s->unprocessed_incoming_frames_buffer,
+                  &s->decompressed_data_buffer, NULL,
+                  GRPC_HEADER_SIZE_IN_BYTES - s->decompressed_header_bytes,
+                  &end_of_context)) {
             grpc_slice_buffer_reset_and_unref_internal(exec_ctx,
                                                        &s->frame_storage);
             grpc_slice_buffer_reset_and_unref_internal(
@@ -1923,9 +1922,13 @@ void grpc_chttp2_maybe_complete_recv_message(grpc_exec_ctx *exec_ctx,
             error = GRPC_ERROR_CREATE_FROM_STATIC_STRING(
                 "Stream decompression error.");
           } else {
+            s->decompressed_header_bytes += s->decompressed_data_buffer.length;
+            if (s->decompressed_header_bytes == GRPC_HEADER_SIZE_IN_BYTES) {
+              s->decompressed_header_bytes = 0;
+            }
             error = grpc_deframe_unprocessed_incoming_frames(
-                exec_ctx, &s->data_parser, s, s->decompressed_data_buffer, NULL,
-                s->recv_message);
+                exec_ctx, &s->data_parser, s, &s->decompressed_data_buffer,
+                NULL, s->recv_message);
             if (end_of_context) {
               grpc_stream_compression_context_destroy(
                   s->stream_decompression_ctx);
@@ -1974,15 +1977,14 @@ void grpc_chttp2_maybe_complete_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
     }
     bool pending_data = s->pending_byte_stream ||
                         s->unprocessed_incoming_frames_buffer.length > 0;
-    if (s->stream_compression_recv_enabled && s->read_closed &&
-        s->frame_storage.length > 0 && !pending_data && !s->seen_error &&
-        s->recv_trailing_metadata_finished != NULL) {
+    if (s->read_closed && s->frame_storage.length > 0 && !pending_data &&
+        !s->seen_error && s->recv_trailing_metadata_finished != NULL) {
       /* Maybe some SYNC_FLUSH data is left in frame_storage. Consume them and
        * maybe decompress the next 5 bytes in the stream. */
       bool end_of_context;
       if (!s->stream_decompression_ctx) {
         s->stream_decompression_ctx = grpc_stream_compression_context_create(
-            GRPC_STREAM_COMPRESSION_DECOMPRESS);
+            s->stream_decompression_method);
       }
       if (!grpc_stream_decompress(s->stream_decompression_ctx,
                                   &s->frame_storage,
@@ -1995,6 +1997,7 @@ void grpc_chttp2_maybe_complete_recv_trailing_metadata(grpc_exec_ctx *exec_ctx,
       } else {
         if (s->unprocessed_incoming_frames_buffer.length > 0) {
           s->unprocessed_incoming_frames_decompressed = true;
+          pending_data = true;
         }
         if (end_of_context) {
           grpc_stream_compression_context_destroy(s->stream_decompression_ctx);
@@ -2813,7 +2816,7 @@ static void reset_byte_stream(grpc_exec_ctx *exec_ctx, void *arg,
     GRPC_ERROR_UNREF(s->byte_stream_error);
     s->byte_stream_error = GRPC_ERROR_NONE;
     grpc_chttp2_cancel_stream(exec_ctx, s->t, s, GRPC_ERROR_REF(error));
-    s->byte_stream_error = error;
+    s->byte_stream_error = GRPC_ERROR_REF(error);
   }
 }
 
@@ -2911,24 +2914,23 @@ static grpc_error *incoming_byte_stream_pull(grpc_exec_ctx *exec_ctx,
   grpc_error *error;
 
   if (s->unprocessed_incoming_frames_buffer.length > 0) {
-    if (s->stream_compression_recv_enabled &&
-        !s->unprocessed_incoming_frames_decompressed) {
+    if (!s->unprocessed_incoming_frames_decompressed) {
       bool end_of_context;
       if (!s->stream_decompression_ctx) {
         s->stream_decompression_ctx = grpc_stream_compression_context_create(
-            GRPC_STREAM_COMPRESSION_DECOMPRESS);
+            s->stream_decompression_method);
       }
       if (!grpc_stream_decompress(s->stream_decompression_ctx,
                                   &s->unprocessed_incoming_frames_buffer,
-                                  s->decompressed_data_buffer, NULL, MAX_SIZE_T,
-                                  &end_of_context)) {
+                                  &s->decompressed_data_buffer, NULL,
+                                  MAX_SIZE_T, &end_of_context)) {
         error =
             GRPC_ERROR_CREATE_FROM_STATIC_STRING("Stream decompression error.");
         return error;
       }
       GPR_ASSERT(s->unprocessed_incoming_frames_buffer.length == 0);
       grpc_slice_buffer_swap(&s->unprocessed_incoming_frames_buffer,
-                             s->decompressed_data_buffer);
+                             &s->decompressed_data_buffer);
       s->unprocessed_incoming_frames_decompressed = true;
       if (end_of_context) {
         grpc_stream_compression_context_destroy(s->stream_decompression_ctx);

src/core/ext/transport/chttp2/transport/frame_data.c

@@ -210,7 +210,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
 
         if (cur != end) {
           grpc_slice_buffer_undo_take_first(
-              &s->unprocessed_incoming_frames_buffer,
+              slices,
               grpc_slice_sub(slice, (size_t)(cur - beg), (size_t)(end - beg)));
         }
         grpc_slice_unref_internal(exec_ctx, slice);
@@ -277,7 +277,7 @@ grpc_error *grpc_deframe_unprocessed_incoming_frames(
           p->state = GRPC_CHTTP2_DATA_FH_0;
           cur += p->frame_size;
           grpc_slice_buffer_undo_take_first(
-              &s->unprocessed_incoming_frames_buffer,
+              slices,
               grpc_slice_sub(slice, (size_t)(cur - beg), (size_t)(end - beg)));
           grpc_slice_unref_internal(exec_ctx, slice);
           return GRPC_ERROR_NONE;

src/core/ext/transport/chttp2/transport/hpack_parser.c

@@ -1683,17 +1683,12 @@ static void parse_stream_compression_md(grpc_exec_ctx *exec_ctx,
                                         grpc_chttp2_transport *t,
                                         grpc_chttp2_stream *s,
                                         grpc_metadata_batch *initial_metadata) {
-  if (initial_metadata->idx.named.content_encoding != NULL) {
-    grpc_slice content_encoding =
-        GRPC_MDVALUE(initial_metadata->idx.named.content_encoding->md);
-    if (!grpc_slice_eq(content_encoding, GRPC_MDSTR_IDENTITY)) {
-      if (grpc_slice_eq(content_encoding, GRPC_MDSTR_GZIP)) {
-        s->stream_compression_recv_enabled = true;
-        s->decompressed_data_buffer =
-            (grpc_slice_buffer *)gpr_malloc(sizeof(grpc_slice_buffer));
-        grpc_slice_buffer_init(s->decompressed_data_buffer);
-      }
-    }
+  if (initial_metadata->idx.named.content_encoding == NULL ||
+      grpc_stream_compression_method_parse(
+          GRPC_MDVALUE(initial_metadata->idx.named.content_encoding->md), false,
+          &s->stream_decompression_method) == 0) {
+    s->stream_decompression_method =
+        GRPC_STREAM_COMPRESSION_IDENTITY_DECOMPRESS;
   }
 }
 

src/core/ext/transport/chttp2/transport/internal.h

@@ -592,25 +592,27 @@ struct grpc_chttp2_stream {
   grpc_chttp2_write_cb *finish_after_write;
   size_t sending_bytes;
 
-  /** Whether stream compression send is enabled */
-  bool stream_compression_recv_enabled;
-  /** Whether stream compression recv is enabled */
-  bool stream_compression_send_enabled;
-  /** Whether bytes stored in unprocessed_incoming_byte_stream is decompressed
-   */
-  bool unprocessed_incoming_frames_decompressed;
+  /* Stream compression method to be used. */
+  grpc_stream_compression_method stream_compression_method;
+  /* Stream decompression method to be used. */
+  grpc_stream_compression_method stream_decompression_method;
   /** Stream compression decompress context */
   grpc_stream_compression_context *stream_decompression_ctx;
   /** Stream compression compress context */
   grpc_stream_compression_context *stream_compression_ctx;
 
   /** Buffer storing data that is compressed but not sent */
-  grpc_slice_buffer *compressed_data_buffer;
+  grpc_slice_buffer compressed_data_buffer;
   /** Amount of uncompressed bytes sent out when compressed_data_buffer is
    * emptied */
   size_t uncompressed_data_size;
   /** Temporary buffer storing decompressed data */
-  grpc_slice_buffer *decompressed_data_buffer;
+  grpc_slice_buffer decompressed_data_buffer;
+  /** Whether bytes stored in unprocessed_incoming_byte_stream is decompressed
+   */
+  bool unprocessed_incoming_frames_decompressed;
+  /** gRPC header bytes that are already decompressed */
+  size_t decompressed_header_bytes;
 };
 
 /** Transport writing call flow:

src/core/ext/transport/chttp2/transport/writing.c

@@ -317,8 +317,7 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
     if (sent_initial_metadata) {
       /* send any body bytes, if allowed by flow control */
       if (s->flow_controlled_buffer.length > 0 ||
-          (s->stream_compression_send_enabled &&
-           s->compressed_data_buffer->length > 0)) {
+          s->compressed_data_buffer.length > 0) {
         uint32_t stream_remote_window = (uint32_t)GPR_MAX(
             0,
             s->flow_control.remote_window_delta +
@@ -332,56 +331,59 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
           bool is_last_data_frame = false;
           bool is_last_frame = false;
           size_t sending_bytes_before = s->sending_bytes;
-          if (s->stream_compression_send_enabled) {
-            while ((s->flow_controlled_buffer.length > 0 ||
-                    s->compressed_data_buffer->length > 0) &&
-                   max_outgoing > 0) {
-              if (s->compressed_data_buffer->length > 0) {
-                uint32_t send_bytes = (uint32_t)GPR_MIN(
-                    max_outgoing, s->compressed_data_buffer->length);
-                is_last_data_frame =
-                    (send_bytes == s->compressed_data_buffer->length &&
-                     s->flow_controlled_buffer.length == 0 &&
-                     s->fetching_send_message == NULL);
-                is_last_frame =
-                    is_last_data_frame && s->send_trailing_metadata != NULL &&
-                    grpc_metadata_batch_is_empty(s->send_trailing_metadata);
-                grpc_chttp2_encode_data(s->id, s->compressed_data_buffer,
-                                        send_bytes, is_last_frame,
-                                        &s->stats.outgoing, &t->outbuf);
-                grpc_chttp2_flowctl_sent_data(&t->flow_control,
-                                              &s->flow_control, send_bytes);
-                max_outgoing -= send_bytes;
-                if (s->compressed_data_buffer->length == 0) {
-                  s->sending_bytes += s->uncompressed_data_size;
+          while ((s->flow_controlled_buffer.length > 0 ||
+                  s->compressed_data_buffer.length > 0) &&
+                 max_outgoing > 0) {
+            if (s->compressed_data_buffer.length > 0) {
+              uint32_t send_bytes = (uint32_t)GPR_MIN(
+                  max_outgoing, s->compressed_data_buffer.length);
+              is_last_data_frame =
+                  (send_bytes == s->compressed_data_buffer.length &&
+                   s->flow_controlled_buffer.length == 0 &&
+                   s->fetching_send_message == NULL);
+              if (is_last_data_frame && s->send_trailing_metadata != NULL &&
+                  s->stream_compression_ctx != NULL) {
+                if (!grpc_stream_compress(
+                        s->stream_compression_ctx, &s->flow_controlled_buffer,
+                        &s->compressed_data_buffer, NULL, MAX_SIZE_T,
+                        GRPC_STREAM_COMPRESSION_FLUSH_FINISH)) {
+                  gpr_log(GPR_ERROR, "Stream compression failed.");
                 }
-              } else {
-                if (s->stream_compression_ctx == NULL) {
-                  s->stream_compression_ctx =
-                      grpc_stream_compression_context_create(
-                          GRPC_STREAM_COMPRESSION_COMPRESS);
-                }
-                s->uncompressed_data_size = s->flow_controlled_buffer.length;
-                GPR_ASSERT(grpc_stream_compress(
-                    s->stream_compression_ctx, &s->flow_controlled_buffer,
-                    s->compressed_data_buffer, NULL, MAX_SIZE_T,
-                    GRPC_STREAM_COMPRESSION_FLUSH_SYNC));
+                grpc_stream_compression_context_destroy(
+                    s->stream_compression_ctx);
+                s->stream_compression_ctx = NULL;
+                /* After finish, bytes in s->compressed_data_buffer may be
+                 * more than max_outgoing. Start another round of the current
+                 * while loop so that send_bytes and is_last_data_frame are
+                 * recalculated. */
+                continue;
+              }
+              is_last_frame =
+                  is_last_data_frame && s->send_trailing_metadata != NULL &&
+                  grpc_metadata_batch_is_empty(s->send_trailing_metadata);
+              grpc_chttp2_encode_data(s->id, &s->compressed_data_buffer,
+                                      send_bytes, is_last_frame,
+                                      &s->stats.outgoing, &t->outbuf);
+              grpc_chttp2_flowctl_sent_data(&t->flow_control, &s->flow_control,
+                                            send_bytes);
+              max_outgoing -= send_bytes;
+              if (s->compressed_data_buffer.length == 0) {
+                s->sending_bytes += s->uncompressed_data_size;
+              }
+            } else {
+              if (s->stream_compression_ctx == NULL) {
+                s->stream_compression_ctx =
+                    grpc_stream_compression_context_create(
+                        s->stream_compression_method);
+              }
+              s->uncompressed_data_size = s->flow_controlled_buffer.length;
+              if (!grpc_stream_compress(
+                      s->stream_compression_ctx, &s->flow_controlled_buffer,
+                      &s->compressed_data_buffer, NULL, MAX_SIZE_T,
+                      GRPC_STREAM_COMPRESSION_FLUSH_SYNC)) {
+                gpr_log(GPR_ERROR, "Stream compression failed.");
               }
             }
-          } else {
-            uint32_t send_bytes = (uint32_t)GPR_MIN(
-                max_outgoing, s->flow_controlled_buffer.length);
-            is_last_data_frame = s->fetching_send_message == NULL &&
-                                 send_bytes == s->flow_controlled_buffer.length;
-            is_last_frame =
-                is_last_data_frame && s->send_trailing_metadata != NULL &&
-                grpc_metadata_batch_is_empty(s->send_trailing_metadata);
-            grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer,
-                                    send_bytes, is_last_frame,
-                                    &s->stats.outgoing, &t->outbuf);
-            grpc_chttp2_flowctl_sent_data(&t->flow_control, &s->flow_control,
-                                          send_bytes);
-            s->sending_bytes += send_bytes;
           }
           if (!t->is_client) {
             t->ping_recv_state.last_ping_recv_time =
@@ -406,8 +408,7 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
                           &s->flow_controlled_bytes_flowed, GRPC_ERROR_NONE);
           now_writing = true;
           if (s->flow_controlled_buffer.length > 0 ||
-              (s->stream_compression_send_enabled &&
-               s->compressed_data_buffer->length > 0)) {
+              s->compressed_data_buffer.length > 0) {
             GRPC_CHTTP2_STREAM_REF(s, "chttp2_writing:fork");
             grpc_chttp2_list_add_writable_stream(t, s);
           }
@@ -423,8 +424,7 @@ grpc_chttp2_begin_write_result grpc_chttp2_begin_write(
       if (s->send_trailing_metadata != NULL &&
           s->fetching_send_message == NULL &&
           s->flow_controlled_buffer.length == 0 &&
-          (!s->stream_compression_send_enabled ||
-           s->compressed_data_buffer->length == 0)) {
+          s->compressed_data_buffer.length == 0) {
         GRPC_CHTTP2_IF_TRACING(gpr_log(GPR_INFO, "sending trailing_metadata"));
         if (grpc_metadata_batch_is_empty(s->send_trailing_metadata)) {
           grpc_chttp2_encode_data(s->id, &s->flow_controlled_buffer, 0, true,

src/core/lib/compression/stream_compression.c

@@ -16,177 +16,62 @@
  *
  */
 
-#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 
 #include "src/core/lib/compression/stream_compression.h"
-#include "src/core/lib/iomgr/exec_ctx.h"
-#include "src/core/lib/slice/slice_internal.h"
+#include "src/core/lib/compression/stream_compression_gzip.h"
 
-#define OUTPUT_BLOCK_SIZE (1024)
-
-static bool gzip_flate(grpc_stream_compression_context *ctx,
-                       grpc_slice_buffer *in, grpc_slice_buffer *out,
-                       size_t *output_size, size_t max_output_size, int flush,
-                       bool *end_of_context) {
-  GPR_ASSERT(flush == 0 || flush == Z_SYNC_FLUSH || flush == Z_FINISH);
-  /* Full flush is not allowed when inflating. */
-  GPR_ASSERT(!(ctx->flate == inflate && (flush == Z_FINISH)));
-
-  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
-  int r;
-  bool eoc = false;
-  size_t original_max_output_size = max_output_size;
-  while (max_output_size > 0 && (in->length > 0 || flush) && !eoc) {
-    size_t slice_size = max_output_size < OUTPUT_BLOCK_SIZE ? max_output_size
-                                                            : OUTPUT_BLOCK_SIZE;
-    grpc_slice slice_out = GRPC_SLICE_MALLOC(slice_size);
-    ctx->zs.avail_out = (uInt)slice_size;
-    ctx->zs.next_out = GRPC_SLICE_START_PTR(slice_out);
-    while (ctx->zs.avail_out > 0 && in->length > 0 && !eoc) {
-      grpc_slice slice = grpc_slice_buffer_take_first(in);
-      ctx->zs.avail_in = (uInt)GRPC_SLICE_LENGTH(slice);
-      ctx->zs.next_in = GRPC_SLICE_START_PTR(slice);
-      r = ctx->flate(&ctx->zs, Z_NO_FLUSH);
-      if (r < 0 && r != Z_BUF_ERROR) {
-        gpr_log(GPR_ERROR, "zlib error (%d)", r);
-        grpc_slice_unref_internal(&exec_ctx, slice_out);
-        grpc_exec_ctx_finish(&exec_ctx);
-        return false;
-      } else if (r == Z_STREAM_END && ctx->flate == inflate) {
-        eoc = true;
-      }
-      if (ctx->zs.avail_in > 0) {
-        grpc_slice_buffer_undo_take_first(
-            in,
-            grpc_slice_sub(slice, GRPC_SLICE_LENGTH(slice) - ctx->zs.avail_in,
-                           GRPC_SLICE_LENGTH(slice)));
-      }
-      grpc_slice_unref_internal(&exec_ctx, slice);
-    }
-    if (flush != 0 && ctx->zs.avail_out > 0 && !eoc) {
-      GPR_ASSERT(in->length == 0);
-      r = ctx->flate(&ctx->zs, flush);
-      if (flush == Z_SYNC_FLUSH) {
-        switch (r) {
-          case Z_OK:
-            /* Maybe flush is not complete; just made some partial progress. */
-            if (ctx->zs.avail_out > 0) {
-              flush = 0;
-            }
-            break;
-          case Z_BUF_ERROR:
-          case Z_STREAM_END:
-            flush = 0;
-            break;
-          default:
-            gpr_log(GPR_ERROR, "zlib error (%d)", r);
-            grpc_slice_unref_internal(&exec_ctx, slice_out);
-            grpc_exec_ctx_finish(&exec_ctx);
-            return false;
-        }
-      } else if (flush == Z_FINISH) {
-        switch (r) {
-          case Z_OK:
-          case Z_BUF_ERROR:
-            /* Wait for the next loop to assign additional output space. */
-            GPR_ASSERT(ctx->zs.avail_out == 0);
-            break;
-          case Z_STREAM_END:
-            flush = 0;
-            break;
-          default:
-            gpr_log(GPR_ERROR, "zlib error (%d)", r);
-            grpc_slice_unref_internal(&exec_ctx, slice_out);
-            grpc_exec_ctx_finish(&exec_ctx);
-            return false;
-        }
-      }
-    }
-
-    if (ctx->zs.avail_out == 0) {
-      grpc_slice_buffer_add(out, slice_out);
-    } else if (ctx->zs.avail_out < slice_size) {
-      slice_out.data.refcounted.length -= ctx->zs.avail_out;
-      grpc_slice_buffer_add(out, slice_out);
-    } else {
-      grpc_slice_unref_internal(&exec_ctx, slice_out);
-    }
-    max_output_size -= (slice_size - ctx->zs.avail_out);
-  }
-  grpc_exec_ctx_finish(&exec_ctx);
-  if (end_of_context) {
-    *end_of_context = eoc;
-  }
-  if (output_size) {
-    *output_size = original_max_output_size - max_output_size;
-  }
-  return true;
-}
+extern const grpc_stream_compression_vtable
+    grpc_stream_compression_identity_vtable;
 
 bool grpc_stream_compress(grpc_stream_compression_context *ctx,
                           grpc_slice_buffer *in, grpc_slice_buffer *out,
                           size_t *output_size, size_t max_output_size,
                           grpc_stream_compression_flush flush) {
-  GPR_ASSERT(ctx->flate == deflate);
-  int gzip_flush;
-  switch (flush) {
-    case GRPC_STREAM_COMPRESSION_FLUSH_NONE:
-      gzip_flush = 0;
-      break;
-    case GRPC_STREAM_COMPRESSION_FLUSH_SYNC:
-      gzip_flush = Z_SYNC_FLUSH;
-      break;
-    case GRPC_STREAM_COMPRESSION_FLUSH_FINISH:
-      gzip_flush = Z_FINISH;
-      break;
-    default:
-      gzip_flush = 0;
-  }
-  return gzip_flate(ctx, in, out, output_size, max_output_size, gzip_flush,
-                    NULL);
+  return ctx->vtable->compress(ctx, in, out, output_size, max_output_size,
+                               flush);
 }
 
 bool grpc_stream_decompress(grpc_stream_compression_context *ctx,
                             grpc_slice_buffer *in, grpc_slice_buffer *out,
                             size_t *output_size, size_t max_output_size,
                             bool *end_of_context) {
-  GPR_ASSERT(ctx->flate == inflate);
-  return gzip_flate(ctx, in, out, output_size, max_output_size, Z_SYNC_FLUSH,
-                    end_of_context);
+  return ctx->vtable->decompress(ctx, in, out, output_size, max_output_size,
+                                 end_of_context);
 }
 
 grpc_stream_compression_context *grpc_stream_compression_context_create(
     grpc_stream_compression_method method) {
-  grpc_stream_compression_context *ctx =
-      (grpc_stream_compression_context *)gpr_zalloc(
-          sizeof(grpc_stream_compression_context));
-  int r;
-  if (ctx == NULL) {
-    return NULL;
-  }
-  if (method == GRPC_STREAM_COMPRESSION_DECOMPRESS) {
-    r = inflateInit2(&ctx->zs, 0x1F);
-    ctx->flate = inflate;
-  } else {
-    r = deflateInit2(&ctx->zs, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 0x1F, 8,
-                     Z_DEFAULT_STRATEGY);
-    ctx->flate = deflate;
-  }
-  if (r != Z_OK) {
-    gpr_free(ctx);
-    return NULL;
+  switch (method) {
+    case GRPC_STREAM_COMPRESSION_IDENTITY_COMPRESS:
+    case GRPC_STREAM_COMPRESSION_IDENTITY_DECOMPRESS:
+      return grpc_stream_compression_identity_vtable.context_create(method);
+    case GRPC_STREAM_COMPRESSION_GZIP_COMPRESS:
+    case GRPC_STREAM_COMPRESSION_GZIP_DECOMPRESS:
+      return grpc_stream_compression_gzip_vtable.context_create(method);
+    default:
+      gpr_log(GPR_ERROR, "Unknown stream compression method: %d", method);
+      return NULL;
   }
-
-  return ctx;
 }
 
 void grpc_stream_compression_context_destroy(
     grpc_stream_compression_context *ctx) {
-  if (ctx->flate == inflate) {
-    inflateEnd(&ctx->zs);
+  ctx->vtable->context_destroy(ctx);
+}
+
+int grpc_stream_compression_method_parse(
+    grpc_slice value, bool is_compress,
+    grpc_stream_compression_method *method) {
+  if (grpc_slice_eq(value, GRPC_MDSTR_IDENTITY)) {
+    *method = is_compress ? GRPC_STREAM_COMPRESSION_IDENTITY_COMPRESS
+                          : GRPC_STREAM_COMPRESSION_IDENTITY_DECOMPRESS;
+    return 1;
+  } else if (grpc_slice_eq(value, GRPC_MDSTR_GZIP)) {
+    *method = is_compress ? GRPC_STREAM_COMPRESSION_GZIP_COMPRESS
+                          : GRPC_STREAM_COMPRESSION_GZIP_DECOMPRESS;
+    return 1;
   } else {
-    deflateEnd(&ctx->zs);
+    return 0;
   }
-  gpr_free(ctx);
 }

src/core/lib/compression/stream_compression.h

@@ -24,15 +24,20 @@
 #include <grpc/slice_buffer.h>
 #include <zlib.h>
 
+#include "src/core/lib/transport/static_metadata.h"
+
+typedef struct grpc_stream_compression_vtable grpc_stream_compression_vtable;
+
 /* Stream compression/decompression context */
 typedef struct grpc_stream_compression_context {
-  z_stream zs;
-  int (*flate)(z_stream *zs, int flush);
+  const grpc_stream_compression_vtable *vtable;
 } grpc_stream_compression_context;
 
 typedef enum grpc_stream_compression_method {
-  GRPC_STREAM_COMPRESSION_COMPRESS = 0,
-  GRPC_STREAM_COMPRESSION_DECOMPRESS,
+  GRPC_STREAM_COMPRESSION_IDENTITY_COMPRESS = 0,
+  GRPC_STREAM_COMPRESSION_IDENTITY_DECOMPRESS,
+  GRPC_STREAM_COMPRESSION_GZIP_COMPRESS,
+  GRPC_STREAM_COMPRESSION_GZIP_DECOMPRESS,
   GRPC_STREAM_COMPRESSION_METHOD_COUNT
 } grpc_stream_compression_method;
 
@@ -43,6 +48,19 @@ typedef enum grpc_stream_compression_flush {
   GRPC_STREAM_COMPRESSION_FLUSH_COUNT
 } grpc_stream_compression_flush;
 
+struct grpc_stream_compression_vtable {
+  bool (*compress)(grpc_stream_compression_context *ctx, grpc_slice_buffer *in,
+                   grpc_slice_buffer *out, size_t *output_size,
+                   size_t max_output_size, grpc_stream_compression_flush flush);
+  bool (*decompress)(grpc_stream_compression_context *ctx,
+                     grpc_slice_buffer *in, grpc_slice_buffer *out,
+                     size_t *output_size, size_t max_output_size,
+                     bool *end_of_context);
+  grpc_stream_compression_context *(*context_create)(
+      grpc_stream_compression_method method);
+  void (*context_destroy)(grpc_stream_compression_context *ctx);
+};
+
 /**
  * Compress bytes provided in \a in with a given context, with an optional flush
  * at the end of compression. Emits at most \a max_output_size compressed bytes
@@ -87,4 +105,10 @@ grpc_stream_compression_context *grpc_stream_compression_context_create(
 void grpc_stream_compression_context_destroy(
     grpc_stream_compression_context *ctx);
 
+/**
+ * Parse stream compression method based on algorithm name
+ */
+int grpc_stream_compression_method_parse(
+    grpc_slice value, bool is_compress, grpc_stream_compression_method *method);
+
 #endif

src/core/lib/compression/stream_compression_gzip.c

@@ -0,0 +1,228 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/compression/stream_compression_gzip.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/slice/slice_internal.h"
+
+#define OUTPUT_BLOCK_SIZE (1024)
+
+typedef struct grpc_stream_compression_context_gzip {
+  grpc_stream_compression_context base;
+
+  z_stream zs;
+  int (*flate)(z_stream *zs, int flush);
+} grpc_stream_compression_context_gzip;
+
+static bool gzip_flate(grpc_stream_compression_context_gzip *ctx,
+                       grpc_slice_buffer *in, grpc_slice_buffer *out,
+                       size_t *output_size, size_t max_output_size, int flush,
+                       bool *end_of_context) {
+  GPR_ASSERT(flush == 0 || flush == Z_SYNC_FLUSH || flush == Z_FINISH);
+  /* Full flush is not allowed when inflating. */
+  GPR_ASSERT(!(ctx->flate == inflate && (flush == Z_FINISH)));
+
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  int r;
+  bool eoc = false;
+  size_t original_max_output_size = max_output_size;
+  while (max_output_size > 0 && (in->length > 0 || flush) && !eoc) {
+    size_t slice_size = max_output_size < OUTPUT_BLOCK_SIZE ? max_output_size
+                                                            : OUTPUT_BLOCK_SIZE;
+    grpc_slice slice_out = GRPC_SLICE_MALLOC(slice_size);
+    ctx->zs.avail_out = (uInt)slice_size;
+    ctx->zs.next_out = GRPC_SLICE_START_PTR(slice_out);
+    while (ctx->zs.avail_out > 0 && in->length > 0 && !eoc) {
+      grpc_slice slice = grpc_slice_buffer_take_first(in);
+      ctx->zs.avail_in = (uInt)GRPC_SLICE_LENGTH(slice);
+      ctx->zs.next_in = GRPC_SLICE_START_PTR(slice);
+      r = ctx->flate(&ctx->zs, Z_NO_FLUSH);
+      if (r < 0 && r != Z_BUF_ERROR) {
+        gpr_log(GPR_ERROR, "zlib error (%d)", r);
+        grpc_slice_unref_internal(&exec_ctx, slice_out);
+        grpc_exec_ctx_finish(&exec_ctx);
+        return false;
+      } else if (r == Z_STREAM_END && ctx->flate == inflate) {
+        eoc = true;
+      }
+      if (ctx->zs.avail_in > 0) {
+        grpc_slice_buffer_undo_take_first(
+            in,
+            grpc_slice_sub(slice, GRPC_SLICE_LENGTH(slice) - ctx->zs.avail_in,
+                           GRPC_SLICE_LENGTH(slice)));
+      }
+      grpc_slice_unref_internal(&exec_ctx, slice);
+    }
+    if (flush != 0 && ctx->zs.avail_out > 0 && !eoc) {
+      GPR_ASSERT(in->length == 0);
+      r = ctx->flate(&ctx->zs, flush);
+      if (flush == Z_SYNC_FLUSH) {
+        switch (r) {
+          case Z_OK:
+            /* Maybe flush is not complete; just made some partial progress. */
+            if (ctx->zs.avail_out > 0) {
+              flush = 0;
+            }
+            break;
+          case Z_BUF_ERROR:
+          case Z_STREAM_END:
+            flush = 0;
+            break;
+          default:
+            gpr_log(GPR_ERROR, "zlib error (%d)", r);
+            grpc_slice_unref_internal(&exec_ctx, slice_out);
+            grpc_exec_ctx_finish(&exec_ctx);
+            return false;
+        }
+      } else if (flush == Z_FINISH) {
+        switch (r) {
+          case Z_OK:
+          case Z_BUF_ERROR:
+            /* Wait for the next loop to assign additional output space. */
+            GPR_ASSERT(ctx->zs.avail_out == 0);
+            break;
+          case Z_STREAM_END:
+            flush = 0;
+            break;
+          default:
+            gpr_log(GPR_ERROR, "zlib error (%d)", r);
+            grpc_slice_unref_internal(&exec_ctx, slice_out);
+            grpc_exec_ctx_finish(&exec_ctx);
+            return false;
+        }
+      }
+    }
+
+    if (ctx->zs.avail_out == 0) {
+      grpc_slice_buffer_add(out, slice_out);
+    } else if (ctx->zs.avail_out < slice_size) {
+      slice_out.data.refcounted.length -= ctx->zs.avail_out;
+      grpc_slice_buffer_add(out, slice_out);
+    } else {
+      grpc_slice_unref_internal(&exec_ctx, slice_out);
+    }
+    max_output_size -= (slice_size - ctx->zs.avail_out);
+  }
+  grpc_exec_ctx_finish(&exec_ctx);
+  if (end_of_context) {
+    *end_of_context = eoc;
+  }
+  if (output_size) {
+    *output_size = original_max_output_size - max_output_size;
+  }
+  return true;
+}
+
+static bool grpc_stream_compress_gzip(grpc_stream_compression_context *ctx,
+                                      grpc_slice_buffer *in,
+                                      grpc_slice_buffer *out,
+                                      size_t *output_size,
+                                      size_t max_output_size,
+                                      grpc_stream_compression_flush flush) {
+  if (ctx == NULL) {
+    return false;
+  }
+  grpc_stream_compression_context_gzip *gzip_ctx =
+      (grpc_stream_compression_context_gzip *)ctx;
+  GPR_ASSERT(gzip_ctx->flate == deflate);
+  int gzip_flush;
+  switch (flush) {
+    case GRPC_STREAM_COMPRESSION_FLUSH_NONE:
+      gzip_flush = 0;
+      break;
+    case GRPC_STREAM_COMPRESSION_FLUSH_SYNC:
+      gzip_flush = Z_SYNC_FLUSH;
+      break;
+    case GRPC_STREAM_COMPRESSION_FLUSH_FINISH:
+      gzip_flush = Z_FINISH;
+      break;
+    default:
+      gzip_flush = 0;
+  }
+  return gzip_flate(gzip_ctx, in, out, output_size, max_output_size, gzip_flush,
+                    NULL);
+}
+
+static bool grpc_stream_decompress_gzip(grpc_stream_compression_context *ctx,
+                                        grpc_slice_buffer *in,
+                                        grpc_slice_buffer *out,
+                                        size_t *output_size,
+                                        size_t max_output_size,
+                                        bool *end_of_context) {
+  if (ctx == NULL) {
+    return false;
+  }
+  grpc_stream_compression_context_gzip *gzip_ctx =
+      (grpc_stream_compression_context_gzip *)ctx;
+  GPR_ASSERT(gzip_ctx->flate == inflate);
+  return gzip_flate(gzip_ctx, in, out, output_size, max_output_size,
+                    Z_SYNC_FLUSH, end_of_context);
+}
+
+static grpc_stream_compression_context *
+grpc_stream_compression_context_create_gzip(
+    grpc_stream_compression_method method) {
+  GPR_ASSERT(method == GRPC_STREAM_COMPRESSION_GZIP_COMPRESS ||
+             method == GRPC_STREAM_COMPRESSION_GZIP_DECOMPRESS);
+  grpc_stream_compression_context_gzip *gzip_ctx =
+      (grpc_stream_compression_context_gzip *)gpr_zalloc(
+          sizeof(grpc_stream_compression_context_gzip));
+  int r;
+  if (gzip_ctx == NULL) {
+    return NULL;
+  }
+  if (method == GRPC_STREAM_COMPRESSION_GZIP_DECOMPRESS) {
+    r = inflateInit2(&gzip_ctx->zs, 0x1F);
+    gzip_ctx->flate = inflate;
+  } else {
+    r = deflateInit2(&gzip_ctx->zs, Z_DEFAULT_COMPRESSION, Z_DEFLATED, 0x1F, 8,
+                     Z_DEFAULT_STRATEGY);
+    gzip_ctx->flate = deflate;
+  }
+  if (r != Z_OK) {
+    gpr_free(gzip_ctx);
+    return NULL;
+  }
+
+  gzip_ctx->base.vtable = &grpc_stream_compression_gzip_vtable;
+  return (grpc_stream_compression_context *)gzip_ctx;
+}
+
+static void grpc_stream_compression_context_destroy_gzip(
+    grpc_stream_compression_context *ctx) {
+  if (ctx == NULL) {
+    return;
+  }
+  grpc_stream_compression_context_gzip *gzip_ctx =
+      (grpc_stream_compression_context_gzip *)ctx;
+  if (gzip_ctx->flate == inflate) {
+    inflateEnd(&gzip_ctx->zs);
+  } else {
+    deflateEnd(&gzip_ctx->zs);
+  }
+  gpr_free(ctx);
+}
+
+const grpc_stream_compression_vtable grpc_stream_compression_gzip_vtable = {
+    .compress = grpc_stream_compress_gzip,
+    .decompress = grpc_stream_decompress_gzip,
+    .context_create = grpc_stream_compression_context_create_gzip,
+    .context_destroy = grpc_stream_compression_context_destroy_gzip};

src/core/lib/compression/stream_compression_gzip.h

@@ -0,0 +1,26 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_COMPRESSION_STREAM_COMPRESSION_GZIP_H
+#define GRPC_CORE_LIB_COMPRESSION_STREAM_COMPRESSION_GZIP_H
+
+#include "src/core/lib/compression/stream_compression.h"
+
+extern const grpc_stream_compression_vtable grpc_stream_compression_gzip_vtable;
+
+#endif

src/core/lib/compression/stream_compression_identity.c

@@ -0,0 +1,94 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+
+#include "src/core/lib/compression/stream_compression_identity.h"
+#include "src/core/lib/iomgr/exec_ctx.h"
+#include "src/core/lib/slice/slice_internal.h"
+
+#define OUTPUT_BLOCK_SIZE (1024)
+
+/* Singleton context used for all identity streams. */
+static grpc_stream_compression_context identity_ctx = {
+    .vtable = &grpc_stream_compression_identity_vtable};
+
+static void grpc_stream_compression_pass_through(grpc_slice_buffer *in,
+                                                 grpc_slice_buffer *out,
+                                                 size_t *output_size,
+                                                 size_t max_output_size) {
+  if (max_output_size >= in->length) {
+    if (output_size) {
+      *output_size = in->length;
+    }
+    grpc_slice_buffer_move_into(in, out);
+  } else {
+    if (output_size) {
+      *output_size = max_output_size;
+    }
+    grpc_slice_buffer_move_first(in, max_output_size, out);
+  }
+}
+
+static bool grpc_stream_compress_identity(grpc_stream_compression_context *ctx,
+                                          grpc_slice_buffer *in,
+                                          grpc_slice_buffer *out,
+                                          size_t *output_size,
+                                          size_t max_output_size,
+                                          grpc_stream_compression_flush flush) {
+  if (ctx == NULL) {
+    return false;
+  }
+  grpc_stream_compression_pass_through(in, out, output_size, max_output_size);
+  return true;
+}
+
+static bool grpc_stream_decompress_identity(
+    grpc_stream_compression_context *ctx, grpc_slice_buffer *in,
+    grpc_slice_buffer *out, size_t *output_size, size_t max_output_size,
+    bool *end_of_context) {
+  if (ctx == NULL) {
+    return false;
+  }
+  grpc_stream_compression_pass_through(in, out, output_size, max_output_size);
+  if (end_of_context) {
+    *end_of_context = false;
+  }
+  return true;
+}
+
+static grpc_stream_compression_context *
+grpc_stream_compression_context_create_identity(
+    grpc_stream_compression_method method) {
+  GPR_ASSERT(method == GRPC_STREAM_COMPRESSION_IDENTITY_COMPRESS ||
+             method == GRPC_STREAM_COMPRESSION_IDENTITY_DECOMPRESS);
+  /* No context needed in this case. Use fake context instead. */
+  return (grpc_stream_compression_context *)&identity_ctx;
+}
+
+static void grpc_stream_compression_context_destroy_identity(
+    grpc_stream_compression_context *ctx) {
+  return;
+}
+
+const grpc_stream_compression_vtable grpc_stream_compression_identity_vtable = {
+    .compress = grpc_stream_compress_identity,
+    .decompress = grpc_stream_decompress_identity,
+    .context_create = grpc_stream_compression_context_create_identity,
+    .context_destroy = grpc_stream_compression_context_destroy_identity};

src/core/lib/compression/stream_compression_identity.h

@@ -0,0 +1,27 @@
+/*
+ *
+ * Copyright 2017 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPC_CORE_LIB_COMPRESSION_STREAM_COMPRESSION_IDENTITY_H
+#define GRPC_CORE_LIB_COMPRESSION_STREAM_COMPRESSION_IDENTITY_H
+
+#include "src/core/lib/compression/stream_compression.h"
+
+extern const grpc_stream_compression_vtable
+    grpc_stream_compression_identity_vtable;
+
+#endif

src/core/lib/debug/stats_data.c

@@ -109,8 +109,6 @@ const char *grpc_stats_counter_name[GRPC_STATS_COUNTER_COUNT] = {
     "executor_wakeup_initiated",
     "executor_queue_drained",
     "executor_push_retries",
-    "executor_threads_created",
-    "executor_threads_used",
     "server_requested_calls",
     "server_slowpath_requests_queued",
 };
@@ -219,8 +217,6 @@ const char *grpc_stats_counter_doc[GRPC_STATS_COUNTER_COUNT] = {
     "Number of times an executor queue was drained",
     "Number of times we raced and were forced to retry pushing a closure to "
     "the executor",
-    "Size of the backing thread pool for overflow gRPC Core work",
-    "How many executor threads actually got used",
     "How many calls were requested (not necessarily received) by the server",
     "How many times was the server slow path taken (indicates too few "
     "outstanding requests)",
@@ -238,7 +234,6 @@ const char *grpc_stats_histogram_name[GRPC_STATS_HISTOGRAM_COUNT] = {
     "http2_send_message_per_write",
     "http2_send_trailing_metadata_per_write",
     "http2_send_flowctl_per_write",
-    "executor_closures_per_wakeup",
     "server_cqs_checked",
 };
 const char *grpc_stats_histogram_doc[GRPC_STATS_HISTOGRAM_COUNT] = {
@@ -254,7 +249,6 @@ const char *grpc_stats_histogram_doc[GRPC_STATS_HISTOGRAM_COUNT] = {
     "Number of streams whose payload was written per TCP write",
     "Number of streams terminated per TCP write",
     "Number of flow control updates written per TCP write",
-    "Number of closures executed each time an executor wakes up",
     "How many completion queues were checked looking for a CQ that had "
     "requested the incoming call",
 };
@@ -326,7 +320,6 @@ const uint8_t grpc_stats_table_7[102] = {
 const int grpc_stats_table_8[9] = {0, 1, 2, 4, 7, 13, 23, 39, 64};
 const uint8_t grpc_stats_table_9[9] = {0, 0, 1, 2, 2, 3, 4, 4, 5};
 void grpc_stats_inc_call_initial_size(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 262144);
   if (value < 6) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx), GRPC_STATS_HISTOGRAM_CALL_INITIAL_SIZE,
@@ -352,7 +345,6 @@ void grpc_stats_inc_call_initial_size(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_0, 64));
 }
 void grpc_stats_inc_poll_events_returned(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 29) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx),
@@ -379,7 +371,6 @@ void grpc_stats_inc_poll_events_returned(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_2, 128));
 }
 void grpc_stats_inc_tcp_write_size(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 16777216);
   if (value < 5) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx), GRPC_STATS_HISTOGRAM_TCP_WRITE_SIZE,
@@ -405,7 +396,6 @@ void grpc_stats_inc_tcp_write_size(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_4, 64));
 }
 void grpc_stats_inc_tcp_write_iov_size(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx),
@@ -431,7 +421,6 @@ void grpc_stats_inc_tcp_write_iov_size(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_6, 64));
 }
 void grpc_stats_inc_tcp_read_size(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 16777216);
   if (value < 5) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx), GRPC_STATS_HISTOGRAM_TCP_READ_SIZE,
@@ -457,7 +446,6 @@ void grpc_stats_inc_tcp_read_size(grpc_exec_ctx *exec_ctx, int value) {
                                (exec_ctx), value, grpc_stats_table_4, 64));
 }
 void grpc_stats_inc_tcp_read_offer(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 16777216);
   if (value < 5) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx), GRPC_STATS_HISTOGRAM_TCP_READ_OFFER,
@@ -484,7 +472,6 @@ void grpc_stats_inc_tcp_read_offer(grpc_exec_ctx *exec_ctx, int value) {
 }
 void grpc_stats_inc_tcp_read_offer_iov_size(grpc_exec_ctx *exec_ctx,
                                             int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -512,7 +499,6 @@ void grpc_stats_inc_tcp_read_offer_iov_size(grpc_exec_ctx *exec_ctx,
 }
 void grpc_stats_inc_http2_send_message_size(grpc_exec_ctx *exec_ctx,
                                             int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 16777216);
   if (value < 5) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -540,7 +526,6 @@ void grpc_stats_inc_http2_send_message_size(grpc_exec_ctx *exec_ctx,
 }
 void grpc_stats_inc_http2_send_initial_metadata_per_write(
     grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -570,7 +555,6 @@ void grpc_stats_inc_http2_send_initial_metadata_per_write(
 }
 void grpc_stats_inc_http2_send_message_per_write(grpc_exec_ctx *exec_ctx,
                                                  int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -598,7 +582,6 @@ void grpc_stats_inc_http2_send_message_per_write(grpc_exec_ctx *exec_ctx,
 }
 void grpc_stats_inc_http2_send_trailing_metadata_per_write(
     grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -628,7 +611,6 @@ void grpc_stats_inc_http2_send_trailing_metadata_per_write(
 }
 void grpc_stats_inc_http2_send_flowctl_per_write(grpc_exec_ctx *exec_ctx,
                                                  int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 1024);
   if (value < 13) {
     GRPC_STATS_INC_HISTOGRAM(
@@ -654,36 +636,7 @@ void grpc_stats_inc_http2_send_flowctl_per_write(grpc_exec_ctx *exec_ctx,
                            grpc_stats_histo_find_bucket_slow(
                                (exec_ctx), value, grpc_stats_table_6, 64));
 }
-void grpc_stats_inc_executor_closures_per_wakeup(grpc_exec_ctx *exec_ctx,
-                                                 int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
-  value = GPR_CLAMP(value, 0, 1024);
-  if (value < 13) {
-    GRPC_STATS_INC_HISTOGRAM(
-        (exec_ctx), GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP, value);
-    return;
-  }
-  union {
-    double dbl;
-    uint64_t uint;
-  } _val, _bkt;
-  _val.dbl = value;
-  if (_val.uint < 4637863191261478912ull) {
-    int bucket =
-        grpc_stats_table_7[((_val.uint - 4623507967449235456ull) >> 48)] + 13;
-    _bkt.dbl = grpc_stats_table_6[bucket];
-    bucket -= (_val.uint < _bkt.uint);
-    GRPC_STATS_INC_HISTOGRAM(
-        (exec_ctx), GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP, bucket);
-    return;
-  }
-  GRPC_STATS_INC_HISTOGRAM((exec_ctx),
-                           GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP,
-                           grpc_stats_histo_find_bucket_slow(
-                               (exec_ctx), value, grpc_stats_table_6, 64));
-}
 void grpc_stats_inc_server_cqs_checked(grpc_exec_ctx *exec_ctx, int value) {
-  /* Automatically generated by tools/codegen/core/gen_stats_data.py */
   value = GPR_CLAMP(value, 0, 64);
   if (value < 3) {
     GRPC_STATS_INC_HISTOGRAM((exec_ctx),
@@ -708,17 +661,17 @@ void grpc_stats_inc_server_cqs_checked(grpc_exec_ctx *exec_ctx, int value) {
                            grpc_stats_histo_find_bucket_slow(
                                (exec_ctx), value, grpc_stats_table_8, 8));
 }
-const int grpc_stats_histo_buckets[14] = {64, 128, 64, 64, 64, 64, 64,
-                                          64, 64,  64, 64, 64, 64, 8};
-const int grpc_stats_histo_start[14] = {0,   64,  192, 256, 320, 384, 448,
-                                        512, 576, 640, 704, 768, 832, 896};
-const int *const grpc_stats_histo_bucket_boundaries[14] = {
+const int grpc_stats_histo_buckets[13] = {64, 128, 64, 64, 64, 64, 64,
+                                          64, 64,  64, 64, 64, 8};
+const int grpc_stats_histo_start[13] = {0,   64,  192, 256, 320, 384, 448,
+                                        512, 576, 640, 704, 768, 832};
+const int *const grpc_stats_histo_bucket_boundaries[13] = {
     grpc_stats_table_0, grpc_stats_table_2, grpc_stats_table_4,
     grpc_stats_table_6, grpc_stats_table_4, grpc_stats_table_4,
     grpc_stats_table_6, grpc_stats_table_4, grpc_stats_table_6,
     grpc_stats_table_6, grpc_stats_table_6, grpc_stats_table_6,
-    grpc_stats_table_6, grpc_stats_table_8};
-void (*const grpc_stats_inc_histogram[14])(grpc_exec_ctx *exec_ctx, int x) = {
+    grpc_stats_table_8};
+void (*const grpc_stats_inc_histogram[13])(grpc_exec_ctx *exec_ctx, int x) = {
     grpc_stats_inc_call_initial_size,
     grpc_stats_inc_poll_events_returned,
     grpc_stats_inc_tcp_write_size,
@@ -731,5 +684,4 @@ void (*const grpc_stats_inc_histogram[14])(grpc_exec_ctx *exec_ctx, int x) = {
     grpc_stats_inc_http2_send_message_per_write,
     grpc_stats_inc_http2_send_trailing_metadata_per_write,
     grpc_stats_inc_http2_send_flowctl_per_write,
-    grpc_stats_inc_executor_closures_per_wakeup,
     grpc_stats_inc_server_cqs_checked};

src/core/lib/debug/stats_data.h

@@ -111,8 +111,6 @@ typedef enum {
   GRPC_STATS_COUNTER_EXECUTOR_WAKEUP_INITIATED,
   GRPC_STATS_COUNTER_EXECUTOR_QUEUE_DRAINED,
   GRPC_STATS_COUNTER_EXECUTOR_PUSH_RETRIES,
-  GRPC_STATS_COUNTER_EXECUTOR_THREADS_CREATED,
-  GRPC_STATS_COUNTER_EXECUTOR_THREADS_USED,
   GRPC_STATS_COUNTER_SERVER_REQUESTED_CALLS,
   GRPC_STATS_COUNTER_SERVER_SLOWPATH_REQUESTS_QUEUED,
   GRPC_STATS_COUNTER_COUNT
@@ -132,7 +130,6 @@ typedef enum {
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_MESSAGE_PER_WRITE,
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_TRAILING_METADATA_PER_WRITE,
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_FLOWCTL_PER_WRITE,
-  GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP,
   GRPC_STATS_HISTOGRAM_SERVER_CQS_CHECKED,
   GRPC_STATS_HISTOGRAM_COUNT
 } grpc_stats_histograms;
@@ -163,11 +160,9 @@ typedef enum {
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_TRAILING_METADATA_PER_WRITE_BUCKETS = 64,
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_FLOWCTL_PER_WRITE_FIRST_SLOT = 768,
   GRPC_STATS_HISTOGRAM_HTTP2_SEND_FLOWCTL_PER_WRITE_BUCKETS = 64,
-  GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP_FIRST_SLOT = 832,
-  GRPC_STATS_HISTOGRAM_EXECUTOR_CLOSURES_PER_WAKEUP_BUCKETS = 64,
-  GRPC_STATS_HISTOGRAM_SERVER_CQS_CHECKED_FIRST_SLOT = 896,
+  GRPC_STATS_HISTOGRAM_SERVER_CQS_CHECKED_FIRST_SLOT = 832,
   GRPC_STATS_HISTOGRAM_SERVER_CQS_CHECKED_BUCKETS = 8,
-  GRPC_STATS_HISTOGRAM_BUCKETS = 904
+  GRPC_STATS_HISTOGRAM_BUCKETS = 840
 } grpc_stats_histogram_constants;
 #define GRPC_STATS_INC_CLIENT_CALLS_CREATED(exec_ctx) \
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_CLIENT_CALLS_CREATED)
@@ -417,11 +412,6 @@ typedef enum {
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_EXECUTOR_QUEUE_DRAINED)
 #define GRPC_STATS_INC_EXECUTOR_PUSH_RETRIES(exec_ctx) \
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_EXECUTOR_PUSH_RETRIES)
-#define GRPC_STATS_INC_EXECUTOR_THREADS_CREATED(exec_ctx) \
-  GRPC_STATS_INC_COUNTER((exec_ctx),                      \
-                         GRPC_STATS_COUNTER_EXECUTOR_THREADS_CREATED)
-#define GRPC_STATS_INC_EXECUTOR_THREADS_USED(exec_ctx) \
-  GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_EXECUTOR_THREADS_USED)
 #define GRPC_STATS_INC_SERVER_REQUESTED_CALLS(exec_ctx) \
   GRPC_STATS_INC_COUNTER((exec_ctx), GRPC_STATS_COUNTER_SERVER_REQUESTED_CALLS)
 #define GRPC_STATS_INC_SERVER_SLOWPATH_REQUESTS_QUEUED(exec_ctx) \
@@ -468,17 +458,13 @@ void grpc_stats_inc_http2_send_trailing_metadata_per_write(
   grpc_stats_inc_http2_send_flowctl_per_write((exec_ctx), (int)(value))
 void grpc_stats_inc_http2_send_flowctl_per_write(grpc_exec_ctx *exec_ctx,
                                                  int x);
-#define GRPC_STATS_INC_EXECUTOR_CLOSURES_PER_WAKEUP(exec_ctx, value) \
-  grpc_stats_inc_executor_closures_per_wakeup((exec_ctx), (int)(value))
-void grpc_stats_inc_executor_closures_per_wakeup(grpc_exec_ctx *exec_ctx,
-                                                 int x);
 #define GRPC_STATS_INC_SERVER_CQS_CHECKED(exec_ctx, value) \
   grpc_stats_inc_server_cqs_checked((exec_ctx), (int)(value))
 void grpc_stats_inc_server_cqs_checked(grpc_exec_ctx *exec_ctx, int x);
-extern const int grpc_stats_histo_buckets[14];
-extern const int grpc_stats_histo_start[14];
-extern const int *const grpc_stats_histo_bucket_boundaries[14];
-extern void (*const grpc_stats_inc_histogram[14])(grpc_exec_ctx *exec_ctx,
+extern const int grpc_stats_histo_buckets[13];
+extern const int grpc_stats_histo_start[13];
+extern const int *const grpc_stats_histo_bucket_boundaries[13];
+extern void (*const grpc_stats_inc_histogram[13])(grpc_exec_ctx *exec_ctx,
                                                   int x);
 
 #endif /* GRPC_CORE_LIB_DEBUG_STATS_DATA_H */

src/core/lib/debug/stats_data.yaml

@@ -259,14 +259,6 @@
 - counter: executor_push_retries
   doc: Number of times we raced and were forced to retry pushing a closure to
        the executor
-- counter: executor_threads_created
-  doc: Size of the backing thread pool for overflow gRPC Core work
-- counter: executor_threads_used
-  doc: How many executor threads actually got used
-- histogram: executor_closures_per_wakeup
-  max: 1024
-  buckets: 64
-  doc: Number of closures executed each time an executor wakes up
 # server
 - counter: server_requested_calls
   doc: How many calls were requested (not necessarily received) by the server

src/core/lib/debug/stats_data_bq_schema.sql

@@ -84,7 +84,5 @@ executor_scheduled_to_self_per_iteration:FLOAT,
 executor_wakeup_initiated_per_iteration:FLOAT,
 executor_queue_drained_per_iteration:FLOAT,
 executor_push_retries_per_iteration:FLOAT,
-executor_threads_created_per_iteration:FLOAT,
-executor_threads_used_per_iteration:FLOAT,
 server_requested_calls_per_iteration:FLOAT,
 server_slowpath_requests_queued_per_iteration:FLOAT

src/core/lib/iomgr/executor.c

@@ -32,14 +32,16 @@
 #include "src/core/lib/iomgr/exec_ctx.h"
 #include "src/core/lib/support/spinlock.h"
 
+#define MAX_DEPTH 2
+
 typedef struct {
   gpr_mu mu;
   gpr_cv cv;
   grpc_closure_list elems;
+  size_t depth;
   bool shutdown;
   bool queued_long_job;
   gpr_thd_id id;
-  grpc_closure_list local_elems;
 } thread_state;
 
 static thread_state *g_thread_state;
@@ -54,35 +56,32 @@ static grpc_tracer_flag executor_trace =
 
 static void executor_thread(void *arg);
 
-static void run_closures(grpc_exec_ctx *exec_ctx, grpc_closure_list *list) {
-  int n = 0;  // number of closures executed
+static size_t run_closures(grpc_exec_ctx *exec_ctx, grpc_closure_list list) {
+  size_t n = 0;
 
-  while (!grpc_closure_list_empty(*list)) {
-    grpc_closure *c = list->head;
-    grpc_closure_list_init(list);
-    while (c != NULL) {
-      grpc_closure *next = c->next_data.next;
-      grpc_error *error = c->error_data.error;
-      if (GRPC_TRACER_ON(executor_trace)) {
+  grpc_closure *c = list.head;
+  while (c != NULL) {
+    grpc_closure *next = c->next_data.next;
+    grpc_error *error = c->error_data.error;
+    if (GRPC_TRACER_ON(executor_trace)) {
 #ifndef NDEBUG
-        gpr_log(GPR_DEBUG, "EXECUTOR: run %p [created by %s:%d]", c,
-                c->file_created, c->line_created);
+      gpr_log(GPR_DEBUG, "EXECUTOR: run %p [created by %s:%d]", c,
+              c->file_created, c->line_created);
 #else
-        gpr_log(GPR_DEBUG, "EXECUTOR: run %p", c);
+      gpr_log(GPR_DEBUG, "EXECUTOR: run %p", c);
 #endif
-      }
+    }
 #ifndef NDEBUG
-      c->scheduled = false;
+    c->scheduled = false;
 #endif
-      n++;
-      c->cb(exec_ctx, c->cb_arg, error);
-      GRPC_ERROR_UNREF(error);
-      c = next;
-      grpc_exec_ctx_flush(exec_ctx);
-    }
+    c->cb(exec_ctx, c->cb_arg, error);
+    GRPC_ERROR_UNREF(error);
+    c = next;
+    n++;
+    grpc_exec_ctx_flush(exec_ctx);
   }
 
-  GRPC_STATS_INC_EXECUTOR_CLOSURES_PER_WAKEUP(exec_ctx, n);
+  return n;
 }
 
 bool grpc_executor_is_threaded() {
@@ -127,7 +126,7 @@ void grpc_executor_set_threading(grpc_exec_ctx *exec_ctx, bool threading) {
     for (size_t i = 0; i < g_max_threads; i++) {
       gpr_mu_destroy(&g_thread_state[i].mu);
       gpr_cv_destroy(&g_thread_state[i].cv);
-      run_closures(exec_ctx, &g_thread_state[i].elems);
+      run_closures(exec_ctx, g_thread_state[i].elems);
     }
     gpr_free(g_thread_state);
     gpr_tls_destroy(&g_this_thread_state);
@@ -151,14 +150,14 @@ static void executor_thread(void *arg) {
   grpc_exec_ctx exec_ctx =
       GRPC_EXEC_CTX_INITIALIZER(0, grpc_never_ready_to_finish, NULL);
 
-  GRPC_STATS_INC_EXECUTOR_THREADS_CREATED(&exec_ctx);
-
-  bool used = false;
+  size_t subtract_depth = 0;
   for (;;) {
     if (GRPC_TRACER_ON(executor_trace)) {
-      gpr_log(GPR_DEBUG, "EXECUTOR[%d]: step", (int)(ts - g_thread_state));
+      gpr_log(GPR_DEBUG, "EXECUTOR[%d]: step (sub_depth=%" PRIdPTR ")",
+              (int)(ts - g_thread_state), subtract_depth);
     }
     gpr_mu_lock(&ts->mu);
+    ts->depth -= subtract_depth;
     while (grpc_closure_list_empty(ts->elems) && !ts->shutdown) {
       ts->queued_long_job = false;
       gpr_cv_wait(&ts->cv, &ts->mu, gpr_inf_future(GPR_CLOCK_REALTIME));
@@ -171,20 +170,15 @@ static void executor_thread(void *arg) {
       gpr_mu_unlock(&ts->mu);
       break;
     }
-    if (!used) {
-      GRPC_STATS_INC_EXECUTOR_THREADS_USED(&exec_ctx);
-      used = true;
-    }
     GRPC_STATS_INC_EXECUTOR_QUEUE_DRAINED(&exec_ctx);
-    GPR_ASSERT(grpc_closure_list_empty(ts->local_elems));
-    ts->local_elems = ts->elems;
+    grpc_closure_list exec = ts->elems;
     ts->elems = (grpc_closure_list)GRPC_CLOSURE_LIST_INIT;
     gpr_mu_unlock(&ts->mu);
     if (GRPC_TRACER_ON(executor_trace)) {
       gpr_log(GPR_DEBUG, "EXECUTOR[%d]: execute", (int)(ts - g_thread_state));
     }
 
-    run_closures(&exec_ctx, &ts->local_elems);
+    subtract_depth = run_closures(&exec_ctx, exec);
   }
   grpc_exec_ctx_finish(&exec_ctx);
 }
@@ -217,10 +211,6 @@ static void executor_push(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
       ts = &g_thread_state[GPR_HASH_POINTER(exec_ctx, cur_thread_count)];
     } else {
       GRPC_STATS_INC_EXECUTOR_SCHEDULED_TO_SELF(exec_ctx);
-      if (is_short) {
-        grpc_closure_list_append(&ts->local_elems, closure, error);
-        return;
-      }
     }
     thread_state *orig_ts = ts;
 
@@ -260,7 +250,8 @@ static void executor_push(grpc_exec_ctx *exec_ctx, grpc_closure *closure,
         gpr_cv_signal(&ts->cv);
       }
       grpc_closure_list_append(&ts->elems, closure, error);
-      try_new_thread = ts->elems.head != closure &&
+      ts->depth++;
+      try_new_thread = ts->depth > MAX_DEPTH &&
                        cur_thread_count < g_max_threads && !ts->shutdown;
       if (!is_short) ts->queued_long_job = true;
       gpr_mu_unlock(&ts->mu);

src/core/lib/iomgr/socket_utils_windows.c

@@ -26,12 +26,8 @@
 #include <grpc/support/log.h>
 
 const char *grpc_inet_ntop(int af, const void *src, char *dst, size_t size) {
-#ifdef GPR_WIN_INET_NTOP
-  return inet_ntop(af, src, dst, size);
-#else
   /* Windows InetNtopA wants a mutable ip pointer */
   return InetNtopA(af, (void *)src, dst, size);
-#endif /* GPR_WIN_INET_NTOP */
 }
 
 #endif /* GRPC_WINDOWS_SOCKETUTILS */

src/core/lib/iomgr/tcp_client_uv.c

@@ -145,7 +145,7 @@ static void tcp_client_connect_impl(grpc_exec_ctx *exec_ctx,
   connect->resource_quota = resource_quota;
   uv_tcp_init(uv_default_loop(), connect->tcp_handle);
   connect->connect_req.data = connect;
-  connect->refs = 1;
+  connect->refs = 2;  // One for the connect operation, one for the timer.
 
   if (GRPC_TRACER_ON(grpc_tcp_trace)) {
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: asynchronously connecting",

src/core/lib/iomgr/timer_generic.c

@@ -79,6 +79,125 @@ static timer_shard g_shards[NUM_SHARDS];
  * Access to this is protected by g_shared_mutables.mu */
 static timer_shard *g_shard_queue[NUM_SHARDS];
 
+#ifndef NDEBUG
+
+/* == Hash table for duplicate timer detection == */
+
+#define NUM_HASH_BUCKETS 1009 /* Prime number close to 1000 */
+
+static gpr_mu g_hash_mu[NUM_HASH_BUCKETS]; /* One mutex per bucket */
+static grpc_timer *g_timer_ht[NUM_HASH_BUCKETS] = {NULL};
+
+static void init_timer_ht() {
+  for (int i = 0; i < NUM_HASH_BUCKETS; i++) {
+    gpr_mu_init(&g_hash_mu[i]);
+  }
+}
+
+static bool is_in_ht(grpc_timer *t) {
+  size_t i = GPR_HASH_POINTER(t, NUM_HASH_BUCKETS);
+
+  gpr_mu_lock(&g_hash_mu[i]);
+  grpc_timer *p = g_timer_ht[i];
+  while (p != NULL && p != t) {
+    p = p->hash_table_next;
+  }
+  gpr_mu_unlock(&g_hash_mu[i]);
+
+  return (p == t);
+}
+
+static void add_to_ht(grpc_timer *t) {
+  GPR_ASSERT(!t->hash_table_next);
+  size_t i = GPR_HASH_POINTER(t, NUM_HASH_BUCKETS);
+
+  gpr_mu_lock(&g_hash_mu[i]);
+  grpc_timer *p = g_timer_ht[i];
+  while (p != NULL && p != t) {
+    p = p->hash_table_next;
+  }
+
+  if (p == t) {
+    grpc_closure *c = t->closure;
+    gpr_log(GPR_ERROR,
+            "** Duplicate timer (%p) being added. Closure: (%p), created at: "
+            "(%s:%d), scheduled at: (%s:%d) **",
+            t, c, c->file_created, c->line_created, c->file_initiated,
+            c->line_initiated);
+    abort();
+  }
+
+  /* Timer not present in the bucket. Insert at head of the list */
+  t->hash_table_next = g_timer_ht[i];
+  g_timer_ht[i] = t;
+  gpr_mu_unlock(&g_hash_mu[i]);
+}
+
+static void remove_from_ht(grpc_timer *t) {
+  size_t i = GPR_HASH_POINTER(t, NUM_HASH_BUCKETS);
+  bool removed = false;
+
+  gpr_mu_lock(&g_hash_mu[i]);
+  if (g_timer_ht[i] == t) {
+    g_timer_ht[i] = g_timer_ht[i]->hash_table_next;
+    removed = true;
+  } else if (g_timer_ht[i] != NULL) {
+    grpc_timer *p = g_timer_ht[i];
+    while (p->hash_table_next != NULL && p->hash_table_next != t) {
+      p = p->hash_table_next;
+    }
+
+    if (p->hash_table_next == t) {
+      p->hash_table_next = t->hash_table_next;
+      removed = true;
+    }
+  }
+  gpr_mu_unlock(&g_hash_mu[i]);
+
+  if (!removed) {
+    grpc_closure *c = t->closure;
+    gpr_log(GPR_ERROR,
+            "** Removing timer (%p) that is not added to hash table. Closure "
+            "(%p), created at: (%s:%d), scheduled at: (%s:%d) **",
+            t, c, c->file_created, c->line_created, c->file_initiated,
+            c->line_initiated);
+    abort();
+  }
+
+  t->hash_table_next = NULL;
+}
+
+/* If a timer is added to a timer shard (either heap or a list), it cannot
+ * be pending. A timer is added to hash table only-if it is added to the
+ * timer shard.
+ * Therefore, if timer->pending is false, it cannot be in hash table */
+static void validate_non_pending_timer(grpc_timer *t) {
+  if (!t->pending && is_in_ht(t)) {
+    grpc_closure *c = t->closure;
+    gpr_log(GPR_ERROR,
+            "** gpr_timer_cancel() called on a non-pending timer (%p) which "
+            "is in the hash table. Closure: (%p), created at: (%s:%d), "
+            "scheduled at: (%s:%d) **",
+            t, c, c->file_created, c->line_created, c->file_initiated,
+            c->line_initiated);
+    abort();
+  }
+}
+
+#define INIT_TIMER_HASH_TABLE() init_timer_ht()
+#define ADD_TO_HASH_TABLE(t) add_to_ht((t))
+#define REMOVE_FROM_HASH_TABLE(t) remove_from_ht((t))
+#define VALIDATE_NON_PENDING_TIMER(t) validate_non_pending_timer((t))
+
+#else
+
+#define INIT_TIMER_HASH_TABLE()
+#define ADD_TO_HASH_TABLE(t)
+#define REMOVE_FROM_HASH_TABLE(t)
+#define VALIDATE_NON_PENDING_TIMER(t)
+
+#endif
+
 /* Thread local variable that stores the deadline of the next timer the thread
  * has last-seen. This is an optimization to prevent the thread from checking
  * shared_mutables.min_timer (which requires acquiring shared_mutables.mu lock,
@@ -175,6 +294,8 @@ void grpc_timer_list_init(gpr_timespec now) {
     shard->min_deadline = compute_min_deadline(shard);
     g_shard_queue[i] = shard;
   }
+
+  INIT_TIMER_HASH_TABLE();
 }
 
 void grpc_timer_list_shutdown(grpc_exec_ctx *exec_ctx) {
@@ -245,6 +366,10 @@ void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
   timer->closure = closure;
   gpr_atm deadline_atm = timer->deadline = timespec_to_atm_round_up(deadline);
 
+#ifndef NDEBUG
+  timer->hash_table_next = NULL;
+#endif
+
   if (GRPC_TRACER_ON(grpc_timer_trace)) {
     gpr_log(GPR_DEBUG, "TIMER %p: SET %" PRId64 ".%09d [%" PRIdPTR
                        "] now %" PRId64 ".%09d [%" PRIdPTR "] call %p[%p]",
@@ -272,6 +397,9 @@ void grpc_timer_init(grpc_exec_ctx *exec_ctx, grpc_timer *timer,
 
   grpc_time_averaged_stats_add_sample(&shard->stats,
                                       ts_to_dbl(gpr_time_sub(deadline, now)));
+
+  ADD_TO_HASH_TABLE(timer);
+
   if (deadline_atm < shard->queue_deadline_cap) {
     is_first_timer = grpc_timer_heap_add(&shard->heap, timer);
   } else {
@@ -333,7 +461,10 @@ void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer) {
     gpr_log(GPR_DEBUG, "TIMER %p: CANCEL pending=%s", timer,
             timer->pending ? "true" : "false");
   }
+
   if (timer->pending) {
+    REMOVE_FROM_HASH_TABLE(timer);
+
     GRPC_CLOSURE_SCHED(exec_ctx, timer->closure, GRPC_ERROR_CANCELLED);
     timer->pending = false;
     if (timer->heap_index == INVALID_HEAP_INDEX) {
@@ -341,6 +472,8 @@ void grpc_timer_cancel(grpc_exec_ctx *exec_ctx, grpc_timer *timer) {
     } else {
       grpc_timer_heap_remove(&shard->heap, timer);
     }
+  } else {
+    VALIDATE_NON_PENDING_TIMER(timer);
   }
   gpr_mu_unlock(&shard->mu);
 }
@@ -424,6 +557,7 @@ static size_t pop_timers(grpc_exec_ctx *exec_ctx, timer_shard *shard,
   grpc_timer *timer;
   gpr_mu_lock(&shard->mu);
   while ((timer = pop_one(shard, now))) {
+    REMOVE_FROM_HASH_TABLE(timer);
     GRPC_CLOSURE_SCHED(exec_ctx, timer->closure, GRPC_ERROR_REF(error));
     n++;
   }

src/core/lib/iomgr/timer_generic.h

@@ -29,6 +29,9 @@ struct grpc_timer {
   struct grpc_timer *next;
   struct grpc_timer *prev;
   grpc_closure *closure;
+#ifndef NDEBUG
+  struct grpc_timer *hash_table_next;
+#endif
 };
 
 #endif /* GRPC_CORE_LIB_IOMGR_TIMER_GENERIC_H */

src/core/lib/security/credentials/composite/composite_credentials.c

@@ -87,6 +87,7 @@ static bool composite_call_get_request_metadata(
   ctx->on_request_metadata = on_request_metadata;
   GRPC_CLOSURE_INIT(&ctx->internal_on_request_metadata,
                     composite_call_metadata_cb, ctx, grpc_schedule_on_exec_ctx);
+  bool synchronous = true;
   while (ctx->creds_index < ctx->composite_creds->inner.num_creds) {
     grpc_call_credentials *inner_creds =
         ctx->composite_creds->inner.creds_array[ctx->creds_index++];
@@ -95,19 +96,12 @@ static bool composite_call_get_request_metadata(
             ctx->md_array, &ctx->internal_on_request_metadata, error)) {
       if (*error != GRPC_ERROR_NONE) break;
     } else {
+      synchronous = false;  // Async return.
       break;
     }
   }
-  // If we got through all creds synchronously or we got a synchronous
-  // error on one of them, return synchronously.
-  if (ctx->creds_index == ctx->composite_creds->inner.num_creds ||
-      *error != GRPC_ERROR_NONE) {
-    gpr_free(ctx);
-    return true;
-  }
-  // At least one inner cred is returning asynchronously, so we'll
-  // return asynchronously as well.
-  return false;
+  if (synchronous) gpr_free(ctx);
+  return synchronous;
 }
 
 static void composite_call_cancel_get_request_metadata(

src/core/lib/security/credentials/plugin/plugin_credentials.c

@@ -31,6 +31,9 @@
 #include "src/core/lib/surface/api_trace.h"
 #include "src/core/lib/surface/validate_metadata.h"
 
+grpc_tracer_flag grpc_plugin_credentials_trace =
+    GRPC_TRACER_INITIALIZER(false, "plugin_credentials");
+
 static void plugin_destruct(grpc_exec_ctx *exec_ctx,
                             grpc_call_credentials *creds) {
   grpc_plugin_credentials *c = (grpc_plugin_credentials *)creds;
@@ -53,6 +56,62 @@ static void pending_request_remove_locked(
   }
 }
 
+// Checks if the request has been cancelled.
+// If not, removes it from the pending list, so that it cannot be
+// cancelled out from under us.
+// When this returns, r->cancelled indicates whether the request was
+// cancelled before completion.
+static void pending_request_complete(
+    grpc_exec_ctx *exec_ctx, grpc_plugin_credentials_pending_request *r) {
+  gpr_mu_lock(&r->creds->mu);
+  if (!r->cancelled) pending_request_remove_locked(r->creds, r);
+  gpr_mu_unlock(&r->creds->mu);
+  // Ref to credentials not needed anymore.
+  grpc_call_credentials_unref(exec_ctx, &r->creds->base);
+}
+
+static grpc_error *process_plugin_result(
+    grpc_exec_ctx *exec_ctx, grpc_plugin_credentials_pending_request *r,
+    const grpc_metadata *md, size_t num_md, grpc_status_code status,
+    const char *error_details) {
+  grpc_error *error = GRPC_ERROR_NONE;
+  if (status != GRPC_STATUS_OK) {
+    char *msg;
+    gpr_asprintf(&msg, "Getting metadata from plugin failed with error: %s",
+                 error_details);
+    error = GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg);
+    gpr_free(msg);
+  } else {
+    bool seen_illegal_header = false;
+    for (size_t i = 0; i < num_md; ++i) {
+      if (!GRPC_LOG_IF_ERROR("validate_metadata_from_plugin",
+                             grpc_validate_header_key_is_legal(md[i].key))) {
+        seen_illegal_header = true;
+        break;
+      } else if (!grpc_is_binary_header(md[i].key) &&
+                 !GRPC_LOG_IF_ERROR(
+                     "validate_metadata_from_plugin",
+                     grpc_validate_header_nonbin_value_is_legal(md[i].value))) {
+        gpr_log(GPR_ERROR, "Plugin added invalid metadata value.");
+        seen_illegal_header = true;
+        break;
+      }
+    }
+    if (seen_illegal_header) {
+      error = GRPC_ERROR_CREATE_FROM_STATIC_STRING("Illegal metadata");
+    } else {
+      for (size_t i = 0; i < num_md; ++i) {
+        grpc_mdelem mdelem = grpc_mdelem_from_slices(
+            exec_ctx, grpc_slice_ref_internal(md[i].key),
+            grpc_slice_ref_internal(md[i].value));
+        grpc_credentials_mdelem_array_add(r->md_array, mdelem);
+        GRPC_MDELEM_UNREF(exec_ctx, mdelem);
+      }
+    }
+  }
+  return error;
+}
+
 static void plugin_md_request_metadata_ready(void *request,
                                              const grpc_metadata *md,
                                              size_t num_md,
@@ -64,54 +123,24 @@ static void plugin_md_request_metadata_ready(void *request,
       NULL, NULL);
   grpc_plugin_credentials_pending_request *r =
       (grpc_plugin_credentials_pending_request *)request;
-  // Check if the request has been cancelled.
-  // If not, remove it from the pending list, so that it cannot be
-  // cancelled out from under us.
-  gpr_mu_lock(&r->creds->mu);
-  if (!r->cancelled) pending_request_remove_locked(r->creds, r);
-  gpr_mu_unlock(&r->creds->mu);
-  grpc_call_credentials_unref(&exec_ctx, &r->creds->base);
+  if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+    gpr_log(GPR_INFO,
+            "plugin_credentials[%p]: request %p: plugin returned "
+            "asynchronously",
+            r->creds, r);
+  }
+  // Remove request from pending list if not previously cancelled.
+  pending_request_complete(&exec_ctx, r);
   // If it has not been cancelled, process it.
   if (!r->cancelled) {
-    if (status != GRPC_STATUS_OK) {
-      char *msg;
-      gpr_asprintf(&msg, "Getting metadata from plugin failed with error: %s",
-                   error_details);
-      GRPC_CLOSURE_SCHED(&exec_ctx, r->on_request_metadata,
-                         GRPC_ERROR_CREATE_FROM_COPIED_STRING(msg));
-      gpr_free(msg);
-    } else {
-      bool seen_illegal_header = false;
-      for (size_t i = 0; i < num_md; ++i) {
-        if (!GRPC_LOG_IF_ERROR("validate_metadata_from_plugin",
-                               grpc_validate_header_key_is_legal(md[i].key))) {
-          seen_illegal_header = true;
-          break;
-        } else if (!grpc_is_binary_header(md[i].key) &&
-                   !GRPC_LOG_IF_ERROR(
-                       "validate_metadata_from_plugin",
-                       grpc_validate_header_nonbin_value_is_legal(
-                           md[i].value))) {
-          gpr_log(GPR_ERROR, "Plugin added invalid metadata value.");
-          seen_illegal_header = true;
-          break;
-        }
-      }
-      if (seen_illegal_header) {
-        GRPC_CLOSURE_SCHED(
-            &exec_ctx, r->on_request_metadata,
-            GRPC_ERROR_CREATE_FROM_STATIC_STRING("Illegal metadata"));
-      } else {
-        for (size_t i = 0; i < num_md; ++i) {
-          grpc_mdelem mdelem = grpc_mdelem_from_slices(
-              &exec_ctx, grpc_slice_ref_internal(md[i].key),
-              grpc_slice_ref_internal(md[i].value));
-          grpc_credentials_mdelem_array_add(r->md_array, mdelem);
-          GRPC_MDELEM_UNREF(&exec_ctx, mdelem);
-        }
-        GRPC_CLOSURE_SCHED(&exec_ctx, r->on_request_metadata, GRPC_ERROR_NONE);
-      }
-    }
+    grpc_error *error =
+        process_plugin_result(&exec_ctx, r, md, num_md, status, error_details);
+    GRPC_CLOSURE_SCHED(&exec_ctx, r->on_request_metadata, error);
+  } else if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+    gpr_log(GPR_INFO,
+            "plugin_credentials[%p]: request %p: plugin was previously "
+            "cancelled",
+            r->creds, r);
   }
   gpr_free(r);
   grpc_exec_ctx_finish(&exec_ctx);
@@ -125,6 +154,7 @@ static bool plugin_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                         grpc_closure *on_request_metadata,
                                         grpc_error **error) {
   grpc_plugin_credentials *c = (grpc_plugin_credentials *)creds;
+  bool retval = true;  // Synchronous return.
   if (c->plugin.get_metadata != NULL) {
     // Create pending_request object.
     grpc_plugin_credentials_pending_request *pending_request =
@@ -142,12 +172,60 @@ static bool plugin_get_request_metadata(grpc_exec_ctx *exec_ctx,
     c->pending_requests = pending_request;
     gpr_mu_unlock(&c->mu);
     // Invoke the plugin.  The callback holds a ref to us.
+    if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+      gpr_log(GPR_INFO, "plugin_credentials[%p]: request %p: invoking plugin",
+              c, pending_request);
+    }
     grpc_call_credentials_ref(creds);
-    c->plugin.get_metadata(c->plugin.state, context,
-                           plugin_md_request_metadata_ready, pending_request);
-    return false;
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX];
+    size_t num_creds_md = 0;
+    grpc_status_code status = GRPC_STATUS_OK;
+    const char *error_details = NULL;
+    if (!c->plugin.get_metadata(c->plugin.state, context,
+                                plugin_md_request_metadata_ready,
+                                pending_request, creds_md, &num_creds_md,
+                                &status, &error_details)) {
+      if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+        gpr_log(GPR_INFO,
+                "plugin_credentials[%p]: request %p: plugin will return "
+                "asynchronously",
+                c, pending_request);
+      }
+      return false;  // Asynchronous return.
+    }
+    // Returned synchronously.
+    // Remove request from pending list if not previously cancelled.
+    pending_request_complete(exec_ctx, pending_request);
+    // If the request was cancelled, the error will have been returned
+    // asynchronously by plugin_cancel_get_request_metadata(), so return
+    // false.  Otherwise, process the result.
+    if (pending_request->cancelled) {
+      if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+        gpr_log(GPR_INFO,
+                "plugin_credentials[%p]: request %p was cancelled, error "
+                "will be returned asynchronously",
+                c, pending_request);
+      }
+      retval = false;
+    } else {
+      if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+        gpr_log(GPR_INFO,
+                "plugin_credentials[%p]: request %p: plugin returned "
+                "synchronously",
+                c, pending_request);
+      }
+      *error = process_plugin_result(exec_ctx, pending_request, creds_md,
+                                     num_creds_md, status, error_details);
+    }
+    // Clean up.
+    for (size_t i = 0; i < num_creds_md; ++i) {
+      grpc_slice_unref_internal(exec_ctx, creds_md[i].key);
+      grpc_slice_unref_internal(exec_ctx, creds_md[i].value);
+    }
+    gpr_free((void *)error_details);
+    gpr_free(pending_request);
   }
-  return true;
+  return retval;
 }
 
 static void plugin_cancel_get_request_metadata(
@@ -159,6 +237,10 @@ static void plugin_cancel_get_request_metadata(
            c->pending_requests;
        pending_request != NULL; pending_request = pending_request->next) {
     if (pending_request->md_array == md_array) {
+      if (GRPC_TRACER_ON(grpc_plugin_credentials_trace)) {
+        gpr_log(GPR_INFO, "plugin_credentials[%p]: cancelling request %p", c,
+                pending_request);
+      }
       pending_request->cancelled = true;
       GRPC_CLOSURE_SCHED(exec_ctx, pending_request->on_request_metadata,
                          GRPC_ERROR_REF(error));

src/core/lib/security/credentials/plugin/plugin_credentials.h

@@ -21,6 +21,8 @@
 
 #include "src/core/lib/security/credentials/credentials.h"
 
+extern grpc_tracer_flag grpc_plugin_credentials_trace;
+
 struct grpc_plugin_credentials;
 
 typedef struct grpc_plugin_credentials_pending_request {

src/core/lib/surface/init_secure.c

@@ -25,6 +25,7 @@
 
 #include "src/core/lib/debug/trace.h"
 #include "src/core/lib/security/credentials/credentials.h"
+#include "src/core/lib/security/credentials/plugin/plugin_credentials.h"
 #include "src/core/lib/security/transport/auth_filters.h"
 #include "src/core/lib/security/transport/secure_endpoint.h"
 #include "src/core/lib/security/transport/security_connector.h"
@@ -84,4 +85,7 @@ void grpc_register_security_filters(void) {
                                    maybe_prepend_server_auth_filter, NULL);
 }
 
-void grpc_security_init() { grpc_security_register_handshaker_factories(); }
+void grpc_security_init() {
+  grpc_security_register_handshaker_factories();
+  grpc_register_tracer(&grpc_plugin_credentials_trace);
+}

src/core/lib/surface/version.c

@@ -23,4 +23,4 @@
 
 const char *grpc_version_string(void) { return "5.0.0-dev"; }
 
-const char *grpc_g_stands_for(void) { return "gambit"; }
+const char *grpc_g_stands_for(void) { return "generous"; }

src/cpp/client/generic_stub.cc

@@ -47,4 +47,14 @@ std::unique_ptr<GenericClientAsyncReaderWriter> GenericStub::PrepareCall(
   return CallInternal(channel_.get(), context, method, cq, false, nullptr);
 }
 
+// setup a unary call to a named method
+std::unique_ptr<GenericClientAsyncResponseReader> GenericStub::PrepareUnaryCall(
+    ClientContext* context, const grpc::string& method,
+    const ByteBuffer& request, CompletionQueue* cq) {
+  return std::unique_ptr<GenericClientAsyncResponseReader>(
+      GenericClientAsyncResponseReader::Create(
+          channel_.get(), cq, RpcMethod(method.c_str(), RpcMethod::NORMAL_RPC),
+          context, request, false));
+}
+
 }  // namespace grpc

src/cpp/client/secure_credentials.cc

@@ -21,6 +21,7 @@
 #include <grpc++/impl/grpc_library.h>
 #include <grpc++/support/channel_arguments.h>
 #include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
 #include "src/cpp/client/create_channel_internal.h"
 #include "src/cpp/common/secure_auth_context.h"
 
@@ -150,6 +151,18 @@ std::shared_ptr<ChannelCredentials> CompositeChannelCredentials(
   return nullptr;
 }
 
+std::shared_ptr<CallCredentials> CompositeCallCredentials(
+    const std::shared_ptr<CallCredentials>& creds1,
+    const std::shared_ptr<CallCredentials>& creds2) {
+  SecureCallCredentials* s_creds1 = creds1->AsSecureCredentials();
+  SecureCallCredentials* s_creds2 = creds2->AsSecureCredentials();
+  if (s_creds1 != nullptr && s_creds2 != nullptr) {
+    return WrapCallCredentials(grpc_composite_call_credentials_create(
+        s_creds1->GetRawCreds(), s_creds2->GetRawCreds(), nullptr));
+  }
+  return nullptr;
+}
+
 void MetadataCredentialsPluginWrapper::Destroy(void* wrapper) {
   if (wrapper == nullptr) return;
   MetadataCredentialsPluginWrapper* w =
@@ -157,28 +170,50 @@ void MetadataCredentialsPluginWrapper::Destroy(void* wrapper) {
   delete w;
 }
 
-void MetadataCredentialsPluginWrapper::GetMetadata(
+int MetadataCredentialsPluginWrapper::GetMetadata(
     void* wrapper, grpc_auth_metadata_context context,
-    grpc_credentials_plugin_metadata_cb cb, void* user_data) {
+    grpc_credentials_plugin_metadata_cb cb, void* user_data,
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+    size_t* num_creds_md, grpc_status_code* status,
+    const char** error_details) {
   GPR_ASSERT(wrapper);
   MetadataCredentialsPluginWrapper* w =
       reinterpret_cast<MetadataCredentialsPluginWrapper*>(wrapper);
   if (!w->plugin_) {
-    cb(user_data, NULL, 0, GRPC_STATUS_OK, NULL);
-    return;
+    *num_creds_md = 0;
+    *status = GRPC_STATUS_OK;
+    *error_details = nullptr;
+    return true;
   }
   if (w->plugin_->IsBlocking()) {
+    // Asynchronous return.
     w->thread_pool_->Add(
         std::bind(&MetadataCredentialsPluginWrapper::InvokePlugin, w, context,
-                  cb, user_data));
+                  cb, user_data, nullptr, nullptr, nullptr, nullptr));
+    return 0;
   } else {
-    w->InvokePlugin(context, cb, user_data);
+    // Synchronous return.
+    w->InvokePlugin(context, cb, user_data, creds_md, num_creds_md, status,
+                    error_details);
+    return 1;
+  }
+}
+
+namespace {
+
+void UnrefMetadata(const std::vector<grpc_metadata>& md) {
+  for (auto it = md.begin(); it != md.end(); ++it) {
+    grpc_slice_unref(it->key);
+    grpc_slice_unref(it->value);
   }
 }
 
+}  // namespace
+
 void MetadataCredentialsPluginWrapper::InvokePlugin(
     grpc_auth_metadata_context context, grpc_credentials_plugin_metadata_cb cb,
-    void* user_data) {
+    void* user_data, grpc_metadata creds_md[4], size_t* num_creds_md,
+    grpc_status_code* status_code, const char** error_details) {
   std::multimap<grpc::string, grpc::string> metadata;
 
   // const_cast is safe since the SecureAuthContext does not take owndership and
@@ -196,12 +231,31 @@ void MetadataCredentialsPluginWrapper::InvokePlugin(
     md_entry.flags = 0;
     md.push_back(md_entry);
   }
-  cb(user_data, md.empty() ? nullptr : &md[0], md.size(),
-     static_cast<grpc_status_code>(status.error_code()),
-     status.error_message().c_str());
-  for (auto it = md.begin(); it != md.end(); ++it) {
-    grpc_slice_unref(it->key);
-    grpc_slice_unref(it->value);
+  if (creds_md != nullptr) {
+    // Synchronous return.
+    if (md.size() > GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX) {
+      *num_creds_md = 0;
+      *status_code = GRPC_STATUS_INTERNAL;
+      *error_details = gpr_strdup(
+          "blocking plugin credentials returned too many metadata keys");
+      UnrefMetadata(md);
+    } else {
+      for (const auto& elem : md) {
+        creds_md[*num_creds_md].key = elem.key;
+        creds_md[*num_creds_md].value = elem.value;
+        creds_md[*num_creds_md].flags = elem.flags;
+        ++(*num_creds_md);
+      }
+      *status_code = static_cast<grpc_status_code>(status.error_code());
+      *error_details =
+          status.ok() ? nullptr : gpr_strdup(status.error_message().c_str());
+    }
+  } else {
+    // Asynchronous return.
+    cb(user_data, md.empty() ? nullptr : &md[0], md.size(),
+       static_cast<grpc_status_code>(status.error_code()),
+       status.error_message().c_str());
+    UnrefMetadata(md);
   }
 }
 

src/cpp/client/secure_credentials.h

@@ -58,16 +58,23 @@ class SecureCallCredentials final : public CallCredentials {
 class MetadataCredentialsPluginWrapper final : private GrpcLibraryCodegen {
  public:
   static void Destroy(void* wrapper);
-  static void GetMetadata(void* wrapper, grpc_auth_metadata_context context,
-                          grpc_credentials_plugin_metadata_cb cb,
-                          void* user_data);
+  static int GetMetadata(
+      void* wrapper, grpc_auth_metadata_context context,
+      grpc_credentials_plugin_metadata_cb cb, void* user_data,
+      grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+      size_t* num_creds_md, grpc_status_code* status,
+      const char** error_details);
 
   explicit MetadataCredentialsPluginWrapper(
       std::unique_ptr<MetadataCredentialsPlugin> plugin);
 
  private:
-  void InvokePlugin(grpc_auth_metadata_context context,
-                    grpc_credentials_plugin_metadata_cb cb, void* user_data);
+  void InvokePlugin(
+      grpc_auth_metadata_context context,
+      grpc_credentials_plugin_metadata_cb cb, void* user_data,
+      grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+      size_t* num_creds_md, grpc_status_code* status_code,
+      const char** error_details);
   std::unique_ptr<ThreadPoolInterface> thread_pool_;
   std::unique_ptr<MetadataCredentialsPlugin> plugin_;
 };

src/cpp/common/channel_arguments.cc

@@ -86,6 +86,10 @@ void ChannelArguments::SetCompressionAlgorithm(
   SetInt(GRPC_COMPRESSION_CHANNEL_DEFAULT_ALGORITHM, algorithm);
 }
 
+void ChannelArguments::SetGrpclbFallbackTimeout(int fallback_timeout) {
+  SetInt(GRPC_ARG_GRPCLB_FALLBACK_TIMEOUT_MS, fallback_timeout);
+}
+
 void ChannelArguments::SetSocketMutator(grpc_socket_mutator* mutator) {
   if (!mutator) {
     return;

src/cpp/common/version_cc.cc

@@ -22,5 +22,5 @@
 #include <grpc++/grpc++.h>
 
 namespace grpc {
-grpc::string Version() { return "1.7.0-dev"; }
+grpc::string Version() { return "1.8.0-dev"; }
 }

src/csharp/Grpc.Core/Internal/AsyncCall.cs

@@ -34,6 +34,9 @@ namespace Grpc.Core.Internal
         readonly CallInvocationDetails<TRequest, TResponse> details;
         readonly INativeCall injectedNativeCall;  // for testing
 
+        // Dispose of to de-register cancellation token registration
+        IDisposable cancellationTokenRegistration;
+
         // Completion of a pending unary response if not null.
         TaskCompletionSource<TResponse> unaryResponseTcs;
 
@@ -320,6 +323,7 @@ namespace Grpc.Core.Internal
         protected override void OnAfterReleaseResources()
         {
             details.Channel.RemoveCallReference(this);
+            cancellationTokenRegistration?.Dispose();
         }
 
         protected override bool IsClient
@@ -405,7 +409,7 @@ namespace Grpc.Core.Internal
             var token = details.Options.CancellationToken;
             if (token.CanBeCanceled)
             {
-                token.Register(() => this.Cancel());
+                cancellationTokenRegistration = token.Register(() => this.Cancel());
             }
         }
 

src/csharp/Grpc.Core/Internal/NativeMetadataCredentialsPlugin.cs

@@ -61,12 +61,9 @@ namespace Grpc.Core.Internal
 
             try
             {
-                var context = new AuthInterceptorContext(Marshal.PtrToStringAnsi(serviceUrlPtr),
-                                                         Marshal.PtrToStringAnsi(methodNamePtr));
-                // Don't await, we are in a native callback and need to return.
-                #pragma warning disable 4014
-                GetMetadataAsync(context, callbackPtr, userDataPtr);
-                #pragma warning restore 4014
+                var context = new AuthInterceptorContext(Marshal.PtrToStringAnsi(serviceUrlPtr), Marshal.PtrToStringAnsi(methodNamePtr));
+                // Make a guarantee that credentials_notify_from_plugin is invoked async to be compliant with c-core API.
+                ThreadPool.QueueUserWorkItem(async (stateInfo) => await GetMetadataAsync(context, callbackPtr, userDataPtr));
             }
             catch (Exception e)
             {

src/csharp/Grpc.Core/Version.csproj.include

@@ -1,7 +1,7 @@
 <!-- This file is generated -->
 <Project>
   <PropertyGroup>
-    <GrpcCsharpVersion>1.7.0-dev</GrpcCsharpVersion>
+    <GrpcCsharpVersion>1.8.0-dev</GrpcCsharpVersion>
     <GoogleProtobufVersion>3.3.0</GoogleProtobufVersion>
   </PropertyGroup>
 </Project>

src/csharp/Grpc.Core/VersionInfo.cs

@@ -33,11 +33,11 @@ namespace Grpc.Core
         /// <summary>
         /// Current <c>AssemblyFileVersion</c> of gRPC C# assemblies
         /// </summary>
-        public const string CurrentAssemblyFileVersion = "1.7.0.0";
+        public const string CurrentAssemblyFileVersion = "1.8.0.0";
 
         /// <summary>
         /// Current version of gRPC C#
         /// </summary>
-        public const string CurrentVersion = "1.7.0-dev";
+        public const string CurrentVersion = "1.8.0-dev";
     }
 }

src/csharp/Grpc.IntegrationTesting/MetadataCredentialsTest.cs

@@ -89,6 +89,54 @@ namespace Grpc.IntegrationTesting
             client.UnaryCall(new SimpleRequest { }, new CallOptions(credentials: callCredentials));
         }
 
+        [Test]
+        public async Task MetadataCredentials_Composed()
+        {
+            var first = CallCredentials.FromInterceptor(new AsyncAuthInterceptor((context, metadata) => {
+                // Attempt to exercise the case where async callback is inlineable/synchronously-runnable.
+                metadata.Add("first_authorization", "FIRST_SECRET_TOKEN");
+                return TaskUtils.CompletedTask;
+            }));
+            var second = CallCredentials.FromInterceptor(new AsyncAuthInterceptor((context, metadata) => {
+                metadata.Add("second_authorization", "SECOND_SECRET_TOKEN");
+                return TaskUtils.CompletedTask;
+            }));
+            var third = CallCredentials.FromInterceptor(new AsyncAuthInterceptor((context, metadata) => {
+                metadata.Add("third_authorization", "THIRD_SECRET_TOKEN");
+                return TaskUtils.CompletedTask;
+            }));
+            var channelCredentials = ChannelCredentials.Create(TestCredentials.CreateSslCredentials(),
+                CallCredentials.Compose(first, second, third));
+            channel = new Channel(Host, server.Ports.Single().BoundPort, channelCredentials, options);
+            var client = new TestService.TestServiceClient(channel);
+            var call = client.StreamingOutputCall(new StreamingOutputCallRequest { });
+            Assert.IsTrue(await call.ResponseStream.MoveNext());
+            Assert.IsFalse(await call.ResponseStream.MoveNext());
+        }
+
+        [Test]
+        public async Task MetadataCredentials_ComposedPerCall()
+        {
+            channel = new Channel(Host, server.Ports.Single().BoundPort, TestCredentials.CreateSslCredentials(), options);
+            var client = new TestService.TestServiceClient(channel);
+            var first = CallCredentials.FromInterceptor(new AsyncAuthInterceptor((context, metadata) => {
+                metadata.Add("first_authorization", "FIRST_SECRET_TOKEN");
+                return TaskUtils.CompletedTask;
+            }));
+            var second = CallCredentials.FromInterceptor(new AsyncAuthInterceptor((context, metadata) => {
+                metadata.Add("second_authorization", "SECOND_SECRET_TOKEN");
+                return TaskUtils.CompletedTask;
+            }));
+            var third = CallCredentials.FromInterceptor(new AsyncAuthInterceptor((context, metadata) => {
+                metadata.Add("third_authorization", "THIRD_SECRET_TOKEN");
+                return TaskUtils.CompletedTask;
+            }));
+            var call = client.StreamingOutputCall(new StreamingOutputCallRequest{ },
+                new CallOptions(credentials: CallCredentials.Compose(first, second, third)));
+            Assert.IsTrue(await call.ResponseStream.MoveNext());
+            Assert.IsFalse(await call.ResponseStream.MoveNext());
+        }
+
         [Test]
         public void MetadataCredentials_InterceptorLeavesMetadataEmpty()
         {
@@ -125,6 +173,17 @@ namespace Grpc.IntegrationTesting
                 Assert.AreEqual("SECRET_TOKEN", authToken);
                 return Task.FromResult(new SimpleResponse());
             }
+
+            public override async Task StreamingOutputCall(StreamingOutputCallRequest request, IServerStreamWriter<StreamingOutputCallResponse> responseStream, ServerCallContext context)
+            {
+                var first = context.RequestHeaders.First((entry) => entry.Key == "first_authorization").Value;
+                Assert.AreEqual("FIRST_SECRET_TOKEN", first);
+                var second = context.RequestHeaders.First((entry) => entry.Key == "second_authorization").Value;
+                Assert.AreEqual("SECOND_SECRET_TOKEN", second);
+                var third = context.RequestHeaders.First((entry) => entry.Key == "third_authorization").Value;
+                Assert.AreEqual("THIRD_SECRET_TOKEN", third);
+                await responseStream.WriteAsync(new StreamingOutputCallResponse());
+            }
         }
     }
 }

src/csharp/build_packages_dotnetcli.bat

@@ -13,7 +13,7 @@
 @rem limitations under the License.
 
 @rem Current package versions
-set VERSION=1.7.0-dev
+set VERSION=1.8.0-dev
 
 @rem Adjust the location of nuget.exe
 set NUGET=C:\nuget\nuget.exe

src/csharp/build_packages_dotnetcli.sh

@@ -39,7 +39,7 @@ dotnet pack --configuration Release Grpc.Auth --output ../../../artifacts
 dotnet pack --configuration Release Grpc.HealthCheck --output ../../../artifacts
 dotnet pack --configuration Release Grpc.Reflection --output ../../../artifacts
 
-nuget pack Grpc.nuspec -Version "1.7.0-dev" -OutputDirectory ../../artifacts
-nuget pack Grpc.Tools.nuspec -Version "1.7.0-dev" -OutputDirectory ../../artifacts
+nuget pack Grpc.nuspec -Version "1.8.0-dev" -OutputDirectory ../../artifacts
+nuget pack Grpc.Tools.nuspec -Version "1.8.0-dev" -OutputDirectory ../../artifacts
 
 (cd ../../artifacts && zip csharp_nugets_dotnetcli.zip *.nupkg)

src/csharp/ext/grpc_csharp_ext.c

@@ -1023,13 +1023,17 @@ typedef void(GPR_CALLTYPE *grpcsharp_metadata_interceptor_func)(
     grpc_credentials_plugin_metadata_cb cb, void *user_data,
     int32_t is_destroy);
 
-static void grpcsharp_get_metadata_handler(
+static int grpcsharp_get_metadata_handler(
     void *state, grpc_auth_metadata_context context,
-    grpc_credentials_plugin_metadata_cb cb, void *user_data) {
+    grpc_credentials_plugin_metadata_cb cb, void *user_data,
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+    size_t *num_creds_md, grpc_status_code *status,
+    const char **error_details) {
   grpcsharp_metadata_interceptor_func interceptor =
       (grpcsharp_metadata_interceptor_func)(intptr_t)state;
   interceptor(state, context.service_url, context.method_name, cb, user_data,
               0);
+  return 0; /* Asynchronous return. */
 }
 
 static void grpcsharp_metadata_credentials_destroy_handler(void *state) {

src/node/ext/call_credentials.cc

@@ -238,9 +238,12 @@ NAUV_WORK_CB(SendPluginCallback) {
   }
 }
 
-void plugin_get_metadata(void *state, grpc_auth_metadata_context context,
-                         grpc_credentials_plugin_metadata_cb cb,
-                         void *user_data) {
+int plugin_get_metadata(
+    void *state, grpc_auth_metadata_context context,
+    grpc_credentials_plugin_metadata_cb cb, void *user_data,
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+    size_t *num_creds_md, grpc_status_code *status,
+    const char **error_details) {
   plugin_state *p_state = reinterpret_cast<plugin_state *>(state);
   plugin_callback_data *data = new plugin_callback_data;
   data->service_url = context.service_url;
@@ -252,6 +255,7 @@ void plugin_get_metadata(void *state, grpc_auth_metadata_context context,
   uv_mutex_unlock(&p_state->plugin_mutex);
 
   uv_async_send(&p_state->plugin_async);
+  return 0;  // Async processing.
 }
 
 void plugin_uv_close_cb(uv_handle_t *handle) {

src/node/ext/call_credentials.h

@@ -75,9 +75,11 @@ typedef struct plugin_state {
   uv_async_t plugin_async;
 } plugin_state;
 
-void plugin_get_metadata(void *state, grpc_auth_metadata_context context,
-                         grpc_credentials_plugin_metadata_cb cb,
-                         void *user_data);
+int plugin_get_metadata(
+    void *state, grpc_auth_metadata_context context,
+    grpc_credentials_plugin_metadata_cb cb, void *user_data,
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+    size_t *num_creds_md, grpc_status_code *status, const char **error_details);
 
 void plugin_destroy_state(void *state);
 

src/node/health_check/package.json

@@ -1,6 +1,6 @@
 {
   "name": "grpc-health-check",
-  "version": "1.7.0-dev",
+  "version": "1.8.0-dev",
   "author": "Google Inc.",
   "description": "Health check service for use with gRPC",
   "repository": {
@@ -15,7 +15,7 @@
     }
   ],
   "dependencies": {
-    "grpc": "^1.7.0-dev",
+    "grpc": "^1.8.0-dev",
     "lodash": "^3.9.3",
     "google-protobuf": "^3.0.0"
   },

src/node/tools/package.json

@@ -1,6 +1,6 @@
 {
   "name": "grpc-tools",
-  "version": "1.7.0-dev",
+  "version": "1.8.0-dev",
   "author": "Google Inc.",
   "description": "Tools for developing with gRPC on Node.js",
   "homepage": "https://grpc.io/",

src/objective-c/!ProtoCompiler-gRPCPlugin.podspec

@@ -42,7 +42,7 @@ Pod::Spec.new do |s|
   # exclamation mark ensures that other "regular" pods will be able to find it as it'll be installed
   # before them.
   s.name     = '!ProtoCompiler-gRPCPlugin'
-  v = '1.7.0-dev'
+  v = '1.8.0-dev'
   s.version  = v
   s.summary  = 'The gRPC ProtoC plugin generates Objective-C files from .proto services.'
   s.description = <<-DESC

src/objective-c/GRPCClient/private/version.h

@@ -23,4 +23,4 @@
 // `tools/buildgen/generate_projects.sh`.
 
 
-#define GRPC_OBJC_VERSION_STRING @"1.7.0-dev"
+#define GRPC_OBJC_VERSION_STRING @"1.8.0-dev"

src/php/composer.json

@@ -2,7 +2,7 @@
   "name": "grpc/grpc-dev",
   "description": "gRPC library for PHP - for Developement use only",
   "license": "Apache-2.0",
-  "version": "1.7.0",
+  "version": "1.8.0",
   "require": {
     "php": ">=5.5.0",
     "google/protobuf": "^v3.3.0"

src/php/ext/grpc/call_credentials.c

@@ -35,6 +35,7 @@
 
 #include <grpc/grpc.h>
 #include <grpc/grpc_security.h>
+#include <grpc/support/string_util.h>
 
 zend_class_entry *grpc_ce_call_credentials;
 #if PHP_MAJOR_VERSION >= 7
@@ -143,9 +144,12 @@ PHP_METHOD(CallCredentials, createFromPlugin) {
 }
 
 /* Callback function for plugin creds API */
-void plugin_get_metadata(void *ptr, grpc_auth_metadata_context context,
-                         grpc_credentials_plugin_metadata_cb cb,
-                         void *user_data) {
+int plugin_get_metadata(
+    void *ptr, grpc_auth_metadata_context context,
+    grpc_credentials_plugin_metadata_cb cb, void *user_data,
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+    size_t *num_creds_md, grpc_status_code *status,
+    const char **error_details) {
   TSRMLS_FETCH();
 
   plugin_state *state = (plugin_state *)ptr;
@@ -175,15 +179,19 @@ void plugin_get_metadata(void *ptr, grpc_auth_metadata_context context,
   /* call the user callback function */
   zend_call_function(state->fci, state->fci_cache TSRMLS_CC);
 
-  grpc_status_code code = GRPC_STATUS_OK;
+  *num_creds_md = 0;
+  *status = GRPC_STATUS_OK;
+  *error_details = NULL;
+
   grpc_metadata_array metadata;
-  bool cleanup = true;
 
   if (retval == NULL || Z_TYPE_P(retval) != IS_ARRAY) {
-    cleanup = false;
-    code = GRPC_STATUS_INVALID_ARGUMENT;
-  } else if (!create_metadata_array(retval, &metadata)) {
-    code = GRPC_STATUS_INVALID_ARGUMENT;
+    *status = GRPC_STATUS_INVALID_ARGUMENT;
+    return true;  // Synchronous return.
+  }
+  if (!create_metadata_array(retval, &metadata)) {
+    *status = GRPC_STATUS_INVALID_ARGUMENT;
+    return true;  // Synchronous return.
   }
 
   if (retval != NULL) {
@@ -197,14 +205,24 @@ void plugin_get_metadata(void *ptr, grpc_auth_metadata_context context,
 #endif
   }
 
-  /* Pass control back to core */
-  cb(user_data, metadata.metadata, metadata.count, code, NULL);
-  if (cleanup) {
-    for (int i = 0; i < metadata.count; i++) {
+  if (metadata.count > GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX) {
+    *status = GRPC_STATUS_INTERNAL;
+    *error_details = gpr_strdup(
+        "PHP plugin credentials returned too many metadata entries");
+    for (size_t i = 0; i < metadata.count; i++) {
+      // TODO(stanleycheung): Why don't we need to unref the key here?
       grpc_slice_unref(metadata.metadata[i].value);
     }
-    grpc_metadata_array_destroy(&metadata);
+  } else {
+    // Return data to core.
+    *num_creds_md = metadata.count;
+    for (size_t i = 0; i < metadata.count; ++i) {
+      creds_md[i] = metadata.metadata[i];
+    }
   }
+
+  grpc_metadata_array_destroy(&metadata);
+  return true;  // Synchronous return.
 }
 
 /* Cleanup function for plugin creds API */

src/php/ext/grpc/call_credentials.h

@@ -65,9 +65,12 @@ typedef struct plugin_state {
 } plugin_state;
 
 /* Callback function for plugin creds API */
-void plugin_get_metadata(void *state, grpc_auth_metadata_context context,
-                         grpc_credentials_plugin_metadata_cb cb,
-                         void *user_data);
+int plugin_get_metadata(
+  void *ptr, grpc_auth_metadata_context context,
+  grpc_credentials_plugin_metadata_cb cb, void *user_data,
+  grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+  size_t *num_creds_md, grpc_status_code *status,
+  const char **error_details);
 
 /* Cleanup function for plugin creds API */
 void plugin_destroy_state(void *ptr);

src/php/ext/grpc/version.h

@@ -20,6 +20,6 @@
 #ifndef VERSION_H
 #define VERSION_H
 
-#define PHP_GRPC_VERSION "1.7.0dev"
+#define PHP_GRPC_VERSION "1.8.0dev"
 
 #endif /* VERSION_H */

src/python/grpcio/grpc/_cython/_cygrpc/credentials.pxd.pxi

@@ -41,7 +41,8 @@ cdef class CredentialsMetadataPlugin:
   cdef object plugin_callback
   cdef bytes plugin_name
 
-  cdef grpc_metadata_credentials_plugin make_c_plugin(self)
+
+cdef grpc_metadata_credentials_plugin _c_plugin(CredentialsMetadataPlugin plugin)
 
 
 cdef class AuthMetadataContext:
@@ -49,8 +50,11 @@ cdef class AuthMetadataContext:
   cdef grpc_auth_metadata_context context
 
 
-cdef void plugin_get_metadata(
+cdef int plugin_get_metadata(
     void *state, grpc_auth_metadata_context context,
-    grpc_credentials_plugin_metadata_cb cb, void *user_data) with gil
+    grpc_credentials_plugin_metadata_cb cb, void *user_data,
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+    size_t *num_creds_md, grpc_status_code *status,
+    const char **error_details) with gil
 
 cdef void plugin_destroy_c_plugin_state(void *state) with gil

src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx.pxi

@@ -14,6 +14,7 @@
 
 cimport cpython
 
+import threading
 import traceback
 
 
@@ -89,20 +90,20 @@ cdef class CredentialsMetadataPlugin:
     self.plugin_callback = plugin_callback
     self.plugin_name = name
 
-  @staticmethod
-  cdef grpc_metadata_credentials_plugin make_c_plugin(self):
-    cdef grpc_metadata_credentials_plugin result
-    result.get_metadata = plugin_get_metadata
-    result.destroy = plugin_destroy_c_plugin_state
-    result.state = <void *>self
-    result.type = self.plugin_name
-    cpython.Py_INCREF(self)
-    return result
-
   def __dealloc__(self):
     grpc_shutdown()
 
 
+cdef grpc_metadata_credentials_plugin _c_plugin(CredentialsMetadataPlugin plugin):
+  cdef grpc_metadata_credentials_plugin c_plugin
+  c_plugin.get_metadata = plugin_get_metadata
+  c_plugin.destroy = plugin_destroy_c_plugin_state
+  c_plugin.state = <void *>plugin
+  c_plugin.type = plugin.plugin_name
+  cpython.Py_INCREF(plugin)
+  return c_plugin
+
+
 cdef class AuthMetadataContext:
 
   def __cinit__(self):
@@ -122,9 +123,12 @@ cdef class AuthMetadataContext:
     grpc_shutdown()
 
 
-cdef void plugin_get_metadata(
+cdef int plugin_get_metadata(
     void *state, grpc_auth_metadata_context context,
-    grpc_credentials_plugin_metadata_cb cb, void *user_data) with gil:
+    grpc_credentials_plugin_metadata_cb cb, void *user_data,
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+    size_t *num_creds_md, grpc_status_code *status,
+    const char **error_details) with gil:
   called_flag = [False]
   def python_callback(
       Metadata metadata, grpc_status_code status,
@@ -134,12 +138,15 @@ cdef void plugin_get_metadata(
   cdef CredentialsMetadataPlugin self = <CredentialsMetadataPlugin>state
   cdef AuthMetadataContext cy_context = AuthMetadataContext()
   cy_context.context = context
-  try:
-    self.plugin_callback(cy_context, python_callback)
-  except Exception as error:
-    if not called_flag[0]:
-      cb(user_data, NULL, 0, StatusCode.unknown,
-         traceback.format_exc().encode())
+  def async_callback():
+    try:
+      self.plugin_callback(cy_context, python_callback)
+    except Exception as error:
+      if not called_flag[0]:
+        cb(user_data, NULL, 0, StatusCode.unknown,
+           traceback.format_exc().encode())
+  threading.Thread(group=None, target=async_callback).start()
+  return 0  # Asynchronous return
 
 cdef void plugin_destroy_c_plugin_state(void *state) with gil:
   cpython.Py_DECREF(<CredentialsMetadataPlugin>state)
@@ -239,7 +246,7 @@ def call_credentials_google_iam(authorization_token, authority_selector):
 
 def call_credentials_metadata_plugin(CredentialsMetadataPlugin plugin):
   cdef CallCredentials credentials = CallCredentials()
-  cdef grpc_metadata_credentials_plugin c_plugin = plugin.make_c_plugin()
+  cdef grpc_metadata_credentials_plugin c_plugin = _c_plugin(plugin)
   with nogil:
     credentials.c_credentials = (
         grpc_metadata_credentials_create_from_plugin(c_plugin, NULL))

src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxi

@@ -375,6 +375,10 @@ cdef extern from "grpc/grpc.h":
 
 cdef extern from "grpc/grpc_security.h":
 
+  # Declare this as an enum, this is the only way to make it a const in
+  # cython
+  enum: GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX
+
   ctypedef enum grpc_ssl_roots_override_result:
     GRPC_SSL_ROOTS_OVERRIDE_OK
     GRPC_SSL_ROOTS_OVERRIDE_FAILED_PERMANENTLY
@@ -462,9 +466,12 @@ cdef extern from "grpc/grpc_security.h":
       grpc_status_code status, const char *error_details)
 
   ctypedef struct grpc_metadata_credentials_plugin:
-    void (*get_metadata)(
+    int (*get_metadata)(
         void *state, grpc_auth_metadata_context context,
-        grpc_credentials_plugin_metadata_cb cb, void *user_data)
+        grpc_credentials_plugin_metadata_cb cb, void *user_data,
+        grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+        size_t *num_creds_md, grpc_status_code *status,
+        const char **error_details)
     void (*destroy)(void *state)
     void *state
     const char *type

src/python/grpcio/grpc/_cython/_cygrpc/records.pyx.pxi

@@ -171,14 +171,6 @@ cdef class Timespec:
         gpr_convert_clock_type(self.c_time, GPR_CLOCK_REALTIME))
     return <double>real_time.seconds + <double>real_time.nanoseconds / 1e9
 
-  @staticmethod
-  def infinite_future():
-    return Timespec(float("+inf"))
-
-  @staticmethod
-  def infinite_past():
-    return Timespec(float("-inf"))
-
   def __richcmp__(Timespec self not None, Timespec other not None, int op):
     cdef gpr_timespec self_c_time = self.c_time
     cdef gpr_timespec other_c_time = other.c_time
@@ -454,7 +446,7 @@ cdef class _MetadataIterator:
       self.i = self.i + 1
       return result
     else:
-      raise StopIteration
+      raise StopIteration()
 
 
 # TODO(https://github.com/grpc/grpc/issues/7950): Eliminate this; just use an
@@ -518,7 +510,7 @@ cdef class MetadataArray:
 
   def __getitem__(self, size_t i):
     if i >= self.c_metadata_array.count:
-      raise IndexError
+      raise IndexError()
     key = _slice_bytes(self.c_metadata_array.metadata[i].key)
     value = _slice_bytes(self.c_metadata_array.metadata[i].value)
     return Metadatum(key=key, value=value)
@@ -720,7 +712,7 @@ cdef class _OperationsIterator:
       self.i = self.i + 1
       return result
     else:
-      raise StopIteration
+      raise StopIteration()
 
 
 cdef class Operations:

src/python/grpcio/grpc/_grpcio_metadata.py

@@ -14,4 +14,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc/_grpcio_metadata.py.template`!!!
 
-__version__ = """1.7.0.dev0"""
+__version__ = """1.8.0.dev0"""

src/python/grpcio/grpc_core_dependencies.py

@@ -72,6 +72,8 @@ CORE_SOURCE_FILES = [
   'src/core/lib/compression/compression.c',
   'src/core/lib/compression/message_compress.c',
   'src/core/lib/compression/stream_compression.c',
+  'src/core/lib/compression/stream_compression_gzip.c',
+  'src/core/lib/compression/stream_compression_identity.c',
   'src/core/lib/debug/stats.c',
   'src/core/lib/debug/stats_data.c',
   'src/core/lib/http/format_request.c',

src/python/grpcio/grpc_version.py

@@ -14,4 +14,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc_version.py.template`!!!
 
-VERSION='1.7.0.dev0'
+VERSION='1.8.0.dev0'

src/python/grpcio/support.py

@@ -94,7 +94,7 @@ def diagnose_attribute_error(build_ext, error):
 
 _ERROR_DIAGNOSES = {
     errors.CompileError: diagnose_compile_error,
-    AttributeError: diagnose_attribute_error
+    AttributeError: diagnose_attribute_error,
 }
 
 
@@ -102,8 +102,10 @@ def diagnose_build_ext_error(build_ext, error, formatted):
     diagnostic = _ERROR_DIAGNOSES.get(type(error))
     if diagnostic is None:
         raise commands.CommandError(
-            "\n\nWe could not diagnose your build failure. Please file an issue at "
-            "http://www.github.com/grpc/grpc with `[Python install]` in the title."
-            "\n\n{}".format(formatted))
+            "\n\nWe could not diagnose your build failure. If you are unable to "
+            "proceed, please file an issue at http://www.github.com/grpc/grpc "
+            "with `[Python install]` in the title; please attach the whole log "
+            "(including everything that may have appeared above the Python "
+            "backtrace).\n\n{}".format(formatted))
     else:
         diagnostic(build_ext, error)

src/python/grpcio_health_checking/grpc_version.py

@@ -14,4 +14,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio_health_checking/grpc_version.py.template`!!!
 
-VERSION='1.7.0.dev0'
+VERSION='1.8.0.dev0'

src/python/grpcio_reflection/grpc_version.py

@@ -14,4 +14,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio_reflection/grpc_version.py.template`!!!
 
-VERSION='1.7.0.dev0'
+VERSION='1.8.0.dev0'

src/python/grpcio_testing/grpc_version.py

@@ -14,4 +14,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio_testing/grpc_version.py.template`!!!
 
-VERSION='1.7.0.dev0'
+VERSION='1.8.0.dev0'

src/python/grpcio_tests/grpc_version.py

@@ -14,4 +14,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio_tests/grpc_version.py.template`!!!
 
-VERSION='1.7.0.dev0'
+VERSION='1.8.0.dev0'

src/python/grpcio_tests/tests/unit/_metadata_code_details_test.py

@@ -29,7 +29,7 @@ _SERIALIZED_RESPONSE = b'\x49\x50\x51'
 _REQUEST_SERIALIZER = lambda unused_request: _SERIALIZED_REQUEST
 _REQUEST_DESERIALIZER = lambda unused_serialized_request: object()
 _RESPONSE_SERIALIZER = lambda unused_response: _SERIALIZED_RESPONSE
-_RESPONSE_DESERIALIZER = lambda unused_serialized_resopnse: object()
+_RESPONSE_DESERIALIZER = lambda unused_serialized_response: object()
 
 _SERVICE = 'test.TestService'
 _UNARY_UNARY = 'UnaryUnary'

src/ruby/end2end/killed_client_thread_client.rb

@@ -35,7 +35,7 @@ def main
                                       :this_channel_is_insecure)
     stub.echo(Echo::EchoRequest.new(request: 'hello'))
     fail 'the clients rpc in this test shouldnt complete. ' \
-      'expecting SIGINT to happen in the middle of the call'
+      'expecting SIGTERM to happen in the middle of the call'
   end
   thd.join
 end

src/ruby/end2end/killed_client_thread_driver.rb

@@ -69,9 +69,9 @@ def main
     call_started_cv.wait(call_started_mu) until call_started.val
   end
 
-  # SIGINT the child process now that it's
+  # SIGTERM the child process now that it's
   # in the middle of an RPC (happening on a non-main thread)
-  Process.kill('SIGINT', client_pid)
+  Process.kill('SIGTERM', client_pid)
   STDERR.puts 'sent shutdown'
 
   begin
@@ -88,8 +88,8 @@ def main
   end
 
   client_exit_code = $CHILD_STATUS
-  if client_exit_code.termsig != 2 # SIGINT
-    fail 'expected client exit from SIGINT ' \
+  if client_exit_code.termsig != 15 # SIGTERM
+    fail 'expected client exit from SIGTERM ' \
       "but got child status: #{client_exit_code}"
   end
 

src/ruby/ext/grpc/rb_call_credentials.c

@@ -112,9 +112,12 @@ static void grpc_rb_call_credentials_callback_with_gil(void *param) {
   gpr_free(params);
 }
 
-static void grpc_rb_call_credentials_plugin_get_metadata(
+static int grpc_rb_call_credentials_plugin_get_metadata(
     void *state, grpc_auth_metadata_context context,
-    grpc_credentials_plugin_metadata_cb cb, void *user_data) {
+    grpc_credentials_plugin_metadata_cb cb, void *user_data,
+    grpc_metadata creds_md[GRPC_METADATA_CREDENTIALS_PLUGIN_SYNC_MAX],
+    size_t *num_creds_md, grpc_status_code *status,
+    const char **error_details) {
   callback_params *params = gpr_malloc(sizeof(callback_params));
   params->get_metadata = (VALUE)state;
   params->context = context;
@@ -123,6 +126,7 @@ static void grpc_rb_call_credentials_plugin_get_metadata(
 
   grpc_rb_event_queue_enqueue(grpc_rb_call_credentials_callback_with_gil,
                               (void *)(params));
+  return 0;  // Async return.
 }
 
 static void grpc_rb_call_credentials_plugin_destroy(void *state) {

src/ruby/lib/grpc.rb

@@ -24,6 +24,7 @@ require_relative 'grpc/generic/active_call'
 require_relative 'grpc/generic/client_stub'
 require_relative 'grpc/generic/service'
 require_relative 'grpc/generic/rpc_server'
+require_relative 'grpc/generic/interceptors'
 
 begin
   file = File.open(ssl_roots_path)

src/ruby/lib/grpc/generic/active_call.rb

@@ -154,6 +154,15 @@ module GRPC
       Operation.new(self)
     end
 
+    ##
+    # Returns a restricted view of this ActiveCall for use in interceptors
+    #
+    # @return [InterceptableView]
+    #
+    def interceptable
+      InterceptableView.new(self)
+    end
+
     def receive_and_check_status
       batch_result = @call.run_batch(RECV_STATUS_ON_CLIENT => nil)
       set_input_stream_done
@@ -515,15 +524,27 @@ module GRPC
     # This does not mean that must necessarily be one.  E.g, the replies
     # produced by gen_each_reply could ignore the received_msgs
     #
-    # @param gen_each_reply [Proc] generates the BiDi stream replies
-    def run_server_bidi(gen_each_reply)
-      bd = BidiCall.new(@call,
-                        @marshal,
-                        @unmarshal,
-                        metadata_received: @metadata_received,
-                        req_view: MultiReqView.new(self))
-
-      bd.run_on_server(gen_each_reply, proc { set_input_stream_done })
+    # @param mth [Proc] generates the BiDi stream replies
+    # @param interception_ctx [InterceptionContext]
+    #
+    def run_server_bidi(mth, interception_ctx)
+      view = multi_req_view
+      bidi_call = BidiCall.new(
+        @call,
+        @marshal,
+        @unmarshal,
+        metadata_received: @metadata_received,
+        req_view: view
+      )
+      requests = bidi_call.read_next_loop(proc { set_input_stream_done }, false)
+      interception_ctx.intercept!(
+        :bidi_streamer,
+        call: view,
+        method: mth,
+        requests: requests
+      ) do
+        bidi_call.run_on_server(mth, requests)
+      end
     end
 
     # Waits till an operation completes
@@ -645,5 +666,9 @@ module GRPC
     Operation = view_class(:cancel, :cancelled?, :deadline, :execute,
                            :metadata, :status, :start_call, :wait, :write_flag,
                            :write_flag=, :trailing_metadata)
+
+    # InterceptableView further limits access to an ActiveCall's methods
+    # for use in interceptors on the client, exposing only the deadline
+    InterceptableView = view_class(:deadline)
   end
 end

src/ruby/lib/grpc/generic/bidi_call.rb

@@ -87,23 +87,32 @@ module GRPC
     # This does not mean that must necessarily be one.  E.g, the replies
     # produced by gen_each_reply could ignore the received_msgs
     #
-    # @param gen_each_reply [Proc] generates the BiDi stream replies.
-    # @param set_input_steam_done [Proc] call back to call when
-    #   the reads have been completely read through.
-    def run_on_server(gen_each_reply, set_input_stream_done)
+    # @param [Proc] gen_each_reply generates the BiDi stream replies.
+    # @param [Enumerable] requests The enumerable of requests to run
+    def run_on_server(gen_each_reply, requests)
+      replies = nil
+
       # Pass in the optional call object parameter if possible
       if gen_each_reply.arity == 1
-        replys = gen_each_reply.call(
-          read_loop(set_input_stream_done, is_client: false))
+        replies = gen_each_reply.call(requests)
       elsif gen_each_reply.arity == 2
-        replys = gen_each_reply.call(
-          read_loop(set_input_stream_done, is_client: false),
-          @req_view)
+        replies = gen_each_reply.call(requests, @req_view)
       else
         fail 'Illegal arity of reply generator'
       end
 
-      write_loop(replys, is_client: false)
+      write_loop(replies, is_client: false)
+    end
+
+    ##
+    # Read the next stream iteration
+    #
+    # @param [Proc] finalize_stream callback to call when the reads have been
+    #   completely read through.
+    # @param [Boolean] is_client If this is a client or server request
+    #
+    def read_next_loop(finalize_stream, is_client = false)
+      read_loop(finalize_stream, is_client: is_client)
     end
 
     private

src/ruby/lib/grpc/generic/client_stub.rb

@@ -89,17 +89,23 @@ module GRPC
     #     used within a gRPC server.
     # @param channel_args [Hash] the channel arguments. Note: this argument is
     #     ignored if the channel_override argument is provided.
+    # @param interceptors [Array<GRPC::ClientInterceptor>] An array of
+    #     GRPC::ClientInterceptor objects that will be used for
+    #     intercepting calls before they are executed
+    #     Interceptors are an EXPERIMENTAL API.
     def initialize(host, creds,
                    channel_override: nil,
                    timeout: nil,
                    propagate_mask: nil,
-                   channel_args: {})
+                   channel_args: {},
+                   interceptors: [])
       @ch = ClientStub.setup_channel(channel_override, host, creds,
                                      channel_args)
       alt_host = channel_args[Core::Channel::SSL_TARGET]
       @host = alt_host.nil? ? host : alt_host
       @propagate_mask = propagate_mask
       @timeout = timeout.nil? ? DEFAULT_TIMEOUT : timeout
+      @interceptors = InterceptorRegistry.new(interceptors)
     end
 
     # request_response sends a request to a GRPC server, and returns the
@@ -149,16 +155,29 @@ module GRPC
                           deadline: deadline,
                           parent: parent,
                           credentials: credentials)
-      return c.request_response(req, metadata: metadata) unless return_op
-
-      # return the operation view of the active_call; define #execute as a
-      # new method for this instance that invokes #request_response.
-      c.merge_metadata_to_send(metadata)
-      op = c.operation
-      op.define_singleton_method(:execute) do
-        c.request_response(req, metadata: metadata)
+      interception_context = @interceptors.build_context
+      intercept_args = {
+        method: method,
+        request: req,
+        call: c.interceptable,
+        metadata: metadata
+      }
+      if return_op
+        # return the operation view of the active_call; define #execute as a
+        # new method for this instance that invokes #request_response.
+        c.merge_metadata_to_send(metadata)
+        op = c.operation
+        op.define_singleton_method(:execute) do
+          interception_context.intercept!(:request_response, intercept_args) do
+            c.request_response(req, metadata: metadata)
+          end
+        end
+        op
+      else
+        interception_context.intercept!(:request_response, intercept_args) do
+          c.request_response(req, metadata: metadata)
+        end
       end
-      op
     end
 
     # client_streamer sends a stream of requests to a GRPC server, and
@@ -213,16 +232,29 @@ module GRPC
                           deadline: deadline,
                           parent: parent,
                           credentials: credentials)
-      return c.client_streamer(requests, metadata: metadata) unless return_op
-
-      # return the operation view of the active_call; define #execute as a
-      # new method for this instance that invokes #client_streamer.
-      c.merge_metadata_to_send(metadata)
-      op = c.operation
-      op.define_singleton_method(:execute) do
-        c.client_streamer(requests)
+      interception_context = @interceptors.build_context
+      intercept_args = {
+        method: method,
+        requests: requests,
+        call: c.interceptable,
+        metadata: metadata
+      }
+      if return_op
+        # return the operation view of the active_call; define #execute as a
+        # new method for this instance that invokes #client_streamer.
+        c.merge_metadata_to_send(metadata)
+        op = c.operation
+        op.define_singleton_method(:execute) do
+          interception_context.intercept!(:client_streamer, intercept_args) do
+            c.client_streamer(requests)
+          end
+        end
+        op
+      else
+        interception_context.intercept!(:client_streamer, intercept_args) do
+          c.client_streamer(requests, metadata: metadata)
+        end
       end
-      op
     end
 
     # server_streamer sends one request to the GRPC server, which yields a
@@ -292,16 +324,29 @@ module GRPC
                           deadline: deadline,
                           parent: parent,
                           credentials: credentials)
-      return c.server_streamer(req, metadata: metadata, &blk) unless return_op
-
-      # return the operation view of the active_call; define #execute
-      # as a new method for this instance that invokes #server_streamer
-      c.merge_metadata_to_send(metadata)
-      op = c.operation
-      op.define_singleton_method(:execute) do
-        c.server_streamer(req, &blk)
+      interception_context = @interceptors.build_context
+      intercept_args = {
+        method: method,
+        request: req,
+        call: c.interceptable,
+        metadata: metadata
+      }
+      if return_op
+        # return the operation view of the active_call; define #execute
+        # as a new method for this instance that invokes #server_streamer
+        c.merge_metadata_to_send(metadata)
+        op = c.operation
+        op.define_singleton_method(:execute) do
+          interception_context.intercept!(:server_streamer, intercept_args) do
+            c.server_streamer(req, &blk)
+          end
+        end
+        op
+      else
+        interception_context.intercept!(:server_streamer, intercept_args) do
+          c.server_streamer(req, metadata: metadata, &blk)
+        end
       end
-      op
     end
 
     # bidi_streamer sends a stream of requests to the GRPC server, and yields
@@ -405,17 +450,29 @@ module GRPC
                           deadline: deadline,
                           parent: parent,
                           credentials: credentials)
-      return c.bidi_streamer(requests, metadata: metadata,
-                             &blk) unless return_op
-
-      # return the operation view of the active_call; define #execute
-      # as a new method for this instance that invokes #bidi_streamer
-      c.merge_metadata_to_send(metadata)
-      op = c.operation
-      op.define_singleton_method(:execute) do
-        c.bidi_streamer(requests, &blk)
+      interception_context = @interceptors.build_context
+      intercept_args = {
+        method: method,
+        requests: requests,
+        call: c.interceptable,
+        metadata: metadata
+      }
+      if return_op
+        # return the operation view of the active_call; define #execute
+        # as a new method for this instance that invokes #bidi_streamer
+        c.merge_metadata_to_send(metadata)
+        op = c.operation
+        op.define_singleton_method(:execute) do
+          interception_context.intercept!(:bidi_streamer, intercept_args) do
+            c.bidi_streamer(requests, &blk)
+          end
+        end
+        op
+      else
+        interception_context.intercept!(:bidi_streamer, intercept_args) do
+          c.bidi_streamer(requests, metadata: metadata, &blk)
+        end
       end
-      op
     end
 
     private