Add tests for c-ares wrapper using a local DNS server.

CMakeLists.txt

@@ -760,6 +760,18 @@ add_dependencies(buildtests_cxx thread_stress_test)
 if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
 add_dependencies(buildtests_cxx writes_per_rpc_test)
 endif()
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+add_dependencies(buildtests_cxx resolver_component_test_unsecure)
+endif()
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+add_dependencies(buildtests_cxx resolver_component_test)
+endif()
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+add_dependencies(buildtests_cxx resolver_component_tests_runner_invoker_unsecure)
+endif()
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+add_dependencies(buildtests_cxx resolver_component_tests_runner_invoker)
+endif()
 
 add_custom_target(buildtests
   DEPENDS buildtests_c buildtests_cxx)
@@ -14113,6 +14125,178 @@ target_link_libraries(inproc_nosec_test
   gpr
 )
 
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+
+add_executable(resolver_component_test_unsecure
+  test/cpp/naming/resolver_component_test.cc
+  third_party/googletest/googletest/src/gtest-all.cc
+  third_party/googletest/googlemock/src/gmock-all.cc
+)
+
+
+target_include_directories(resolver_component_test_unsecure
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${BORINGSSL_ROOT_DIR}/include
+  PRIVATE ${PROTOBUF_ROOT_DIR}/src
+  PRIVATE ${BENCHMARK_ROOT_DIR}/include
+  PRIVATE ${ZLIB_ROOT_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib
+  PRIVATE ${CARES_INCLUDE_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/cares/cares
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+  PRIVATE third_party/googletest/googletest/include
+  PRIVATE third_party/googletest/googletest
+  PRIVATE third_party/googletest/googlemock/include
+  PRIVATE third_party/googletest/googlemock
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(resolver_component_test_unsecure
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc++_test_util_unsecure
+  grpc_test_util_unsecure
+  gpr_test_util
+  grpc++_unsecure
+  grpc_unsecure
+  gpr
+  grpc++_test_config
+  ${_gRPC_GFLAGS_LIBRARIES}
+)
+
+endif()
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+
+add_executable(resolver_component_test
+  test/cpp/naming/resolver_component_test.cc
+  third_party/googletest/googletest/src/gtest-all.cc
+  third_party/googletest/googlemock/src/gmock-all.cc
+)
+
+
+target_include_directories(resolver_component_test
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${BORINGSSL_ROOT_DIR}/include
+  PRIVATE ${PROTOBUF_ROOT_DIR}/src
+  PRIVATE ${BENCHMARK_ROOT_DIR}/include
+  PRIVATE ${ZLIB_ROOT_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib
+  PRIVATE ${CARES_INCLUDE_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/cares/cares
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+  PRIVATE third_party/googletest/googletest/include
+  PRIVATE third_party/googletest/googletest
+  PRIVATE third_party/googletest/googlemock/include
+  PRIVATE third_party/googletest/googlemock
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(resolver_component_test
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc++_test_util
+  grpc_test_util
+  gpr_test_util
+  grpc++
+  grpc
+  gpr
+  grpc++_test_config
+  ${_gRPC_GFLAGS_LIBRARIES}
+)
+
+endif()
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+
+add_executable(resolver_component_tests_runner_invoker_unsecure
+  test/cpp/naming/resolver_component_tests_runner_invoker.cc
+  third_party/googletest/googletest/src/gtest-all.cc
+  third_party/googletest/googlemock/src/gmock-all.cc
+)
+
+
+target_include_directories(resolver_component_tests_runner_invoker_unsecure
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${BORINGSSL_ROOT_DIR}/include
+  PRIVATE ${PROTOBUF_ROOT_DIR}/src
+  PRIVATE ${BENCHMARK_ROOT_DIR}/include
+  PRIVATE ${ZLIB_ROOT_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib
+  PRIVATE ${CARES_INCLUDE_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/cares/cares
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+  PRIVATE third_party/googletest/googletest/include
+  PRIVATE third_party/googletest/googletest
+  PRIVATE third_party/googletest/googlemock/include
+  PRIVATE third_party/googletest/googlemock
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(resolver_component_tests_runner_invoker_unsecure
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc++_test_util
+  grpc_test_util
+  gpr_test_util
+  grpc++
+  grpc
+  gpr
+  grpc++_test_config
+  ${_gRPC_GFLAGS_LIBRARIES}
+)
+
+endif()
+endif (gRPC_BUILD_TESTS)
+if (gRPC_BUILD_TESTS)
+if(_gRPC_PLATFORM_LINUX OR _gRPC_PLATFORM_MAC OR _gRPC_PLATFORM_POSIX)
+
+add_executable(resolver_component_tests_runner_invoker
+  test/cpp/naming/resolver_component_tests_runner_invoker.cc
+  third_party/googletest/googletest/src/gtest-all.cc
+  third_party/googletest/googlemock/src/gmock-all.cc
+)
+
+
+target_include_directories(resolver_component_tests_runner_invoker
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}
+  PRIVATE ${CMAKE_CURRENT_SOURCE_DIR}/include
+  PRIVATE ${BORINGSSL_ROOT_DIR}/include
+  PRIVATE ${PROTOBUF_ROOT_DIR}/src
+  PRIVATE ${BENCHMARK_ROOT_DIR}/include
+  PRIVATE ${ZLIB_ROOT_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/zlib
+  PRIVATE ${CARES_INCLUDE_DIR}
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/cares/cares
+  PRIVATE ${CMAKE_CURRENT_BINARY_DIR}/third_party/gflags/include
+  PRIVATE third_party/googletest/googletest/include
+  PRIVATE third_party/googletest/googletest
+  PRIVATE third_party/googletest/googlemock/include
+  PRIVATE third_party/googletest/googlemock
+  PRIVATE ${_gRPC_PROTO_GENS_DIR}
+)
+
+target_link_libraries(resolver_component_tests_runner_invoker
+  ${_gRPC_PROTOBUF_LIBRARIES}
+  ${_gRPC_ALLTARGETS_LIBRARIES}
+  grpc++_test_util
+  grpc_test_util
+  gpr_test_util
+  grpc++
+  grpc
+  gpr
+  grpc++_test_config
+  ${_gRPC_GFLAGS_LIBRARIES}
+)
+
+endif()
 endif (gRPC_BUILD_TESTS)
 if (gRPC_BUILD_TESTS)
 

Makefile

@@ -1266,6 +1266,10 @@ h2_sockpair+trace_nosec_test: $(BINDIR)/$(CONFIG)/h2_sockpair+trace_nosec_test
 h2_sockpair_1byte_nosec_test: $(BINDIR)/$(CONFIG)/h2_sockpair_1byte_nosec_test
 h2_uds_nosec_test: $(BINDIR)/$(CONFIG)/h2_uds_nosec_test
 inproc_nosec_test: $(BINDIR)/$(CONFIG)/inproc_nosec_test
+resolver_component_test_unsecure: $(BINDIR)/$(CONFIG)/resolver_component_test_unsecure
+resolver_component_test: $(BINDIR)/$(CONFIG)/resolver_component_test
+resolver_component_tests_runner_invoker_unsecure: $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker_unsecure
+resolver_component_tests_runner_invoker: $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker
 api_fuzzer_one_entry: $(BINDIR)/$(CONFIG)/api_fuzzer_one_entry
 client_fuzzer_one_entry: $(BINDIR)/$(CONFIG)/client_fuzzer_one_entry
 hpack_parser_fuzzer_test_one_entry: $(BINDIR)/$(CONFIG)/hpack_parser_fuzzer_test_one_entry
@@ -1652,6 +1656,10 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/boringssl_x509_test \
   $(BINDIR)/$(CONFIG)/boringssl_tab_test \
   $(BINDIR)/$(CONFIG)/boringssl_v3name_test \
+  $(BINDIR)/$(CONFIG)/resolver_component_test_unsecure \
+  $(BINDIR)/$(CONFIG)/resolver_component_test \
+  $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker_unsecure \
+  $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker \
 
 else
 buildtests_cxx: privatelibs_cxx \
@@ -1730,6 +1738,10 @@ buildtests_cxx: privatelibs_cxx \
   $(BINDIR)/$(CONFIG)/thread_manager_test \
   $(BINDIR)/$(CONFIG)/thread_stress_test \
   $(BINDIR)/$(CONFIG)/writes_per_rpc_test \
+  $(BINDIR)/$(CONFIG)/resolver_component_test_unsecure \
+  $(BINDIR)/$(CONFIG)/resolver_component_test \
+  $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker_unsecure \
+  $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker \
 
 endif
 
@@ -2141,6 +2153,10 @@ test_cxx: buildtests_cxx
 	$(Q) $(BINDIR)/$(CONFIG)/thread_stress_test || ( echo test thread_stress_test failed ; exit 1 )
 	$(E) "[RUN]     Testing writes_per_rpc_test"
 	$(Q) $(BINDIR)/$(CONFIG)/writes_per_rpc_test || ( echo test writes_per_rpc_test failed ; exit 1 )
+	$(E) "[RUN]     Testing resolver_component_tests_runner_invoker_unsecure"
+	$(Q) $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker_unsecure || ( echo test resolver_component_tests_runner_invoker_unsecure failed ; exit 1 )
+	$(E) "[RUN]     Testing resolver_component_tests_runner_invoker"
+	$(Q) $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker || ( echo test resolver_component_tests_runner_invoker failed ; exit 1 )
 
 
 flaky_test_cxx: buildtests_cxx
@@ -19480,6 +19496,178 @@ ifneq ($(NO_DEPS),true)
 endif
 
 
+RESOLVER_COMPONENT_TEST_UNSECURE_SRC = \
+    test/cpp/naming/resolver_component_test.cc \
+
+RESOLVER_COMPONENT_TEST_UNSECURE_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(RESOLVER_COMPONENT_TEST_UNSECURE_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/resolver_component_test_unsecure: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/resolver_component_test_unsecure: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/resolver_component_test_unsecure: $(PROTOBUF_DEP) $(RESOLVER_COMPONENT_TEST_UNSECURE_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util_unsecure.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util_unsecure.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a $(LIBDIR)/$(CONFIG)/libgrpc_unsecure.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(RESOLVER_COMPONENT_TEST_UNSECURE_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util_unsecure.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util_unsecure.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a $(LIBDIR)/$(CONFIG)/libgrpc_unsecure.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/resolver_component_test_unsecure
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/naming/resolver_component_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util_unsecure.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util_unsecure.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++_unsecure.a $(LIBDIR)/$(CONFIG)/libgrpc_unsecure.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+
+deps_resolver_component_test_unsecure: $(RESOLVER_COMPONENT_TEST_UNSECURE_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(RESOLVER_COMPONENT_TEST_UNSECURE_OBJS:.o=.dep)
+endif
+endif
+
+
+RESOLVER_COMPONENT_TEST_SRC = \
+    test/cpp/naming/resolver_component_test.cc \
+
+RESOLVER_COMPONENT_TEST_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(RESOLVER_COMPONENT_TEST_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/resolver_component_test: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/resolver_component_test: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/resolver_component_test: $(PROTOBUF_DEP) $(RESOLVER_COMPONENT_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(RESOLVER_COMPONENT_TEST_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/resolver_component_test
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/naming/resolver_component_test.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+
+deps_resolver_component_test: $(RESOLVER_COMPONENT_TEST_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(RESOLVER_COMPONENT_TEST_OBJS:.o=.dep)
+endif
+endif
+
+
+RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_UNSECURE_SRC = \
+    test/cpp/naming/resolver_component_tests_runner_invoker.cc \
+
+RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_UNSECURE_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_UNSECURE_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker_unsecure: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker_unsecure: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker_unsecure: $(PROTOBUF_DEP) $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_UNSECURE_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_UNSECURE_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker_unsecure
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/naming/resolver_component_tests_runner_invoker.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+
+deps_resolver_component_tests_runner_invoker_unsecure: $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_UNSECURE_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_UNSECURE_OBJS:.o=.dep)
+endif
+endif
+
+
+RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_SRC = \
+    test/cpp/naming/resolver_component_tests_runner_invoker.cc \
+
+RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_OBJS = $(addprefix $(OBJDIR)/$(CONFIG)/, $(addsuffix .o, $(basename $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_SRC))))
+ifeq ($(NO_SECURE),true)
+
+# You can't build secure targets if you don't have OpenSSL.
+
+$(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker: openssl_dep_error
+
+else
+
+
+
+
+ifeq ($(NO_PROTOBUF),true)
+
+# You can't build the protoc plugins or protobuf-enabled targets if you don't have protobuf 3.0.0+.
+
+$(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker: protobuf_dep_error
+
+else
+
+$(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker: $(PROTOBUF_DEP) $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+	$(E) "[LD]      Linking $@"
+	$(Q) mkdir -p `dirname $@`
+	$(Q) $(LDXX) $(LDFLAGS) $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_OBJS) $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a $(LDLIBSXX) $(LDLIBS_PROTOBUF) $(LDLIBS) $(LDLIBS_SECURE) $(GTEST_LIB) -o $(BINDIR)/$(CONFIG)/resolver_component_tests_runner_invoker
+
+endif
+
+endif
+
+$(OBJDIR)/$(CONFIG)/test/cpp/naming/resolver_component_tests_runner_invoker.o:  $(LIBDIR)/$(CONFIG)/libgrpc++_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc_test_util.a $(LIBDIR)/$(CONFIG)/libgpr_test_util.a $(LIBDIR)/$(CONFIG)/libgrpc++.a $(LIBDIR)/$(CONFIG)/libgrpc.a $(LIBDIR)/$(CONFIG)/libgpr.a $(LIBDIR)/$(CONFIG)/libgrpc++_test_config.a
+
+deps_resolver_component_tests_runner_invoker: $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_OBJS:.o=.dep)
+
+ifneq ($(NO_SECURE),true)
+ifneq ($(NO_DEPS),true)
+-include $(RESOLVER_COMPONENT_TESTS_RUNNER_INVOKER_OBJS:.o=.dep)
+endif
+endif
+
+
 API_FUZZER_ONE_ENTRY_SRC = \
     test/core/end2end/fuzzers/api_fuzzer.c \
     test/core/util/one_corpus_entry_fuzzer.c \

bazel/grpc_build_system.bzl

@@ -106,6 +106,22 @@ def grpc_sh_test(name, srcs, args = [], data = []):
     args = args,
     data = data)
 
+def grpc_sh_binary(name, srcs, data = []):
+  native.sh_test(
+    name = name,
+    srcs = srcs,
+    data = data)
+
+def grpc_py_binary(name, srcs, data = [], deps = []):
+  if name == "test_dns_server":
+    # TODO: allow running test_dns_server in oss bazel test suite
+    deps = []
+  native.py_binary(
+    name = name,
+    srcs = srcs,
+    data = data,
+    deps = deps)
+
 def grpc_package(name, visibility = "private", features = []):
   if visibility == "tests":
     visibility = ["//test:__subpackages__"]

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

@@ -204,7 +204,7 @@ static char *choose_service_config(char *service_config_choice_json) {
         int random_pct = rand() % 100;
         int percentage;
         if (sscanf(field->value, "%d", &percentage) != 1 ||
-            random_pct > percentage) {
+            random_pct > percentage || percentage == 0) {
           service_config_json = NULL;
           break;
         }

templates/test/cpp/naming/resolver_component_tests_defs.include

@@ -0,0 +1,92 @@
+<%def name="resolver_component_tests(tests)">#!/bin/bash
+# Copyright 2015 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.
+
+# This file is auto-generated
+
+set -ex
+
+# all command args required in this set order
+FLAGS_test_bin_path=`echo "$1" | grep '\--test_bin_path=' | cut -d "=" -f 2`
+FLAGS_dns_server_bin_path=`echo "$2" | grep '\--dns_server_bin_path=' | cut -d "=" -f 2`
+FLAGS_records_config_path=`echo "$3" | grep '\--records_config_path=' | cut -d "=" -f 2`
+FLAGS_test_dns_server_port=`echo "$4" | grep '\--test_dns_server_port=' | cut -d "=" -f 2`
+
+for cmd_arg in "$FLAGS_test_bin_path" "$FLAGS_dns_server_bin_path" "$FLAGS_records_config_path" "$FLAGS_test_dns_server_port"; do
+  if [[ "$cmd_arg" == "" ]]; then
+    echo "Missing a CMD arg" && exit 1
+  fi
+done
+
+if [[ "$GRPC_DNS_RESOLVER" != "" && "$GRPC_DNS_RESOLVER" != ares ]]; then
+  echo "This test only works under GRPC_DNS_RESOLVER=ares. Have GRPC_DNS_RESOLVER=$GRPC_DNS_RESOLVER" && exit 1
+fi
+export GRPC_DNS_RESOLVER=ares
+
+"$FLAGS_dns_server_bin_path" --records_config_path="$FLAGS_records_config_path" --port="$FLAGS_test_dns_server_port" 2>&1 > /dev/null &
+DNS_SERVER_PID=$!
+echo "Local DNS server started. PID: $DNS_SERVER_PID"
+
+# Health check local DNS server TCP and UDP ports
+for ((i=0;i<30;i++));
+do
+  echo "Retry health-check DNS query to local DNS server over tcp and udp"
+  RETRY=0
+  dig A health-check-local-dns-server-is-alive.resolver-tests.grpctestingexp. @localhost -p "$FLAGS_test_dns_server_port" +tries=1 +timeout=1 | grep '123.123.123.123' || RETRY=1
+  dig A health-check-local-dns-server-is-alive.resolver-tests.grpctestingexp. @localhost -p "$FLAGS_test_dns_server_port" +tries=1 +timeout=1 +tcp | grep '123.123.123.123' || RETRY=1
+  if [[ "$RETRY" == 0 ]]; then
+    break
+  fi;
+  sleep 0.1
+done
+
+if [[ $RETRY == 1 ]]; then
+  echo "FAILED TO START LOCAL DNS SERVER"
+  kill -SIGTERM $DNS_SERVER_PID
+  wait
+  exit 1
+fi
+
+function terminate_all {
+  echo "Received signal. Terminating $! and $DNS_SERVER_PID"
+  kill -SIGTERM $! || true
+  kill -SIGTERM $DNS_SERVER_PID || true
+  wait
+  exit 1
+}
+
+trap terminate_all SIGTERM SIGINT
+
+EXIT_CODE=0
+# TODO: this test should check for GCE residency and skip tests using _grpclb._tcp.* SRV records once GCE residency checks are made
+# in the resolver.
+
+% for test in tests:
+$FLAGS_test_bin_path \\
+
+  --target_name='${test['target_name']}' \\
+
+  --expected_addrs='${test['expected_addrs']}' \\
+
+  --expected_chosen_service_config='${test['expected_chosen_service_config']}' \\
+
+  --expected_lb_policy='${test['expected_lb_policy']}' \\
+
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+% endfor
+kill -SIGTERM $DNS_SERVER_PID || true
+wait
+exit $EXIT_CODE</%def>

templates/test/cpp/naming/resolver_component_tests_runner.sh.template

@@ -0,0 +1,4 @@
+%YAML 1.2
+--- |
+  <%namespace file="resolver_component_tests_defs.include" import="*"/>\
+  ${resolver_component_tests(resolver_component_test_cases)}

templates/tools/dockerfile/apt_get_basic.include

@@ -6,6 +6,7 @@ RUN apt-get update && apt-get install -y ${'\\'}
   bzip2 ${'\\'}
   ccache ${'\\'}
   curl ${'\\'}
+  dnsutils ${'\\'}
   gcc ${'\\'}
   gcc-multilib ${'\\'}
   git ${'\\'}

templates/tools/dockerfile/python_deps.include

@@ -11,4 +11,4 @@ RUN apt-get update && apt-get install -y ${'\\'}
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0

test/cpp/naming/BUILD

@@ -0,0 +1,49 @@
+# 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.
+
+package(
+    default_visibility = ["//visibility:public"],
+    features = [
+        "-layering_check",
+        "-parse_headers",
+    ],
+)
+
+licenses(["notice"])  # Apache v2
+
+load("//bazel:grpc_build_system.bzl", "grpc_sh_binary", "grpc_py_binary")
+
+load(":generate_resolver_component_tests.bzl", "generate_resolver_component_tests")
+
+# Meant to be invoked only through the top-level shell script driver.
+grpc_sh_binary(
+    name = "resolver_component_tests_runner",
+    srcs = [
+        "resolver_component_tests_runner.sh",
+    ],
+)
+
+grpc_py_binary(
+  name = "test_dns_server",
+  srcs = ["test_dns_server.py"],
+  data = [
+      "resolver_test_record_groups.yaml",
+  ],
+  deps = [
+      "twisted",
+      "yaml",
+  ]
+)
+
+generate_resolver_component_tests()

test/cpp/naming/gen_build_yaml.py

@@ -0,0 +1,99 @@
+#!/usr/bin/env python2.7
+# Copyright 2015 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.
+
+
+"""Generates the appropriate build.json data for all the naming tests."""
+
+
+import yaml
+import collections
+import hashlib
+import json
+
+_LOCAL_DNS_SERVER_ADDRESS = '127.0.0.1:15353'
+
+def _append_zone_name(name, zone_name):
+  return '%s.%s' % (name, zone_name)
+
+def _build_expected_addrs_cmd_arg(expected_addrs):
+  out = []
+  for addr in expected_addrs:
+    out.append('%s,%s' % (addr['address'], str(addr['is_balancer'])))
+  return ';'.join(out)
+
+def main():
+  resolver_component_data = ''
+  with open('test/cpp/naming/resolver_test_record_groups.yaml') as f:
+    resolver_component_data = yaml.load(f)
+
+  json = {
+      'resolver_component_test_cases': [
+          {
+              'target_name': _append_zone_name(test_case['record_to_resolve'],
+                                                 resolver_component_data['resolver_component_tests_common_zone_name']),
+              'expected_addrs': _build_expected_addrs_cmd_arg(test_case['expected_addrs']),
+              'expected_chosen_service_config': (test_case['expected_chosen_service_config'] or ''),
+              'expected_lb_policy': (test_case['expected_lb_policy'] or ''),
+          } for test_case in resolver_component_data['resolver_component_tests']
+      ],
+      'targets': [
+          {
+              'name': 'resolver_component_test' + unsecure_build_config_suffix,
+              'build': 'test',
+              'language': 'c++',
+              'gtest': False,
+              'run': False,
+              'src': ['test/cpp/naming/resolver_component_test.cc'],
+              'platforms': ['linux', 'posix', 'mac'],
+              'deps': [
+                  'grpc++_test_util' + unsecure_build_config_suffix,
+                  'grpc_test_util' + unsecure_build_config_suffix,
+                  'gpr_test_util',
+                  'grpc++' + unsecure_build_config_suffix,
+                  'grpc' + unsecure_build_config_suffix,
+                  'gpr',
+                  'grpc++_test_config',
+              ],
+          } for unsecure_build_config_suffix in ['_unsecure', '']
+      ] + [
+          {
+              'name': 'resolver_component_tests_runner_invoker' + unsecure_build_config_suffix,
+              'build': 'test',
+              'language': 'c++',
+              'gtest': False,
+              'run': True,
+              'src': ['test/cpp/naming/resolver_component_tests_runner_invoker.cc'],
+              'platforms': ['linux', 'posix', 'mac'],
+              'deps': [
+                  'grpc++_test_util',
+                  'grpc_test_util',
+                  'gpr_test_util',
+                  'grpc++',
+                  'grpc',
+                  'gpr',
+                  'grpc++_test_config',
+              ],
+              'args': [
+                  '--test_bin_name=resolver_component_test%s' % unsecure_build_config_suffix,
+                  '--running_under_bazel=false',
+              ],
+          } for unsecure_build_config_suffix in ['_unsecure', '']
+      ]
+  }
+
+  print(yaml.dump(json))
+
+if __name__ == '__main__':
+  main()

test/cpp/naming/generate_resolver_component_tests.bzl

@@ -0,0 +1,64 @@
+#!/usr/bin/env python2.7
+# Copyright 2015 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.
+
+load("//bazel:grpc_build_system.bzl", "grpc_sh_binary", "grpc_cc_test", "grpc_cc_binary")
+
+def generate_resolver_component_tests():
+  for unsecure_build_config_suffix in ['_unsecure', '']:
+    # meant to be invoked only through the top-level shell script driver
+    grpc_cc_binary(
+        name = "resolver_component_test%s" % unsecure_build_config_suffix,
+        testonly = 1,
+        srcs = [
+            "resolver_component_test.cc",
+        ],
+        external_deps = [
+            "gmock",
+        ],
+        deps = [
+            "//test/cpp/util:test_util%s" % unsecure_build_config_suffix,
+            "//test/core/util:grpc_test_util%s" % unsecure_build_config_suffix,
+            "//test/core/util:gpr_test_util",
+            "//:grpc++%s" % unsecure_build_config_suffix,
+            "//:grpc%s" % unsecure_build_config_suffix,
+            "//:gpr",
+            "//test/cpp/util:test_config",
+        ],
+    )
+    grpc_cc_test(
+        name = "resolver_component_tests_runner_invoker%s" % unsecure_build_config_suffix,
+        srcs = [
+            "resolver_component_tests_runner_invoker.cc",
+        ],
+        deps = [
+            "//test/cpp/util:test_util",
+            "//test/core/util:grpc_test_util",
+            "//test/core/util:gpr_test_util",
+            "//:grpc++",
+            "//:grpc",
+            "//:gpr",
+            "//test/cpp/util:test_config",
+        ],
+        data = [
+            ":resolver_component_tests_runner",
+            ":resolver_component_test%s" % unsecure_build_config_suffix,
+            ":test_dns_server",
+            "resolver_test_record_groups.yaml", # include the transitive dependency so that the dns sever py binary can locate this
+        ],
+        args = [
+            "--test_bin_name=resolver_component_test%s" % unsecure_build_config_suffix,
+            "--running_under_bazel=true",
+        ]
+    )

test/cpp/naming/resolver_component_test.cc

@@ -0,0 +1,323 @@
+/*
+ *
+ * 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/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/host_port.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <grpc/support/sync.h>
+#include <grpc/support/time.h>
+#include <string.h>
+
+#include <gflags/gflags.h>
+#include <gmock/gmock.h>
+#include <vector>
+
+#include "test/cpp/util/subprocess.h"
+#include "test/cpp/util/test_config.h"
+
+extern "C" {
+#include "src/core/ext/filters/client_channel/client_channel.h"
+#include "src/core/ext/filters/client_channel/resolver.h"
+#include "src/core/ext/filters/client_channel/resolver/dns/c_ares/grpc_ares_wrapper.h"
+#include "src/core/ext/filters/client_channel/resolver_registry.h"
+#include "src/core/lib/channel/channel_args.h"
+#include "src/core/lib/iomgr/combiner.h"
+#include "src/core/lib/iomgr/executor.h"
+#include "src/core/lib/iomgr/iomgr.h"
+#include "src/core/lib/iomgr/resolve_address.h"
+#include "src/core/lib/iomgr/sockaddr_utils.h"
+#include "src/core/lib/support/env.h"
+#include "src/core/lib/support/string.h"
+#include "test/core/util/port.h"
+#include "test/core/util/test_config.h"
+}
+
+using std::vector;
+using grpc::SubProcess;
+using testing::UnorderedElementsAreArray;
+
+// Hack copied from "test/cpp/end2end/server_crash_test_client.cc"!
+// In some distros, gflags is in the namespace google, and in some others,
+// in gflags. This hack is enabling us to find both.
+namespace google {}
+namespace gflags {}
+using namespace google;
+using namespace gflags;
+
+DEFINE_string(target_name, "", "Target name to resolve.");
+DEFINE_string(expected_addrs, "",
+              "Comma-separated list of expected "
+              "'<ip0:port0>,<is_balancer0>;<ip1:port1>,<is_balancer1>;...' "
+              "addresses of "
+              "backend and/or balancers. 'is_balancer' should be bool, i.e. "
+              "true or false.");
+DEFINE_string(expected_chosen_service_config, "",
+              "Expected service config json string that gets chosen (no "
+              "whitespace). Empty for none.");
+DEFINE_string(
+    local_dns_server_address, "",
+    "Optional. This address is placed as the uri authority if present.");
+DEFINE_string(expected_lb_policy, "",
+              "Expected lb policy name that appears in resolver result channel "
+              "arg. Empty for none.");
+
+namespace {
+
+class GrpcLBAddress final {
+ public:
+  GrpcLBAddress(std::string address, bool is_balancer)
+      : is_balancer(is_balancer), address(address) {}
+
+  bool operator==(const GrpcLBAddress &other) const {
+    return this->is_balancer == other.is_balancer &&
+           this->address == other.address;
+  }
+
+  bool operator!=(const GrpcLBAddress &other) const {
+    return !(*this == other);
+  }
+
+  bool is_balancer;
+  std::string address;
+};
+
+vector<GrpcLBAddress> ParseExpectedAddrs(std::string expected_addrs) {
+  std::vector<GrpcLBAddress> out;
+  while (expected_addrs.size() != 0) {
+    // get the next <ip>,<port> (v4 or v6)
+    size_t next_comma = expected_addrs.find(",");
+    if (next_comma == std::string::npos) {
+      gpr_log(
+          GPR_ERROR,
+          "Missing ','. Expected_addrs arg should be a semi-colon-separated "
+          "list of "
+          "<ip-port>,<bool> pairs. Left-to-be-parsed arg is |%s|",
+          expected_addrs.c_str());
+      abort();
+    }
+    std::string next_addr = expected_addrs.substr(0, next_comma);
+    expected_addrs = expected_addrs.substr(next_comma + 1, std::string::npos);
+    // get the next is_balancer 'bool' associated with this address
+    size_t next_semicolon = expected_addrs.find(";");
+    bool is_balancer =
+        gpr_is_true(expected_addrs.substr(0, next_semicolon).c_str());
+    out.emplace_back(GrpcLBAddress(next_addr, is_balancer));
+    if (next_semicolon == std::string::npos) {
+      break;
+    }
+    expected_addrs =
+        expected_addrs.substr(next_semicolon + 1, std::string::npos);
+  }
+  if (out.size() == 0) {
+    gpr_log(GPR_ERROR,
+            "expected_addrs arg should be a comma-separated list of "
+            "<ip-port>,<bool> pairs");
+    abort();
+  }
+  return out;
+}
+
+gpr_timespec TestDeadline(void) {
+  return grpc_timeout_seconds_to_deadline(100);
+}
+
+struct ArgsStruct {
+  gpr_event ev;
+  gpr_atm done_atm;
+  gpr_mu *mu;
+  grpc_pollset *pollset;
+  grpc_pollset_set *pollset_set;
+  grpc_combiner *lock;
+  grpc_channel_args *channel_args;
+  vector<GrpcLBAddress> expected_addrs;
+  std::string expected_service_config_string;
+  std::string expected_lb_policy;
+};
+
+void ArgsInit(grpc_exec_ctx *exec_ctx, ArgsStruct *args) {
+  gpr_event_init(&args->ev);
+  args->pollset = (grpc_pollset *)gpr_zalloc(grpc_pollset_size());
+  grpc_pollset_init(args->pollset, &args->mu);
+  args->pollset_set = grpc_pollset_set_create();
+  grpc_pollset_set_add_pollset(exec_ctx, args->pollset_set, args->pollset);
+  args->lock = grpc_combiner_create();
+  gpr_atm_rel_store(&args->done_atm, 0);
+  args->channel_args = NULL;
+}
+
+void DoNothing(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *error) {}
+
+void ArgsFinish(grpc_exec_ctx *exec_ctx, ArgsStruct *args) {
+  GPR_ASSERT(gpr_event_wait(&args->ev, TestDeadline()));
+  grpc_pollset_set_del_pollset(exec_ctx, args->pollset_set, args->pollset);
+  grpc_pollset_set_destroy(exec_ctx, args->pollset_set);
+  grpc_closure DoNothing_cb;
+  GRPC_CLOSURE_INIT(&DoNothing_cb, DoNothing, NULL, grpc_schedule_on_exec_ctx);
+  grpc_pollset_shutdown(exec_ctx, args->pollset, &DoNothing_cb);
+  // exec_ctx needs to be flushed before calling grpc_pollset_destroy()
+  grpc_channel_args_destroy(exec_ctx, args->channel_args);
+  grpc_exec_ctx_flush(exec_ctx);
+  grpc_pollset_destroy(exec_ctx, args->pollset);
+  gpr_free(args->pollset);
+  GRPC_COMBINER_UNREF(exec_ctx, args->lock, NULL);
+}
+
+gpr_timespec NSecondDeadline(int seconds) {
+  return gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
+                      gpr_time_from_seconds(seconds, GPR_TIMESPAN));
+}
+
+void PollPollsetUntilRequestDone(ArgsStruct *args) {
+  gpr_timespec deadline = NSecondDeadline(10);
+  while (true) {
+    bool done = gpr_atm_acq_load(&args->done_atm) != 0;
+    if (done) {
+      break;
+    }
+    gpr_timespec time_left =
+        gpr_time_sub(deadline, gpr_now(GPR_CLOCK_REALTIME));
+    gpr_log(GPR_DEBUG, "done=%d, time_left=%" PRId64 ".%09d", done,
+            time_left.tv_sec, time_left.tv_nsec);
+    GPR_ASSERT(gpr_time_cmp(time_left, gpr_time_0(GPR_TIMESPAN)) >= 0);
+    grpc_pollset_worker *worker = NULL;
+    grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+    gpr_mu_lock(args->mu);
+    GRPC_LOG_IF_ERROR(
+        "pollset_work",
+        grpc_pollset_work(&exec_ctx, args->pollset, &worker,
+                          gpr_now(GPR_CLOCK_REALTIME), NSecondDeadline(1)));
+    gpr_mu_unlock(args->mu);
+    grpc_exec_ctx_finish(&exec_ctx);
+  }
+  gpr_event_set(&args->ev, (void *)1);
+}
+
+void CheckServiceConfigResultLocked(grpc_channel_args *channel_args,
+                                    ArgsStruct *args) {
+  const grpc_arg *service_config_arg =
+      grpc_channel_args_find(channel_args, GRPC_ARG_SERVICE_CONFIG);
+  if (args->expected_service_config_string != "") {
+    GPR_ASSERT(service_config_arg != NULL);
+    GPR_ASSERT(service_config_arg->type == GRPC_ARG_STRING);
+    EXPECT_EQ(service_config_arg->value.string,
+              args->expected_service_config_string);
+  } else {
+    GPR_ASSERT(service_config_arg == NULL);
+  }
+}
+
+void CheckLBPolicyResultLocked(grpc_channel_args *channel_args,
+                               ArgsStruct *args) {
+  const grpc_arg *lb_policy_arg =
+      grpc_channel_args_find(channel_args, GRPC_ARG_LB_POLICY_NAME);
+  if (args->expected_lb_policy != "") {
+    GPR_ASSERT(lb_policy_arg != NULL);
+    GPR_ASSERT(lb_policy_arg->type == GRPC_ARG_STRING);
+    EXPECT_EQ(lb_policy_arg->value.string, args->expected_lb_policy);
+  } else {
+    GPR_ASSERT(lb_policy_arg == NULL);
+  }
+}
+
+void CheckResolverResultLocked(grpc_exec_ctx *exec_ctx, void *argsp,
+                               grpc_error *err) {
+  ArgsStruct *args = (ArgsStruct *)argsp;
+  grpc_channel_args *channel_args = args->channel_args;
+  const grpc_arg *channel_arg =
+      grpc_channel_args_find(channel_args, GRPC_ARG_LB_ADDRESSES);
+  GPR_ASSERT(channel_arg != NULL);
+  GPR_ASSERT(channel_arg->type == GRPC_ARG_POINTER);
+  grpc_lb_addresses *addresses =
+      (grpc_lb_addresses *)channel_arg->value.pointer.p;
+  gpr_log(GPR_INFO, "num addrs found: %" PRIdPTR ". expected %" PRIdPTR,
+          addresses->num_addresses, args->expected_addrs.size());
+  GPR_ASSERT(addresses->num_addresses == args->expected_addrs.size());
+  std::vector<GrpcLBAddress> found_lb_addrs;
+  for (size_t i = 0; i < addresses->num_addresses; i++) {
+    grpc_lb_address addr = addresses->addresses[i];
+    char *str;
+    grpc_sockaddr_to_string(&str, &addr.address, 1 /* normalize */);
+    gpr_log(GPR_INFO, "%s", str);
+    found_lb_addrs.emplace_back(
+        GrpcLBAddress(std::string(str), addr.is_balancer));
+    gpr_free(str);
+  }
+  if (args->expected_addrs.size() != found_lb_addrs.size()) {
+    gpr_log(GPR_DEBUG, "found lb addrs size is: %" PRIdPTR
+                       ". expected addrs size is %" PRIdPTR,
+            found_lb_addrs.size(), args->expected_addrs.size());
+    abort();
+  }
+  EXPECT_THAT(args->expected_addrs, UnorderedElementsAreArray(found_lb_addrs));
+  CheckServiceConfigResultLocked(channel_args, args);
+  CheckLBPolicyResultLocked(channel_args, args);
+  gpr_atm_rel_store(&args->done_atm, 1);
+  gpr_mu_lock(args->mu);
+  GRPC_LOG_IF_ERROR("pollset_kick", grpc_pollset_kick(args->pollset, NULL));
+  gpr_mu_unlock(args->mu);
+}
+
+TEST(ResolverComponentTest, TestResolvesRelevantRecords) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  ArgsStruct args;
+  ArgsInit(&exec_ctx, &args);
+  args.expected_addrs = ParseExpectedAddrs(FLAGS_expected_addrs);
+  args.expected_service_config_string = FLAGS_expected_chosen_service_config;
+  args.expected_lb_policy = FLAGS_expected_lb_policy;
+  // maybe build the address with an authority
+  char *whole_uri = NULL;
+  GPR_ASSERT(asprintf(&whole_uri, "dns://%s/%s",
+                      FLAGS_local_dns_server_address.c_str(),
+                      FLAGS_target_name.c_str()));
+  // create resolver and resolve
+  grpc_resolver *resolver = grpc_resolver_create(&exec_ctx, whole_uri, NULL,
+                                                 args.pollset_set, args.lock);
+  gpr_free(whole_uri);
+  grpc_closure on_resolver_result_changed;
+  GRPC_CLOSURE_INIT(&on_resolver_result_changed, CheckResolverResultLocked,
+                    (void *)&args, grpc_combiner_scheduler(args.lock));
+  grpc_resolver_next_locked(&exec_ctx, resolver, &args.channel_args,
+                            &on_resolver_result_changed);
+  grpc_exec_ctx_flush(&exec_ctx);
+  PollPollsetUntilRequestDone(&args);
+  GRPC_RESOLVER_UNREF(&exec_ctx, resolver, NULL);
+  ArgsFinish(&exec_ctx, &args);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
+}  // namespace
+
+int main(int argc, char **argv) {
+  grpc_init();
+  grpc_test_init(argc, argv);
+  ::testing::InitGoogleTest(&argc, argv);
+  ParseCommandLineFlags(&argc, &argv, true);
+  if (FLAGS_target_name == "") {
+    gpr_log(GPR_ERROR, "Missing target_name param.");
+    abort();
+  }
+  if (FLAGS_local_dns_server_address != "") {
+    gpr_log(GPR_INFO, "Specifying authority in uris to: %s",
+            FLAGS_local_dns_server_address.c_str());
+  }
+  auto result = RUN_ALL_TESTS();
+  grpc_shutdown();
+  return result;
+}

test/cpp/naming/resolver_component_tests_runner.sh

@@ -0,0 +1,173 @@
+#!/bin/bash
+# Copyright 2015 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.
+
+# This file is auto-generated
+
+set -ex
+
+# all command args required in this set order
+FLAGS_test_bin_path=`echo "$1" | grep '\--test_bin_path=' | cut -d "=" -f 2`
+FLAGS_dns_server_bin_path=`echo "$2" | grep '\--dns_server_bin_path=' | cut -d "=" -f 2`
+FLAGS_records_config_path=`echo "$3" | grep '\--records_config_path=' | cut -d "=" -f 2`
+FLAGS_test_dns_server_port=`echo "$4" | grep '\--test_dns_server_port=' | cut -d "=" -f 2`
+
+for cmd_arg in "$FLAGS_test_bin_path" "$FLAGS_dns_server_bin_path" "$FLAGS_records_config_path" "$FLAGS_test_dns_server_port"; do
+  if [[ "$cmd_arg" == "" ]]; then
+    echo "Missing a CMD arg" && exit 1
+  fi
+done
+
+if [[ "$GRPC_DNS_RESOLVER" != "" && "$GRPC_DNS_RESOLVER" != ares ]]; then
+  echo "This test only works under GRPC_DNS_RESOLVER=ares. Have GRPC_DNS_RESOLVER=$GRPC_DNS_RESOLVER" && exit 1
+fi
+export GRPC_DNS_RESOLVER=ares
+
+"$FLAGS_dns_server_bin_path" --records_config_path="$FLAGS_records_config_path" --port="$FLAGS_test_dns_server_port" 2>&1 > /dev/null &
+DNS_SERVER_PID=$!
+echo "Local DNS server started. PID: $DNS_SERVER_PID"
+
+# Health check local DNS server TCP and UDP ports
+for ((i=0;i<30;i++));
+do
+  echo "Retry health-check DNS query to local DNS server over tcp and udp"
+  RETRY=0
+  dig A health-check-local-dns-server-is-alive.resolver-tests.grpctestingexp. @localhost -p "$FLAGS_test_dns_server_port" +tries=1 +timeout=1 | grep '123.123.123.123' || RETRY=1
+  dig A health-check-local-dns-server-is-alive.resolver-tests.grpctestingexp. @localhost -p "$FLAGS_test_dns_server_port" +tries=1 +timeout=1 +tcp | grep '123.123.123.123' || RETRY=1
+  if [[ "$RETRY" == 0 ]]; then
+    break
+  fi;
+  sleep 0.1
+done
+
+if [[ $RETRY == 1 ]]; then
+  echo "FAILED TO START LOCAL DNS SERVER"
+  kill -SIGTERM $DNS_SERVER_PID
+  wait
+  exit 1
+fi
+
+function terminate_all {
+  echo "Received signal. Terminating $! and $DNS_SERVER_PID"
+  kill -SIGTERM $! || true
+  kill -SIGTERM $DNS_SERVER_PID || true
+  wait
+  exit 1
+}
+
+trap terminate_all SIGTERM SIGINT
+
+EXIT_CODE=0
+# TODO: this test should check for GCE residency and skip tests using _grpclb._tcp.* SRV records once GCE residency checks are made
+# in the resolver.
+
+$FLAGS_test_bin_path \
+  --target_name='srv-ipv4-single-target.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.4:1234,True' \
+  --expected_chosen_service_config='' \
+  --expected_lb_policy='' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='srv-ipv4-multi-target.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.5:1234,True;1.2.3.6:1234,True;1.2.3.7:1234,True' \
+  --expected_chosen_service_config='' \
+  --expected_lb_policy='' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='srv-ipv6-single-target.resolver-tests.grpctestingexp.' \
+  --expected_addrs='[2607:f8b0:400a:801::1001]:1234,True' \
+  --expected_chosen_service_config='' \
+  --expected_lb_policy='' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='srv-ipv6-multi-target.resolver-tests.grpctestingexp.' \
+  --expected_addrs='[2607:f8b0:400a:801::1002]:1234,True;[2607:f8b0:400a:801::1003]:1234,True;[2607:f8b0:400a:801::1004]:1234,True' \
+  --expected_chosen_service_config='' \
+  --expected_lb_policy='' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='srv-ipv4-simple-service-config.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.4:1234,True' \
+  --expected_chosen_service_config='{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"SimpleService","waitForReady":true}]}]}' \
+  --expected_lb_policy='round_robin' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='ipv4-no-srv-simple-service-config.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.4:443,False' \
+  --expected_chosen_service_config='{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"NoSrvSimpleService","waitForReady":true}]}]}' \
+  --expected_lb_policy='round_robin' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='ipv4-no-config-for-cpp.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.4:443,False' \
+  --expected_chosen_service_config='' \
+  --expected_lb_policy='' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='ipv4-cpp-config-has-zero-percentage.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.4:443,False' \
+  --expected_chosen_service_config='' \
+  --expected_lb_policy='' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='ipv4-second-language-is-cpp.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.4:443,False' \
+  --expected_chosen_service_config='{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"CppService","waitForReady":true}]}]}' \
+  --expected_lb_policy='round_robin' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='ipv4-config-with-percentages.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.4:443,False' \
+  --expected_chosen_service_config='{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"AlwaysPickedService","waitForReady":true}]}]}' \
+  --expected_lb_policy='round_robin' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='srv-ipv4-target-has-backend-and-balancer.resolver-tests.grpctestingexp.' \
+  --expected_addrs='1.2.3.4:1234,True;1.2.3.4:443,False' \
+  --expected_chosen_service_config='' \
+  --expected_lb_policy='' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+$FLAGS_test_bin_path \
+  --target_name='srv-ipv6-target-has-backend-and-balancer.resolver-tests.grpctestingexp.' \
+  --expected_addrs='[2607:f8b0:400a:801::1002]:1234,True;[2607:f8b0:400a:801::1002]:443,False' \
+  --expected_chosen_service_config='' \
+  --expected_lb_policy='' \
+  --local_dns_server_address=127.0.0.1:$FLAGS_test_dns_server_port &
+wait $! || EXIT_CODE=1
+
+kill -SIGTERM $DNS_SERVER_PID || true
+wait
+exit $EXIT_CODE

test/cpp/naming/resolver_component_tests_runner_invoker.cc

@@ -0,0 +1,189 @@
+/*
+ *
+ * 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/grpc.h>
+#include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
+#include <grpc/support/string_util.h>
+#include <signal.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <gflags/gflags.h>
+#include <string>
+#include <thread>
+#include <vector>
+
+#include "test/cpp/util/subprocess.h"
+#include "test/cpp/util/test_config.h"
+
+extern "C" {
+#include "src/core/lib/support/env.h"
+#include "test/core/util/port.h"
+}
+
+DEFINE_bool(
+    running_under_bazel, false,
+    "True if this test is running under bazel. "
+    "False indicates that this test is running under run_tests.py. "
+    "Child process test binaries are located differently based on this flag. ");
+
+DEFINE_string(test_bin_name, "",
+              "Name, without the preceding path, of the test binary");
+
+DEFINE_string(grpc_test_directory_relative_to_test_srcdir, "/__main__",
+              "This flag only applies if runner_under_bazel is true. This "
+              "flag is ignored if runner_under_bazel is false. "
+              "Directory of the <repo-root>/test directory relative to bazel's "
+              "TEST_SRCDIR environment variable");
+
+using grpc::SubProcess;
+
+static volatile sig_atomic_t abort_wait_for_child = 0;
+
+static void sighandler(int sig) { abort_wait_for_child = 1; }
+
+static void register_sighandler() {
+  struct sigaction act;
+  memset(&act, 0, sizeof(act));
+  act.sa_handler = sighandler;
+  sigaction(SIGINT, &act, NULL);
+  sigaction(SIGTERM, &act, NULL);
+}
+
+namespace {
+
+const int kTestTimeoutSeconds = 60 * 2;
+
+void RunSigHandlingThread(SubProcess *test_driver, gpr_mu *test_driver_mu,
+                          gpr_cv *test_driver_cv, int *test_driver_done) {
+  gpr_timespec overall_deadline =
+      gpr_time_add(gpr_now(GPR_CLOCK_MONOTONIC),
+                   gpr_time_from_seconds(kTestTimeoutSeconds, GPR_TIMESPAN));
+  while (true) {
+    gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
+    if (gpr_time_cmp(now, overall_deadline) > 0 || abort_wait_for_child) break;
+    gpr_mu_lock(test_driver_mu);
+    if (*test_driver_done) {
+      gpr_mu_unlock(test_driver_mu);
+      return;
+    }
+    gpr_timespec wait_deadline = gpr_time_add(
+        gpr_now(GPR_CLOCK_MONOTONIC), gpr_time_from_seconds(1, GPR_TIMESPAN));
+    gpr_cv_wait(test_driver_cv, test_driver_mu, wait_deadline);
+    gpr_mu_unlock(test_driver_mu);
+  }
+  gpr_log(GPR_DEBUG,
+          "Test timeout reached or received signal. Interrupting test driver "
+          "child process.");
+  test_driver->Interrupt();
+  return;
+}
+}
+
+namespace grpc {
+
+namespace testing {
+
+void InvokeResolverComponentTestsRunner(std::string test_runner_bin_path,
+                                        std::string test_bin_path,
+                                        std::string dns_server_bin_path,
+                                        std::string records_config_path) {
+  int test_dns_server_port = grpc_pick_unused_port_or_die();
+
+  SubProcess *test_driver = new SubProcess(
+      {test_runner_bin_path, "--test_bin_path=" + test_bin_path,
+       "--dns_server_bin_path=" + dns_server_bin_path,
+       "--records_config_path=" + records_config_path,
+       "--test_dns_server_port=" + std::to_string(test_dns_server_port)});
+  gpr_mu test_driver_mu;
+  gpr_mu_init(&test_driver_mu);
+  gpr_cv test_driver_cv;
+  gpr_cv_init(&test_driver_cv);
+  int test_driver_done = 0;
+  register_sighandler();
+  std::thread sig_handling_thread(RunSigHandlingThread, test_driver,
+                                  &test_driver_mu, &test_driver_cv,
+                                  &test_driver_done);
+  int status = test_driver->Join();
+  if (WIFEXITED(status)) {
+    if (WEXITSTATUS(status)) {
+      gpr_log(GPR_INFO,
+              "Resolver component test test-runner exited with code %d",
+              WEXITSTATUS(status));
+      abort();
+    }
+  } else if (WIFSIGNALED(status)) {
+    gpr_log(GPR_INFO,
+            "Resolver component test test-runner ended from signal %d",
+            WTERMSIG(status));
+    abort();
+  } else {
+    gpr_log(GPR_INFO,
+            "Resolver component test test-runner ended with unknown status %d",
+            status);
+    abort();
+  }
+  gpr_mu_lock(&test_driver_mu);
+  test_driver_done = 1;
+  gpr_cv_signal(&test_driver_cv);
+  gpr_mu_unlock(&test_driver_mu);
+  sig_handling_thread.join();
+  delete test_driver;
+  gpr_mu_destroy(&test_driver_mu);
+  gpr_cv_destroy(&test_driver_cv);
+}
+
+}  // namespace testing
+
+}  // namespace grpc
+
+int main(int argc, char **argv) {
+  grpc::testing::InitTest(&argc, &argv, true);
+  grpc_init();
+  GPR_ASSERT(FLAGS_test_bin_name != "");
+  std::string my_bin = argv[0];
+  if (FLAGS_running_under_bazel) {
+    GPR_ASSERT(FLAGS_grpc_test_directory_relative_to_test_srcdir != "");
+    // Use bazel's TEST_SRCDIR environment variable to locate the "test data"
+    // binaries.
+    std::string const bin_dir =
+        gpr_getenv("TEST_SRCDIR") +
+        FLAGS_grpc_test_directory_relative_to_test_srcdir +
+        std::string("/test/cpp/naming");
+    // Invoke bazel's executeable links to the .sh and .py scripts (don't use
+    // the .sh and .py suffixes) to make
+    // sure that we're using bazel's test environment.
+    grpc::testing::InvokeResolverComponentTestsRunner(
+        bin_dir + "/resolver_component_tests_runner",
+        bin_dir + "/" + FLAGS_test_bin_name, bin_dir + "/test_dns_server",
+        bin_dir + "/resolver_test_record_groups.yaml");
+  } else {
+    // Get the current binary's directory relative to repo root to invoke the
+    // correct build config (asan/tsan/dbg, etc.).
+    std::string const bin_dir = my_bin.substr(0, my_bin.rfind('/'));
+    // Invoke the .sh and .py scripts directly where they are in source code.
+    grpc::testing::InvokeResolverComponentTestsRunner(
+        "test/cpp/naming/resolver_component_tests_runner.sh",
+        bin_dir + "/" + FLAGS_test_bin_name,
+        "test/cpp/naming/test_dns_server.py",
+        "test/cpp/naming/resolver_test_record_groups.yaml");
+  }
+  grpc_shutdown();
+  return 0;
+}

test/cpp/naming/resolver_test_record_groups.yaml

@@ -0,0 +1,155 @@
+resolver_component_tests_common_zone_name: resolver-tests.grpctestingexp.
+resolver_component_tests:
+- expected_addrs:
+  - {address: '1.2.3.4:1234', is_balancer: true}
+  expected_chosen_service_config: null
+  expected_lb_policy: null
+  record_to_resolve: srv-ipv4-single-target
+  records:
+    _grpclb._tcp.srv-ipv4-single-target:
+    - {TTL: '2100', data: 0 0 1234 ipv4-single-target, type: SRV}
+    ipv4-single-target:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+- expected_addrs:
+  - {address: '1.2.3.5:1234', is_balancer: true}
+  - {address: '1.2.3.6:1234', is_balancer: true}
+  - {address: '1.2.3.7:1234', is_balancer: true}
+  expected_chosen_service_config: null
+  expected_lb_policy: null
+  record_to_resolve: srv-ipv4-multi-target
+  records:
+    _grpclb._tcp.srv-ipv4-multi-target:
+    - {TTL: '2100', data: 0 0 1234 ipv4-multi-target, type: SRV}
+    ipv4-multi-target:
+    - {TTL: '2100', data: 1.2.3.5, type: A}
+    - {TTL: '2100', data: 1.2.3.6, type: A}
+    - {TTL: '2100', data: 1.2.3.7, type: A}
+- expected_addrs:
+  - {address: '[2607:f8b0:400a:801::1001]:1234', is_balancer: true}
+  expected_chosen_service_config: null
+  expected_lb_policy: null
+  record_to_resolve: srv-ipv6-single-target
+  records:
+    _grpclb._tcp.srv-ipv6-single-target:
+    - {TTL: '2100', data: 0 0 1234 ipv6-single-target, type: SRV}
+    ipv6-single-target:
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1001', type: AAAA}
+- expected_addrs:
+  - {address: '[2607:f8b0:400a:801::1002]:1234', is_balancer: true}
+  - {address: '[2607:f8b0:400a:801::1003]:1234', is_balancer: true}
+  - {address: '[2607:f8b0:400a:801::1004]:1234', is_balancer: true}
+  expected_chosen_service_config: null
+  expected_lb_policy: null
+  record_to_resolve: srv-ipv6-multi-target
+  records:
+    _grpclb._tcp.srv-ipv6-multi-target:
+    - {TTL: '2100', data: 0 0 1234 ipv6-multi-target, type: SRV}
+    ipv6-multi-target:
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1002', type: AAAA}
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1003', type: AAAA}
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1004', type: AAAA}
+- expected_addrs:
+  - {address: '1.2.3.4:1234', is_balancer: true}
+  expected_chosen_service_config: '{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"SimpleService","waitForReady":true}]}]}'
+  expected_lb_policy: round_robin
+  record_to_resolve: srv-ipv4-simple-service-config
+  records:
+    _grpclb._tcp.srv-ipv4-simple-service-config:
+    - {TTL: '2100', data: 0 0 1234 ipv4-simple-service-config, type: SRV}
+    ipv4-simple-service-config:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    srv-ipv4-simple-service-config:
+    - {TTL: '2100', data: 'grpc_config=[{"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"SimpleService","waitForReady":true}]}]}}]',
+      type: TXT}
+- expected_addrs:
+  - {address: '1.2.3.4:443', is_balancer: false}
+  expected_chosen_service_config: '{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"NoSrvSimpleService","waitForReady":true}]}]}'
+  expected_lb_policy: round_robin
+  record_to_resolve: ipv4-no-srv-simple-service-config
+  records:
+    ipv4-no-srv-simple-service-config:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    - {TTL: '2100', data: 'grpc_config=[{"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"NoSrvSimpleService","waitForReady":true}]}]}}]',
+      type: TXT}
+- expected_addrs:
+  - {address: '1.2.3.4:443', is_balancer: false}
+  expected_chosen_service_config: null
+  expected_lb_policy: null
+  record_to_resolve: ipv4-no-config-for-cpp
+  records:
+    ipv4-no-config-for-cpp:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    - {TTL: '2100', data: 'grpc_config=[{"clientLanguage":["python"],"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"PythonService","waitForReady":true}]}]}}]',
+      type: TXT}
+- expected_addrs:
+  - {address: '1.2.3.4:443', is_balancer: false}
+  expected_chosen_service_config: null
+  expected_lb_policy: null
+  record_to_resolve: ipv4-cpp-config-has-zero-percentage
+  records:
+    ipv4-cpp-config-has-zero-percentage:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    - {TTL: '2100', data: 'grpc_config=[{"percentage":0,"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"CppService","waitForReady":true}]}]}}]',
+      type: TXT}
+- expected_addrs:
+  - {address: '1.2.3.4:443', is_balancer: false}
+  expected_chosen_service_config: '{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"CppService","waitForReady":true}]}]}'
+  expected_lb_policy: round_robin
+  record_to_resolve: ipv4-second-language-is-cpp
+  records:
+    ipv4-second-language-is-cpp:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    - {TTL: '2100', data: 'grpc_config=[{"clientLanguage":["go"],"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"GoService","waitForReady":true}]}]}},{"clientLanguage":["c++"],"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"CppService","waitForReady":true}]}]}}]',
+      type: TXT}
+- expected_addrs:
+  - {address: '1.2.3.4:443', is_balancer: false}
+  expected_chosen_service_config: '{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"AlwaysPickedService","waitForReady":true}]}]}'
+  expected_lb_policy: round_robin
+  record_to_resolve: ipv4-config-with-percentages
+  records:
+    ipv4-config-with-percentages:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    - {TTL: '2100', data: 'grpc_config=[{"percentage":0,"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"NeverPickedService","waitForReady":true}]}]}},{"percentage":100,"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"AlwaysPickedService","waitForReady":true}]}]}}]',
+      type: TXT}
+- expected_addrs:
+  - {address: '1.2.3.4:1234', is_balancer: true}
+  - {address: '1.2.3.4:443', is_balancer: false}
+  expected_chosen_service_config: null
+  expected_lb_policy: null
+  record_to_resolve: srv-ipv4-target-has-backend-and-balancer
+  records:
+    _grpclb._tcp.srv-ipv4-target-has-backend-and-balancer:
+    - {TTL: '2100', data: 0 0 1234 balancer-for-ipv4-has-backend-and-balancer, type: SRV}
+    balancer-for-ipv4-has-backend-and-balancer:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    srv-ipv4-target-has-backend-and-balancer:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+- expected_addrs:
+  - {address: '[2607:f8b0:400a:801::1002]:1234', is_balancer: true}
+  - {address: '[2607:f8b0:400a:801::1002]:443', is_balancer: false}
+  expected_chosen_service_config: null
+  expected_lb_policy: null
+  record_to_resolve: srv-ipv6-target-has-backend-and-balancer
+  records:
+    _grpclb._tcp.srv-ipv6-target-has-backend-and-balancer:
+    - {TTL: '2100', data: 0 0 1234 balancer-for-ipv6-has-backend-and-balancer, type: SRV}
+    balancer-for-ipv6-has-backend-and-balancer:
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1002', type: AAAA}
+    srv-ipv6-target-has-backend-and-balancer:
+    - {TTL: '2100', data: '2607:f8b0:400a:801::1002', type: AAAA}
+
+resolver_component_tests_TODO:
+- 'TODO: enable this large-txt-record test once working. (it is much longer than 512
+  bytes, likely to cause use of TCP even if max payload for UDP is changed somehow,
+  e.g. via notes in RFC 2671)'
+- expected_addrs:
+  - {address: '1.2.3.4:443', is_balancer: false}
+  expected_chosen_service_config: '{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwo","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooThree","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooFour","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooFive","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooSix","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooSeven","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooEight","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooNine","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTen","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooEleven","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwelve","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwelve","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwelve","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwelve","service":"SimpleService","waitForReady":true}]}]}'
+  expected_lb_policy: null
+  record_to_resolve: srv-ipv6-target-has-backend-and-balancer
+  record_to_resolve: ipv4-config-causing-fallback-to-tcp
+  records:
+    ipv4-config-causing-fallback-to-tcp:
+    - {TTL: '2100', data: 1.2.3.4, type: A}
+    - {TTL: '2100', data: 'grpc_config=[{"serviceConfig":{"loadBalancingPolicy":"round_robin","methodConfig":[{"name":[{"method":"Foo","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwo","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooThree","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooFour","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooFive","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooSix","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooSeven","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooEight","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooNine","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTen","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooEleven","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwelve","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwelve","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwelve","service":"SimpleService","waitForReady":true}]},{"name":[{"method":"FooTwelve","service":"SimpleService","waitForReady":true}]}]}}]',
+      type: TXT}

test/cpp/naming/test_dns_server.py

@@ -0,0 +1,134 @@
+#!/usr/bin/env python2.7
+# Copyright 2015 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.
+
+"""Starts a local DNS server for use in tests"""
+
+import argparse
+import sys
+import yaml
+import signal
+import os
+
+import twisted
+import twisted.internet
+import twisted.internet.reactor
+import twisted.internet.threads
+import twisted.internet.defer
+import twisted.internet.protocol
+import twisted.names
+import twisted.names.client
+import twisted.names.dns
+import twisted.names.server
+from twisted.names import client, server, common, authority, dns
+import argparse
+
+_SERVER_HEALTH_CHECK_RECORD_NAME = 'health-check-local-dns-server-is-alive.resolver-tests.grpctestingexp' # missing end '.' for twisted syntax
+_SERVER_HEALTH_CHECK_RECORD_DATA = '123.123.123.123'
+
+class NoFileAuthority(authority.FileAuthority):
+  def __init__(self, soa, records):
+    # skip FileAuthority
+    common.ResolverBase.__init__(self)
+    self.soa = soa
+    self.records = records
+
+def start_local_dns_server(args):
+  all_records = {}
+  def _push_record(name, r):
+    print('pushing record: |%s|' % name)
+    if all_records.get(name) is not None:
+      all_records[name].append(r)
+      return
+    all_records[name] = [r]
+
+  def _maybe_split_up_txt_data(name, txt_data, r_ttl):
+    start = 0
+    txt_data_list = []
+    while len(txt_data[start:]) > 0:
+      next_read = len(txt_data[start:])
+      if next_read > 255:
+        next_read = 255
+      txt_data_list.append(txt_data[start:start+next_read])
+      start += next_read
+    _push_record(name, dns.Record_TXT(*txt_data_list, ttl=r_ttl))
+
+  with open(args.records_config_path) as config:
+    test_records_config = yaml.load(config)
+  common_zone_name = test_records_config['resolver_component_tests_common_zone_name']
+  for group in test_records_config['resolver_component_tests']:
+    for name in group['records'].keys():
+      for record in group['records'][name]:
+        r_type = record['type']
+        r_data = record['data']
+        r_ttl = int(record['TTL'])
+        record_full_name = '%s.%s' % (name, common_zone_name)
+        assert record_full_name[-1] == '.'
+        record_full_name = record_full_name[:-1]
+        if r_type == 'A':
+          _push_record(record_full_name, dns.Record_A(r_data, ttl=r_ttl))
+        if r_type == 'AAAA':
+          _push_record(record_full_name, dns.Record_AAAA(r_data, ttl=r_ttl))
+        if r_type == 'SRV':
+          p, w, port, target = r_data.split(' ')
+          p = int(p)
+          w = int(w)
+          port = int(port)
+          target_full_name = '%s.%s' % (target, common_zone_name)
+          r_data = '%s %s %s %s' % (p, w, port, target_full_name)
+          _push_record(record_full_name, dns.Record_SRV(p, w, port, target_full_name, ttl=r_ttl))
+        if r_type == 'TXT':
+          _maybe_split_up_txt_data(record_full_name, r_data, r_ttl)
+  # Server health check record
+  _push_record(_SERVER_HEALTH_CHECK_RECORD_NAME, dns.Record_A(_SERVER_HEALTH_CHECK_RECORD_DATA, ttl=0))
+  soa_record = dns.Record_SOA(mname = common_zone_name)
+  test_domain_com = NoFileAuthority(
+    soa = (common_zone_name, soa_record),
+    records = all_records,
+  )
+  server = twisted.names.server.DNSServerFactory(
+      authorities=[test_domain_com], verbose=2)
+  server.noisy = 2
+  twisted.internet.reactor.listenTCP(args.port, server)
+  dns_proto = twisted.names.dns.DNSDatagramProtocol(server)
+  dns_proto.noisy = 2
+  twisted.internet.reactor.listenUDP(args.port, dns_proto)
+  print('starting local dns server on 127.0.0.1:%s' % args.port)
+  print('starting twisted.internet.reactor')
+  twisted.internet.reactor.suggestThreadPoolSize(1)
+  twisted.internet.reactor.run()
+
+def _quit_on_signal(signum, _frame):
+  print('Received SIGNAL %d. Quitting with exit code 0' % signum)
+  twisted.internet.reactor.stop()
+  sys.stdout.flush()
+  sys.exit(0)
+
+def main():
+  argp = argparse.ArgumentParser(description='Local DNS Server for resolver tests')
+  argp.add_argument('-p', '--port', default=None, type=int,
+                    help='Port for DNS server to listen on for TCP and UDP.')
+  argp.add_argument('-r', '--records_config_path', default=None, type=str,
+                    help=('Directory of resolver_test_record_groups.yaml file. '
+                          'Defauls to path needed when the test is invoked as part of run_tests.py.'))
+  args = argp.parse_args()
+  signal.signal(signal.SIGALRM, _quit_on_signal)
+  signal.signal(signal.SIGTERM, _quit_on_signal)
+  signal.signal(signal.SIGINT, _quit_on_signal)
+  # Prevent zombies. Tests that use this server are short-lived.
+  signal.alarm(2 * 60)
+  start_local_dns_server(args)
+
+if __name__ == '__main__':
+  main()

tools/buildgen/generate_build_additions.sh

@@ -24,6 +24,7 @@ gen_build_yaml_dirs="  \
   test/core/bad_client \
   test/core/bad_ssl    \
   test/core/end2end    \
+  test/cpp/naming \
   test/cpp/qps"
 gen_build_files=""
 for gen_build_yaml in $gen_build_yaml_dirs

tools/dockerfile/interoptest/grpc_interop_csharp/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -61,7 +62,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #================
 # C# dependencies

tools/dockerfile/interoptest/grpc_interop_cxx/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -61,7 +62,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #=================
 # C++ dependencies

tools/dockerfile/interoptest/grpc_interop_go/Dockerfile

@@ -30,7 +30,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 # Define the default command.
 CMD ["bash"]

tools/dockerfile/interoptest/grpc_interop_go1.7/Dockerfile

@@ -30,7 +30,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 # Define the default command.
 CMD ["bash"]

tools/dockerfile/interoptest/grpc_interop_go1.8/Dockerfile

@@ -30,7 +30,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 # Define the default command.
 CMD ["bash"]

tools/dockerfile/interoptest/grpc_interop_http2/Dockerfile

@@ -30,7 +30,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 RUN pip install twisted h2==2.6.1 hyper
 

tools/dockerfile/interoptest/grpc_interop_java/Dockerfile

@@ -45,7 +45,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 
 # Trigger download of as many Gradle artifacts as possible.

tools/dockerfile/interoptest/grpc_interop_java_oracle8/Dockerfile

@@ -45,7 +45,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 
 # Trigger download of as many Gradle artifacts as possible.

tools/dockerfile/interoptest/grpc_interop_node/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -61,7 +62,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #==================
 # Node dependencies

tools/dockerfile/interoptest/grpc_interop_php/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \

tools/dockerfile/interoptest/grpc_interop_python/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -61,7 +62,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 # Prepare ccache
 RUN ln -s /usr/bin/ccache /usr/local/bin/gcc

tools/dockerfile/interoptest/grpc_interop_ruby/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -61,7 +62,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #==================
 # Ruby dependencies

tools/dockerfile/test/csharp_jessie_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #================
 # C# dependencies

tools/dockerfile/test/cxx_jessie_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #=================
 # C++ dependencies

tools/dockerfile/test/cxx_jessie_x86/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #=================
 # C++ dependencies

tools/dockerfile/test/cxx_ubuntu1404_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #=================
 # C++ dependencies

tools/dockerfile/test/cxx_ubuntu1604_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #=================
 # C++ dependencies

tools/dockerfile/test/fuzzer/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #=================
 # C++ dependencies

tools/dockerfile/test/multilang_jessie_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -122,7 +123,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 # Install coverage for Python test coverage reporting
 RUN pip install coverage

tools/dockerfile/test/node_jessie_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -76,7 +77,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #==================
 # Node dependencies

tools/dockerfile/test/php7_jessie_x64/Dockerfile

@@ -77,7 +77,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 # Prepare ccache
 RUN ln -s /usr/bin/ccache /usr/local/bin/gcc

tools/dockerfile/test/php_jessie_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #=================
 # PHP dependencies

tools/dockerfile/test/python_jessie_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 # Prepare ccache
 RUN ln -s /usr/bin/ccache /usr/local/bin/gcc

tools/dockerfile/test/python_pyenv_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 # Install dependencies for pyenv
 RUN apt-get update && apt-get install -y \

tools/dockerfile/test/ruby_jessie_x64/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #==================
 # Ruby dependencies

tools/dockerfile/test/sanity/Dockerfile

@@ -22,6 +22,7 @@ RUN apt-get update && apt-get install -y \
   bzip2 \
   ccache \
   curl \
+  dnsutils \
   gcc \
   gcc-multilib \
   git \
@@ -65,7 +66,7 @@ RUN apt-get update && apt-get install -y \
 # Install Python packages from PyPI
 RUN pip install pip --upgrade
 RUN pip install virtualenv
-RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0
+RUN pip install futures==2.2.0 enum34==1.0.4 protobuf==3.2.0 six==1.10.0 twisted==17.5.0
 
 #========================
 # Sanity test dependencies

tools/internal_ci/helper_scripts/prepare_build_macos_rc

@@ -46,7 +46,7 @@ pod repo update  # needed by python
 # python
 brew install coreutils  # we need grealpath
 pip install virtualenv --user python
-pip install -U six tox setuptools --user python
+pip install -U six tox setuptools twisted pyyaml --user python
 export PYTHONPATH=/Library/Python/3.4/site-packages
 
 # set xcode version for Obj-C tests

tools/run_tests/generated/sources_and_headers.json

@@ -5627,6 +5627,86 @@
     "third_party": false, 
     "type": "target"
   }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc++_test_config", 
+      "grpc++_test_util_unsecure", 
+      "grpc++_unsecure", 
+      "grpc_test_util_unsecure", 
+      "grpc_unsecure"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "resolver_component_test_unsecure", 
+    "src": [
+      "test/cpp/naming/resolver_component_test.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc++", 
+      "grpc++_test_config", 
+      "grpc++_test_util", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "resolver_component_test", 
+    "src": [
+      "test/cpp/naming/resolver_component_test.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc++", 
+      "grpc++_test_config", 
+      "grpc++_test_util", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "resolver_component_tests_runner_invoker_unsecure", 
+    "src": [
+      "test/cpp/naming/resolver_component_tests_runner_invoker.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
+  {
+    "deps": [
+      "gpr", 
+      "gpr_test_util", 
+      "grpc", 
+      "grpc++", 
+      "grpc++_test_config", 
+      "grpc++_test_util", 
+      "grpc_test_util"
+    ], 
+    "headers": [], 
+    "is_filegroup": false, 
+    "language": "c++", 
+    "name": "resolver_component_tests_runner_invoker", 
+    "src": [
+      "test/cpp/naming/resolver_component_tests_runner_invoker.cc"
+    ], 
+    "third_party": false, 
+    "type": "target"
+  }, 
   {
     "deps": [
       "gpr", 

tools/run_tests/generated/tests.json

@@ -4404,6 +4404,52 @@
       "posix"
     ]
   }, 
+  {
+    "args": [
+      "--test_bin_name=resolver_component_test_unsecure", 
+      "--running_under_bazel=false"
+    ], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "gtest": false, 
+    "language": "c++", 
+    "name": "resolver_component_tests_runner_invoker_unsecure", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
+  {
+    "args": [
+      "--test_bin_name=resolver_component_test", 
+      "--running_under_bazel=false"
+    ], 
+    "ci_platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ], 
+    "cpu_cost": 1.0, 
+    "exclude_configs": [], 
+    "exclude_iomgrs": [], 
+    "flaky": false, 
+    "gtest": false, 
+    "language": "c++", 
+    "name": "resolver_component_tests_runner_invoker", 
+    "platforms": [
+      "linux", 
+      "mac", 
+      "posix"
+    ]
+  }, 
   {
     "args": [
       "third_party/boringssl/crypto/aes/aes_tests.txt"