Merge github.com:grpc/grpc into endpoints

INSTALL

@@ -9,25 +9,40 @@ wiki pages:
 * If you are in a hurry *
 *************************
 
+On Linux (Debian):
+
+ Note: you will need to add the Debian 'unstable' distribution to your sources
+ file first.
+
+ Add the following line to your `/etc/apt/sources.list` file:
+
+   deb http://ftp.us.debian.org/debian unstable main contrib non-free
+
+ Install the gRPC library:
+
+ $ [sudo] apt-get install libgrpc-dev
+
+OR
+
  $ git clone https://github.com/grpc/grpc.git
  $ cd grpc
  $ git submodule update --init
  $ make 
- $ sudo make install
+ $ [sudo] make install
 
 You don't need anything else than GNU Make, gcc and autotools. Under a Debian
 or Ubuntu system, this should boil down to the following packages:
 
-  $ apt-get install build-essential autoconf libtool
+ $ [sudo] apt-get install build-essential autoconf libtool
 
 Building the python wrapper requires the following:
 
-  # apt-get install python-all-dev python-virtualenv
+ $ [sudo] apt-get install python-all-dev python-virtualenv
 
 If you want to install in a different directory than the default /usr/lib, you can
 override it on the command line:
 
-  # make install prefix=/opt
+ $ [sudo] make install prefix=/opt
 
 
 *******************************

build.json

@@ -592,8 +592,7 @@
       "external_deps": [
         "zookeeper"
       ],
-      "secure": "no",
-      "vs_project_guid": "{F14EBEC1-DC43-45D3-8A7D-1A47072EFE50}"
+      "secure": "no"
     },
     {
       "name": "reconnect_server",
@@ -1366,6 +1365,20 @@
         "gpr"
       ]
     },
+    {
+      "name": "grpc_channel_args_test",
+      "build": "test",
+      "language": "c",
+      "src": [
+        "test/core/channel/channel_args_test.c"
+      ],
+      "deps": [
+        "grpc_test_util",
+        "grpc",
+        "gpr_test_util",
+        "gpr"
+      ]
+    },
     {
       "name": "grpc_channel_stack_test",
       "build": "test",
@@ -2489,6 +2502,9 @@
         "gpr",
         "grpc++_test_config"
       ],
+      "exclude_configs": [
+        "tsan"
+      ],
       "platforms": [
         "mac",
         "linux",
@@ -2611,6 +2627,22 @@
         "gpr"
       ]
     },
+    {
+      "name": "shutdown_test",
+      "build": "test",
+      "language": "c++",
+      "src": [
+        "test/cpp/end2end/shutdown_test.cc"
+      ],
+      "deps": [
+        "grpc++_test_util",
+        "grpc_test_util",
+        "grpc++",
+        "grpc",
+        "gpr_test_util",
+        "gpr"
+      ]
+    },
     {
       "name": "status_test",
       "build": "test",

doc/connection-backoff-interop-test-description.md

@@ -31,9 +31,9 @@ Clients should accept these arguments:
 * --server_retry_port=PORT
     * The server port to connect to for testing backoffs. For example, "8081"
 
-The client must connect to the control port without TLS. The client should
-either assert on the server returned backoff status or check the returned
-backoffs on its own.
+The client must connect to the control port without TLS. The client must connect
+to the retry port with TLS. The client should either assert on the server
+returned backoff status or check the returned backoffs on its own.
 
 Procedure of client:
 

doc/connection-backoff.md

@@ -44,3 +44,12 @@ different jitter logic.
 Alternate implementations must ensure that connection backoffs started at the
 same time disperse, and must not attempt connections substantially more often
 than the above algorithm.
+
+## Reset Backoff
+
+The back off should be reset to INITIAL_BACKOFF at some time point, so that the
+reconnecting behavior is consistent no matter the connection is a newly started
+one or a previously disconnected one.
+
+We choose to reset the Backoff when the SETTINGS frame is received, at that time
+point, we know for sure that this connection was accepted by the server.

include/grpc++/impl/README.md

@@ -0,0 +1,4 @@
+**The APIs in this directory are not stable!**
+
+This directory contains header files that need to be installed but are not part
+of the public API. Users should not use these headers directly.

include/grpc++/impl/call.h

@@ -541,8 +541,7 @@ class CallOpSet : public CallOpSetInterface,
 template <class Op1 = CallNoOp<1>, class Op2 = CallNoOp<2>,
           class Op3 = CallNoOp<3>, class Op4 = CallNoOp<4>,
           class Op5 = CallNoOp<5>, class Op6 = CallNoOp<6>>
-class SneakyCallOpSet GRPC_FINAL
-    : public CallOpSet<Op1, Op2, Op3, Op4, Op5, Op6> {
+class SneakyCallOpSet : public CallOpSet<Op1, Op2, Op3, Op4, Op5, Op6> {
  public:
   bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
     typedef CallOpSet<Op1, Op2, Op3, Op4, Op5, Op6> Base;

include/grpc++/impl/rpc_service_method.h

@@ -211,13 +211,19 @@ class BidiStreamingHandler : public MethodHandler {
 // Handle unknown method by returning UNIMPLEMENTED error.
 class UnknownMethodHandler : public MethodHandler {
  public:
-  void RunHandler(const HandlerParameter& param) GRPC_FINAL {
+  template <class T>
+  static void FillOps(ServerContext* context, T* ops) {
     Status status(StatusCode::UNIMPLEMENTED, "");
-    CallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus> ops;
-    if (!param.server_context->sent_initial_metadata_) {
-      ops.SendInitialMetadata(param.server_context->initial_metadata_);
+    if (!context->sent_initial_metadata_) {
+      ops->SendInitialMetadata(context->initial_metadata_);
+      context->sent_initial_metadata_ = true;
     }
-    ops.ServerSendStatus(param.server_context->trailing_metadata_, status);
+    ops->ServerSendStatus(context->trailing_metadata_, status);
+  }
+
+  void RunHandler(const HandlerParameter& param) GRPC_FINAL {
+    CallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus> ops;
+    FillOps(param.server_context, &ops);
     param.call->PerformOps(&ops);
     param.call->cq()->Pluck(&ops);
   }

include/grpc++/server.h

@@ -63,7 +63,14 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
   ~Server();
 
   // Shutdown the server, block until all rpc processing finishes.
-  void Shutdown();
+  // Forcefully terminate pending calls after deadline expires.
+  template <class T>
+  void Shutdown(const T& deadline) {
+    ShutdownInternal(TimePoint<T>(deadline).raw_time());
+  }
+
+  // Shutdown the server, waiting for all rpc processing to finish.
+  void Shutdown() { ShutdownInternal(gpr_inf_future(GPR_CLOCK_MONOTONIC)); }
 
   // Block waiting for all work to complete (the server must either
   // be shutting down or some other thread must call Shutdown for this
@@ -91,7 +98,7 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
   // Add a listening port. Can be called multiple times.
   int AddListeningPort(const grpc::string& addr, ServerCredentials* creds);
   // Start the server.
-  bool Start();
+  bool Start(ServerCompletionQueue** cqs, size_t num_cqs);
 
   void HandleQueueClosed();
   void RunRpc();
@@ -99,11 +106,14 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
 
   void PerformOpsOnCall(CallOpSetInterface* ops, Call* call) GRPC_OVERRIDE;
 
+  void ShutdownInternal(gpr_timespec deadline);
+
   class BaseAsyncRequest : public CompletionQueueTag {
    public:
     BaseAsyncRequest(Server* server, ServerContext* context,
                      ServerAsyncStreamingInterface* stream,
-                     CompletionQueue* call_cq, void* tag);
+                     CompletionQueue* call_cq, void* tag,
+                     bool delete_on_finalize);
     virtual ~BaseAsyncRequest();
 
     bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
@@ -114,6 +124,7 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
     ServerAsyncStreamingInterface* const stream_;
     CompletionQueue* const call_cq_;
     void* const tag_;
+    const bool delete_on_finalize_;
     grpc_call* call_;
     grpc_metadata_array initial_metadata_array_;
   };
@@ -175,12 +186,13 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
     Message* const request_;
   };
 
-  class GenericAsyncRequest GRPC_FINAL : public BaseAsyncRequest {
+  class GenericAsyncRequest : public BaseAsyncRequest {
    public:
     GenericAsyncRequest(Server* server, GenericServerContext* context,
                         ServerAsyncStreamingInterface* stream,
                         CompletionQueue* call_cq,
-                        ServerCompletionQueue* notification_cq, void* tag);
+                        ServerCompletionQueue* notification_cq, void* tag,
+                        bool delete_on_finalize);
 
     bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
 
@@ -188,6 +200,10 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
     grpc_call_details call_details_;
   };
 
+  class UnimplementedAsyncRequestContext;
+  class UnimplementedAsyncRequest;
+  class UnimplementedAsyncResponse;
+
   template <class Message>
   void RequestAsyncCall(void* registered_method, ServerContext* context,
                         ServerAsyncStreamingInterface* stream,
@@ -212,7 +228,7 @@ class Server GRPC_FINAL : public GrpcLibrary, private CallHook {
                                ServerCompletionQueue* notification_cq,
                                void* tag) {
     new GenericAsyncRequest(this, context, stream, call_cq, notification_cq,
-                            tag);
+                            tag, true);
   }
 
   const int max_message_size_;

include/grpc++/server_builder.h

@@ -101,8 +101,8 @@ class ServerBuilder {
   void SetThreadPool(ThreadPoolInterface* thread_pool);
 
   // Add a completion queue for handling asynchronous services
-  // Caller is required to keep this completion queue live until calling
-  // BuildAndStart()
+  // Caller is required to keep this completion queue live until
+  // the server is destroyed.
   std::unique_ptr<ServerCompletionQueue> AddCompletionQueue();
 
   // Return a running server which is ready for processing rpcs.

include/grpc++/stream.h

@@ -761,6 +761,8 @@ class ServerAsyncReaderWriter GRPC_FINAL : public ServerAsyncStreamingInterface,
   }
 
  private:
+  friend class ::grpc::Server;
+
   void BindCall(Call* call) GRPC_OVERRIDE { call_ = *call; }
 
   Call call_;

include/grpc/compression.h

@@ -36,12 +36,15 @@
 
 #include <stdlib.h>
 
+#include <grpc/support/port_platform.h>
+
 #ifdef __cplusplus
 extern "C" {
 #endif
 
 /** To be used in channel arguments */
 #define GRPC_COMPRESSION_ALGORITHM_ARG "grpc.compression_algorithm"
+#define GRPC_COMPRESSION_ALGORITHM_STATE_ARG "grpc.compression_algorithm_state"
 
 /* The various compression algorithms supported by GRPC */
 typedef enum {
@@ -60,6 +63,11 @@ typedef enum {
   GRPC_COMPRESS_LEVEL_COUNT
 } grpc_compression_level;
 
+typedef struct grpc_compression_options {
+  gpr_uint32 enabled_algorithms_bitset; /**< All algs are enabled by default */
+  grpc_compression_algorithm default_compression_algorithm; /**< for channel */
+} grpc_compression_options;
+
 /** Parses the first \a name_length bytes of \a name as a
  * grpc_compression_algorithm instance, updating \a algorithm. Returns 1 upon
  * success, 0 otherwise. */
@@ -83,6 +91,20 @@ grpc_compression_level grpc_compression_level_for_algorithm(
 grpc_compression_algorithm grpc_compression_algorithm_for_level(
     grpc_compression_level level);
 
+void grpc_compression_options_init(grpc_compression_options *opts);
+
+/** Mark \a algorithm as enabled in \a opts. */
+void grpc_compression_options_enable_algorithm(
+     grpc_compression_options *opts, grpc_compression_algorithm algorithm);
+
+/** Mark \a algorithm as disabled in \a opts. */
+void grpc_compression_options_disable_algorithm(
+    grpc_compression_options *opts, grpc_compression_algorithm algorithm);
+
+/** Returns true if \a algorithm is marked as enabled in \a opts. */
+int grpc_compression_options_is_algorithm_enabled(
+    const grpc_compression_options *opts, grpc_compression_algorithm algorithm);
+
 #ifdef __cplusplus
 }
 #endif

include/grpc/grpc.h

@@ -386,13 +386,6 @@ typedef struct grpc_op {
     the reverse order they were initialized. */
 void grpc_register_plugin(void (*init)(void), void (*destroy)(void));
 
-/** Frees the memory used by all the plugin information.
-
-    While grpc_init and grpc_shutdown can be called multiple times, the plugins
-    won't be unregistered and their memory cleaned up unless you call that
-    function. Using atexit(grpc_unregister_all_plugins) is a valid method. */
-void grpc_unregister_all_plugins();
-
 /* Propagation bits: this can be bitwise or-ed to form propagation_mask for
  * grpc_call */
 /** Propagate deadline */

include/grpc/grpc_security.h

@@ -275,12 +275,18 @@ int grpc_auth_context_set_peer_identity_property_name(grpc_auth_context *ctx,
 /* --- Auth Metadata Processing --- */
 
 /* Callback function that is called when the metadata processing is done.
-   success is 1 if processing succeeded, 0 otherwise.
-   Consumed metadata will be removed from the set of metadata available on the
-   call. */
+   - Consumed metadata will be removed from the set of metadata available on the
+     call. consumed_md may be NULL if no metadata has been consumed.
+   - Response metadata will be set on the response. response_md may be NULL.
+   - status is GRPC_STATUS_OK for success or a specific status for an error.
+     Common error status for auth metadata processing is either
+     GRPC_STATUS_UNAUTHENTICATED in case of an authentication failure or
+     GRPC_STATUS PERMISSION_DENIED in case of an authorization failure.
+   - error_details gives details about the error. May be NULL. */
 typedef void (*grpc_process_auth_metadata_done_cb)(
     void *user_data, const grpc_metadata *consumed_md, size_t num_consumed_md,
-    int success);
+    const grpc_metadata *response_md, size_t num_response_md,
+    grpc_status_code status, const char *error_details);
 
 /* Pluggable server-side metadata processor object. */
 typedef struct {

src/core/channel/channel_args.c

@@ -37,6 +37,7 @@
 
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
 
 #include <string.h>
 
@@ -146,3 +147,65 @@ grpc_channel_args *grpc_channel_args_set_compression_algorithm(
   tmp.value.integer = algorithm;
   return grpc_channel_args_copy_and_add(a, &tmp, 1);
 }
+
+/** Returns 1 if the argument for compression algorithm's enabled states bitset
+ * was found in \a a, returning the arg's value in \a states. Otherwise, returns
+ * 0. */
+static int find_compression_algorithm_states_bitset(
+    const grpc_channel_args *a, int **states_arg) {
+  if (a != NULL) {
+    size_t i;
+    for (i = 0; i < a->num_args; ++i) {
+      if (a->args[i].type == GRPC_ARG_INTEGER &&
+          !strcmp(GRPC_COMPRESSION_ALGORITHM_STATE_ARG, a->args[i].key)) {
+        *states_arg = &a->args[i].value.integer;
+        return 1; /* GPR_TRUE */
+      }
+    }
+  }
+  return 0; /* GPR_FALSE */
+}
+
+grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
+    grpc_channel_args **a,
+    grpc_compression_algorithm algorithm,
+    int state) {
+  int *states_arg;
+  grpc_channel_args *result = *a;
+  const int states_arg_found =
+      find_compression_algorithm_states_bitset(*a, &states_arg);
+
+  if (states_arg_found) {
+    if (state != 0) {
+      GPR_BITSET(states_arg, algorithm);
+    } else {
+      GPR_BITCLEAR(states_arg, algorithm);
+    }
+  } else {
+    /* create a new arg */
+    grpc_arg tmp;
+    tmp.type = GRPC_ARG_INTEGER;
+    tmp.key = GRPC_COMPRESSION_ALGORITHM_STATE_ARG;
+    /* all enabled by default */
+    tmp.value.integer = (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1;
+    if (state != 0) {
+      GPR_BITSET(&tmp.value.integer, algorithm);
+    } else {
+      GPR_BITCLEAR(&tmp.value.integer, algorithm);
+    }
+    result = grpc_channel_args_copy_and_add(*a, &tmp, 1);
+    grpc_channel_args_destroy(*a);
+    *a = result;
+  }
+  return result;
+}
+
+int grpc_channel_args_compression_algorithm_get_states(
+    const grpc_channel_args *a) {
+  int *states_arg;
+  if (find_compression_algorithm_states_bitset(a, &states_arg)) {
+    return *states_arg;
+  } else {
+    return (1u << GRPC_COMPRESS_ALGORITHMS_COUNT) - 1; /* All algs. enabled */
+  }
+}

src/core/channel/channel_args.h

@@ -67,4 +67,24 @@ grpc_compression_algorithm grpc_channel_args_get_compression_algorithm(
 grpc_channel_args *grpc_channel_args_set_compression_algorithm(
     grpc_channel_args *a, grpc_compression_algorithm algorithm);
 
+/** Sets the support for the given compression algorithm. By default, all
+ * compression algorithms are enabled. It's an error to disable an algorithm set
+ * by grpc_channel_args_set_compression_algorithm.
+ *
+ * Returns an instance will the updated algorithm states. The \a a pointer is
+ * modified to point to the returned instance (which may be different from the
+ * input value of \a a). */
+grpc_channel_args *grpc_channel_args_compression_algorithm_set_state(
+    grpc_channel_args **a,
+    grpc_compression_algorithm algorithm,
+    int enabled);
+
+/** Returns the bitset representing the support state (true for enabled, false
+ * for disabled) for compression algorithms.
+ *
+ * The i-th bit of the returned bitset corresponds to the i-th entry in the
+ * grpc_compression_algorithm enum. */
+int grpc_channel_args_compression_algorithm_get_states(
+    const grpc_channel_args *a);
+
 #endif /* GRPC_INTERNAL_CORE_CHANNEL_CHANNEL_ARGS_H */

src/core/channel/client_channel.c

@@ -505,13 +505,13 @@ static void cc_on_config_changed(void *arg, int iomgr_success) {
   if (iomgr_success && chand->resolver) {
     grpc_resolver *resolver = chand->resolver;
     GRPC_RESOLVER_REF(resolver, "channel-next");
+    grpc_connectivity_state_set(&chand->state_tracker, state,
+                                "new_lb+resolver");
     gpr_mu_unlock(&chand->mu_config);
     GRPC_CHANNEL_INTERNAL_REF(chand->master, "resolver");
     grpc_resolver_next(resolver, &chand->incoming_configuration,
                        &chand->on_config_changed);
     GRPC_RESOLVER_UNREF(resolver, "channel-next");
-    grpc_connectivity_state_set(&chand->state_tracker, state,
-                                "new_lb+resolver");
     if (lb_policy != NULL) {
       watch_lb_policy(chand, lb_policy, state);
     }

src/core/channel/compress_filter.c

@@ -216,7 +216,7 @@ static void process_send_ops(grpc_call_element *elem,
                                   [calld->compression_algorithm]));
 
           /* convey supported compression algorithms */
-          grpc_metadata_batch_add_head(
+          grpc_metadata_batch_add_tail(
               &(sop->data.metadata), &calld->accept_encoding_storage,
               GRPC_MDELEM_REF(channeld->mdelem_accept_encoding));
 

src/core/iomgr/pollset.h

@@ -74,10 +74,9 @@ void grpc_pollset_destroy(grpc_pollset *pollset);
    grpc_pollset_work, and it is guaranteed that GRPC_POLLSET_MU(pollset) will
    not be released by grpc_pollset_work AFTER worker has been destroyed.
 
-   Returns true if some work has been done, and false if the deadline
-   expired. */
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline);
+   Tries not to block past deadline. */
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+                       gpr_timespec now, gpr_timespec deadline);
 
 /* Break one polling thread out of polling work for this pollset.
    If specific_worker is GRPC_POLLSET_KICK_BROADCAST, kick ALL the workers.

src/core/iomgr/pollset_multipoller_with_epoll.c

@@ -181,7 +181,7 @@ static void multipoll_with_epoll_pollset_maybe_work(
   pfds[1].events = POLLIN;
   pfds[1].revents = 0;
 
-  poll_rv = poll(pfds, 2, timeout_ms);
+  poll_rv = grpc_poll_function(pfds, 2, timeout_ms);
 
   if (poll_rv < 0) {
     if (errno != EINTR) {

src/core/iomgr/pollset_multipoller_with_poll_posix.c

@@ -144,7 +144,7 @@ static void multipoll_with_poll_pollset_maybe_work(
                                         POLLOUT, &watchers[i]);
   }
 
-  r = poll(pfds, pfd_count, timeout);
+  r = grpc_poll_function(pfds, pfd_count, timeout);
 
   for (i = 1; i < pfd_count; i++) {
     grpc_fd_end_poll(&watchers[i], pfds[i].revents & POLLIN,

src/core/iomgr/pollset_posix.c

@@ -38,7 +38,6 @@
 #include "src/core/iomgr/pollset_posix.h"
 
 #include <errno.h>
-#include <poll.h>
 #include <stdlib.h>
 #include <string.h>
 #include <unistd.h>
@@ -57,6 +56,8 @@
 GPR_TLS_DECL(g_current_thread_poller);
 GPR_TLS_DECL(g_current_thread_worker);
 
+grpc_poll_function_type grpc_poll_function = poll;
+
 static void remove_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
   worker->prev->next = worker->next;
   worker->next->prev = worker->prev;
@@ -89,6 +90,7 @@ static void push_front_worker(grpc_pollset *p, grpc_pollset_worker *worker) {
 }
 
 void grpc_pollset_kick(grpc_pollset *p, grpc_pollset_worker *specific_worker) {
+  /* pollset->mu already held */
   if (specific_worker != NULL) {
     if (specific_worker == GRPC_POLLSET_KICK_BROADCAST) {
       for (specific_worker = p->root_worker.next;
@@ -168,14 +170,10 @@ static void finish_shutdown(grpc_pollset *pollset) {
   pollset->shutdown_done_cb(pollset->shutdown_done_arg);
 }
 
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline) {
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
+                       gpr_timespec now, gpr_timespec deadline) {
   /* pollset->mu already held */
-  gpr_timespec now = gpr_now(GPR_CLOCK_MONOTONIC);
   int added_worker = 0;
-  if (gpr_time_cmp(now, deadline) > 0) {
-    return 0;
-  }
   /* this must happen before we (potentially) drop pollset->mu */
   worker->next = worker->prev = NULL;
   /* TODO(ctiller): pool these */
@@ -217,7 +215,6 @@ done:
       gpr_mu_lock(&pollset->mu);
     }
   }
-  return 1;
 }
 
 void grpc_pollset_shutdown(grpc_pollset *pollset,
@@ -456,7 +453,7 @@ static void basic_pollset_maybe_work(grpc_pollset *pollset,
 
   /* poll fd count (argument 2) is shortened by one if we have no events
      to poll on - such that it only includes the kicker */
-  r = poll(pfd, nfds, timeout);
+  r = grpc_poll_function(pfd, nfds, timeout);
   GRPC_TIMER_MARK(GRPC_PTAG_POLL_FINISHED, r);
 
   if (fd) {

src/core/iomgr/pollset_posix.h

@@ -34,6 +34,8 @@
 #ifndef GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 #define GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H
 
+#include <poll.h>
+
 #include <grpc/support/sync.h>
 #include "src/core/iomgr/wakeup_fd_posix.h"
 
@@ -118,4 +120,8 @@ void grpc_poll_become_multipoller(grpc_pollset *pollset, struct grpc_fd **fds,
  * be locked) */
 int grpc_pollset_has_workers(grpc_pollset *pollset);
 
+/* override to allow tests to hook poll() usage */
+typedef int (*grpc_poll_function_type)(struct pollfd *, nfds_t, int);
+extern grpc_poll_function_type grpc_poll_function;
+
 #endif /* GRPC_INTERNAL_CORE_IOMGR_POLLSET_POSIX_H */

src/core/iomgr/pollset_windows.c

@@ -99,14 +99,9 @@ void grpc_pollset_destroy(grpc_pollset *pollset) {
   gpr_mu_destroy(&pollset->mu);
 }
 
-int grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker,
-                      gpr_timespec deadline) {
-  gpr_timespec now;
+void grpc_pollset_work(grpc_pollset *pollset, grpc_pollset_worker *worker, 
+                       gpr_timespec now, gpr_timespec deadline) {
   int added_worker = 0;
-  now = gpr_now(GPR_CLOCK_MONOTONIC);
-  if (gpr_time_cmp(now, deadline) > 0) {
-    return 0 /* GPR_FALSE */;
-  }
   worker->next = worker->prev = NULL;
   gpr_cv_init(&worker->cv);
   if (grpc_maybe_call_delayed_callbacks(&pollset->mu, 1 /* GPR_TRUE */)) {
@@ -127,7 +122,6 @@ done:
   if (added_worker) {
     remove_worker(pollset, worker);
   }
-  return 1 /* GPR_TRUE */;
 }
 
 void grpc_pollset_kick(grpc_pollset *p, grpc_pollset_worker *specific_worker) {

src/core/security/google_default_credentials.c

@@ -115,7 +115,7 @@ static int is_stack_running_on_compute_engine(void) {
   gpr_mu_lock(GRPC_POLLSET_MU(&detector.pollset));
   while (!detector.is_done) {
     grpc_pollset_worker worker;
-    grpc_pollset_work(&detector.pollset, &worker,
+    grpc_pollset_work(&detector.pollset, &worker, gpr_now(GPR_CLOCK_MONOTONIC),
                       gpr_inf_future(GPR_CLOCK_MONOTONIC));
   }
   gpr_mu_unlock(GRPC_POLLSET_MU(&detector.pollset));

src/core/security/server_auth_filter.c

@@ -104,24 +104,34 @@ static grpc_mdelem *remove_consumed_md(void *user_data, grpc_mdelem *md) {
   return md;
 }
 
-static void on_md_processing_done(void *user_data,
-                                  const grpc_metadata *consumed_md,
-                                  size_t num_consumed_md, int success) {
+static void on_md_processing_done(
+    void *user_data, const grpc_metadata *consumed_md, size_t num_consumed_md,
+    const grpc_metadata *response_md, size_t num_response_md,
+    grpc_status_code status, const char *error_details) {
   grpc_call_element *elem = user_data;
   call_data *calld = elem->call_data;
 
-  if (success) {
+  /* TODO(jboeuf): Implement support for response_md. */
+  if (response_md != NULL && num_response_md > 0) {
+    gpr_log(GPR_INFO,
+            "response_md in auth metadata processing not supported for now. "
+            "Ignoring...");
+  }
+
+  if (status == GRPC_STATUS_OK) {
     calld->consumed_md = consumed_md;
     calld->num_consumed_md = num_consumed_md;
     grpc_metadata_batch_filter(&calld->md_op->data.metadata, remove_consumed_md,
                                elem);
-    calld->on_done_recv->cb(calld->on_done_recv->cb_arg, success);
+    calld->on_done_recv->cb(calld->on_done_recv->cb_arg, 1);
   } else {
-    gpr_slice message = gpr_slice_from_copied_string(
-        "Authentication metadata processing failed.");
+    gpr_slice message;
+    error_details = error_details != NULL
+                    ? error_details
+                    : "Authentication metadata processing failed.";
+    message = gpr_slice_from_copied_string(error_details);
     grpc_sopb_reset(calld->recv_ops);
-    grpc_transport_stream_op_add_close(&calld->transport_op,
-                                       GRPC_STATUS_UNAUTHENTICATED, &message);
+    grpc_transport_stream_op_add_close(&calld->transport_op, status, &message);
     grpc_call_next_op(elem, &calld->transport_op);
   }
 }

src/core/surface/call.c

@@ -1573,7 +1573,8 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
   const grpc_op *op;
   grpc_ioreq *req;
   void (*finish_func)(grpc_call *, int, void *) = finish_batch;
-  GPR_ASSERT(!reserved);
+
+  if (reserved != NULL) return GRPC_CALL_ERROR;
 
   GRPC_CALL_LOG_BATCH(GPR_INFO, call, ops, nops, tag);
 
@@ -1588,6 +1589,7 @@ grpc_call_error grpc_call_start_batch(grpc_call *call, const grpc_op *ops,
   /* rewrite batch ops into ioreq ops */
   for (in = 0, out = 0; in < nops; in++) {
     op = &ops[in];
+    if (op->reserved != NULL) return GRPC_CALL_ERROR;
     switch (op->op) {
       case GRPC_OP_SEND_INITIAL_METADATA:
         /* Flag validation: currently allow no flags */

src/core/surface/completion_queue.c

@@ -170,6 +170,9 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
                                       gpr_timespec deadline, void *reserved) {
   grpc_event ret;
   grpc_pollset_worker worker;
+  int first_loop = 1;
+  gpr_timespec now;
+
   GPR_ASSERT(!reserved);
 
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
@@ -196,12 +199,15 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
       ret.type = GRPC_QUEUE_SHUTDOWN;
       break;
     }
-    if (!grpc_pollset_work(&cc->pollset, &worker, deadline)) {
+    now = gpr_now(GPR_CLOCK_MONOTONIC);
+    if (!first_loop && gpr_time_cmp(now, deadline) >= 0) {
       gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
+    first_loop = 0;
+    grpc_pollset_work(&cc->pollset, &worker, now, deadline);
   }
   GRPC_SURFACE_TRACE_RETURNED_EVENT(cc, &ret);
   GRPC_CQ_INTERNAL_UNREF(cc, "next");
@@ -239,6 +245,9 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
   grpc_cq_completion *c;
   grpc_cq_completion *prev;
   grpc_pollset_worker worker;
+  gpr_timespec now;
+  int first_loop = 1;
+
   GPR_ASSERT(!reserved);
 
   deadline = gpr_convert_clock_type(deadline, GPR_CLOCK_MONOTONIC);
@@ -281,13 +290,16 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
-    if (!grpc_pollset_work(&cc->pollset, &worker, deadline)) {
+    now = gpr_now(GPR_CLOCK_MONOTONIC);
+    if (!first_loop && gpr_time_cmp(now, deadline) >= 0) {
       del_plucker(cc, tag, &worker);
       gpr_mu_unlock(GRPC_POLLSET_MU(&cc->pollset));
       memset(&ret, 0, sizeof(ret));
       ret.type = GRPC_QUEUE_TIMEOUT;
       break;
     }
+    first_loop = 0;
+    grpc_pollset_work(&cc->pollset, &worker, now, deadline);
     del_plucker(cc, tag, &worker);
   }
 done:

src/core/surface/server.c

@@ -975,6 +975,11 @@ void grpc_server_setup_transport(grpc_server *s, grpc_transport *transport,
   grpc_transport_perform_op(transport, &op);
 }
 
+void done_published_shutdown(void *done_arg, grpc_cq_completion *storage) {
+  (void) done_arg;
+  gpr_free(storage);
+}
+
 void grpc_server_shutdown_and_notify(grpc_server *server,
                                      grpc_completion_queue *cq, void *tag) {
   listener *l;
@@ -986,6 +991,12 @@ void grpc_server_shutdown_and_notify(grpc_server *server,
   /* lock, and gather up some stuff to do */
   gpr_mu_lock(&server->mu_global);
   grpc_cq_begin_op(cq);
+  if (server->shutdown_published) {
+    grpc_cq_end_op(cq, tag, 1, done_published_shutdown, NULL,
+                   gpr_malloc(sizeof(grpc_cq_completion)));
+    gpr_mu_unlock(&server->mu_global);
+    return;
+  }
   server->shutdown_tags =
       gpr_realloc(server->shutdown_tags,
                   sizeof(shutdown_tag) * (server->num_shutdown_tags + 1));
@@ -1135,6 +1146,7 @@ grpc_call_error grpc_server_request_call(
     return GRPC_CALL_ERROR_NOT_SERVER_COMPLETION_QUEUE;
   }
   grpc_cq_begin_op(cq_for_notification);
+  details->reserved = NULL;
   rc->type = BATCH_CALL;
   rc->server = server;
   rc->tag = tag;

src/core/surface/version.c

@@ -36,4 +36,6 @@
 
 #include <grpc/grpc.h>
 
-const char *grpc_version_string(void) { return "0.10.1.0"; }
+const char *grpc_version_string(void) {
+	return "0.10.1.0";
+}

src/cpp/client/channel.cc

@@ -71,7 +71,7 @@ Call Channel::CreateCall(const RpcMethod& method, ClientContext* context,
   } else {
     const char* host_str = NULL;
     if (!context->authority().empty()) {
-      host_str = context->authority().c_str();
+      host_str = context->authority_.c_str();
     } else if (!host_.empty()) {
       host_str = host_.c_str();
     }

src/cpp/server/server.cc

@@ -50,6 +50,52 @@
 
 namespace grpc {
 
+class Server::UnimplementedAsyncRequestContext {
+ protected:
+  UnimplementedAsyncRequestContext() : generic_stream_(&server_context_) {}
+
+  GenericServerContext server_context_;
+  GenericServerAsyncReaderWriter generic_stream_;
+};
+
+class Server::UnimplementedAsyncRequest GRPC_FINAL
+    : public UnimplementedAsyncRequestContext,
+      public GenericAsyncRequest {
+ public:
+  UnimplementedAsyncRequest(Server* server, ServerCompletionQueue* cq)
+      : GenericAsyncRequest(server, &server_context_, &generic_stream_, cq, cq,
+                            NULL, false),
+        server_(server),
+        cq_(cq) {}
+
+  bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE;
+
+  ServerContext* context() { return &server_context_; }
+  GenericServerAsyncReaderWriter* stream() { return &generic_stream_; }
+
+ private:
+  Server* const server_;
+  ServerCompletionQueue* const cq_;
+};
+
+typedef SneakyCallOpSet<CallOpSendInitialMetadata, CallOpServerSendStatus>
+    UnimplementedAsyncResponseOp;
+class Server::UnimplementedAsyncResponse GRPC_FINAL
+    : public UnimplementedAsyncResponseOp {
+ public:
+  UnimplementedAsyncResponse(UnimplementedAsyncRequest* request);
+  ~UnimplementedAsyncResponse() { delete request_; }
+
+  bool FinalizeResult(void** tag, bool* status) GRPC_OVERRIDE {
+    bool r = UnimplementedAsyncResponseOp::FinalizeResult(tag, status);
+    delete this;
+    return r;
+  }
+
+ private:
+  UnimplementedAsyncRequest* const request_;
+};
+
 class Server::ShutdownRequest GRPC_FINAL : public CompletionQueueTag {
  public:
   bool FinalizeResult(void** tag, bool* status) {
@@ -90,6 +136,26 @@ class Server::SyncRequest GRPC_FINAL : public CompletionQueueTag {
     return mrd;
   }
 
+  static bool AsyncWait(CompletionQueue* cq, SyncRequest** req, bool* ok,
+                        gpr_timespec deadline) {
+    void* tag = nullptr;
+    *ok = false;
+    switch (cq->AsyncNext(&tag, ok, deadline)) {
+      case CompletionQueue::TIMEOUT:
+        *req = nullptr;
+        return true;
+      case CompletionQueue::SHUTDOWN:
+        *req = nullptr;
+        return false;
+      case CompletionQueue::GOT_EVENT:
+        *req = static_cast<SyncRequest*>(tag);
+        GPR_ASSERT((*req)->in_flight_);
+        return true;
+    }
+    gpr_log(GPR_ERROR, "Should never reach here");
+    abort();
+  }
+
   void SetupRequest() { cq_ = grpc_completion_queue_create(nullptr); }
 
   void TeardownRequest() {
@@ -277,18 +343,23 @@ int Server::AddListeningPort(const grpc::string& addr,
   return creds->AddPortToServer(addr, server_);
 }
 
-bool Server::Start() {
+bool Server::Start(ServerCompletionQueue** cqs, size_t num_cqs) {
   GPR_ASSERT(!started_);
   started_ = true;
   grpc_server_start(server_);
 
   if (!has_generic_service_) {
-    unknown_method_.reset(new RpcServiceMethod(
-        "unknown", RpcMethod::BIDI_STREAMING, new UnknownMethodHandler));
-    // Use of emplace_back with just constructor arguments is not accepted here
-    // by gcc-4.4 because it can't match the anonymous nullptr with a proper
-    // constructor implicitly. Construct the object and use push_back.
-    sync_methods_->push_back(SyncRequest(unknown_method_.get(), nullptr));
+    if (!sync_methods_->empty()) {
+      unknown_method_.reset(new RpcServiceMethod(
+          "unknown", RpcMethod::BIDI_STREAMING, new UnknownMethodHandler));
+      // Use of emplace_back with just constructor arguments is not accepted
+      // here by gcc-4.4 because it can't match the anonymous nullptr with a 
+      // proper constructor implicitly. Construct the object and use push_back.
+      sync_methods_->push_back(SyncRequest(unknown_method_.get(), nullptr));
+    }
+    for (size_t i = 0; i < num_cqs; i++) {
+      new UnimplementedAsyncRequest(this, cqs[i]);
+    }
   }
   // Start processing rpcs.
   if (!sync_methods_->empty()) {
@@ -303,12 +374,27 @@ bool Server::Start() {
   return true;
 }
 
-void Server::Shutdown() {
+void Server::ShutdownInternal(gpr_timespec deadline) {
   grpc::unique_lock<grpc::mutex> lock(mu_);
   if (started_ && !shutdown_) {
     shutdown_ = true;
     grpc_server_shutdown_and_notify(server_, cq_.cq(), new ShutdownRequest());
     cq_.Shutdown();
+    // Spin, eating requests until the completion queue is completely shutdown.
+    // If the deadline expires then cancel anything that's pending and keep
+    // spinning forever until the work is actually drained.
+    // Since nothing else needs to touch state guarded by mu_, holding it 
+    // through this loop is fine.
+    SyncRequest* request;
+    bool ok;
+    while (SyncRequest::AsyncWait(&cq_, &request, &ok, deadline)) {
+      if (request == NULL) {  // deadline expired
+        grpc_server_cancel_all_calls(server_);
+        deadline = gpr_inf_future(GPR_CLOCK_MONOTONIC);
+      } else if (ok) {
+        SyncRequest::CallData call_data(this, request);
+      }
+    }
 
     // Wait for running callbacks to finish.
     while (num_running_cb_ != 0) {
@@ -335,12 +421,14 @@ void Server::PerformOpsOnCall(CallOpSetInterface* ops, Call* call) {
 
 Server::BaseAsyncRequest::BaseAsyncRequest(
     Server* server, ServerContext* context,
-    ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag)
+    ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag,
+    bool delete_on_finalize)
     : server_(server),
       context_(context),
       stream_(stream),
       call_cq_(call_cq),
       tag_(tag),
+      delete_on_finalize_(delete_on_finalize),
       call_(nullptr) {
   memset(&initial_metadata_array_, 0, sizeof(initial_metadata_array_));
 }
@@ -367,14 +455,16 @@ bool Server::BaseAsyncRequest::FinalizeResult(void** tag, bool* status) {
   // just the pointers inside call are copied here
   stream_->BindCall(&call);
   *tag = tag_;
-  delete this;
+  if (delete_on_finalize_) {
+    delete this;
+  }
   return true;
 }
 
 Server::RegisteredAsyncRequest::RegisteredAsyncRequest(
     Server* server, ServerContext* context,
     ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq, void* tag)
-    : BaseAsyncRequest(server, context, stream, call_cq, tag) {}
+    : BaseAsyncRequest(server, context, stream, call_cq, tag, true) {}
 
 void Server::RegisteredAsyncRequest::IssueRequest(
     void* registered_method, grpc_byte_buffer** payload,
@@ -388,8 +478,9 @@ void Server::RegisteredAsyncRequest::IssueRequest(
 Server::GenericAsyncRequest::GenericAsyncRequest(
     Server* server, GenericServerContext* context,
     ServerAsyncStreamingInterface* stream, CompletionQueue* call_cq,
-    ServerCompletionQueue* notification_cq, void* tag)
-    : BaseAsyncRequest(server, context, stream, call_cq, tag) {
+    ServerCompletionQueue* notification_cq, void* tag, bool delete_on_finalize)
+    : BaseAsyncRequest(server, context, stream, call_cq, tag,
+                       delete_on_finalize) {
   grpc_call_details_init(&call_details_);
   GPR_ASSERT(notification_cq);
   GPR_ASSERT(call_cq);
@@ -410,6 +501,25 @@ bool Server::GenericAsyncRequest::FinalizeResult(void** tag, bool* status) {
   return BaseAsyncRequest::FinalizeResult(tag, status);
 }
 
+bool Server::UnimplementedAsyncRequest::FinalizeResult(void** tag,
+                                                       bool* status) {
+  if (GenericAsyncRequest::FinalizeResult(tag, status) && *status) {
+    new UnimplementedAsyncRequest(server_, cq_);
+    new UnimplementedAsyncResponse(this);
+  } else {
+    delete this;
+  }
+  return false;
+}
+
+Server::UnimplementedAsyncResponse::UnimplementedAsyncResponse(
+    UnimplementedAsyncRequest* request)
+    : request_(request) {
+  Status status(StatusCode::UNIMPLEMENTED, "");
+  UnknownMethodHandler::FillOps(request_->context(), this);
+  request_->stream()->call_.PerformOps(this);
+}
+
 void Server::ScheduleCallback() {
   {
     grpc::unique_lock<grpc::mutex> lock(mu_);

src/cpp/server/server_builder.cc

@@ -103,12 +103,6 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
     thread_pool_ = CreateDefaultThreadPool();
     thread_pool_owned = true;
   }
-  // Async services only, create a thread pool to handle requests to unknown
-  // services.
-  if (!thread_pool_ && !generic_service_ && !async_services_.empty()) {
-    thread_pool_ = new FixedSizeThreadPool(1);
-    thread_pool_owned = true;
-  }
   std::unique_ptr<Server> server(
       new Server(thread_pool_, thread_pool_owned, max_message_size_));
   for (auto cq = cqs_.begin(); cq != cqs_.end(); ++cq) {
@@ -138,7 +132,7 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
       *port->selected_port = r;
     }
   }
-  if (!server->Start()) {
+  if (!server->Start(&cqs_[0], cqs_.size())) {
     return nullptr;
   }
   return server;

src/csharp/.gitignore

@@ -5,4 +5,5 @@ test-results
 packages
 Grpc.v12.suo
 TestResult.xml
+/TestResults
 *.nupkg

src/csharp/Grpc.Auth/AuthInterceptors.cs

@@ -0,0 +1,84 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Threading;
+
+using Google.Apis.Auth.OAuth2;
+using Grpc.Core;
+using Grpc.Core.Utils;
+
+namespace Grpc.Auth
+{
+    /// <summary>
+    /// Factory methods to create authorization interceptors.
+    /// </summary>
+    public static class AuthInterceptors
+    {
+        private const string AuthorizationHeader = "Authorization";
+        private const string Schema = "Bearer";
+
+        /// <summary>
+        /// Creates interceptor that will obtain access token from any credential type that implements
+        /// <c>ITokenAccess</c>. (e.g. <c>GoogleCredential</c>).
+        /// </summary>
+        public static HeaderInterceptor FromCredential(ITokenAccess credential)
+        {
+            return new HeaderInterceptor((method, authUri, metadata) =>
+            {
+                // TODO(jtattermusch): Rethink synchronous wait to obtain the result.
+                var accessToken = credential.GetAccessTokenForRequestAsync(authUri, CancellationToken.None)
+                        .ConfigureAwait(false).GetAwaiter().GetResult();
+                metadata.Add(CreateBearerTokenHeader(accessToken));
+            });
+        }
+
+        /// <summary>
+        /// Creates OAuth2 interceptor that will use given access token as authorization.
+        /// </summary>
+        /// <param name="accessToken">OAuth2 access token.</param>
+        public static HeaderInterceptor FromAccessToken(string accessToken)
+        {
+            Preconditions.CheckNotNull(accessToken);
+            return new HeaderInterceptor((method, authUri, metadata) =>
+            {
+                metadata.Add(CreateBearerTokenHeader(accessToken));
+            });
+        }
+
+        private static Metadata.Entry CreateBearerTokenHeader(string accessToken)
+        {
+            return new Metadata.Entry(AuthorizationHeader, Schema + " " + accessToken);
+        }
+    }
+}

src/csharp/Grpc.Auth/Grpc.Auth.csproj

@@ -3,8 +3,6 @@
   <PropertyGroup>
     <Configuration Condition=" '$(Configuration)' == '' ">Debug</Configuration>
     <Platform Condition=" '$(Platform)' == '' ">AnyCPU</Platform>
-    <ProductVersion>10.0.0</ProductVersion>
-    <SchemaVersion>2.0</SchemaVersion>
     <ProjectGuid>{AE21D0EE-9A2C-4C15-AB7F-5224EED5B0EA}</ProjectGuid>
     <OutputType>Library</OutputType>
     <RootNamespace>Grpc.Auth</RootNamespace>
@@ -41,57 +39,47 @@
     <AssemblyOriginatorKeyFile>C:\keys\Grpc.snk</AssemblyOriginatorKeyFile>
   </PropertyGroup>
   <ItemGroup>
-    <Reference Include="BouncyCastle.Crypto, Version=1.7.4137.9688, Culture=neutral, PublicKeyToken=a4292a325f69b123, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="System" />
+    <Reference Include="System.Net" />
+    <Reference Include="System.Net.Http" />
+    <Reference Include="System.Net.Http.WebRequest" />
+    <Reference Include="BouncyCastle.Crypto">
       <HintPath>..\packages\BouncyCastle.1.7.0\lib\Net40-Client\BouncyCastle.Crypto.dll</HintPath>
     </Reference>
-    <Reference Include="Google.Apis.Auth, Version=1.9.3.19379, Culture=neutral, PublicKeyToken=4b01fa6e34db77ab, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Google.Apis.Auth">
       <HintPath>..\packages\Google.Apis.Auth.1.9.3\lib\net40\Google.Apis.Auth.dll</HintPath>
     </Reference>
-    <Reference Include="Google.Apis.Auth.PlatformServices, Version=1.9.3.19383, Culture=neutral, PublicKeyToken=4b01fa6e34db77ab, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Google.Apis.Auth.PlatformServices">
       <HintPath>..\packages\Google.Apis.Auth.1.9.3\lib\net40\Google.Apis.Auth.PlatformServices.dll</HintPath>
     </Reference>
-    <Reference Include="Google.Apis.Core, Version=1.9.3.19379, Culture=neutral, PublicKeyToken=4b01fa6e34db77ab, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Google.Apis.Core">
       <HintPath>..\packages\Google.Apis.Core.1.9.3\lib\portable-net40+sl50+win+wpa81+wp80\Google.Apis.Core.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks, Version=1.0.12.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Microsoft.Threading.Tasks">
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks.Extensions, Version=1.0.12.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Microsoft.Threading.Tasks.Extensions">
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.dll</HintPath>
     </Reference>
-    <Reference Include="Microsoft.Threading.Tasks.Extensions.Desktop, Version=1.0.168.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Microsoft.Threading.Tasks.Extensions.Desktop">
       <HintPath>..\packages\Microsoft.Bcl.Async.1.0.168\lib\net40\Microsoft.Threading.Tasks.Extensions.Desktop.dll</HintPath>
     </Reference>
-    <Reference Include="Newtonsoft.Json, Version=7.0.0.0, Culture=neutral, PublicKeyToken=30ad4fe6b2a6aeed, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="Newtonsoft.Json">
       <HintPath>..\packages\Newtonsoft.Json.7.0.1\lib\net45\Newtonsoft.Json.dll</HintPath>
     </Reference>
-    <Reference Include="System" />
-    <Reference Include="System.Net" />
-    <Reference Include="System.Net.Http" />
-    <Reference Include="System.Net.Http.Extensions, Version=2.2.29.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="System.Net.Http.Extensions">
       <HintPath>..\packages\Microsoft.Net.Http.2.2.29\lib\net45\System.Net.Http.Extensions.dll</HintPath>
     </Reference>
-    <Reference Include="System.Net.Http.Primitives, Version=4.2.29.0, Culture=neutral, PublicKeyToken=b03f5f7f11d50a3a, processorArchitecture=MSIL">
-      <SpecificVersion>False</SpecificVersion>
+    <Reference Include="System.Net.Http.Primitives">
       <HintPath>..\packages\Microsoft.Net.Http.2.2.29\lib\net45\System.Net.Http.Primitives.dll</HintPath>
     </Reference>
-    <Reference Include="System.Net.Http.WebRequest" />
   </ItemGroup>
   <ItemGroup>
     <Compile Include="..\Grpc.Core\Version.cs">
       <Link>Version.cs</Link>
     </Compile>
     <Compile Include="Properties\AssemblyInfo.cs" />
-    <Compile Include="OAuth2Interceptors.cs" />
+    <Compile Include="AuthInterceptors.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>

src/csharp/Grpc.Auth/OAuth2Interceptors.cs

@@ -1,115 +0,0 @@
-#region Copyright notice and license
-
-// Copyright 2015, Google Inc.
-// All rights reserved.
-//
-// Redistribution and use in source and binary forms, with or without
-// modification, are permitted provided that the following conditions are
-// met:
-//
-//     * Redistributions of source code must retain the above copyright
-// notice, this list of conditions and the following disclaimer.
-//     * Redistributions in binary form must reproduce the above
-// copyright notice, this list of conditions and the following disclaimer
-// in the documentation and/or other materials provided with the
-// distribution.
-//     * Neither the name of Google Inc. nor the names of its
-// contributors may be used to endorse or promote products derived from
-// this software without specific prior written permission.
-//
-// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
-// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
-// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
-// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
-// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
-// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
-// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
-// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
-// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
-// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
-// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
-
-#endregion
-
-using System;
-using System.Collections.Generic;
-using System.Diagnostics;
-using System.IO;
-using System.Security.Cryptography.X509Certificates;
-using System.Text.RegularExpressions;
-using System.Threading;
-using System.Threading.Tasks;
-
-using Google.Apis.Auth.OAuth2;
-using Google.Apis.Util;
-using Grpc.Core;
-using Grpc.Core.Utils;
-
-namespace Grpc.Auth
-{
-    public static class OAuth2Interceptors
-    {
-        /// <summary>
-        /// Creates OAuth2 interceptor that will obtain access token from GoogleCredentials.
-        /// </summary>
-        public static MetadataInterceptorDelegate FromCredential(GoogleCredential googleCredential)
-        {
-            var interceptor = new OAuth2Interceptor(googleCredential, SystemClock.Default);
-            return new MetadataInterceptorDelegate(interceptor.InterceptHeaders);
-        }
-
-        /// <summary>
-        /// Creates OAuth2 interceptor that will use given OAuth2 token.
-        /// </summary>
-        /// <param name="oauth2Token"></param>
-        /// <returns></returns>
-        public static MetadataInterceptorDelegate FromAccessToken(string oauth2Token)
-        {
-            Preconditions.CheckNotNull(oauth2Token);
-            return new MetadataInterceptorDelegate((authUri, metadata) =>
-            {
-                metadata.Add(OAuth2Interceptor.CreateBearerTokenHeader(oauth2Token));
-            });
-        }
-
-        /// <summary>
-        /// Injects OAuth2 authorization header into initial metadata (= request headers).
-        /// </summary>
-        private class OAuth2Interceptor
-        {
-            private const string AuthorizationHeader = "Authorization";
-            private const string Schema = "Bearer";
-
-            private ITokenAccess credential;
-            private IClock clock;
-
-            public OAuth2Interceptor(ITokenAccess credential, IClock clock)
-            {
-                this.credential = credential;
-                this.clock = clock;
-            }
-
-            /// <summary>
-            /// Gets access token and requests refreshing it if is going to expire soon.
-            /// </summary>
-            /// <param name="cancellationToken"></param>
-            /// <returns></returns>
-            public string GetAccessToken(string authUri, CancellationToken cancellationToken)
-            {
-                // TODO(jtattermusch): Rethink synchronous wait to obtain the result.
-                return credential.GetAccessTokenForRequestAsync(authUri, cancellationToken: cancellationToken).GetAwaiter().GetResult();
-            }
-
-            public void InterceptHeaders(string authUri, Metadata metadata)
-            {
-                var accessToken = GetAccessToken(authUri, CancellationToken.None);
-                metadata.Add(CreateBearerTokenHeader(accessToken));
-            }
-
-            public static Metadata.Entry CreateBearerTokenHeader(string accessToken)
-            {
-                return new Metadata.Entry(AuthorizationHeader, Schema + " " + accessToken);
-            }
-        }
-    }
-}

src/csharp/Grpc.Core.Tests/ChannelTest.cs

@@ -41,12 +41,6 @@ namespace Grpc.Core.Tests
 {
     public class ChannelTest
     {
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void Constructor_RejectsInvalidParams()
         {
@@ -56,36 +50,33 @@ namespace Grpc.Core.Tests
         [Test]
         public void State_IdleAfterCreation()
         {
-            using (var channel = new Channel("localhost", Credentials.Insecure))
-            {
-                Assert.AreEqual(ChannelState.Idle, channel.State);
-            }
+            var channel = new Channel("localhost", Credentials.Insecure);
+            Assert.AreEqual(ChannelState.Idle, channel.State);
+            channel.ShutdownAsync().Wait();
         }
 
         [Test]
         public void WaitForStateChangedAsync_InvalidArgument()
         {
-            using (var channel = new Channel("localhost", Credentials.Insecure))
-            {
-                Assert.Throws(typeof(ArgumentException), () => channel.WaitForStateChangedAsync(ChannelState.FatalFailure));
-            }
+            var channel = new Channel("localhost", Credentials.Insecure);
+            Assert.Throws(typeof(ArgumentException), () => channel.WaitForStateChangedAsync(ChannelState.FatalFailure));
+            channel.ShutdownAsync().Wait();
         }
 
         [Test]
         public void ResolvedTarget()
         {
-            using (var channel = new Channel("127.0.0.1", Credentials.Insecure))
-            {
-                Assert.IsTrue(channel.ResolvedTarget.Contains("127.0.0.1"));
-            }
+            var channel = new Channel("127.0.0.1", Credentials.Insecure);
+            Assert.IsTrue(channel.ResolvedTarget.Contains("127.0.0.1"));
+            channel.ShutdownAsync().Wait();
         }
 
         [Test]
-        public void Dispose_IsIdempotent()
+        public void Shutdown_AllowedOnlyOnce()
         {
             var channel = new Channel("localhost", Credentials.Insecure);
-            channel.Dispose();
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
+            Assert.Throws(typeof(InvalidOperationException), () => channel.ShutdownAsync().GetAwaiter().GetResult());
         }
     }
 }

src/csharp/Grpc.Core.Tests/ClientServerTest.cs

@@ -63,16 +63,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public async Task UnaryCall()
         {
@@ -207,13 +201,6 @@ namespace Grpc.Core.Tests
             CollectionAssert.AreEqual(headers[1].ValueBytes, trailers[1].ValueBytes);
         }
 
-        [Test]
-        public void UnaryCall_DisposedChannel()
-        {
-            channel.Dispose();
-            Assert.Throws(typeof(ObjectDisposedException), () => Calls.BlockingUnaryCall(helper.CreateUnaryCall(), "ABC"));
-        }
-
         [Test]
         public void UnaryCallPerformance()
         {

src/csharp/Grpc.Core.Tests/CompressionTest.cs

@@ -62,16 +62,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void WriteOptions_Unary()
         {

src/csharp/Grpc.Core.Tests/ContextPropagationTest.cs

@@ -62,16 +62,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public async Task PropagateCancellation()
         {

src/csharp/Grpc.Core.Tests/Grpc.Core.Tests.csproj

@@ -64,6 +64,8 @@
       <Link>Version.cs</Link>
     </Compile>
     <Compile Include="ClientBaseTest.cs" />
+    <Compile Include="ShutdownTest.cs" />
+    <Compile Include="Internal\AsyncCallTest.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="ClientServerTest.cs" />
     <Compile Include="ServerTest.cs" />
@@ -82,6 +84,7 @@
     <Compile Include="ResponseHeadersTest.cs" />
     <Compile Include="CompressionTest.cs" />
     <Compile Include="ContextPropagationTest.cs" />
+    <Compile Include="MetadataTest.cs" />
   </ItemGroup>
   <Import Project="$(MSBuildBinPath)\Microsoft.CSharp.targets" />
   <ItemGroup>

src/csharp/Grpc.Core.Tests/GrpcEnvironmentTest.cs

@@ -43,31 +43,40 @@ namespace Grpc.Core.Tests
         [Test]
         public void InitializeAndShutdownGrpcEnvironment()
         {
-            var env = GrpcEnvironment.GetInstance();
+            var env = GrpcEnvironment.AddRef();
             Assert.IsNotNull(env.CompletionQueue);
-            GrpcEnvironment.Shutdown();
+            GrpcEnvironment.Release();
         }
 
         [Test]
         public void SubsequentInvocations()
         {
-            var env1 = GrpcEnvironment.GetInstance();
-            var env2 = GrpcEnvironment.GetInstance();
-            Assert.IsTrue(object.ReferenceEquals(env1, env2));
-            GrpcEnvironment.Shutdown();
-            GrpcEnvironment.Shutdown();
+            var env1 = GrpcEnvironment.AddRef();
+            var env2 = GrpcEnvironment.AddRef();
+            Assert.AreSame(env1, env2);
+            GrpcEnvironment.Release();
+            GrpcEnvironment.Release();
         }
 
         [Test]
         public void InitializeAfterShutdown()
         {
-            var env1 = GrpcEnvironment.GetInstance();
-            GrpcEnvironment.Shutdown();
+            Assert.AreEqual(0, GrpcEnvironment.GetRefCount());
 
-            var env2 = GrpcEnvironment.GetInstance();
-            GrpcEnvironment.Shutdown();
+            var env1 = GrpcEnvironment.AddRef();
+            GrpcEnvironment.Release();
 
-            Assert.IsFalse(object.ReferenceEquals(env1, env2));
+            var env2 = GrpcEnvironment.AddRef();
+            GrpcEnvironment.Release();
+
+            Assert.AreNotSame(env1, env2);
+        }
+
+        [Test]
+        public void ReleaseWithoutAddRef()
+        {
+            Assert.AreEqual(0, GrpcEnvironment.GetRefCount());
+            Assert.Throws(typeof(InvalidOperationException), () => GrpcEnvironment.Release());
         }
 
         [Test]

src/csharp/Grpc.Core.Tests/Internal/AsyncCallTest.cs

@@ -0,0 +1,222 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Runtime.InteropServices;
+using System.Threading.Tasks;
+
+using Grpc.Core.Internal;
+using NUnit.Framework;
+
+namespace Grpc.Core.Internal.Tests
+{
+    public class AsyncCallTest
+    {
+        Channel channel;
+        FakeNativeCall fakeCall;
+        AsyncCall<string, string> asyncCall;
+
+        [SetUp]
+        public void Init()
+        {
+            channel = new Channel("localhost", Credentials.Insecure);
+
+            fakeCall = new FakeNativeCall();
+
+            var callDetails = new CallInvocationDetails<string, string>(channel, "someMethod", null, Marshallers.StringMarshaller, Marshallers.StringMarshaller, new CallOptions());
+            asyncCall = new AsyncCall<string, string>(callDetails, fakeCall);
+        }
+
+        [TearDown]
+        public void Cleanup()
+        {
+            channel.ShutdownAsync().Wait();
+        }
+
+        [Test]
+        public void AsyncUnary_CompletionSuccess()
+        {
+            var resultTask = asyncCall.UnaryCallAsync("abc");
+            fakeCall.UnaryResponseClientHandler(true, new ClientSideStatus(Status.DefaultSuccess, new Metadata()), new byte[] { 1, 2, 3 }, new Metadata());
+            Assert.IsTrue(resultTask.IsCompleted);
+            Assert.IsTrue(fakeCall.IsDisposed);
+            Assert.AreEqual(Status.DefaultSuccess, asyncCall.GetStatus());
+        }
+
+        [Test]
+        public void AsyncUnary_CompletionFailure()
+        {
+            var resultTask = asyncCall.UnaryCallAsync("abc");
+            fakeCall.UnaryResponseClientHandler(false, new ClientSideStatus(new Status(StatusCode.Internal, ""), null), new byte[] { 1, 2, 3 }, new Metadata());
+
+            Assert.IsTrue(resultTask.IsCompleted);
+            Assert.IsTrue(fakeCall.IsDisposed);
+
+            Assert.AreEqual(StatusCode.Internal, asyncCall.GetStatus().StatusCode);
+            Assert.IsNull(asyncCall.GetTrailers());
+            var ex = Assert.Throws<RpcException>(() => resultTask.GetAwaiter().GetResult());
+            Assert.AreEqual(StatusCode.Internal, ex.Status.StatusCode);
+        }
+
+        internal class FakeNativeCall : INativeCall
+        {
+            public UnaryResponseClientHandler UnaryResponseClientHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedStatusOnClientHandler ReceivedStatusOnClientHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedMessageHandler ReceivedMessageHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedResponseHeadersHandler ReceivedResponseHeadersHandler
+            {
+                get;
+                set;
+            }
+
+            public SendCompletionHandler SendCompletionHandler
+            {
+                get;
+                set;
+            }
+
+            public ReceivedCloseOnServerHandler ReceivedCloseOnServerHandler
+            {
+                get;
+                set;
+            }
+
+            public bool IsCancelled
+            {
+                get;
+                set;
+            }
+
+            public bool IsDisposed
+            {
+                get;
+                set;
+            }
+
+            public void Cancel()
+            {
+                IsCancelled = true;
+            }
+
+            public void CancelWithStatus(Status status)
+            {
+                IsCancelled = true;
+            }
+
+            public string GetPeer()
+            {
+                return "PEER";
+            }
+
+            public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                UnaryResponseClientHandler = callback;
+            }
+
+            public void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                throw new NotImplementedException();
+            }
+
+            public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                UnaryResponseClientHandler = callback;
+            }
+
+            public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+            {
+                ReceivedStatusOnClientHandler = callback;
+            }
+
+            public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                ReceivedStatusOnClientHandler = callback;
+            }
+
+            public void StartReceiveMessage(ReceivedMessageHandler callback)
+            {
+                ReceivedMessageHandler = callback;
+            }
+
+            public void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback)
+            {
+                ReceivedResponseHeadersHandler = callback;
+            }
+
+            public void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendMessage(SendCompletionHandler callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendCloseFromClient(SendCompletionHandler callback)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+            {
+                SendCompletionHandler = callback;
+            }
+
+            public void StartServerSide(ReceivedCloseOnServerHandler callback)
+            {
+                ReceivedCloseOnServerHandler = callback;
+            }
+
+            public void Dispose()
+            {
+                IsDisposed = true;
+            }
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/MetadataTest.cs

@@ -0,0 +1,120 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Diagnostics;
+using System.Runtime.InteropServices;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class MetadataTest
+    {
+        [Test]
+        public void AsciiEntry()
+        {
+            var entry = new Metadata.Entry("ABC", "XYZ");
+            Assert.IsFalse(entry.IsBinary);
+            Assert.AreEqual("abc", entry.Key);  // key is in lowercase.
+            Assert.AreEqual("XYZ", entry.Value);
+            CollectionAssert.AreEqual(new[] { (byte)'X', (byte)'Y', (byte)'Z' }, entry.ValueBytes);
+
+            Assert.Throws(typeof(ArgumentException), () => new Metadata.Entry("abc-bin", "xyz"));
+
+            Assert.AreEqual("[Entry: key=abc, value=XYZ]", entry.ToString());
+        }
+
+        [Test]
+        public void BinaryEntry()
+        {
+            var bytes = new byte[] { 1, 2, 3 };
+            var entry = new Metadata.Entry("ABC-BIN", bytes);
+            Assert.IsTrue(entry.IsBinary);
+            Assert.AreEqual("abc-bin", entry.Key);  // key is in lowercase.
+            Assert.Throws(typeof(InvalidOperationException), () => { var v = entry.Value; });
+            CollectionAssert.AreEqual(bytes, entry.ValueBytes);
+
+            Assert.Throws(typeof(ArgumentException), () => new Metadata.Entry("abc", bytes));
+
+            Assert.AreEqual("[Entry: key=abc-bin, valueBytes=System.Byte[]]", entry.ToString());
+        }
+
+        [Test]
+        public void Entry_ConstructionPreconditions()
+        {
+            Assert.Throws(typeof(ArgumentNullException), () => new Metadata.Entry(null, "xyz"));
+            Assert.Throws(typeof(ArgumentNullException), () => new Metadata.Entry("abc", (string)null));
+            Assert.Throws(typeof(ArgumentNullException), () => new Metadata.Entry("abc-bin", (byte[])null));
+        }
+
+        [Test]
+        public void Entry_Immutable()
+        {
+            var origBytes = new byte[] { 1, 2, 3 };
+            var bytes = new byte[] { 1, 2, 3 };
+            var entry = new Metadata.Entry("ABC-BIN", bytes);
+            bytes[0] = 255;  // changing the array passed to constructor should have any effect.
+            CollectionAssert.AreEqual(origBytes, entry.ValueBytes);
+
+            entry.ValueBytes[0] = 255;
+            CollectionAssert.AreEqual(origBytes, entry.ValueBytes);
+        }
+
+        [Test]
+        public void Entry_CreateUnsafe_Ascii()
+        {
+            var bytes = new byte[] { (byte)'X', (byte)'y' };
+            var entry = Metadata.Entry.CreateUnsafe("abc", bytes);
+            Assert.IsFalse(entry.IsBinary);
+            Assert.AreEqual("abc", entry.Key);
+            Assert.AreEqual("Xy", entry.Value);
+            CollectionAssert.AreEqual(bytes, entry.ValueBytes);
+        }
+
+        [Test]
+        public void Entry_CreateUnsafe_Binary()
+        {
+            var bytes = new byte[] { 1, 2, 3 };
+            var entry = Metadata.Entry.CreateUnsafe("abc-bin", bytes);
+            Assert.IsTrue(entry.IsBinary);
+            Assert.AreEqual("abc-bin", entry.Key);
+            Assert.Throws(typeof(InvalidOperationException), () => { var v = entry.Value; });
+            CollectionAssert.AreEqual(bytes, entry.ValueBytes);
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/ResponseHeadersTest.cs

@@ -32,13 +32,16 @@
 #endregion
 
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;
 using System.Threading.Tasks;
+
 using Grpc.Core;
 using Grpc.Core.Internal;
 using Grpc.Core.Utils;
+
 using NUnit.Framework;
 
 namespace Grpc.Core.Tests
@@ -69,14 +72,82 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
+        [Test]
+        public async Task ResponseHeadersAsync_UnaryCall()
+        {
+            helper.UnaryHandler = new UnaryServerMethod<string, string>(async (request, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                return "PASS";
+            });
+
+            var call = Calls.AsyncUnaryCall(helper.CreateUnaryCall(), "");
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual(headers.Count, responseHeaders.Count);
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            Assert.AreEqual("abcdefg", responseHeaders[0].Value);
+
+            Assert.AreEqual("PASS", await call.ResponseAsync);
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_ClientStreamingCall()
+        {
+            helper.ClientStreamingHandler = new ClientStreamingServerMethod<string, string>(async (requestStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                return "PASS";
+            });
+
+            var call = Calls.AsyncClientStreamingCall(helper.CreateClientStreamingCall());
+            await call.RequestStream.CompleteAsync();
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            Assert.AreEqual("PASS", await call.ResponseAsync);
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_ServerStreamingCall()
+        {
+            helper.ServerStreamingHandler = new ServerStreamingServerMethod<string, string>(async (request, responseStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                await responseStream.WriteAsync("PASS");
+            });
+
+            var call = Calls.AsyncServerStreamingCall(helper.CreateServerStreamingCall(), "");
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            CollectionAssert.AreEqual(new[] { "PASS" }, await call.ResponseStream.ToListAsync());
+        }
+
+        [Test]
+        public async Task ResponseHeadersAsync_DuplexStreamingCall()
         {
-            GrpcEnvironment.Shutdown();
+            helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
+            {
+                await context.WriteResponseHeadersAsync(headers);
+                while (await requestStream.MoveNext())
+                {
+                    await responseStream.WriteAsync(requestStream.Current);
+                }
+            });
+
+            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall());
+            var responseHeaders = await call.ResponseHeadersAsync;
+
+            var messages = new[] { "PASS" };
+            await call.RequestStream.WriteAllAsync(messages);
+
+            Assert.AreEqual("ascii-header", responseHeaders[0].Key);
+            CollectionAssert.AreEqual(messages, await call.ResponseStream.ToListAsync());
         }
 
         [Test]

src/csharp/Grpc.Core.Tests/ServerTest.cs

@@ -51,7 +51,6 @@ namespace Grpc.Core.Tests
             };
             server.Start();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
@@ -67,8 +66,7 @@ namespace Grpc.Core.Tests
             Assert.Greater(boundPort.BoundPort, 0);
 
             server.Start();
-            server.ShutdownAsync();
-            GrpcEnvironment.Shutdown();
+            server.ShutdownAsync().Wait();
         }
 
         [Test]
@@ -83,7 +81,6 @@ namespace Grpc.Core.Tests
             Assert.Throws(typeof(InvalidOperationException), () => server.Services.Add(ServerServiceDefinition.CreateBuilder("serviceName").Build()));
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
     }
 }

src/csharp/Grpc.Core.Tests/ShutdownTest.cs

@@ -0,0 +1,77 @@
+#region Copyright notice and license
+
+// Copyright 2015, Google Inc.
+// All rights reserved.
+//
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+using System.Diagnostics;
+using System.Linq;
+using System.Threading;
+using System.Threading.Tasks;
+using Grpc.Core;
+using Grpc.Core.Internal;
+using Grpc.Core.Utils;
+using NUnit.Framework;
+
+namespace Grpc.Core.Tests
+{
+    public class ShutdownTest
+    {
+        const string Host = "127.0.0.1";
+
+        MockServiceHelper helper;
+        Server server;
+        Channel channel;
+
+        [SetUp]
+        public void Init()
+        {
+            helper = new MockServiceHelper(Host);
+            server = helper.GetServer();
+            server.Start();
+            channel = helper.GetChannel();
+        }
+
+        [Test]
+        public async Task AbandonedCall()
+        {
+            helper.DuplexStreamingHandler = new DuplexStreamingServerMethod<string, string>(async (requestStream, responseStream, context) =>
+            {
+                await requestStream.ToListAsync();
+            });
+
+            var call = Calls.AsyncDuplexStreamingCall(helper.CreateDuplexStreamingCall(new CallOptions(deadline: DateTime.UtcNow.AddMilliseconds(1))));
+
+            channel.ShutdownAsync().Wait();
+            server.ShutdownAsync().Wait();
+        }
+    }
+}

src/csharp/Grpc.Core.Tests/TimeoutsTest.cs

@@ -65,16 +65,10 @@ namespace Grpc.Core.Tests
         [TearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
         }
 
-        [TestFixtureTearDown]
-        public void CleanupClass()
-        {
-            GrpcEnvironment.Shutdown();
-        }
-
         [Test]
         public void InfiniteDeadline()
         {

src/csharp/Grpc.Core/AsyncClientStreamingCall.cs

@@ -44,14 +44,16 @@ namespace Grpc.Core
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly Task<TResponse> responseAsync;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> responseAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        public AsyncClientStreamingCall(IClientStreamWriter<TRequest> requestStream, Task<TResponse> responseAsync, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.responseAsync = responseAsync;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -68,6 +70,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
         /// <summary>
         /// Async stream to send streaming requests.
         /// </summary>
@@ -88,6 +101,24 @@ namespace Grpc.Core
             return responseAsync.GetAwaiter();
         }
 
+        /// <summary>
+        /// Gets the call status if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Status GetStatus()
+        {
+            return getStatusFunc();
+        }
+
+        /// <summary>
+        /// Gets the call trailing metadata if the call has already finished.
+        /// Throws InvalidOperationException otherwise.
+        /// </summary>
+        public Metadata GetTrailers()
+        {
+            return getTrailersFunc();
+        }
+
         /// <summary>
         /// Provides means to cleanup after the call.
         /// If the call has already finished normally (request stream has been completed and call result has been received), doesn't do anything.

src/csharp/Grpc.Core/AsyncDuplexStreamingCall.cs

@@ -32,7 +32,6 @@
 #endregion
 
 using System;
-using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 
 namespace Grpc.Core
@@ -44,14 +43,16 @@ namespace Grpc.Core
     {
         readonly IClientStreamWriter<TRequest> requestStream;
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        public AsyncDuplexStreamingCall(IClientStreamWriter<TRequest> requestStream, IAsyncStreamReader<TResponse> responseStream, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.requestStream = requestStream;
             this.responseStream = responseStream;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -79,6 +80,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
         /// <summary>
         /// Gets the call status if the call has already finished.
         /// Throws InvalidOperationException otherwise.

src/csharp/Grpc.Core/AsyncServerStreamingCall.cs

@@ -32,7 +32,6 @@
 #endregion
 
 using System;
-using System.Runtime.CompilerServices;
 using System.Threading.Tasks;
 
 namespace Grpc.Core
@@ -43,13 +42,15 @@ namespace Grpc.Core
     public sealed class AsyncServerStreamingCall<TResponse> : IDisposable
     {
         readonly IAsyncStreamReader<TResponse> responseStream;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        public AsyncServerStreamingCall(IAsyncStreamReader<TResponse> responseStream, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.responseStream = responseStream;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -66,6 +67,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
         /// <summary>
         /// Gets the call status if the call has already finished.
         /// Throws InvalidOperationException otherwise.

src/csharp/Grpc.Core/AsyncUnaryCall.cs

@@ -43,13 +43,15 @@ namespace Grpc.Core
     public sealed class AsyncUnaryCall<TResponse> : IDisposable
     {
         readonly Task<TResponse> responseAsync;
+        readonly Task<Metadata> responseHeadersAsync;
         readonly Func<Status> getStatusFunc;
         readonly Func<Metadata> getTrailersFunc;
         readonly Action disposeAction;
 
-        public AsyncUnaryCall(Task<TResponse> responseAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
+        public AsyncUnaryCall(Task<TResponse> responseAsync, Task<Metadata> responseHeadersAsync, Func<Status> getStatusFunc, Func<Metadata> getTrailersFunc, Action disposeAction)
         {
             this.responseAsync = responseAsync;
+            this.responseHeadersAsync = responseHeadersAsync;
             this.getStatusFunc = getStatusFunc;
             this.getTrailersFunc = getTrailersFunc;
             this.disposeAction = disposeAction;
@@ -66,6 +68,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// Asynchronous access to response headers.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return this.responseHeadersAsync;
+            }
+        }
+
         /// <summary>
         /// Allows awaiting this object directly.
         /// </summary>

src/csharp/Grpc.Core/Calls.cs

@@ -74,7 +74,7 @@ namespace Grpc.Core
         {
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             var asyncResult = asyncCall.UnaryCallAsync(req);
-            return new AsyncUnaryCall<TResponse>(asyncResult, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncUnaryCall<TResponse>(asyncResult, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
@@ -93,7 +93,7 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             asyncCall.StartServerStreamingCall(req);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncServerStreamingCall<TResponse>(responseStream, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
@@ -110,7 +110,7 @@ namespace Grpc.Core
             var asyncCall = new AsyncCall<TRequest, TResponse>(call);
             var resultTask = asyncCall.ClientStreamingCallAsync();
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
-            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncClientStreamingCall<TRequest, TResponse>(requestStream, resultTask, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
 
         /// <summary>
@@ -130,7 +130,7 @@ namespace Grpc.Core
             asyncCall.StartDuplexStreamingCall();
             var requestStream = new ClientRequestStream<TRequest, TResponse>(asyncCall);
             var responseStream = new ClientResponseStream<TRequest, TResponse>(asyncCall);
-            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
+            return new AsyncDuplexStreamingCall<TRequest, TResponse>(requestStream, responseStream, asyncCall.ResponseHeadersAsync, asyncCall.GetStatus, asyncCall.GetTrailers, asyncCall.Cancel);
         }
     }
 }

src/csharp/Grpc.Core/Channel.cs

@@ -45,15 +45,19 @@ namespace Grpc.Core
     /// <summary>
     /// gRPC Channel
     /// </summary>
-    public class Channel : IDisposable
+    public class Channel
     {
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<Channel>();
 
+        readonly object myLock = new object();
+        readonly AtomicCounter activeCallCounter = new AtomicCounter();
+
         readonly string target;
         readonly GrpcEnvironment environment;
         readonly ChannelSafeHandle handle;
         readonly List<ChannelOption> options;
-        bool disposed;
+
+        bool shutdownRequested;
 
         /// <summary>
         /// Creates a channel that connects to a specific host.
@@ -65,7 +69,7 @@ namespace Grpc.Core
         public Channel(string target, Credentials credentials, IEnumerable<ChannelOption> options = null)
         {
             this.target = Preconditions.CheckNotNull(target, "target");
-            this.environment = GrpcEnvironment.GetInstance();
+            this.environment = GrpcEnvironment.AddRef();
             this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
 
             EnsureUserAgentChannelOption(this.options);
@@ -172,12 +176,26 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Destroys the underlying channel.
+        /// Waits until there are no more active calls for this channel and then cleans up
+        /// resources used by this channel.
         /// </summary>
-        public void Dispose()
+        public async Task ShutdownAsync()
         {
-            Dispose(true);
-            GC.SuppressFinalize(this);
+            lock (myLock)
+            {
+                Preconditions.CheckState(!shutdownRequested);
+                shutdownRequested = true;
+            }
+
+            var activeCallCount = activeCallCounter.Count;
+            if (activeCallCount > 0)
+            {
+                Logger.Warning("Channel shutdown was called but there are still {0} active calls for that channel.", activeCallCount);
+            }
+
+            handle.Dispose();
+
+            await Task.Run(() => GrpcEnvironment.Release());
         }
 
         internal ChannelSafeHandle Handle
@@ -196,13 +214,20 @@ namespace Grpc.Core
             }
         }
 
-        protected virtual void Dispose(bool disposing)
+        internal void AddCallReference(object call)
         {
-            if (disposing && handle != null && !disposed)
-            {
-                disposed = true;
-                handle.Dispose();
-            }
+            activeCallCounter.Increment();
+
+            bool success = false;
+            handle.DangerousAddRef(ref success);
+            Preconditions.CheckState(success);
+        }
+
+        internal void RemoveCallReference(object call)
+        {
+            handle.DangerousRelease();
+
+            activeCallCounter.Decrement();
         }
 
         private static void EnsureUserAgentChannelOption(List<ChannelOption> options)

src/csharp/Grpc.Core/ChannelOptions.cs

@@ -71,7 +71,7 @@ namespace Grpc.Core
         /// Creates a channel option with an integer value.
         /// </summary>
         /// <param name="name">Name.</param>
-        /// <param name="stringValue">String value.</param>
+        /// <param name="intValue">Integer value.</param>
         public ChannelOption(string name, int intValue)
         {
             this.type = OptionType.Integer;

src/csharp/Grpc.Core/ClientBase.cs

@@ -32,15 +32,15 @@
 #endregion
 
 using System;
-using System.Collections.Generic;
 using System.Text.RegularExpressions;
-
-using Grpc.Core.Internal;
-using Grpc.Core.Utils;
+using System.Threading.Tasks;
 
 namespace Grpc.Core
 {
-    public delegate void MetadataInterceptorDelegate(string authUri, Metadata metadata);
+    /// <summary>
+    /// Interceptor for call headers.
+    /// </summary>
+    public delegate void HeaderInterceptor(IMethod method, string authUri, Metadata metadata);
 
     /// <summary>
     /// Base class for client-side stubs.
@@ -60,10 +60,10 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Can be used to register a custom header (initial metadata) interceptor.
-        /// The delegate each time before a new call on this client is started.
+        /// Can be used to register a custom header (request metadata) interceptor.
+        /// The interceptor is invoked each time a new call on this client is started.
         /// </summary>
-        public MetadataInterceptorDelegate HeaderInterceptor
+        public HeaderInterceptor HeaderInterceptor
         {
             get;
             set;
@@ -107,7 +107,7 @@ namespace Grpc.Core
                     options = options.WithHeaders(new Metadata());
                 }
                 var authUri = authUriBase != null ? authUriBase + method.ServiceName : null;
-                interceptor(authUri, options.Headers);
+                interceptor(method, authUri, options.Headers);
             }
             return new CallInvocationDetails<TRequest, TResponse>(channel, method, Host, options);
         }
@@ -119,7 +119,8 @@ namespace Grpc.Core
         internal static string GetAuthUriBase(string target)
         {
             var match = ChannelTargetPattern.Match(target);
-            if (!match.Success) {
+            if (!match.Success)
+            {
                 return null;
             }
             return "https://" + match.Groups[2].Value + "/";

src/csharp/Grpc.Core/ContextPropagationToken.cs

@@ -132,7 +132,6 @@ namespace Grpc.Core
         bool propagateDeadline;
         bool propagateCancellation;
 
-
         /// <summary>
         /// Creates new context propagation options.
         /// </summary>

src/csharp/Grpc.Core/Grpc.Core.csproj

@@ -49,6 +49,7 @@
     <Compile Include="AsyncDuplexStreamingCall.cs" />
     <Compile Include="AsyncServerStreamingCall.cs" />
     <Compile Include="IClientStreamWriter.cs" />
+    <Compile Include="Internal\INativeCall.cs" />
     <Compile Include="IServerStreamWriter.cs" />
     <Compile Include="IAsyncStreamWriter.cs" />
     <Compile Include="IAsyncStreamReader.cs" />

src/csharp/Grpc.Core/GrpcEnvironment.cs

@@ -58,6 +58,7 @@ namespace Grpc.Core
 
         static object staticLock = new object();
         static GrpcEnvironment instance;
+        static int refCount;
 
         static ILogger logger = new ConsoleLogger();
 
@@ -67,13 +68,14 @@ namespace Grpc.Core
         bool isClosed;
 
         /// <summary>
-        /// Returns an instance of initialized gRPC environment.
-        /// Subsequent invocations return the same instance unless Shutdown has been called first.
+        /// Returns a reference-counted instance of initialized gRPC environment.
+        /// Subsequent invocations return the same instance unless reference count has dropped to zero previously.
         /// </summary>
-        internal static GrpcEnvironment GetInstance()
+        internal static GrpcEnvironment AddRef()
         {
             lock (staticLock)
             {
+                refCount++;
                 if (instance == null)
                 {
                     instance = new GrpcEnvironment();
@@ -83,14 +85,16 @@ namespace Grpc.Core
         }
 
         /// <summary>
-        /// Shuts down the gRPC environment if it was initialized before.
-        /// Blocks until the environment has been fully shutdown.
+        /// Decrements the reference count for currently active environment and shuts down the gRPC environment if reference count drops to zero.
+        /// (and blocks until the environment has been fully shutdown).
         /// </summary>
-        public static void Shutdown()
+        internal static void Release()
         {
             lock (staticLock)
             {
-                if (instance != null)
+                Preconditions.CheckState(refCount > 0);
+                refCount--;
+                if (refCount == 0)
                 {
                     instance.Close();
                     instance = null;
@@ -98,6 +102,14 @@ namespace Grpc.Core
             }
         }
 
+        internal static int GetRefCount()
+        {
+            lock (staticLock)
+            {
+                return refCount;
+            }
+        }
+
         /// <summary>
         /// Gets application-wide logger used by gRPC.
         /// </summary>
@@ -125,12 +137,10 @@ namespace Grpc.Core
         private GrpcEnvironment()
         {
             NativeLogRedirector.Redirect();
-            grpcsharp_init();
+            GrpcNativeInit();
             completionRegistry = new CompletionRegistry(this);
             threadPool = new GrpcThreadPool(this, THREAD_POOL_SIZE);
             threadPool.Start();
-            // TODO: use proper logging here
-            Logger.Info("gRPC initialized.");
         }
 
         /// <summary>
@@ -175,6 +185,16 @@ namespace Grpc.Core
             return Marshal.PtrToStringAnsi(ptr);
         }
 
+        internal static void GrpcNativeInit()
+        {
+            grpcsharp_init();
+        }
+
+        internal static void GrpcNativeShutdown()
+        {
+            grpcsharp_shutdown();
+        }
+
         /// <summary>
         /// Shuts down this environment.
         /// </summary>
@@ -185,12 +205,10 @@ namespace Grpc.Core
                 throw new InvalidOperationException("Close has already been called");
             }
             threadPool.Stop();
-            grpcsharp_shutdown();
+            GrpcNativeShutdown();
             isClosed = true;
 
             debugStats.CheckOK();
-
-            Logger.Info("gRPC shutdown.");
         }
     }
 }

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

@@ -51,22 +51,35 @@ namespace Grpc.Core.Internal
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<AsyncCall<TRequest, TResponse>>();
 
         readonly CallInvocationDetails<TRequest, TResponse> details;
+        readonly INativeCall injectedNativeCall;  // for testing
 
         // Completion of a pending unary response if not null.
         TaskCompletionSource<TResponse> unaryResponseTcs;
 
+        // Indicates that steaming call has finished.
+        TaskCompletionSource<object> streamingCallFinishedTcs = new TaskCompletionSource<object>();
+
+        // Response headers set here once received.
+        TaskCompletionSource<Metadata> responseHeadersTcs = new TaskCompletionSource<Metadata>();
+
         // Set after status is received. Used for both unary and streaming response calls.
         ClientSideStatus? finishedStatus;
 
-        bool readObserverCompleted;  // True if readObserver has already been completed.
-
         public AsyncCall(CallInvocationDetails<TRequest, TResponse> callDetails)
-            : base(callDetails.RequestMarshaller.Serializer, callDetails.ResponseMarshaller.Deserializer)
+            : base(callDetails.RequestMarshaller.Serializer, callDetails.ResponseMarshaller.Deserializer, callDetails.Channel.Environment)
         {
             this.details = callDetails.WithOptions(callDetails.Options.Normalize());
             this.initialMetadataSent = true;  // we always send metadata at the very beginning of the call.
         }
 
+        /// <summary>
+        /// This constructor should only be used for testing.
+        /// </summary>
+        public AsyncCall(CallInvocationDetails<TRequest, TResponse> callDetails, INativeCall injectedNativeCall) : this(callDetails)
+        {
+            this.injectedNativeCall = injectedNativeCall;
+        }
+
         // TODO: this method is not Async, so it shouldn't be in AsyncCall class, but 
         // it is reusing fair amount of code in this class, so we are leaving it here.
         /// <summary>
@@ -100,7 +113,7 @@ namespace Grpc.Core.Internal
                         bool success = (ev.success != 0);
                         try
                         {
-                            HandleUnaryResponse(success, ctx);
+                            HandleUnaryResponse(success, ctx.GetReceivedStatusOnClient(), ctx.GetReceivedMessage(), ctx.GetReceivedInitialMetadata());
                         }
                         catch (Exception e)
                         {
@@ -125,7 +138,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 halfcloseRequested = true;
                 readingDone = true;
@@ -152,7 +165,7 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 readingDone = true;
 
@@ -176,10 +189,9 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 halfcloseRequested = true;
-                halfclosed = true;  // halfclose not confirmed yet, but it will be once finishedHandler is called.
 
                 byte[] payload = UnsafeSerialize(msg);
 
@@ -187,6 +199,7 @@ namespace Grpc.Core.Internal
                 {
                     call.StartServerStreaming(HandleFinished, payload, metadataArray, GetWriteFlagsForCall());
                 }
+                call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
             }
         }
 
@@ -201,12 +214,13 @@ namespace Grpc.Core.Internal
                 Preconditions.CheckState(!started);
                 started = true;
 
-                Initialize(details.Channel.Environment.CompletionQueue);
+                Initialize(environment.CompletionQueue);
 
                 using (var metadataArray = MetadataArraySafeHandle.Create(details.Options.Headers))
                 {
                     call.StartDuplexStreaming(HandleFinished, metadataArray);
                 }
+                call.StartReceiveInitialMetadata(HandleReceivedResponseHeaders);
             }
         }
 
@@ -247,6 +261,28 @@ namespace Grpc.Core.Internal
             }
         }
 
+        /// <summary>
+        /// Get the task that completes once if streaming call finishes with ok status and throws RpcException with given status otherwise.
+        /// </summary>
+        public Task StreamingCallFinishedTask
+        {
+            get
+            {
+                return streamingCallFinishedTcs.Task;
+            }
+        }
+
+        /// <summary>
+        /// Get the task that completes once response headers are received.
+        /// </summary>
+        public Task<Metadata> ResponseHeadersAsync
+        {
+            get
+            {
+                return responseHeadersTcs.Task;
+            }
+        }
+
         /// <summary>
         /// Gets the resulting status if the call has already finished.
         /// Throws InvalidOperationException otherwise.
@@ -281,51 +317,31 @@ namespace Grpc.Core.Internal
             }
         }
 
-        /// <summary>
-        /// On client-side, we only fire readCompletionDelegate once all messages have been read 
-        /// and status has been received.
-        /// </summary>
-        protected override void ProcessLastRead(AsyncCompletionDelegate<TResponse> completionDelegate)
+        protected override void OnAfterReleaseResources()
         {
-            if (completionDelegate != null && readingDone && finishedStatus.HasValue)
-            {
-                bool shouldComplete;
-                lock (myLock)
-                {
-                    shouldComplete = !readObserverCompleted;
-                    readObserverCompleted = true;
-                }
-
-                if (shouldComplete)
-                {
-                    var status = finishedStatus.Value.Status;
-                    if (status.StatusCode != StatusCode.OK)
-                    {
-                        FireCompletion(completionDelegate, default(TResponse), new RpcException(status));
-                    }
-                    else
-                    {
-                        FireCompletion(completionDelegate, default(TResponse), null);
-                    }
-                }
-            }
+            details.Channel.RemoveCallReference(this);
         }
 
-        protected override void OnReleaseResources()
+        private void Initialize(CompletionQueueSafeHandle cq)
         {
-            details.Channel.Environment.DebugStats.ActiveClientCalls.Decrement();
+            var call = CreateNativeCall(cq);
+            details.Channel.AddCallReference(this);
+            InitializeInternal(call);
+            RegisterCancellationCallback();
         }
 
-        private void Initialize(CompletionQueueSafeHandle cq)
+        private INativeCall CreateNativeCall(CompletionQueueSafeHandle cq)
         {
+            if (injectedNativeCall != null)
+            {
+                return injectedNativeCall;  // allows injecting a mock INativeCall in tests.
+            }
+
             var parentCall = details.Options.PropagationToken != null ? details.Options.PropagationToken.ParentCall : CallSafeHandle.NullInstance;
 
-            var call = details.Channel.Handle.CreateCall(details.Channel.Environment.CompletionRegistry,
+            return details.Channel.Handle.CreateCall(environment.CompletionRegistry,
                 parentCall, ContextPropagationToken.DefaultMask, cq,
                 details.Method, details.Host, Timespec.FromDateTime(details.Options.Deadline.Value));
-            details.Channel.Environment.DebugStats.ActiveClientCalls.Increment();
-            InitializeInternal(call);
-            RegisterCancellationCallback();
         }
 
         // Make sure that once cancellationToken for this call is cancelled, Cancel() will be called.
@@ -348,31 +364,31 @@ namespace Grpc.Core.Internal
         }
 
         /// <summary>
-        /// Handler for unary response completion.
+        /// Handles receive status completion for calls with streaming response.
         /// </summary>
-        private void HandleUnaryResponse(bool success, BatchContextSafeHandle ctx)
+        private void HandleReceivedResponseHeaders(bool success, Metadata responseHeaders)
         {
-            var fullStatus = ctx.GetReceivedStatusOnClient();
+            responseHeadersTcs.SetResult(responseHeaders);
+        }
 
+        /// <summary>
+        /// Handler for unary response completion.
+        /// </summary>
+        private void HandleUnaryResponse(bool success, ClientSideStatus receivedStatus, byte[] receivedMessage, Metadata responseHeaders)
+        {
             lock (myLock)
             {
                 finished = true;
-                finishedStatus = fullStatus;
-
-                halfclosed = true;
+                finishedStatus = receivedStatus;
 
                 ReleaseResourcesIfPossible();
             }
 
-            if (!success)
-            {
-                unaryResponseTcs.SetException(new RpcException(new Status(StatusCode.Internal, "Internal error occured.")));
-                return;
-            }
+            responseHeadersTcs.SetResult(responseHeaders);
 
-            var status = fullStatus.Status;
+            var status = receivedStatus.Status;
 
-            if (status.StatusCode != StatusCode.OK)
+            if (!success || status.StatusCode != StatusCode.OK)
             {
                 unaryResponseTcs.SetException(new RpcException(status));
                 return;
@@ -380,7 +396,7 @@ namespace Grpc.Core.Internal
 
             // TODO: handle deserialization error
             TResponse msg;
-            TryDeserialize(ctx.GetReceivedMessage(), out msg);
+            TryDeserialize(receivedMessage, out msg);
 
             unaryResponseTcs.SetResult(msg);
         }
@@ -388,22 +404,25 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles receive status completion for calls with streaming response.
         /// </summary>
-        private void HandleFinished(bool success, BatchContextSafeHandle ctx)
+        private void HandleFinished(bool success, ClientSideStatus receivedStatus)
         {
-            var fullStatus = ctx.GetReceivedStatusOnClient();
-
-            AsyncCompletionDelegate<TResponse> origReadCompletionDelegate = null;
             lock (myLock)
             {
                 finished = true;
-                finishedStatus = fullStatus;
-
-                origReadCompletionDelegate = readCompletionDelegate;
+                finishedStatus = receivedStatus;
 
                 ReleaseResourcesIfPossible();
             }
 
-            ProcessLastRead(origReadCompletionDelegate);
+            var status = receivedStatus.Status;
+
+            if (!success || status.StatusCode != StatusCode.OK)
+            {
+                streamingCallFinishedTcs.SetException(new RpcException(status));
+                return;
+            }
+
+            streamingCallFinishedTcs.SetResult(null);
         }
     }
 }

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

@@ -54,30 +54,30 @@ namespace Grpc.Core.Internal
         readonly Func<TWrite, byte[]> serializer;
         readonly Func<byte[], TRead> deserializer;
 
+        protected readonly GrpcEnvironment environment;
         protected readonly object myLock = new object();
 
-        protected CallSafeHandle call;
+        protected INativeCall call;
         protected bool disposed;
 
         protected bool started;
-        protected bool errorOccured;
         protected bool cancelRequested;
 
         protected AsyncCompletionDelegate<object> sendCompletionDelegate;  // Completion of a pending send or sendclose if not null.
         protected AsyncCompletionDelegate<TRead> readCompletionDelegate;  // Completion of a pending send or sendclose if not null.
 
-        protected bool readingDone;
-        protected bool halfcloseRequested;
-        protected bool halfclosed;
+        protected bool readingDone;  // True if last read (i.e. read with null payload) was already received.
+        protected bool halfcloseRequested;  // True if send close have been initiated.
         protected bool finished;  // True if close has been received from the peer.
 
         protected bool initialMetadataSent;
-        protected long streamingWritesCounter;
+        protected long streamingWritesCounter;  // Number of streaming send operations started so far.
 
-        public AsyncCallBase(Func<TWrite, byte[]> serializer, Func<byte[], TRead> deserializer)
+        public AsyncCallBase(Func<TWrite, byte[]> serializer, Func<byte[], TRead> deserializer, GrpcEnvironment environment)
         {
             this.serializer = Preconditions.CheckNotNull(serializer);
             this.deserializer = Preconditions.CheckNotNull(deserializer);
+            this.environment = Preconditions.CheckNotNull(environment);
         }
 
         /// <summary>
@@ -114,7 +114,7 @@ namespace Grpc.Core.Internal
             }
         }
 
-        protected void InitializeInternal(CallSafeHandle call)
+        protected void InitializeInternal(INativeCall call)
         {
             lock (myLock)
             {
@@ -159,16 +159,6 @@ namespace Grpc.Core.Internal
             }
         }
 
-        // TODO(jtattermusch): find more fitting name for this method.
-        /// <summary>
-        /// Default behavior just completes the read observer, but more sofisticated behavior might be required
-        /// by subclasses.
-        /// </summary>
-        protected virtual void ProcessLastRead(AsyncCompletionDelegate<TRead> completionDelegate)
-        {
-            FireCompletion(completionDelegate, default(TRead), null);
-        }
-
         /// <summary>
         /// If there are no more pending actions and no new actions can be started, releases
         /// the underlying native resources.
@@ -177,7 +167,7 @@ namespace Grpc.Core.Internal
         {
             if (!disposed && call != null)
             {
-                bool noMoreSendCompletions = halfclosed || (cancelRequested && sendCompletionDelegate == null);
+                bool noMoreSendCompletions = sendCompletionDelegate == null && (halfcloseRequested || cancelRequested || finished);
                 if (noMoreSendCompletions && readingDone && finished)
                 {
                     ReleaseResources();
@@ -189,34 +179,33 @@ namespace Grpc.Core.Internal
 
         private void ReleaseResources()
         {
-            OnReleaseResources();
             if (call != null)
             {
                 call.Dispose();
             }
             disposed = true;
+            OnAfterReleaseResources();
         }
 
-        protected virtual void OnReleaseResources()
+        protected virtual void OnAfterReleaseResources()
         {
         }
 
         protected void CheckSendingAllowed()
         {
             Preconditions.CheckState(started);
-            Preconditions.CheckState(!errorOccured);
             CheckNotCancelled();
             Preconditions.CheckState(!disposed);
 
             Preconditions.CheckState(!halfcloseRequested, "Already halfclosed.");
+            Preconditions.CheckState(!finished, "Already finished.");
             Preconditions.CheckState(sendCompletionDelegate == null, "Only one write can be pending at a time");
         }
 
-        protected void CheckReadingAllowed()
+        protected virtual void CheckReadingAllowed()
         {
             Preconditions.CheckState(started);
             Preconditions.CheckState(!disposed);
-            Preconditions.CheckState(!errorOccured);
 
             Preconditions.CheckState(!readingDone, "Stream has already been closed.");
             Preconditions.CheckState(readCompletionDelegate == null, "Only one read can be pending at a time");
@@ -280,7 +269,7 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles send completion.
         /// </summary>
-        protected void HandleSendFinished(bool success, BatchContextSafeHandle ctx)
+        protected void HandleSendFinished(bool success)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
@@ -304,12 +293,11 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles halfclose completion.
         /// </summary>
-        protected void HandleHalfclosed(bool success, BatchContextSafeHandle ctx)
+        protected void HandleHalfclosed(bool success)
         {
             AsyncCompletionDelegate<object> origCompletionDelegate = null;
             lock (myLock)
             {
-                halfclosed = true;
                 origCompletionDelegate = sendCompletionDelegate;
                 sendCompletionDelegate = null;
 
@@ -329,23 +317,17 @@ namespace Grpc.Core.Internal
         /// <summary>
         /// Handles streaming read completion.
         /// </summary>
-        protected void HandleReadFinished(bool success, BatchContextSafeHandle ctx)
+        protected void HandleReadFinished(bool success, byte[] receivedMessage)
         {
-            var payload = ctx.GetReceivedMessage();
-
             AsyncCompletionDelegate<TRead> origCompletionDelegate = null;
             lock (myLock)
             {
                 origCompletionDelegate = readCompletionDelegate;
-                if (payload != null)
-                {
-                    readCompletionDelegate = null;
-                }
-                else
+                readCompletionDelegate = null;
+
+                if (receivedMessage == null)
                 {
-                    // This was the last read. Keeping the readCompletionDelegate
-                    // to be either fired by this handler or by client-side finished
-                    // handler.
+                    // This was the last read.
                     readingDone = true;
                 }
 
@@ -354,17 +336,17 @@ namespace Grpc.Core.Internal
 
             // TODO: handle the case when error occured...
 
-            if (payload != null)
+            if (receivedMessage != null)
             {
                 // TODO: handle deserialization error
                 TRead msg;
-                TryDeserialize(payload, out msg);
+                TryDeserialize(receivedMessage, out msg);
 
                 FireCompletion(origCompletionDelegate, msg, null);
             }
             else
             {
-                ProcessLastRead(origCompletionDelegate);
+                FireCompletion(origCompletionDelegate, default(TRead), null);
             }
         }
     }

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

@@ -49,17 +49,18 @@ namespace Grpc.Core.Internal
     {
         readonly TaskCompletionSource<object> finishedServersideTcs = new TaskCompletionSource<object>();
         readonly CancellationTokenSource cancellationTokenSource = new CancellationTokenSource();
-        readonly GrpcEnvironment environment;
+        readonly Server server;
 
-        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment) : base(serializer, deserializer)
+        public AsyncCallServer(Func<TResponse, byte[]> serializer, Func<byte[], TRequest> deserializer, GrpcEnvironment environment, Server server) : base(serializer, deserializer, environment)
         {
-            this.environment = Preconditions.CheckNotNull(environment);
+            this.server = Preconditions.CheckNotNull(server);
         }
 
         public void Initialize(CallSafeHandle call)
         {
             call.SetCompletionRegistry(environment.CompletionRegistry);
-            environment.DebugStats.ActiveServerCalls.Increment();
+
+            server.AddCallReference(this);
             InitializeInternal(call);
         }
 
@@ -168,18 +169,22 @@ namespace Grpc.Core.Internal
             }
         }
 
-        protected override void OnReleaseResources()
+        protected override void CheckReadingAllowed()
         {
-            environment.DebugStats.ActiveServerCalls.Decrement();
+            base.CheckReadingAllowed();
+            Preconditions.CheckArgument(!cancelRequested);
+        }
+
+        protected override void OnAfterReleaseResources()
+        {
+            server.RemoveCallReference(this);
         }
 
         /// <summary>
         /// Handles the server side close completion.
         /// </summary>
-        private void HandleFinishedServerside(bool success, BatchContextSafeHandle ctx)
+        private void HandleFinishedServerside(bool success, bool cancelled)
         {
-            bool cancelled = ctx.GetReceivedCloseOnServerCancelled();
-
             lock (myLock)
             {
                 finished = true;

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

@@ -134,7 +134,7 @@ namespace Grpc.Core.Internal
         }
 
         // Gets data of server_rpc_new completion.
-        public ServerRpcNew GetServerRpcNew()
+        public ServerRpcNew GetServerRpcNew(Server server)
         {
             var call = grpcsharp_batch_context_server_rpc_new_call(this);
 
@@ -145,7 +145,7 @@ namespace Grpc.Core.Internal
             IntPtr metadataArrayPtr = grpcsharp_batch_context_server_rpc_new_request_metadata(this);
             var metadata = MetadataArraySafeHandle.ReadMetadataFromPtrUnsafe(metadataArrayPtr);
 
-            return new ServerRpcNew(call, method, host, deadline, metadata);
+            return new ServerRpcNew(server, call, method, host, deadline, metadata);
         }
 
         // Gets data of receive_close_on_server completion.
@@ -198,14 +198,16 @@ namespace Grpc.Core.Internal
     /// </summary>
     internal struct ServerRpcNew
     {
+        readonly Server server;
         readonly CallSafeHandle call;
         readonly string method;
         readonly string host;
         readonly Timespec deadline;
         readonly Metadata requestMetadata;
 
-        public ServerRpcNew(CallSafeHandle call, string method, string host, Timespec deadline, Metadata requestMetadata)
+        public ServerRpcNew(Server server, CallSafeHandle call, string method, string host, Timespec deadline, Metadata requestMetadata)
         {
+            this.server = server;
             this.call = call;
             this.method = method;
             this.host = host;
@@ -213,6 +215,14 @@ namespace Grpc.Core.Internal
             this.requestMetadata = requestMetadata;
         }
 
+        public Server Server
+        {
+            get
+            {
+                return this.server;
+            }
+        }
+
         public CallSafeHandle Call
         {
             get

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

@@ -40,7 +40,7 @@ namespace Grpc.Core.Internal
     /// <summary>
     /// grpc_call from <grpc/grpc.h>
     /// </summary>
-    internal class CallSafeHandle : SafeHandleZeroIsInvalid
+    internal class CallSafeHandle : SafeHandleZeroIsInvalid, INativeCall
     {
         public static readonly CallSafeHandle NullInstance = new CallSafeHandle();
 
@@ -86,6 +86,10 @@ namespace Grpc.Core.Internal
         static extern GRPCCallError grpcsharp_call_recv_message(CallSafeHandle call,
             BatchContextSafeHandle ctx);
 
+        [DllImport("grpc_csharp_ext.dll")]
+        static extern GRPCCallError grpcsharp_call_recv_initial_metadata(CallSafeHandle call,
+            BatchContextSafeHandle ctx);
+
         [DllImport("grpc_csharp_ext.dll")]
         static extern GRPCCallError grpcsharp_call_start_serverside(CallSafeHandle call,
             BatchContextSafeHandle ctx);
@@ -109,10 +113,10 @@ namespace Grpc.Core.Internal
             this.completionRegistry = completionRegistry;
         }
 
-        public void StartUnary(BatchCompletionDelegate callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient(), context.GetReceivedMessage(), context.GetReceivedInitialMetadata()));
             grpcsharp_call_start_unary(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags)
                 .CheckOk();
         }
@@ -123,66 +127,73 @@ namespace Grpc.Core.Internal
                 .CheckOk();
         }
 
-        public void StartClientStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient(), context.GetReceivedMessage(), context.GetReceivedInitialMetadata()));
             grpcsharp_call_start_client_streaming(this, ctx, metadataArray).CheckOk();
         }
 
-        public void StartServerStreaming(BatchCompletionDelegate callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
+        public void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, WriteFlags writeFlags)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient()));
             grpcsharp_call_start_server_streaming(this, ctx, payload, new UIntPtr((ulong)payload.Length), metadataArray, writeFlags).CheckOk();
         }
 
-        public void StartDuplexStreaming(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedStatusOnClient()));
             grpcsharp_call_start_duplex_streaming(this, ctx, metadataArray).CheckOk();
         }
 
-        public void StartSendMessage(BatchCompletionDelegate callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
+        public void StartSendMessage(SendCompletionHandler callback, byte[] payload, WriteFlags writeFlags, bool sendEmptyInitialMetadata)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_message(this, ctx, payload, new UIntPtr((ulong)payload.Length), writeFlags, sendEmptyInitialMetadata).CheckOk();
         }
 
-        public void StartSendCloseFromClient(BatchCompletionDelegate callback)
+        public void StartSendCloseFromClient(SendCompletionHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_close_from_client(this, ctx).CheckOk();
         }
 
-        public void StartSendStatusFromServer(BatchCompletionDelegate callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
+        public void StartSendStatusFromServer(SendCompletionHandler callback, Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_status_from_server(this, ctx, status.StatusCode, status.Detail, metadataArray, sendEmptyInitialMetadata).CheckOk();
         }
 
-        public void StartReceiveMessage(BatchCompletionDelegate callback)
+        public void StartReceiveMessage(ReceivedMessageHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedMessage()));
             grpcsharp_call_recv_message(this, ctx).CheckOk();
         }
 
-        public void StartServerSide(BatchCompletionDelegate callback)
+        public void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback)
+        {
+            var ctx = BatchContextSafeHandle.Create();
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedInitialMetadata()));
+            grpcsharp_call_recv_initial_metadata(this, ctx).CheckOk();
+        }
+
+        public void StartServerSide(ReceivedCloseOnServerHandler callback)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success, context.GetReceivedCloseOnServerCancelled()));
             grpcsharp_call_start_serverside(this, ctx).CheckOk();
         }
 
-        public void StartSendInitialMetadata(BatchCompletionDelegate callback, MetadataArraySafeHandle metadataArray)
+        public void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray)
         {
             var ctx = BatchContextSafeHandle.Create();
-            completionRegistry.RegisterBatchCompletion(ctx, callback);
+            completionRegistry.RegisterBatchCompletion(ctx, (success, context) => callback(success));
             grpcsharp_call_send_initial_metadata(this, ctx, metadataArray).CheckOk();
         }
 

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

@@ -68,11 +68,17 @@ namespace Grpc.Core.Internal
 
         public static ChannelSafeHandle CreateInsecure(string target, ChannelArgsSafeHandle channelArgs)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_insecure_channel_create(target, channelArgs);
         }
 
         public static ChannelSafeHandle CreateSecure(CredentialsSafeHandle credentials, string target, ChannelArgsSafeHandle channelArgs)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_secure_channel_create(credentials, target, channelArgs);
         }
 
@@ -107,6 +113,7 @@ namespace Grpc.Core.Internal
         protected override bool ReleaseHandle()
         {
             grpcsharp_channel_destroy(handle);
+            GrpcEnvironment.GrpcNativeShutdown();
             return true;
         }
     }

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

@@ -72,7 +72,13 @@ namespace Grpc.Core.Internal
             call.StartReadMessage(taskSource.CompletionDelegate);
             var result = await taskSource.Task;
             this.current = result;
-            return result != null;
+
+            if (result == null)
+            {
+                await call.StreamingCallFinishedTask;
+                return false;
+            }
+            return true;
         }
 
         public void Dispose()

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

@@ -38,10 +38,6 @@ namespace Grpc.Core.Internal
 {
     internal class DebugStats
     {
-        public readonly AtomicCounter ActiveClientCalls = new AtomicCounter();
-
-        public readonly AtomicCounter ActiveServerCalls = new AtomicCounter();
-
         public readonly AtomicCounter PendingBatchCompletions = new AtomicCounter();
 
         /// <summary>
@@ -49,16 +45,6 @@ namespace Grpc.Core.Internal
         /// </summary>
         public void CheckOK()
         {
-            var remainingClientCalls = ActiveClientCalls.Count;
-            if (remainingClientCalls != 0)
-            {                
-                DebugWarning(string.Format("Detected {0} client calls that weren't disposed properly.", remainingClientCalls));
-            }
-            var remainingServerCalls = ActiveServerCalls.Count;
-            if (remainingServerCalls != 0)
-            {
-                DebugWarning(string.Format("Detected {0} server calls that weren't disposed properly.", remainingServerCalls));
-            }
             var pendingBatchCompletions = PendingBatchCompletions.Count;
             if (pendingBatchCompletions != 0)
             {

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

@@ -83,8 +83,6 @@ namespace Grpc.Core.Internal
             lock (myLock)
             {
                 cq.Shutdown();
-
-                Logger.Info("Waiting for GRPC threads to finish.");
                 foreach (var thread in threads)
                 {
                     thread.Join();
@@ -136,7 +134,6 @@ namespace Grpc.Core.Internal
                 }
             }
             while (ev.type != GRPCCompletionType.Shutdown);
-            Logger.Info("Completion queue has shutdown successfully, thread {0} exiting.", Thread.CurrentThread.Name);
         }
     }
 }

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

@@ -0,0 +1,85 @@
+#region Copyright notice and license
+// Copyright 2015, Google Inc.
+// All rights reserved.
+// 
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+// 
+//     * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+//     * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following disclaimer
+// in the documentation and/or other materials provided with the
+// distribution.
+//     * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived from
+// this software without specific prior written permission.
+// 
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#endregion
+
+using System;
+
+namespace Grpc.Core.Internal
+{
+    internal delegate void UnaryResponseClientHandler(bool success, ClientSideStatus receivedStatus, byte[] receivedMessage, Metadata responseHeaders);
+
+    // Received status for streaming response calls.
+    internal delegate void ReceivedStatusOnClientHandler(bool success, ClientSideStatus receivedStatus);
+
+    internal delegate void ReceivedMessageHandler(bool success, byte[] receivedMessage);
+
+    internal delegate void ReceivedResponseHeadersHandler(bool success, Metadata responseHeaders);
+
+    internal delegate void SendCompletionHandler(bool success);
+
+    internal delegate void ReceivedCloseOnServerHandler(bool success, bool cancelled);
+
+    /// <summary>
+    /// Abstraction of a native call object.
+    /// </summary>
+    internal interface INativeCall : IDisposable
+    {
+        void Cancel();
+
+        void CancelWithStatus(Grpc.Core.Status status);
+
+        string GetPeer();
+
+        void StartUnary(UnaryResponseClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartUnary(BatchContextSafeHandle ctx, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartClientStreaming(UnaryResponseClientHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartServerStreaming(ReceivedStatusOnClientHandler callback, byte[] payload, MetadataArraySafeHandle metadataArray, Grpc.Core.WriteFlags writeFlags);
+
+        void StartDuplexStreaming(ReceivedStatusOnClientHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartReceiveMessage(ReceivedMessageHandler callback);
+
+        void StartReceiveInitialMetadata(ReceivedResponseHeadersHandler callback);
+
+        void StartSendInitialMetadata(SendCompletionHandler callback, MetadataArraySafeHandle metadataArray);
+
+        void StartSendMessage(SendCompletionHandler callback, byte[] payload, Grpc.Core.WriteFlags writeFlags, bool sendEmptyInitialMetadata);
+
+        void StartSendCloseFromClient(SendCompletionHandler callback);
+
+        void StartSendStatusFromServer(SendCompletionHandler callback, Grpc.Core.Status status, MetadataArraySafeHandle metadataArray, bool sendEmptyInitialMetadata);
+
+        void StartServerSide(ReceivedCloseOnServerHandler callback);
+    }
+}

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

@@ -70,7 +70,8 @@ namespace Grpc.Core.Internal
             var metadataArray = grpcsharp_metadata_array_create(new UIntPtr((ulong)metadata.Count));
             for (int i = 0; i < metadata.Count; i++)
             {
-                grpcsharp_metadata_array_add(metadataArray, metadata[i].Key, metadata[i].ValueBytes, new UIntPtr((ulong)metadata[i].ValueBytes.Length));
+                var valueBytes = metadata[i].GetSerializedValueUnsafe();
+                grpcsharp_metadata_array_add(metadataArray, metadata[i].Key, valueBytes, new UIntPtr((ulong)valueBytes.Length));
             }
             return metadataArray;
         }
@@ -94,7 +95,7 @@ namespace Grpc.Core.Internal
                 string key = Marshal.PtrToStringAnsi(grpcsharp_metadata_array_get_key(metadataArray, index));
                 var bytes = new byte[grpcsharp_metadata_array_get_value_length(metadataArray, index).ToUInt64()];
                 Marshal.Copy(grpcsharp_metadata_array_get_value(metadataArray, index), bytes, 0, bytes.Length);
-                metadata.Add(new Metadata.Entry(key, bytes));
+                metadata.Add(Metadata.Entry.CreateUnsafe(key, bytes));
             }
             return metadata;
         }

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

@@ -67,7 +67,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -123,7 +123,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -179,7 +179,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -239,7 +239,7 @@ namespace Grpc.Core.Internal
             var asyncCall = new AsyncCallServer<TRequest, TResponse>(
                 method.ResponseMarshaller.Serializer,
                 method.RequestMarshaller.Deserializer,
-                environment);
+                environment, newRpc.Server);
 
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();
@@ -278,7 +278,7 @@ namespace Grpc.Core.Internal
         {
             // We don't care about the payload type here.
             var asyncCall = new AsyncCallServer<byte[], byte[]>(
-                (payload) => payload, (payload) => payload, environment);
+                (payload) => payload, (payload) => payload, environment, newRpc.Server);
             
             asyncCall.Initialize(newRpc.Call);
             var finishedTask = asyncCall.ServerSideCallAsync();

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

@@ -74,6 +74,9 @@ namespace Grpc.Core.Internal
 
         public static ServerSafeHandle NewServer(CompletionQueueSafeHandle cq, ChannelArgsSafeHandle args)
         {
+            // Increment reference count for the native gRPC environment to make sure we don't do grpc_shutdown() before destroying the server handle.
+            // Doing so would make object finalizer crash if we end up abandoning the handle.
+            GrpcEnvironment.GrpcNativeInit();
             return grpcsharp_server_create(cq, args);
         }
 
@@ -109,6 +112,7 @@ namespace Grpc.Core.Internal
         protected override bool ReleaseHandle()
         {
             grpcsharp_server_destroy(handle);
+            GrpcEnvironment.GrpcNativeShutdown();
             return true;
         }
             

src/csharp/Grpc.Core/Logging/ConsoleLogger.cs

@@ -51,7 +51,19 @@ namespace Grpc.Core.Logging
         private ConsoleLogger(Type forType)
         {
             this.forType = forType;
-            this.forTypeString = forType != null ? forType.FullName + " " : "";
+            if (forType != null)
+            {
+                var namespaceStr = forType.Namespace ?? "";
+                if (namespaceStr.Length > 0)
+                {
+                     namespaceStr += ".";
+                }
+                this.forTypeString = namespaceStr + forType.Name + " ";
+            }
+            else
+            {
+                this.forTypeString = "";
+            }
         }
  
         /// <summary>

src/csharp/Grpc.Core/Metadata.cs

@@ -45,6 +45,11 @@ namespace Grpc.Core
     /// </summary>
     public sealed class Metadata : IList<Metadata.Entry>
     {
+        /// <summary>
+        /// All binary headers should have this suffix.
+        /// </summary>
+        public const string BinaryHeaderSuffix = "-bin";
+
         /// <summary>
         /// An read-only instance of metadata containing no entries.
         /// </summary>
@@ -181,23 +186,49 @@ namespace Grpc.Core
             private static readonly Encoding Encoding = Encoding.ASCII;
 
             readonly string key;
-            string value;
-            byte[] valueBytes;
+            readonly string value;
+            readonly byte[] valueBytes;
+
+            private Entry(string key, string value, byte[] valueBytes)
+            {
+                this.key = key;
+                this.value = value;
+                this.valueBytes = valueBytes;
+            }
 
+            /// <summary>
+            /// Initializes a new instance of the <see cref="Grpc.Core.Metadata+Entry"/> struct with a binary value.
+            /// </summary>
+            /// <param name="key">Metadata key, needs to have suffix indicating a binary valued metadata entry.</param>
+            /// <param name="valueBytes">Value bytes.</param>
             public Entry(string key, byte[] valueBytes)
             {
-                this.key = Preconditions.CheckNotNull(key, "key");
+                this.key = NormalizeKey(key);
+                Preconditions.CheckArgument(this.key.EndsWith(BinaryHeaderSuffix),
+                    "Key for binary valued metadata entry needs to have suffix indicating binary value.");
                 this.value = null;
-                this.valueBytes = Preconditions.CheckNotNull(valueBytes, "valueBytes");
+                Preconditions.CheckNotNull(valueBytes, "valueBytes");
+                this.valueBytes = new byte[valueBytes.Length];
+                Buffer.BlockCopy(valueBytes, 0, this.valueBytes, 0, valueBytes.Length);  // defensive copy to guarantee immutability
             }
 
+            /// <summary>
+            /// Initializes a new instance of the <see cref="Grpc.Core.Metadata+Entry"/> struct holding an ASCII value.
+            /// </summary>
+            /// <param name="key">Metadata key, must not use suffix indicating a binary valued metadata entry.</param>
+            /// <param name="value">Value string. Only ASCII characters are allowed.</param>
             public Entry(string key, string value)
             {
-                this.key = Preconditions.CheckNotNull(key, "key");
+                this.key = NormalizeKey(key);
+                Preconditions.CheckArgument(!this.key.EndsWith(BinaryHeaderSuffix),
+                    "Key for ASCII valued metadata entry cannot have suffix indicating binary value.");
                 this.value = Preconditions.CheckNotNull(value, "value");
                 this.valueBytes = null;
             }
 
+            /// <summary>
+            /// Gets the metadata entry key.
+            /// </summary>
             public string Key
             {
                 get
@@ -206,33 +237,86 @@ namespace Grpc.Core
                 }
             }
 
+            /// <summary>
+            /// Gets the binary value of this metadata entry.
+            /// </summary>
             public byte[] ValueBytes
             {
                 get
                 {
                     if (valueBytes == null)
                     {
-                        valueBytes = Encoding.GetBytes(value);
+                        return Encoding.GetBytes(value);
                     }
-                    return valueBytes;
+
+                    // defensive copy to guarantee immutability
+                    var bytes = new byte[valueBytes.Length];
+                    Buffer.BlockCopy(valueBytes, 0, bytes, 0, valueBytes.Length);
+                    return bytes;
                 }
             }
 
+            /// <summary>
+            /// Gets the string value of this metadata entry.
+            /// </summary>
             public string Value
             {
                 get
                 {
-                    if (value == null)
-                    {
-                        value = Encoding.GetString(valueBytes);
-                    }
-                    return value;
+                    Preconditions.CheckState(!IsBinary, "Cannot access string value of a binary metadata entry");
+                    return value ?? Encoding.GetString(valueBytes);
                 }
             }
-                
+
+            /// <summary>
+            /// Returns <c>true</c> if this entry is a binary-value entry.
+            /// </summary>
+            public bool IsBinary
+            {
+                get
+                {
+                    return value == null;
+                }
+            }
+
+            /// <summary>
+            /// Returns a <see cref="System.String"/> that represents the current <see cref="Grpc.Core.Metadata+Entry"/>.
+            /// </summary>
             public override string ToString()
             {
-                return string.Format("[Entry: key={0}, value={1}]", Key, Value);
+                if (IsBinary)
+                {
+                    return string.Format("[Entry: key={0}, valueBytes={1}]", key, valueBytes);
+                }
+                
+                return string.Format("[Entry: key={0}, value={1}]", key, value);
+            }
+
+            /// <summary>
+            /// Gets the serialized value for this entry. For binary metadata entries, this leaks
+            /// the internal <c>valueBytes</c> byte array and caller must not change contents of it.
+            /// </summary>
+            internal byte[] GetSerializedValueUnsafe()
+            {
+                return valueBytes ?? Encoding.GetBytes(value);
+            }
+
+            /// <summary>
+            /// Creates a binary value or ascii value metadata entry from data received from the native layer.
+            /// We trust C core to give us well-formed data, so we don't perform any checks or defensive copying.
+            /// </summary>
+            internal static Entry CreateUnsafe(string key, byte[] valueBytes)
+            {
+                if (key.EndsWith(BinaryHeaderSuffix))
+                {
+                    return new Entry(key, null, valueBytes);
+                }
+                return new Entry(key, Encoding.GetString(valueBytes), null);
+            }
+
+            private static string NormalizeKey(string key)
+            {
+                return Preconditions.CheckNotNull(key, "key").ToLower();
             }
         }
     }

src/csharp/Grpc.Core/Method.cs

@@ -54,10 +54,37 @@ namespace Grpc.Core
         DuplexStreaming
     }
 
+    /// <summary>
+    /// A non-generic representation of a remote method.
+    /// </summary>
+    public interface IMethod
+    {
+        /// <summary>
+        /// Gets the type of the method.
+        /// </summary>
+        MethodType Type { get; }
+
+        /// <summary>
+        /// Gets the name of the service to which this method belongs.
+        /// </summary>
+        string ServiceName { get; }
+
+        /// <summary>
+        /// Gets the unqualified name of the method.
+        /// </summary>
+        string Name { get; }
+
+        /// <summary>
+        /// Gets the fully qualified name of the method. On the server side, methods are dispatched
+        /// based on this name.
+        /// </summary>
+        string FullName { get; }
+    }
+
     /// <summary>
     /// A description of a remote method.
     /// </summary>
-    public class Method<TRequest, TResponse>
+    public class Method<TRequest, TResponse> : IMethod
     {
         readonly MethodType type;
         readonly string serviceName;

src/csharp/Grpc.Core/Server.cs

@@ -50,6 +50,8 @@ namespace Grpc.Core
     {
         static readonly ILogger Logger = GrpcEnvironment.Logger.ForType<Server>();
 
+        readonly AtomicCounter activeCallCounter = new AtomicCounter();
+
         readonly ServiceDefinitionCollection serviceDefinitions;
         readonly ServerPortCollection ports;
         readonly GrpcEnvironment environment;
@@ -73,7 +75,7 @@ namespace Grpc.Core
         {
             this.serviceDefinitions = new ServiceDefinitionCollection(this);
             this.ports = new ServerPortCollection(this);
-            this.environment = GrpcEnvironment.GetInstance();
+            this.environment = GrpcEnvironment.AddRef();
             this.options = options != null ? new List<ChannelOption>(options) : new List<ChannelOption>();
             using (var channelArgs = ChannelOptions.CreateChannelArgs(this.options))
             {
@@ -105,6 +107,17 @@ namespace Grpc.Core
             }
         }
 
+        /// <summary>
+        /// To allow awaiting termination of the server.
+        /// </summary>
+        public Task ShutdownTask
+        {
+            get
+            {
+                return shutdownTcs.Task;
+            }
+        }
+
         /// <summary>
         /// Starts the server.
         /// </summary>
@@ -136,18 +149,9 @@ namespace Grpc.Core
 
             handle.ShutdownAndNotify(HandleServerShutdown, environment);
             await shutdownTcs.Task;
-            handle.Dispose();
-        }
+            DisposeHandle();
 
-        /// <summary>
-        /// To allow awaiting termination of the server.
-        /// </summary>
-        public Task ShutdownTask
-        {
-            get
-            {
-                return shutdownTcs.Task;
-            }
+            await Task.Run(() => GrpcEnvironment.Release());
         }
 
         /// <summary>
@@ -166,7 +170,22 @@ namespace Grpc.Core
             handle.ShutdownAndNotify(HandleServerShutdown, environment);
             handle.CancelAllCalls();
             await shutdownTcs.Task;
-            handle.Dispose();
+            DisposeHandle();
+        }
+
+        internal void AddCallReference(object call)
+        {
+            activeCallCounter.Increment();
+
+            bool success = false;
+            handle.DangerousAddRef(ref success);
+            Preconditions.CheckState(success);
+        }
+
+        internal void RemoveCallReference(object call)
+        {
+            handle.DangerousRelease();
+            activeCallCounter.Decrement();
         }
 
         /// <summary>
@@ -227,6 +246,16 @@ namespace Grpc.Core
             }
         }
 
+        private void DisposeHandle()
+        {
+            var activeCallCount = activeCallCounter.Count;
+            if (activeCallCount > 0)
+            {
+                Logger.Warning("Server shutdown has finished but there are still {0} active calls for that server.", activeCallCount);
+            }
+            handle.Dispose();
+        }
+
         /// <summary>
         /// Selects corresponding handler for given call and handles the call.
         /// </summary>
@@ -254,7 +283,7 @@ namespace Grpc.Core
         {
             if (success)
             {
-                ServerRpcNew newRpc = ctx.GetServerRpcNew();
+                ServerRpcNew newRpc = ctx.GetServerRpcNew(this);
 
                 // after server shutdown, the callback returns with null call
                 if (!newRpc.Call.IsInvalid)

src/csharp/Grpc.Examples.MathClient/MathClient.cs

@@ -39,23 +39,21 @@ namespace math
     {
         public static void Main(string[] args)
         {
-            using (Channel channel = new Channel("127.0.0.1", 23456, Credentials.Insecure))
-            {
-                Math.IMathClient client = new Math.MathClient(channel);
-                MathExamples.DivExample(client);
+            var channel = new Channel("127.0.0.1", 23456, Credentials.Insecure);
+            Math.IMathClient client = new Math.MathClient(channel);
+            MathExamples.DivExample(client);
 
-                MathExamples.DivAsyncExample(client).Wait();
+            MathExamples.DivAsyncExample(client).Wait();
 
-                MathExamples.FibExample(client).Wait();
+            MathExamples.FibExample(client).Wait();
 
-                MathExamples.SumExample(client).Wait();
+            MathExamples.SumExample(client).Wait();
 
-                MathExamples.DivManyExample(client).Wait();
+            MathExamples.DivManyExample(client).Wait();
 
-                MathExamples.DependendRequestsExample(client).Wait();
-            }
+            MathExamples.DependendRequestsExample(client).Wait();
 
-            GrpcEnvironment.Shutdown();
+            channel.ShutdownAsync().Wait();
         }
     }
 }

src/csharp/Grpc.Examples.MathServer/MathServer.cs

@@ -56,7 +56,6 @@ namespace math
             Console.ReadKey();
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
     }
 }

src/csharp/Grpc.Examples.Tests/MathClientServerTests.cs

@@ -68,9 +68,8 @@ namespace math.Tests
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]

src/csharp/Grpc.HealthCheck.Tests/HealthClientServerTest.cs

@@ -71,10 +71,9 @@ namespace Grpc.HealthCheck.Tests
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
 
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]

src/csharp/Grpc.IntegrationTesting/InteropClient.cs

@@ -37,13 +37,15 @@ using System.Text.RegularExpressions;
 using System.Threading;
 using System.Threading.Tasks;
 
+using Google.Apis.Auth.OAuth2;
 using Google.ProtocolBuffers;
+
 using grpc.testing;
 using Grpc.Auth;
 using Grpc.Core;
 using Grpc.Core.Utils;
+
 using NUnit.Framework;
-using Google.Apis.Auth.OAuth2;
 
 namespace Grpc.IntegrationTesting
 {
@@ -118,12 +120,10 @@ namespace Grpc.IntegrationTesting
                 };
             }
 
-            using (Channel channel = new Channel(options.serverHost, options.serverPort.Value, credentials, channelOptions))
-            {
-                TestService.TestServiceClient client = new TestService.TestServiceClient(channel);
-                await RunTestCaseAsync(options.testCase, client);
-            }
-            GrpcEnvironment.Shutdown();
+            var channel = new Channel(options.serverHost, options.serverPort.Value, credentials, channelOptions);
+            TestService.TestServiceClient client = new TestService.TestServiceClient(channel);
+            await RunTestCaseAsync(options.testCase, client);
+            channel.ShutdownAsync().Wait();
         }
 
         private async Task RunTestCaseAsync(string testCase, TestService.TestServiceClient client)
@@ -169,6 +169,9 @@ namespace Grpc.IntegrationTesting
                 case "cancel_after_first_response":
                     await RunCancelAfterFirstResponseAsync(client);
                     break;
+                case "timeout_on_sleeping_server":
+                    await RunTimeoutOnSleepingServerAsync(client);
+                    break;
                 case "benchmark_empty_unary":
                     RunBenchmarkEmptyUnary(client);
                     break;
@@ -308,7 +311,7 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("running service_account_creds");
             var credential = await GoogleCredential.GetApplicationDefaultAsync();
             credential = credential.CreateScoped(new[] { AuthScope });
-            client.HeaderInterceptor = OAuth2Interceptors.FromCredential(credential);
+            client.HeaderInterceptor = AuthInterceptors.FromCredential(credential);
 
             var request = SimpleRequest.CreateBuilder()
                 .SetResponseType(PayloadType.COMPRESSABLE)
@@ -332,7 +335,7 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("running compute_engine_creds");
             var credential = await GoogleCredential.GetApplicationDefaultAsync();
             Assert.IsFalse(credential.IsCreateScopedRequired);
-            client.HeaderInterceptor = OAuth2Interceptors.FromCredential(credential);
+            client.HeaderInterceptor = AuthInterceptors.FromCredential(credential);
             
             var request = SimpleRequest.CreateBuilder()
                 .SetResponseType(PayloadType.COMPRESSABLE)
@@ -357,7 +360,7 @@ namespace Grpc.IntegrationTesting
             var credential = await GoogleCredential.GetApplicationDefaultAsync();
             // check this a credential with scope support, but don't add the scope.
             Assert.IsTrue(credential.IsCreateScopedRequired);
-            client.HeaderInterceptor = OAuth2Interceptors.FromCredential(credential);
+            client.HeaderInterceptor = AuthInterceptors.FromCredential(credential);
 
             var request = SimpleRequest.CreateBuilder()
                 .SetResponseType(PayloadType.COMPRESSABLE)
@@ -381,7 +384,7 @@ namespace Grpc.IntegrationTesting
             ITokenAccess credential = (await GoogleCredential.GetApplicationDefaultAsync()).CreateScoped(new[] { AuthScope });
             string oauth2Token = await credential.GetAccessTokenForRequestAsync();
 
-            client.HeaderInterceptor = OAuth2Interceptors.FromAccessToken(oauth2Token);
+            client.HeaderInterceptor = AuthInterceptors.FromAccessToken(oauth2Token);
 
             var request = SimpleRequest.CreateBuilder()
                 .SetFillUsername(true)
@@ -401,7 +404,7 @@ namespace Grpc.IntegrationTesting
 
             ITokenAccess credential = (await GoogleCredential.GetApplicationDefaultAsync()).CreateScoped(new[] { AuthScope });
             string oauth2Token = await credential.GetAccessTokenForRequestAsync();
-            var headerInterceptor = OAuth2Interceptors.FromAccessToken(oauth2Token);
+            var headerInterceptor = AuthInterceptors.FromAccessToken(oauth2Token);
 
             var request = SimpleRequest.CreateBuilder()
                 .SetFillUsername(true)
@@ -409,7 +412,7 @@ namespace Grpc.IntegrationTesting
                 .Build();
 
             var headers = new Metadata();
-            headerInterceptor("", headers);
+            headerInterceptor(null, "", headers);
             var response = client.UnaryCall(request, headers: headers);
 
             Assert.AreEqual(AuthScopeResponse, response.OauthScope);
@@ -458,6 +461,29 @@ namespace Grpc.IntegrationTesting
             Console.WriteLine("Passed!");
         }
 
+        public static async Task RunTimeoutOnSleepingServerAsync(TestService.ITestServiceClient client)
+        {
+            Console.WriteLine("running timeout_on_sleeping_server");
+
+            var deadline = DateTime.UtcNow.AddMilliseconds(1);
+            using (var call = client.FullDuplexCall(deadline: deadline))
+            {
+                try
+                {
+                    await call.RequestStream.WriteAsync(StreamingOutputCallRequest.CreateBuilder()
+                        .SetPayload(CreateZerosPayload(27182)).Build());
+                }
+                catch (InvalidOperationException)
+                {
+                    // Deadline was reached before write has started. Eat the exception and continue.
+                }
+
+                var ex = Assert.Throws<RpcException>(async () => await call.ResponseStream.MoveNext());
+                Assert.AreEqual(StatusCode.DeadlineExceeded, ex.Status.StatusCode);
+            }
+            Console.WriteLine("Passed!");
+        }
+
         // This is not an official interop test, but it's useful.
         public static void RunBenchmarkEmptyUnary(TestService.ITestServiceClient client)
         {

src/csharp/Grpc.IntegrationTesting/InteropClientServerTest.cs

@@ -75,9 +75,8 @@ namespace Grpc.IntegrationTesting
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]
@@ -127,5 +126,11 @@ namespace Grpc.IntegrationTesting
         {
             await InteropClient.RunCancelAfterFirstResponseAsync(client);
         }
+
+        [Test]
+        public async Task TimeoutOnSleepingServerAsync()
+        {
+            await InteropClient.RunTimeoutOnSleepingServerAsync(client);
+        }
     }
 }

src/csharp/Grpc.IntegrationTesting/InteropServer.cs

@@ -107,8 +107,6 @@ namespace Grpc.IntegrationTesting
             server.Start();
 
             server.ShutdownTask.Wait();
-
-            GrpcEnvironment.Shutdown();
         }
 
         private static ServerOptions ParseArguments(string[] args)

src/csharp/Grpc.IntegrationTesting/SslCredentialsTest.cs

@@ -85,9 +85,8 @@ namespace Grpc.IntegrationTesting
         [TestFixtureTearDown]
         public void Cleanup()
         {
-            channel.Dispose();
+            channel.ShutdownAsync().Wait();
             server.ShutdownAsync().Wait();
-            GrpcEnvironment.Shutdown();
         }
 
         [Test]

src/csharp/ext/grpc_csharp_ext.c

@@ -510,22 +510,27 @@ grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[1].data.send_message = ctx->send_message;
   ops[1].flags = write_flags;
+  ops[1].reserved = NULL;
 
   ops[2].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   ops[2].flags = 0;
+  ops[2].reserved = NULL;
 
   ops[3].op = GRPC_OP_RECV_INITIAL_METADATA;
   ops[3].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
   ops[3].flags = 0;
+  ops[3].reserved = NULL;
 
   ops[4].op = GRPC_OP_RECV_MESSAGE;
   ops[4].data.recv_message = &(ctx->recv_message);
   ops[4].flags = 0;
+  ops[4].reserved = NULL;
 
   ops[5].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   ops[5].data.recv_status_on_client.trailing_metadata =
@@ -538,6 +543,7 @@ grpcsharp_call_start_unary(grpc_call *call, grpcsharp_batch_context *ctx,
   ops[5].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
   ops[5].flags = 0;
+  ops[5].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -556,14 +562,17 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_RECV_INITIAL_METADATA;
   ops[1].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
   ops[1].flags = 0;
+  ops[1].reserved = NULL;
 
   ops[2].op = GRPC_OP_RECV_MESSAGE;
   ops[2].data.recv_message = &(ctx->recv_message);
   ops[2].flags = 0;
+  ops[2].reserved = NULL;
 
   ops[3].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
   ops[3].data.recv_status_on_client.trailing_metadata =
@@ -576,6 +585,7 @@ grpcsharp_call_start_client_streaming(grpc_call *call,
   ops[3].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
   ops[3].flags = 0;
+  ops[3].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -585,7 +595,7 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
     grpc_call *call, grpcsharp_batch_context *ctx, const char *send_buffer,
     size_t send_buffer_len, grpc_metadata_array *initial_metadata, gpr_uint32 write_flags) {
   /* TODO: don't use magic number */
-  grpc_op ops[5];
+  grpc_op ops[4];
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -593,30 +603,30 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_start_server_streaming(
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   ops[1].op = GRPC_OP_SEND_MESSAGE;
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[1].data.send_message = ctx->send_message;
   ops[1].flags = write_flags;
+  ops[1].reserved = NULL;
 
   ops[2].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   ops[2].flags = 0;
+  ops[2].reserved = NULL;
 
-  ops[3].op = GRPC_OP_RECV_INITIAL_METADATA;
-  ops[3].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
-  ops[3].flags = 0;
-
-  ops[4].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  ops[4].data.recv_status_on_client.trailing_metadata =
+  ops[3].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
+  ops[3].data.recv_status_on_client.trailing_metadata =
       &(ctx->recv_status_on_client.trailing_metadata);
-  ops[4].data.recv_status_on_client.status =
+  ops[3].data.recv_status_on_client.status =
       &(ctx->recv_status_on_client.status);
   /* not using preallocation for status_details */
-  ops[4].data.recv_status_on_client.status_details =
+  ops[3].data.recv_status_on_client.status_details =
       &(ctx->recv_status_on_client.status_details);
-  ops[4].data.recv_status_on_client.status_details_capacity =
+  ops[3].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
-  ops[4].flags = 0;
+  ops[3].flags = 0;
+  ops[3].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -627,7 +637,7 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
                                       grpcsharp_batch_context *ctx,
                                       grpc_metadata_array *initial_metadata) {
   /* TODO: don't use magic number */
-  grpc_op ops[3];
+  grpc_op ops[2];
   ops[0].op = GRPC_OP_SEND_INITIAL_METADATA;
   grpcsharp_metadata_array_move(&(ctx->send_initial_metadata),
                                 initial_metadata);
@@ -635,27 +645,38 @@ grpcsharp_call_start_duplex_streaming(grpc_call *call,
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
-  ops[1].op = GRPC_OP_RECV_INITIAL_METADATA;
-  ops[1].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
-  ops[1].flags = 0;
-
-  ops[2].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
-  ops[2].data.recv_status_on_client.trailing_metadata =
+  ops[1].op = GRPC_OP_RECV_STATUS_ON_CLIENT;
+  ops[1].data.recv_status_on_client.trailing_metadata =
       &(ctx->recv_status_on_client.trailing_metadata);
-  ops[2].data.recv_status_on_client.status =
+  ops[1].data.recv_status_on_client.status =
       &(ctx->recv_status_on_client.status);
   /* not using preallocation for status_details */
-  ops[2].data.recv_status_on_client.status_details =
+  ops[1].data.recv_status_on_client.status_details =
       &(ctx->recv_status_on_client.status_details);
-  ops[2].data.recv_status_on_client.status_details_capacity =
+  ops[1].data.recv_status_on_client.status_details_capacity =
       &(ctx->recv_status_on_client.status_details_capacity);
-  ops[2].flags = 0;
+  ops[1].flags = 0;
+  ops[1].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
 }
 
+GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_recv_initial_metadata(
+	grpc_call *call, grpcsharp_batch_context *ctx) {
+	/* TODO: don't use magic number */
+	grpc_op ops[1];
+	ops[0].op = GRPC_OP_RECV_INITIAL_METADATA;
+	ops[0].data.recv_initial_metadata = &(ctx->recv_initial_metadata);
+	ops[0].flags = 0;
+	ops[0].reserved = NULL;
+
+	return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
+		NULL);
+}
+
 GPR_EXPORT grpc_call_error GPR_CALLTYPE
 grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
                             const char *send_buffer, size_t send_buffer_len,
@@ -668,10 +689,12 @@ grpcsharp_call_send_message(grpc_call *call, grpcsharp_batch_context *ctx,
   ctx->send_message = string_to_byte_buffer(send_buffer, send_buffer_len);
   ops[0].data.send_message = ctx->send_message;
   ops[0].flags = write_flags;
+  ops[0].reserved = NULL;
   ops[1].op = GRPC_OP_SEND_INITIAL_METADATA;
   ops[1].data.send_initial_metadata.count = 0;
   ops[1].data.send_initial_metadata.metadata = NULL;
   ops[1].flags = 0;
+  ops[1].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, nops, ctx, NULL);
 }
@@ -683,6 +706,7 @@ grpcsharp_call_send_close_from_client(grpc_call *call,
   grpc_op ops[1];
   ops[0].op = GRPC_OP_SEND_CLOSE_FROM_CLIENT;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -706,10 +730,12 @@ GPR_EXPORT grpc_call_error GPR_CALLTYPE grpcsharp_call_send_status_from_server(
   ops[0].data.send_status_from_server.trailing_metadata =
       ctx->send_status_from_server.trailing_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
   ops[1].op = GRPC_OP_SEND_INITIAL_METADATA;
   ops[1].data.send_initial_metadata.count = 0;
   ops[1].data.send_initial_metadata.metadata = NULL;
   ops[1].flags = 0;
+  ops[1].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, nops, ctx, NULL);
 }
@@ -721,6 +747,7 @@ grpcsharp_call_recv_message(grpc_call *call, grpcsharp_batch_context *ctx) {
   ops[0].op = GRPC_OP_RECV_MESSAGE;
   ops[0].data.recv_message = &(ctx->recv_message);
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
 }
@@ -733,6 +760,7 @@ grpcsharp_call_start_serverside(grpc_call *call, grpcsharp_batch_context *ctx) {
   ops[0].data.recv_close_on_server.cancelled =
       (&ctx->recv_close_on_server_cancelled);
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);
@@ -751,6 +779,7 @@ grpcsharp_call_send_initial_metadata(grpc_call *call,
   ops[0].data.send_initial_metadata.metadata =
       ctx->send_initial_metadata.metadata;
   ops[0].flags = 0;
+  ops[0].reserved = NULL;
 
   return grpc_call_start_batch(call, ops, sizeof(ops) / sizeof(ops[0]), ctx,
                                NULL);

src/node/README.md

@@ -5,11 +5,35 @@ Alpha : Ready for early adopters
 
 ## PREREQUISITES
 - `node`: This requires `node` to be installed. If you instead have the `nodejs` executable on Debian, you should install the [`nodejs-legacy`](https://packages.debian.org/sid/nodejs-legacy) package.
-- [homebrew][] on Mac OS X, [linuxbrew][] on Linux.  These simplify the installation of the gRPC C core.
+- [homebrew][] on Mac OS X.  These simplify the installation of the gRPC C core.
 
 ## INSTALLATION
-On Mac OS X, install [homebrew][]. On Linux, install [linuxbrew][].
-Run the following command to install gRPC Node.js.
+
+**Linux (Debian):**
+
+Add [Debian unstable][] to your `sources.list` file. Example:
+
+```sh
+echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+sudo tee -a /etc/apt/sources.list
+```
+
+Install the gRPC Debian package
+
+```sh
+sudo apt-get update
+sudo apt-get install libgrpc-dev
+```
+
+Install the gRPC NPM package
+
+```sh
+npm install grpc
+```
+
+**Mac OS X**
+
+Install [homebrew][]. Run the following command to install gRPC Node.js.
 ```sh
 $ curl -fsSL https://goo.gl/getgrpc | bash -s nodejs
 ```
@@ -88,5 +112,5 @@ ServerCredentials
 An object with factory methods for creating credential objects for servers.
 
 [homebrew]:http://brew.sh
-[linuxbrew]:https://github.com/Homebrew/linuxbrew#installation
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
+[Debian unstable]:https://www.debian.org/releases/sid/

src/node/ext/call.cc

@@ -207,6 +207,13 @@ class SendMessageOp : public Op {
     if (!::node::Buffer::HasInstance(value)) {
       return false;
     }
+    Handle<Object> object_value = value->ToObject();
+    if (object_value->HasOwnProperty(NanNew("grpcWriteFlags"))) {
+      Handle<Value> flag_value = object_value->Get(NanNew("grpcWriteFlags"));
+      if (flag_value->IsUint32()) {
+        out->flags = flag_value->Uint32Value() & GRPC_WRITE_USED_MASK;
+      }
+    }
     out->data.send_message = BufferToByteBuffer(value);
     Persistent<Value> *handle = new Persistent<Value>();
     NanAssignPersistent(*handle, value);
@@ -457,10 +464,6 @@ void Call::Init(Handle<Object> exports) {
                           NanNew<FunctionTemplate>(GetPeer)->GetFunction());
   NanAssignPersistent(fun_tpl, tpl);
   Handle<Function> ctr = tpl->GetFunction();
-  ctr->Set(NanNew("WRITE_BUFFER_HINT"),
-           NanNew<Uint32, uint32_t>(GRPC_WRITE_BUFFER_HINT));
-  ctr->Set(NanNew("WRITE_NO_COMPRESS"),
-           NanNew<Uint32, uint32_t>(GRPC_WRITE_NO_COMPRESS));
   exports->Set(NanNew("Call"), ctr);
   constructor = new NanCallback(ctr);
 }
@@ -581,6 +584,7 @@ NAN_METHOD(Call::StartBatch) {
     uint32_t type = keys->Get(i)->Uint32Value();
     ops[i].op = static_cast<grpc_op_type>(type);
     ops[i].flags = 0;
+    ops[i].reserved = NULL;
     switch (type) {
       case GRPC_OP_SEND_INITIAL_METADATA:
         op.reset(new SendMetadataOp());
@@ -619,7 +623,7 @@ NAN_METHOD(Call::StartBatch) {
       call->wrapped_call, &ops[0], nops, new struct tag(
           callback, op_vector.release(), resources), NULL);
   if (error != GRPC_CALL_OK) {
-    return NanThrowError("startBatch failed", error);
+    return NanThrowError(nanErrorWithCode("startBatch failed", error));
   }
   CompletionQueueAsyncWorker::Next();
   NanReturnUndefined();
@@ -633,7 +637,7 @@ NAN_METHOD(Call::Cancel) {
   Call *call = ObjectWrap::Unwrap<Call>(args.This());
   grpc_call_error error = grpc_call_cancel(call->wrapped_call, NULL);
   if (error != GRPC_CALL_OK) {
-    return NanThrowError("cancel failed", error);
+    return NanThrowError(nanErrorWithCode("cancel failed", error));
   }
   NanReturnUndefined();
 }

src/node/ext/call.h

@@ -51,6 +51,19 @@ namespace node {
 using std::unique_ptr;
 using std::shared_ptr;
 
+/**
+ * Helper function for throwing errors with a grpc_call_error value.
+ * Modified from the answer by Gus Goose to
+ * http://stackoverflow.com/questions/31794200.
+ */
+inline v8::Local<v8::Value> nanErrorWithCode(const char *msg,
+                                             grpc_call_error code) {
+    NanEscapableScope();
+    v8::Local<v8::Object> err = NanError(msg).As<v8::Object>();
+    err->Set(NanNew("code"), NanNew<v8::Uint32>(code));
+    return NanEscapeScope(err);
+}
+
 v8::Handle<v8::Value> ParseMetadata(const grpc_metadata_array *metadata_array);
 
 class PersistentHolder {

src/node/ext/node_grpc.cc

@@ -196,6 +196,16 @@ void InitConnectivityStateConstants(Handle<Object> exports) {
   channel_state->Set(NanNew("FATAL_FAILURE"), FATAL_FAILURE);
 }
 
+void InitWriteFlags(Handle<Object> exports) {
+  NanScope();
+  Handle<Object> write_flags = NanNew<Object>();
+  exports->Set(NanNew("writeFlags"), write_flags);
+  Handle<Value> BUFFER_HINT(NanNew<Uint32, uint32_t>(GRPC_WRITE_BUFFER_HINT));
+  write_flags->Set(NanNew("BUFFER_HINT"), BUFFER_HINT);
+  Handle<Value> NO_COMPRESS(NanNew<Uint32, uint32_t>(GRPC_WRITE_NO_COMPRESS));
+  write_flags->Set(NanNew("NO_COMPRESS"), NO_COMPRESS);
+}
+
 void init(Handle<Object> exports) {
   NanScope();
   grpc_init();
@@ -204,6 +214,7 @@ void init(Handle<Object> exports) {
   InitOpTypeConstants(exports);
   InitPropagateConstants(exports);
   InitConnectivityStateConstants(exports);
+  InitWriteFlags(exports);
 
   grpc::node::Call::Init(exports);
   grpc::node::Channel::Init(exports);

src/node/ext/server.cc

@@ -235,7 +235,7 @@ NAN_METHOD(Server::RequestCall) {
       new struct tag(new NanCallback(args[0].As<Function>()), ops.release(),
                      shared_ptr<Resources>(nullptr)));
   if (error != GRPC_CALL_OK) {
-    return NanThrowError("requestCall failed", error);
+    return NanThrowError(nanErrorWithCode("requestCall failed", error));
   }
   CompletionQueueAsyncWorker::Next();
   NanReturnUndefined();

src/node/ext/server_credentials.cc

@@ -41,6 +41,7 @@
 namespace grpc {
 namespace node {
 
+using v8::Array;
 using v8::Exception;
 using v8::External;
 using v8::Function;
@@ -52,6 +53,7 @@ using v8::Local;
 using v8::Object;
 using v8::ObjectTemplate;
 using v8::Persistent;
+using v8::String;
 using v8::Value;
 
 NanCallback *ServerCredentials::constructor;
@@ -122,25 +124,66 @@ NAN_METHOD(ServerCredentials::CreateSsl) {
   // TODO: have the node API support multiple key/cert pairs.
   NanScope();
   char *root_certs = NULL;
-  grpc_ssl_pem_key_cert_pair key_cert_pair;
   if (::node::Buffer::HasInstance(args[0])) {
     root_certs = ::node::Buffer::Data(args[0]);
   } else if (!(args[0]->IsNull() || args[0]->IsUndefined())) {
     return NanThrowTypeError(
         "createSSl's first argument must be a Buffer if provided");
   }
-  if (!::node::Buffer::HasInstance(args[1])) {
-    return NanThrowTypeError("createSsl's second argument must be a Buffer");
+  if (!args[1]->IsArray()) {
+    return NanThrowTypeError(
+        "createSsl's second argument must be a list of objects");
+  }
+  int force_client_auth = 0;
+  if (args[2]->IsBoolean()) {
+    force_client_auth = (int)args[2]->BooleanValue();
+  } else if (!(args[2]->IsUndefined() || args[2]->IsNull())) {
+    return NanThrowTypeError(
+        "createSsl's third argument must be a boolean if provided");
   }
-  key_cert_pair.private_key = ::node::Buffer::Data(args[1]);
-  if (!::node::Buffer::HasInstance(args[2])) {
-    return NanThrowTypeError("createSsl's third argument must be a Buffer");
+  Handle<Array> pair_list = Local<Array>::Cast(args[1]);
+  uint32_t key_cert_pair_count = pair_list->Length();
+  grpc_ssl_pem_key_cert_pair *key_cert_pairs = new grpc_ssl_pem_key_cert_pair[
+      key_cert_pair_count];
+
+  Handle<String> key_key = NanNew("private_key");
+  Handle<String> cert_key = NanNew("cert_chain");
+
+  for(uint32_t i = 0; i < key_cert_pair_count; i++) {
+    if (!pair_list->Get(i)->IsObject()) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("Key/cert pairs must be objects");
+    }
+    Handle<Object> pair_obj = pair_list->Get(i)->ToObject();
+    if (!pair_obj->HasOwnProperty(key_key)) {
+      delete key_cert_pairs;
+      return NanThrowTypeError(
+          "Key/cert pairs must have a private_key and a cert_chain");
+    }
+    if (!pair_obj->HasOwnProperty(cert_key)) {
+      delete key_cert_pairs;
+      return NanThrowTypeError(
+          "Key/cert pairs must have a private_key and a cert_chain");
+    }
+    if (!::node::Buffer::HasInstance(pair_obj->Get(key_key))) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("private_key must be a Buffer");
+    }
+    if (!::node::Buffer::HasInstance(pair_obj->Get(cert_key))) {
+      delete key_cert_pairs;
+      return NanThrowTypeError("cert_chain must be a Buffer");
+    }
+    key_cert_pairs[i].private_key = ::node::Buffer::Data(
+        pair_obj->Get(key_key));
+    key_cert_pairs[i].cert_chain = ::node::Buffer::Data(
+        pair_obj->Get(cert_key));
   }
-  key_cert_pair.cert_chain = ::node::Buffer::Data(args[2]);
-  // TODO Add a force_client_auth parameter and pass it as the last parameter
-  // here.
   grpc_server_credentials *creds =
-      grpc_ssl_server_credentials_create(root_certs, &key_cert_pair, 1, 0);
+      grpc_ssl_server_credentials_create(root_certs,
+                                         key_cert_pairs,
+                                         key_cert_pair_count,
+                                         force_client_auth);
+  delete key_cert_pairs;
   if (creds == NULL) {
     NanReturnNull();
   }

src/node/health_check/health.js

@@ -45,17 +45,13 @@ function HealthImplementation(statusMap) {
   this.statusMap = _.clone(statusMap);
 }
 
-HealthImplementation.prototype.setStatus = function(host, service, status) {
-  if (!this.statusMap[host]) {
-    this.statusMap[host] = {};
-  }
-  this.statusMap[host][service] = status;
+HealthImplementation.prototype.setStatus = function(service, status) {
+  this.statusMap[service] = status;
 };
 
 HealthImplementation.prototype.check = function(call, callback){
-  var host = call.request.host;
   var service = call.request.service;
-  var status = _.get(this.statusMap, [host, service], null);
+  var status = _.get(this.statusMap, service, null);
   if (status === null) {
     callback({code:grpc.status.NOT_FOUND});
   } else {

src/node/health_check/health.proto

@@ -32,8 +32,7 @@ syntax = "proto3";
 package grpc.health.v1alpha;
 
 message HealthCheckRequest {
-  string host = 1;
-  string service = 2;
+  string service = 1;
 }
 
 message HealthCheckResponse {
@@ -47,4 +46,4 @@ message HealthCheckResponse {
 
 service Health {
   rpc Check(HealthCheckRequest) returns (HealthCheckResponse);
-}
+}

src/node/index.js

@@ -144,6 +144,11 @@ exports.propagate = grpc.propagate;
  */
 exports.callError = grpc.callError;
 
+/**
+ * Write flag name to code number mapping
+ */
+exports.writeFlags = grpc.writeFlags;
+
 /**
  * Credentials factories
  */

src/node/interop/interop_client.js

@@ -264,7 +264,9 @@ function timeoutOnSleepingServer(client, done) {
     payload: {body: zeroBuffer(27182)}
   });
   call.on('error', function(error) {
-    assert.strictEqual(error.code, grpc.status.DEADLINE_EXCEEDED);
+
+    assert(error.code === grpc.status.DEADLINE_EXCEEDED ||
+        error.code === grpc.status.INTERNAL);
     done();
   });
 }

src/node/interop/interop_server.js

@@ -169,8 +169,8 @@ function getServer(port, tls) {
     var key_data = fs.readFileSync(key_path);
     var pem_data = fs.readFileSync(pem_path);
     server_creds = grpc.ServerCredentials.createSsl(null,
-                                                    key_data,
-                                                    pem_data);
+                                                    [{private_key: key_data,
+                                                      cert_chain: pem_data}]);
   } else {
     server_creds = grpc.ServerCredentials.createInsecure();
   }

src/node/src/client.js

@@ -79,13 +79,19 @@ function ClientWritableStream(call, serialize) {
  * implementation of a method needed for implementing stream.Writable.
  * @access private
  * @param {Buffer} chunk The chunk to write
- * @param {string} encoding Ignored
+ * @param {string} encoding Used to pass write flags
  * @param {function(Error=)} callback Called when the write is complete
  */
 function _write(chunk, encoding, callback) {
   /* jshint validthis: true */
   var batch = {};
-  batch[grpc.opType.SEND_MESSAGE] = this.serialize(chunk);
+  var message = this.serialize(chunk);
+  if (_.isFinite(encoding)) {
+    /* Attach the encoding if it is a finite number. This is the closest we
+     * can get to checking that it is valid flags */
+    message.grpcWriteFlags = encoding;
+  }
+  batch[grpc.opType.SEND_MESSAGE] = message;
   this.call.startBatch(batch, function(err, event) {
     if (err) {
       // Something has gone wrong. Stop writing by failing to call callback
@@ -273,8 +279,12 @@ function makeUnaryRequestFunction(method, serialize, deserialize) {
         return;
       }
       var client_batch = {};
+      var message = serialize(argument);
+      if (options) {
+        message.grpcWriteFlags = options.flags;
+      }
       client_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
-      client_batch[grpc.opType.SEND_MESSAGE] = serialize(argument);
+      client_batch[grpc.opType.SEND_MESSAGE] = message;
       client_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
       client_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
       client_batch[grpc.opType.RECV_MESSAGE] = true;
@@ -407,9 +417,13 @@ function makeServerStreamRequestFunction(method, serialize, deserialize) {
         return;
       }
       var start_batch = {};
+      var message = serialize(argument);
+      if (options) {
+        message.grpcWriteFlags = options.flags;
+      }
       start_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
       start_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
-      start_batch[grpc.opType.SEND_MESSAGE] = serialize(argument);
+      start_batch[grpc.opType.SEND_MESSAGE] = message;
       start_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
       call.startBatch(start_batch, function(err, response) {
         if (err) {

src/node/src/server.js

@@ -115,8 +115,10 @@ function waitForCancel(call, emitter) {
  * @param {function(*):Buffer=} serialize Serialization function for the
  *     response
  * @param {Object=} metadata Optional trailing metadata to send with status
+ * @param {number=} flags Flags for modifying how the message is sent.
+ *     Defaults to 0.
  */
-function sendUnaryResponse(call, value, serialize, metadata) {
+function sendUnaryResponse(call, value, serialize, metadata, flags) {
   var end_batch = {};
   var status = {
     code: grpc.status.OK,
@@ -130,7 +132,9 @@ function sendUnaryResponse(call, value, serialize, metadata) {
     end_batch[grpc.opType.SEND_INITIAL_METADATA] = {};
     call.metadataSent = true;
   }
-  end_batch[grpc.opType.SEND_MESSAGE] = serialize(value);
+  var message = serialize(value);
+  message.grpcWriteFlags = flags;
+  end_batch[grpc.opType.SEND_MESSAGE] = message;
   end_batch[grpc.opType.SEND_STATUS_FROM_SERVER] = status;
   call.startBatch(end_batch, function (){});
 }
@@ -254,7 +258,7 @@ function ServerWritableStream(call, serialize) {
  * for implementing stream.Writable.
  * @access private
  * @param {Buffer} chunk The chunk of data to write
- * @param {string} encoding Ignored
+ * @param {string} encoding Used to pass write flags
  * @param {function(Error=)} callback Callback to indicate that the write is
  *     complete
  */
@@ -265,7 +269,13 @@ function _write(chunk, encoding, callback) {
     batch[grpc.opType.SEND_INITIAL_METADATA] = {};
     this.call.metadataSent = true;
   }
-  batch[grpc.opType.SEND_MESSAGE] = this.serialize(chunk);
+  var message = this.serialize(chunk);
+  if (_.isFinite(encoding)) {
+    /* Attach the encoding if it is a finite number. This is the closest we
+     * can get to checking that it is valid flags */
+    message.grpcWriteFlags = encoding;
+  }
+  batch[grpc.opType.SEND_MESSAGE] = message;
   this.call.startBatch(batch, function(err, value) {
     if (err) {
       this.emit('error', err);
@@ -450,14 +460,14 @@ function handleUnary(call, handler, metadata) {
     if (emitter.cancelled) {
       return;
     }
-    handler.func(emitter, function sendUnaryData(err, value, trailer) {
+    handler.func(emitter, function sendUnaryData(err, value, trailer, flags) {
       if (err) {
         if (trailer) {
           err.metadata = trailer;
         }
         handleError(call, err);
       } else {
-        sendUnaryResponse(call, value, handler.serialize, trailer);
+        sendUnaryResponse(call, value, handler.serialize, trailer, flags);
       }
     });
   });
@@ -514,7 +524,7 @@ function handleClientStreaming(call, handler, metadata) {
   });
   waitForCancel(call, stream);
   stream.metadata = metadata;
-  handler.func(stream, function(err, value, trailer) {
+  handler.func(stream, function(err, value, trailer, flags) {
     stream.terminate();
     if (err) {
       if (trailer) {
@@ -522,7 +532,7 @@ function handleClientStreaming(call, handler, metadata) {
       }
       handleError(call, err);
     } else {
-      sendUnaryResponse(call, value, handler.serialize, trailer);
+      sendUnaryResponse(call, value, handler.serialize, trailer, flags);
     }
   });
 }

src/node/test/health_test.js

@@ -41,13 +41,9 @@ var grpc = require('../');
 
 describe('Health Checking', function() {
   var statusMap = {
-    '': {
-      '': 'SERVING',
-      'grpc.test.TestService': 'NOT_SERVING',
-    },
-    virtual_host: {
-      'grpc.test.TestService': 'SERVING'
-    }
+    '': 'SERVING',
+    'grpc.test.TestServiceNotServing': 'NOT_SERVING',
+    'grpc.test.TestServiceServing': 'SERVING'
   };
   var healthServer = new grpc.Server();
   healthServer.addProtoService(health.service,
@@ -71,15 +67,15 @@ describe('Health Checking', function() {
     });
   });
   it('should say that a disabled service is NOT_SERVING', function(done) {
-    healthClient.check({service: 'grpc.test.TestService'},
+    healthClient.check({service: 'grpc.test.TestServiceNotServing'},
                        function(err, response) {
                          assert.ifError(err);
                          assert.strictEqual(response.status, 'NOT_SERVING');
                          done();
                        });
   });
-  it('should say that a service on another host is SERVING', function(done) {
-    healthClient.check({host: 'virtual_host', service: 'grpc.test.TestService'},
+  it('should say that an enabled service is SERVING', function(done) {
+    healthClient.check({service: 'grpc.test.TestServiceServing'},
                        function(err, response) {
                          assert.ifError(err);
                          assert.strictEqual(response.status, 'SERVING');
@@ -93,12 +89,4 @@ describe('Health Checking', function() {
       done();
     });
   });
-  it('should get NOT_FOUND if the host is not registered', function(done) {
-    healthClient.check({host: 'wrong_host', service: 'grpc.test.TestService'},
-                       function(err, response) {
-                         assert(err);
-                         assert.strictEqual(err.code, grpc.status.NOT_FOUND);
-                         done();
-                       });
-  });
 });