merge

39 files changed, 839 insertions, 436 deletions

diff --git a/src/compiler/csharp_generator.cc b/src/compiler/csharp_generator.cc
index 51d8d982e2..7b497df7f4 100644
--- a/src/compiler/csharp_generator.cc
+++ b/src/compiler/csharp_generator.cc
@@ -33,6 +33,7 @@
 
 #include <cctype>
 #include <map>
+#include <sstream>
 #include <vector>
 
 #include "src/compiler/csharp_generator.h"
@@ -44,7 +45,6 @@
 using google::protobuf::compiler::csharp::GetFileNamespace;
 using google::protobuf::compiler::csharp::GetClassName;
 using google::protobuf::compiler::csharp::GetUmbrellaClassName;
-using google::protobuf::SimpleItoa;
 using grpc::protobuf::FileDescriptor;
 using grpc::protobuf::Descriptor;
 using grpc::protobuf::ServiceDescriptor;
@@ -228,11 +228,14 @@ void GenerateStaticMethodField(Printer* out, const MethodDescriptor *method) {
 }
 
 void GenerateServiceDescriptorProperty(Printer* out, const ServiceDescriptor *service) {
+  std::ostringstream index;
+  index << service->index();
   out->Print("// service descriptor\n");
   out->Print("public static global::Google.Protobuf.Reflection.ServiceDescriptor Descriptor\n");
   out->Print("{\n");
   out->Print("  get { return $umbrella$.Descriptor.Services[$index$]; }\n",
-             "umbrella", GetUmbrellaClassName(service->file()), "index", SimpleItoa(service->index()));
+             "umbrella", GetUmbrellaClassName(service->file()), "index",
+             index.str());
   out->Print("}\n");
   out->Print("\n");
 }
diff --git a/src/compiler/csharp_generator.h b/src/compiler/csharp_generator.h
index 67e3ee30b5..90eb7e2984 100644
--- a/src/compiler/csharp_generator.h
+++ b/src/compiler/csharp_generator.h
@@ -36,10 +36,7 @@
 
 #include "src/compiler/config.h"
 
-using namespace std;
-
 #include <google/protobuf/compiler/csharp/csharp_names.h>
-#include <google/protobuf/stubs/strutil.h>
 
 namespace grpc_csharp_generator {
 
diff --git a/src/core/census/context.c b/src/core/census/context.c
index df238ec98c..cab58b653c 100644
--- a/src/core/census/context.c
+++ b/src/core/census/context.c
@@ -44,16 +44,3 @@ size_t census_context_serialize(const census_context *context, char *buffer,
   /* TODO(aveitch): implement serialization */
   return 0;
 }
-
-int census_context_deserialize(const char *buffer, census_context **context) {
-  int ret = 0;
-  if (buffer != NULL) {
-    /* TODO(aveitch): implement deserialization. */
-    ret = 1;
-  }
-  *context = gpr_malloc(sizeof(census_context));
-  memset(*context, 0, sizeof(census_context));
-  return ret;
-}
-
-void census_context_destroy(census_context *context) { gpr_free(context); }
diff --git a/src/core/census/grpc_context.c b/src/core/census/grpc_context.c
index 11f1eb3d5d..429f3ec9db 100644
--- a/src/core/census/grpc_context.c
+++ b/src/core/census/grpc_context.c
@@ -35,24 +35,11 @@
 #include <grpc/grpc.h>
 #include "src/core/surface/call.h"
 
-static void grpc_census_context_destroy(void *context) {
-  census_context_destroy((census_context *)context);
-}
-
 void grpc_census_call_set_context(grpc_call *call, census_context *context) {
   if (census_enabled() == CENSUS_FEATURE_NONE) {
     return;
   }
-  if (context == NULL) {
-    if (grpc_call_is_client(call)) {
-      census_context *context_ptr;
-      census_context_deserialize(NULL, &context_ptr);
-      grpc_call_context_set(call, GRPC_CONTEXT_TRACING, context_ptr,
-                            grpc_census_context_destroy);
-    } else {
-      /* TODO(aveitch): server side context code to be implemented. */
-    }
-  } else {
+  if (context != NULL) {
     grpc_call_context_set(call, GRPC_CONTEXT_TRACING, context, NULL);
   }
 }
diff --git a/src/core/census/operation.c b/src/core/census/operation.c
new file mode 100644
index 0000000000..118eb0a47a
--- /dev/null
+++ b/src/core/census/operation.c
@@ -0,0 +1,63 @@
+/*
+ * 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.
+ *
+ */
+
+#include <grpc/census.h>
+
+/* TODO(aveitch): These are all placeholder implementations. */
+
+census_timestamp census_start_rpc_op_timestamp(void) {
+  census_timestamp ct;
+  /* TODO(aveitch): assumes gpr_timespec implementation of census_timestamp. */
+  ct.ts = gpr_now(GPR_CLOCK_MONOTONIC);
+  return ct;
+}
+
+census_context *census_start_client_rpc_op(
+    const census_context *context, gpr_int64 rpc_name_id,
+    const census_rpc_name_info *rpc_name_info, const char *peer, int trace_mask,
+    const census_timestamp *start_time) {
+  return NULL;
+}
+
+census_context *census_start_server_rpc_op(
+    const char *buffer, gpr_int64 rpc_name_id,
+    const census_rpc_name_info *rpc_name_info, const char *peer, int trace_mask,
+    census_timestamp *start_time) {
+  return NULL;
+}
+
+census_context *census_start_op(census_context *context, const char *family,
+                                const char *name, int trace_mask) {
+  return NULL;
+}
+
+void census_end_op(census_context *context, int status) {}
diff --git a/src/core/census/tracing.c b/src/core/census/tracing.c
new file mode 100644
index 0000000000..ae38773c0a
--- /dev/null
+++ b/src/core/census/tracing.c
@@ -0,0 +1,45 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+#include <grpc/census.h>
+
+/* TODO(aveitch): These are all placeholder implementations. */
+
+int census_trace_mask(const census_context *context) {
+  return CENSUS_TRACE_MASK_NONE;
+}
+
+void census_set_trace_mask(int trace_mask) {}
+
+void census_trace_print(census_context *context, gpr_uint32 type,
+                        const char *buffer, size_t n) {}
diff --git a/src/core/security/credentials.c b/src/core/security/credentials.c
index 362d5f4b6f..1c665f1ede 100644
--- a/src/core/security/credentials.c
+++ b/src/core/security/credentials.c
@@ -618,7 +618,7 @@ static void init_oauth2_token_fetcher(grpc_oauth2_token_fetcher_credentials *c,
   grpc_httpcli_context_init(&c->httpcli_context);
 }
 
-/* -- ComputeEngine credentials. -- */
+/* -- GoogleComputeEngine credentials. -- */
 
 static grpc_credentials_vtable compute_engine_vtable = {
     oauth2_token_fetcher_destroy, oauth2_token_fetcher_has_request_metadata,
@@ -640,7 +640,8 @@ static void compute_engine_fetch_oauth2(
                    metadata_req);
 }
 
-grpc_credentials *grpc_compute_engine_credentials_create(void *reserved) {
+grpc_credentials *grpc_google_compute_engine_credentials_create(
+    void *reserved) {
   grpc_oauth2_token_fetcher_credentials *c =
       gpr_malloc(sizeof(grpc_oauth2_token_fetcher_credentials));
   GPR_ASSERT(reserved == NULL);
@@ -649,81 +650,11 @@ grpc_credentials *grpc_compute_engine_credentials_create(void *reserved) {
   return &c->base;
 }
 
-/* -- ServiceAccount credentials. -- */
-
-static void service_account_destroy(grpc_credentials *creds) {
-  grpc_service_account_credentials *c =
-      (grpc_service_account_credentials *)creds;
-  if (c->scope != NULL) gpr_free(c->scope);
-  grpc_auth_json_key_destruct(&c->key);
-  oauth2_token_fetcher_destroy(&c->base.base);
-}
-
-static grpc_credentials_vtable service_account_vtable = {
-    service_account_destroy, oauth2_token_fetcher_has_request_metadata,
-    oauth2_token_fetcher_has_request_metadata_only,
-    oauth2_token_fetcher_get_request_metadata, NULL};
-
-static void service_account_fetch_oauth2(
-    grpc_credentials_metadata_request *metadata_req,
-    grpc_httpcli_context *httpcli_context, grpc_pollset *pollset,
-    grpc_httpcli_response_cb response_cb, gpr_timespec deadline) {
-  grpc_service_account_credentials *c =
-      (grpc_service_account_credentials *)metadata_req->creds;
-  grpc_httpcli_header header = {"Content-Type",
-                                "application/x-www-form-urlencoded"};
-  grpc_httpcli_request request;
-  char *body = NULL;
-  char *jwt = grpc_jwt_encode_and_sign(&c->key, GRPC_JWT_OAUTH2_AUDIENCE,
-                                       c->token_lifetime, c->scope);
-  if (jwt == NULL) {
-    grpc_httpcli_response response;
-    memset(&response, 0, sizeof(grpc_httpcli_response));
-    response.status = 400; /* Invalid request. */
-    gpr_log(GPR_ERROR, "Could not create signed jwt.");
-    /* Do not even send the request, just call the response callback. */
-    response_cb(metadata_req, &response);
-    return;
-  }
-  gpr_asprintf(&body, "%s%s", GRPC_SERVICE_ACCOUNT_POST_BODY_PREFIX, jwt);
-  memset(&request, 0, sizeof(grpc_httpcli_request));
-  request.host = GRPC_GOOGLE_OAUTH2_SERVICE_HOST;
-  request.path = GRPC_GOOGLE_OAUTH2_SERVICE_TOKEN_PATH;
-  request.hdr_count = 1;
-  request.hdrs = &header;
-  request.handshaker = &grpc_httpcli_ssl;
-  grpc_httpcli_post(httpcli_context, pollset, &request, body, strlen(body),
-                    deadline, response_cb, metadata_req);
-  gpr_free(body);
-  gpr_free(jwt);
-}
-
-grpc_credentials *grpc_service_account_credentials_create(
-    const char *json_key, const char *scope, gpr_timespec token_lifetime,
-    void *reserved) {
-  grpc_service_account_credentials *c;
-  grpc_auth_json_key key = grpc_auth_json_key_create_from_string(json_key);
-  GPR_ASSERT(reserved == NULL);
-  if (scope == NULL || (strlen(scope) == 0) ||
-      !grpc_auth_json_key_is_valid(&key)) {
-    gpr_log(GPR_ERROR,
-            "Invalid input for service account credentials creation");
-    return NULL;
-  }
-  c = gpr_malloc(sizeof(grpc_service_account_credentials));
-  memset(c, 0, sizeof(grpc_service_account_credentials));
-  init_oauth2_token_fetcher(&c->base, service_account_fetch_oauth2);
-  c->base.base.vtable = &service_account_vtable;
-  c->scope = gpr_strdup(scope);
-  c->key = key;
-  c->token_lifetime = token_lifetime;
-  return &c->base.base;
-}
-
-/* -- RefreshToken credentials. -- */
+/* -- GoogleRefreshToken credentials. -- */
 
 static void refresh_token_destroy(grpc_credentials *creds) {
-  grpc_refresh_token_credentials *c = (grpc_refresh_token_credentials *)creds;
+  grpc_google_refresh_token_credentials *c =
+      (grpc_google_refresh_token_credentials *)creds;
   grpc_auth_refresh_token_destruct(&c->refresh_token);
   oauth2_token_fetcher_destroy(&c->base.base);
 }
@@ -737,8 +668,8 @@ static void refresh_token_fetch_oauth2(
     grpc_credentials_metadata_request *metadata_req,
     grpc_httpcli_context *httpcli_context, grpc_pollset *pollset,
     grpc_httpcli_response_cb response_cb, gpr_timespec deadline) {
-  grpc_refresh_token_credentials *c =
-      (grpc_refresh_token_credentials *)metadata_req->creds;
+  grpc_google_refresh_token_credentials *c =
+      (grpc_google_refresh_token_credentials *)metadata_req->creds;
   grpc_httpcli_header header = {"Content-Type",
                                 "application/x-www-form-urlencoded"};
   grpc_httpcli_request request;
@@ -757,22 +688,23 @@ static void refresh_token_fetch_oauth2(
   gpr_free(body);
 }
 
-grpc_credentials *grpc_refresh_token_credentials_create_from_auth_refresh_token(
+grpc_credentials *
+grpc_refresh_token_credentials_create_from_auth_refresh_token(
     grpc_auth_refresh_token refresh_token) {
-  grpc_refresh_token_credentials *c;
+  grpc_google_refresh_token_credentials *c;
   if (!grpc_auth_refresh_token_is_valid(&refresh_token)) {
     gpr_log(GPR_ERROR, "Invalid input for refresh token credentials creation");
     return NULL;
   }
-  c = gpr_malloc(sizeof(grpc_refresh_token_credentials));
-  memset(c, 0, sizeof(grpc_refresh_token_credentials));
+  c = gpr_malloc(sizeof(grpc_google_refresh_token_credentials));
+  memset(c, 0, sizeof(grpc_google_refresh_token_credentials));
   init_oauth2_token_fetcher(&c->base, refresh_token_fetch_oauth2);
   c->base.base.vtable = &refresh_token_vtable;
   c->refresh_token = refresh_token;
   return &c->base.base;
 }
 
-grpc_credentials *grpc_refresh_token_credentials_create(
+grpc_credentials *grpc_google_refresh_token_credentials_create(
     const char *json_refresh_token, void *reserved) {
   GPR_ASSERT(reserved == NULL);
   return grpc_refresh_token_credentials_create_from_auth_refresh_token(
@@ -1194,7 +1126,7 @@ grpc_credentials *grpc_credentials_contains_type(
 /* -- IAM credentials. -- */
 
 static void iam_destroy(grpc_credentials *creds) {
-  grpc_iam_credentials *c = (grpc_iam_credentials *)creds;
+  grpc_google_iam_credentials *c = (grpc_google_iam_credentials *)creds;
   grpc_credentials_md_store_unref(c->iam_md);
   gpr_free(c);
 }
@@ -1210,7 +1142,7 @@ static void iam_get_request_metadata(grpc_credentials *creds,
                                      const char *service_url,
                                      grpc_credentials_metadata_cb cb,
                                      void *user_data) {
-  grpc_iam_credentials *c = (grpc_iam_credentials *)creds;
+  grpc_google_iam_credentials *c = (grpc_google_iam_credentials *)creds;
   cb(user_data, c->iam_md->entries, c->iam_md->num_entries,
      GRPC_CREDENTIALS_OK);
 }
@@ -1219,15 +1151,14 @@ static grpc_credentials_vtable iam_vtable = {
     iam_destroy, iam_has_request_metadata, iam_has_request_metadata_only,
     iam_get_request_metadata, NULL};
 
-grpc_credentials *grpc_iam_credentials_create(const char *token,
-                                              const char *authority_selector,
-                                              void *reserved) {
-  grpc_iam_credentials *c;
+grpc_credentials *grpc_google_iam_credentials_create(
+    const char *token, const char *authority_selector, void *reserved) {
+  grpc_google_iam_credentials *c;
   GPR_ASSERT(reserved == NULL);
   GPR_ASSERT(token != NULL);
   GPR_ASSERT(authority_selector != NULL);
-  c = gpr_malloc(sizeof(grpc_iam_credentials));
-  memset(c, 0, sizeof(grpc_iam_credentials));
+  c = gpr_malloc(sizeof(grpc_google_iam_credentials));
+  memset(c, 0, sizeof(grpc_google_iam_credentials));
   c->base.type = GRPC_CREDENTIALS_TYPE_IAM;
   c->base.vtable = &iam_vtable;
   gpr_ref_init(&c->base.refcount, 1);
diff --git a/src/core/security/credentials.h b/src/core/security/credentials.h
index 29cd1ac87f..d9bd53adc2 100644
--- a/src/core/security/credentials.h
+++ b/src/core/security/credentials.h
@@ -277,21 +277,12 @@ typedef struct {
   grpc_fetch_oauth2_func fetch_func;
 } grpc_oauth2_token_fetcher_credentials;
 
-/* -- ServiceAccount credentials. -- */
-
-typedef struct {
-  grpc_oauth2_token_fetcher_credentials base;
-  grpc_auth_json_key key;
-  char *scope;
-  gpr_timespec token_lifetime;
-} grpc_service_account_credentials;
-
-/* -- RefreshToken credentials. -- */
+/* -- GoogleRefreshToken credentials. -- */
 
 typedef struct {
   grpc_oauth2_token_fetcher_credentials base;
   grpc_auth_refresh_token refresh_token;
-} grpc_refresh_token_credentials;
+} grpc_google_refresh_token_credentials;
 
 /* -- Oauth2 Access Token credentials. -- */
 
@@ -308,12 +299,12 @@ typedef struct {
   int is_async;
 } grpc_md_only_test_credentials;
 
-/* -- IAM credentials. -- */
+/* -- GoogleIAM credentials. -- */
 
 typedef struct {
   grpc_credentials base;
   grpc_credentials_md_store *iam_md;
-} grpc_iam_credentials;
+} grpc_google_iam_credentials;
 
 /* -- Composite credentials. -- */
 
diff --git a/src/core/security/google_default_credentials.c b/src/core/security/google_default_credentials.c
index f9aa5187ce..874dd59e84 100644
--- a/src/core/security/google_default_credentials.c
+++ b/src/core/security/google_default_credentials.c
@@ -194,7 +194,7 @@ grpc_credentials *grpc_google_default_credentials_create(void) {
     int need_compute_engine_creds = is_stack_running_on_compute_engine();
     compute_engine_detection_done = 1;
     if (need_compute_engine_creds) {
-      result = grpc_compute_engine_credentials_create(NULL);
+      result = grpc_google_compute_engine_credentials_create(NULL);
     }
   }
 
diff --git a/src/cpp/client/secure_credentials.cc b/src/cpp/client/secure_credentials.cc
index e0642469b4..2260f6d33e 100644
--- a/src/cpp/client/secure_credentials.cc
+++ b/src/cpp/client/secure_credentials.cc
@@ -81,26 +81,10 @@ std::shared_ptr<Credentials> SslCredentials(
 }
 
 // Builds credentials for use when running in GCE
-std::shared_ptr<Credentials> ComputeEngineCredentials() {
+std::shared_ptr<Credentials> GoogleComputeEngineCredentials() {
   GrpcLibrary init;  // To call grpc_init().
-  return WrapCredentials(grpc_compute_engine_credentials_create(nullptr));
-}
-
-// Builds service account credentials.
-std::shared_ptr<Credentials> ServiceAccountCredentials(
-    const grpc::string& json_key, const grpc::string& scope,
-    long token_lifetime_seconds) {
-  GrpcLibrary init;  // To call grpc_init().
-  if (token_lifetime_seconds <= 0) {
-    gpr_log(GPR_ERROR,
-            "Trying to create ServiceAccountCredentials "
-            "with non-positive lifetime");
-    return WrapCredentials(nullptr);
-  }
-  gpr_timespec lifetime =
-      gpr_time_from_seconds(token_lifetime_seconds, GPR_TIMESPAN);
-  return WrapCredentials(grpc_service_account_credentials_create(
-      json_key.c_str(), scope.c_str(), lifetime, nullptr));
+  return WrapCredentials(
+      grpc_google_compute_engine_credentials_create(nullptr));
 }
 
 // Builds JWT credentials.
@@ -119,10 +103,10 @@ std::shared_ptr<Credentials> ServiceAccountJWTAccessCredentials(
 }
 
 // Builds refresh token credentials.
-std::shared_ptr<Credentials> RefreshTokenCredentials(
+std::shared_ptr<Credentials> GoogleRefreshTokenCredentials(
     const grpc::string& json_refresh_token) {
   GrpcLibrary init;  // To call grpc_init().
-  return WrapCredentials(grpc_refresh_token_credentials_create(
+  return WrapCredentials(grpc_google_refresh_token_credentials_create(
       json_refresh_token.c_str(), nullptr));
 }
 
@@ -135,11 +119,11 @@ std::shared_ptr<Credentials> AccessTokenCredentials(
 }
 
 // Builds IAM credentials.
-std::shared_ptr<Credentials> IAMCredentials(
+std::shared_ptr<Credentials> GoogleIAMCredentials(
     const grpc::string& authorization_token,
     const grpc::string& authority_selector) {
   GrpcLibrary init;  // To call grpc_init().
-  return WrapCredentials(grpc_iam_credentials_create(
+  return WrapCredentials(grpc_google_iam_credentials_create(
       authorization_token.c_str(), authority_selector.c_str(), nullptr));
 }
 
diff --git a/src/csharp/README.md b/src/csharp/README.md
index 30523b3bd2..3fbc1c5f05 100644
--- a/src/csharp/README.md
+++ b/src/csharp/README.md
@@ -158,3 +158,20 @@ Contents
   An example client that sends some requests to math server.
 - Grpc.IntegrationTesting:
   Cross-language gRPC implementation testing (interop testing).
+
+Troubleshooting
+---------------
+
+### Problem: Unable to load DLL 'grpc_csharp_ext.dll'
+
+Internally, gRPC C# uses a native library written in C (gRPC C core) and invokes its functionality via P/Invoke. `grpc_csharp_ext` library is a native extension library that facilitates this by wrapping some C core API into a form that's more digestible for P/Invoke. If you get the above error, it means that the native dependencies could not be located by the C# runtime (or they are incompatible with the current runtime, so they could not be loaded). The solution to this is environment specific.
+
+- If you are developing on Windows in Visual Studio, the `grpc_csharp_ext.dll` that is shipped by gRPC nuget packages should be automatically copied to your build destination folder once you build. By adjusting project properties in your VS project file, you can influence which exact configuration of `grpc_csharp_ext.dll` will be used (based on VS version, bitness, debug/release configuration).
+
+- If you are running your application that is using gRPC on Windows machine that doesn't have Visual Studio installed, you might need to install [Visual C++ 2013 redistributable](https://www.microsoft.com/en-us/download/details.aspx?id=40784) that contains some system .dll libraries that `grpc_csharp_ext.dll` depends on (see #905 for more details).
+
+- On Linux (or Docker), you need to first install gRPC C core and `libgrpc_csharp_ext.so` shared libraries. Currently, the libraries can be installed by `make install_grpc_csharp_ext` or using Linuxbrew (a Debian package is coming soon). Installation on a machine where your application is going to be deployed is no different. 
+
+- On Mac, you need to first install gRPC C core and `libgrpc_csharp_ext.dylib` shared libraries using Homebrew. See above for installation instruction. Installation on a machine where your application is going to be deployed is no different. 
+
+- Possible cause for the problem is that the `grpc_csharp_ext` library is installed, but it has different bitness (32/64bit) than your C# runtime (in case you are using mono) or C# application.
diff --git a/src/node/README.md b/src/node/README.md
index b6411537c7..c96bc96642 100644
--- a/src/node/README.md
+++ b/src/node/README.md
@@ -11,10 +11,10 @@ Alpha : Ready for early adopters
 
 **Linux (Debian):**
 
-Add [Debian unstable][] to your `sources.list` file. Example:
+Add [Debian testing][] to your `sources.list` file. Example:
 
 ```sh
-echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+echo "deb http://ftp.us.debian.org/debian testing main contrib non-free" | \
 sudo tee -a /etc/apt/sources.list
 ```
 
@@ -113,4 +113,4 @@ An object with factory methods for creating credential objects for servers.
 
 [homebrew]:http://brew.sh
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
-[Debian unstable]:https://www.debian.org/releases/sid/
+[Debian testing]:https://www.debian.org/releases/stretch/
diff --git a/src/node/ext/call.cc b/src/node/ext/call.cc
index 18858fa334..560869e6fa 100644
--- a/src/node/ext/call.cc
+++ b/src/node/ext/call.cc
@@ -111,17 +111,19 @@ bool CreateMetadataArray(Handle<Object> metadata, grpc_metadata_array *array,
           NanAssignPersistent(*handle, value);
           resources->handles.push_back(unique_ptr<PersistentHolder>(
               new PersistentHolder(handle)));
-          continue;
+        } else {
+          return false;
         }
-      }
-      if (value->IsString()) {
-        Handle<String> string_value = value->ToString();
-        NanUtf8String *utf8_value = new NanUtf8String(string_value);
-        resources->strings.push_back(unique_ptr<NanUtf8String>(utf8_value));
-        current->value = **utf8_value;
-        current->value_length = string_value->Length();
       } else {
-        return false;
+        if (value->IsString()) {
+          Handle<String> string_value = value->ToString();
+          NanUtf8String *utf8_value = new NanUtf8String(string_value);
+          resources->strings.push_back(unique_ptr<NanUtf8String>(utf8_value));
+          current->value = **utf8_value;
+          current->value_length = string_value->Length();
+        } else {
+          return false;
+        }
       }
       array->count += 1;
     }
@@ -156,8 +158,7 @@ Handle<Value> ParseMetadata(const grpc_metadata_array *metadata_array) {
     }
     if (EndsWith(elem->key, "-bin")) {
       array->Set(index_map[elem->key],
-                 MakeFastBuffer(
-                     NanNewBufferHandle(elem->value, elem->value_length)));
+                 NanNewBufferHandle(elem->value, elem->value_length));
     } else {
       array->Set(index_map[elem->key], NanNew(elem->value));
     }
@@ -460,6 +461,9 @@ void Call::Init(Handle<Object> exports) {
                           NanNew<FunctionTemplate>(StartBatch)->GetFunction());
   NanSetPrototypeTemplate(tpl, "cancel",
                           NanNew<FunctionTemplate>(Cancel)->GetFunction());
+  NanSetPrototypeTemplate(
+      tpl, "cancelWithStatus",
+      NanNew<FunctionTemplate>(CancelWithStatus)->GetFunction());
   NanSetPrototypeTemplate(tpl, "getPeer",
                           NanNew<FunctionTemplate>(GetPeer)->GetFunction());
   NanAssignPersistent(fun_tpl, tpl);
@@ -642,6 +646,26 @@ NAN_METHOD(Call::Cancel) {
   NanReturnUndefined();
 }
 
+NAN_METHOD(Call::CancelWithStatus) {
+  NanScope();
+  if (!HasInstance(args.This())) {
+    return NanThrowTypeError("cancel can only be called on Call objects");
+  }
+  if (!args[0]->IsUint32()) {
+    return NanThrowTypeError(
+        "cancelWithStatus's first argument must be a status code");
+  }
+  if (!args[1]->IsString()) {
+    return NanThrowTypeError(
+        "cancelWithStatus's second argument must be a string");
+  }
+  Call *call = ObjectWrap::Unwrap<Call>(args.This());
+  grpc_status_code code = static_cast<grpc_status_code>(args[0]->Uint32Value());
+  NanUtf8String details(args[0]);
+  grpc_call_cancel_with_status(call->wrapped_call, code, *details, NULL);
+  NanReturnUndefined();
+}
+
 NAN_METHOD(Call::GetPeer) {
   NanScope();
   if (!HasInstance(args.This())) {
diff --git a/src/node/ext/call.h b/src/node/ext/call.h
index ef6e5fcd21..89f81dcf4d 100644
--- a/src/node/ext/call.h
+++ b/src/node/ext/call.h
@@ -133,6 +133,7 @@ class Call : public ::node::ObjectWrap {
   static NAN_METHOD(New);
   static NAN_METHOD(StartBatch);
   static NAN_METHOD(Cancel);
+  static NAN_METHOD(CancelWithStatus);
   static NAN_METHOD(GetPeer);
   static NanCallback *constructor;
   // Used for typechecking instances of this javascript class
diff --git a/src/node/ext/credentials.cc b/src/node/ext/credentials.cc
index 85a823a108..c3b04dcea7 100644
--- a/src/node/ext/credentials.cc
+++ b/src/node/ext/credentials.cc
@@ -186,7 +186,7 @@ NAN_METHOD(Credentials::CreateComposite) {
 
 NAN_METHOD(Credentials::CreateGce) {
   NanScope();
-  grpc_credentials *creds = grpc_compute_engine_credentials_create(NULL);
+  grpc_credentials *creds = grpc_google_compute_engine_credentials_create(NULL);
   if (creds == NULL) {
     NanReturnNull();
   }
@@ -204,7 +204,7 @@ NAN_METHOD(Credentials::CreateIam) {
   NanUtf8String auth_token(args[0]);
   NanUtf8String auth_selector(args[1]);
   grpc_credentials *creds =
-      grpc_iam_credentials_create(*auth_token, *auth_selector, NULL);
+      grpc_google_iam_credentials_create(*auth_token, *auth_selector, NULL);
   if (creds == NULL) {
     NanReturnNull();
   }
diff --git a/src/node/index.js b/src/node/index.js
index 889b0ac0e9..51d3fa590c 100644
--- a/src/node/index.js
+++ b/src/node/index.js
@@ -41,6 +41,8 @@ var client = require('./src/client.js');
 
 var server = require('./src/server.js');
 
+var Metadata = require('./src/metadata.js');
+
 var grpc = require('bindings')('grpc');
 
 /**
@@ -107,18 +109,12 @@ exports.getGoogleAuthDelegate = function getGoogleAuthDelegate(credential) {
    * @param {function(Error, Object)} callback
    */
   return function updateMetadata(authURI, metadata, callback) {
-    metadata = _.clone(metadata);
-    if (metadata.Authorization) {
-      metadata.Authorization = _.clone(metadata.Authorization);
-    } else {
-      metadata.Authorization = [];
-    }
     credential.getRequestMetadata(authURI, function(err, header) {
       if (err) {
         callback(err);
         return;
       }
-      metadata.Authorization.push(header.Authorization);
+      metadata.add('authorization', header.Authorization);
       callback(null, metadata);
     });
   };
@@ -130,6 +126,11 @@ exports.getGoogleAuthDelegate = function getGoogleAuthDelegate(credential) {
 exports.Server = server.Server;
 
 /**
+ * @see module:src/metadata
+ */
+exports.Metadata = Metadata;
+
+/**
  * Status name to code number mapping
  */
 exports.status = grpc.status;
diff --git a/src/node/interop/interop_client.js b/src/node/interop/interop_client.js
index 612dcf01f6..8fb8d66920 100644
--- a/src/node/interop/interop_client.js
+++ b/src/node/interop/interop_client.js
@@ -321,13 +321,7 @@ function oauth2Test(expected_user, scope, per_rpc, client, done) {
     credential.getAccessToken(function(err, token) {
       assert.ifError(err);
       var updateMetadata = function(authURI, metadata, callback) {
-        metadata = _.clone(metadata);
-        if (metadata.Authorization) {
-          metadata.Authorization = _.clone(metadata.Authorization);
-        } else {
-          metadata.Authorization = [];
-        }
-        metadata.Authorization.push('Bearer ' + token);
+        metadata.Add('authorization', 'Bearer ' + token);
         callback(null, metadata);
       };
       var makeTestCall = function(error, client_metadata) {
diff --git a/src/node/src/client.js b/src/node/src/client.js
index 7b7eae51d2..6a49490910 100644
--- a/src/node/src/client.js
+++ b/src/node/src/client.js
@@ -42,7 +42,9 @@ var _ = require('lodash');
 
 var grpc = require('bindings')('grpc.node');
 
-var common = require('./common.js');
+var common = require('./common');
+
+var Metadata = require('./metadata');
 
 var EventEmitter = require('events').EventEmitter;
 
@@ -140,7 +142,14 @@ function _read(size) {
       return;
     }
     var data = event.read;
-    if (self.push(self.deserialize(data)) && data !== null) {
+    var deserialized;
+    try {
+      deserialized = self.deserialize(data);
+    } catch (e) {
+      self.call.cancelWithStatus(grpc.status.INTERNAL,
+                                 'Failed to parse server response');
+    }
+    if (self.push(deserialized) && data !== null) {
       var read_batch = {};
       read_batch[grpc.opType.RECV_MESSAGE] = true;
       self.call.startBatch(read_batch, readCallback);
@@ -254,8 +263,7 @@ function makeUnaryRequestFunction(method, serialize, deserialize) {
    *     serialize
    * @param {function(?Error, value=)} callback The callback to for when the
    *     response is received
-   * @param {array=} metadata Array of metadata key/value pairs to add to the
-   *     call
+   * @param {Metadata=} metadata Metadata to add to the call
    * @param {Object=} options Options map
    * @return {EventEmitter} An event emitter for stream related events
    */
@@ -264,7 +272,9 @@ function makeUnaryRequestFunction(method, serialize, deserialize) {
     var emitter = new EventEmitter();
     var call = getCall(this.channel, method, options);
     if (metadata === null || metadata === undefined) {
-      metadata = {};
+      metadata = new Metadata();
+    } else {
+      metadata = metadata.clone();
     }
     emitter.cancel = function cancel() {
       call.cancel();
@@ -283,29 +293,48 @@ function makeUnaryRequestFunction(method, serialize, deserialize) {
       if (options) {
         message.grpcWriteFlags = options.flags;
       }
-      client_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
+      client_batch[grpc.opType.SEND_INITIAL_METADATA] =
+          metadata._getCoreRepresentation();
       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;
       client_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
       call.startBatch(client_batch, function(err, response) {
-        emitter.emit('status', response.status);
-        if (response.status.code !== grpc.status.OK) {
-          var error = new Error(response.status.details);
-          error.code = response.status.code;
-          error.metadata = response.status.metadata;
-          callback(error);
-          return;
-        } else {
+        response.status.metadata = Metadata._fromCoreRepresentation(
+              response.status.metadata);
+        var status = response.status;
+        var error;
+        var deserialized;
+        if (status.code === grpc.status.OK) {
           if (err) {
             // Got a batch error, but OK status. Something went wrong
             callback(err);
             return;
+          } else {
+            try {
+              deserialized = deserialize(response.read);
+            } catch (e) {
+              /* Change status to indicate bad server response. This will result
+               * in passing an error to the callback */
+              status = {
+                code: grpc.status.INTERNAL,
+                details: 'Failed to parse server response'
+              };
+            }
           }
         }
-        emitter.emit('metadata', response.metadata);
-        callback(null, deserialize(response.read));
+        if (status.code !== grpc.status.OK) {
+          error = new Error(response.status.details);
+          error.code = status.code;
+          error.metadata = status.metadata;
+          callback(error);
+        } else {
+          callback(null, deserialized);
+        }
+        emitter.emit('status', status);
+        emitter.emit('metadata', Metadata._fromCoreRepresentation(
+            response.metadata));
       });
     });
     return emitter;
@@ -328,7 +357,7 @@ function makeClientStreamRequestFunction(method, serialize, deserialize) {
    * @this {Client} Client object. Must have a channel member.
    * @param {function(?Error, value=)} callback The callback to for when the
    *     response is received
-   * @param {array=} metadata Array of metadata key/value pairs to add to the
+   * @param {Metadata=} metadata Array of metadata key/value pairs to add to the
    *     call
    * @param {Object=} options Options map
    * @return {EventEmitter} An event emitter for stream related events
@@ -337,7 +366,9 @@ function makeClientStreamRequestFunction(method, serialize, deserialize) {
     /* jshint validthis: true */
     var call = getCall(this.channel, method, options);
     if (metadata === null || metadata === undefined) {
-      metadata = {};
+      metadata = new Metadata();
+    } else {
+      metadata = metadata.clone();
     }
     var stream = new ClientWritableStream(call, serialize);
     this.updateMetadata(this.auth_uri, metadata, function(error, metadata) {
@@ -347,7 +378,8 @@ function makeClientStreamRequestFunction(method, serialize, deserialize) {
         return;
       }
       var metadata_batch = {};
-      metadata_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
+      metadata_batch[grpc.opType.SEND_INITIAL_METADATA] =
+          metadata._getCoreRepresentation();
       metadata_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
       call.startBatch(metadata_batch, function(err, response) {
         if (err) {
@@ -355,27 +387,45 @@ function makeClientStreamRequestFunction(method, serialize, deserialize) {
           // in the other batch.
           return;
         }
-        stream.emit('metadata', response.metadata);
+        stream.emit('metadata', Metadata._fromCoreRepresentation(
+            response.metadata));
       });
       var client_batch = {};
       client_batch[grpc.opType.RECV_MESSAGE] = true;
       client_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
       call.startBatch(client_batch, function(err, response) {
-        stream.emit('status', response.status);
-        if (response.status.code !== grpc.status.OK) {
-          var error = new Error(response.status.details);
-          error.code = response.status.code;
-          error.metadata = response.status.metadata;
-          callback(error);
-          return;
-        } else {
+        response.status.metadata = Metadata._fromCoreRepresentation(
+              response.status.metadata);
+        var status = response.status;
+        var error;
+        var deserialized;
+        if (status.code === grpc.status.OK) {
           if (err) {
             // Got a batch error, but OK status. Something went wrong
             callback(err);
             return;
+          } else {
+            try {
+              deserialized = deserialize(response.read);
+            } catch (e) {
+              /* Change status to indicate bad server response. This will result
+               * in passing an error to the callback */
+              status = {
+                code: grpc.status.INTERNAL,
+                details: 'Failed to parse server response'
+              };
+            }
           }
         }
-        callback(null, deserialize(response.read));
+        if (status.code !== grpc.status.OK) {
+          error = new Error(response.status.details);
+          error.code = status.code;
+          error.metadata = status.metadata;
+          callback(error);
+        } else {
+          callback(null, deserialized);
+        }
+        stream.emit('status', status);
       });
     });
     return stream;
@@ -398,7 +448,7 @@ function makeServerStreamRequestFunction(method, serialize, deserialize) {
    * @this {SurfaceClient} Client object. Must have a channel member.
    * @param {*} argument The argument to the call. Should be serializable with
    *     serialize
-   * @param {array=} metadata Array of metadata key/value pairs to add to the
+   * @param {Metadata=} metadata Array of metadata key/value pairs to add to the
    *     call
    * @param {Object} options Options map
    * @return {EventEmitter} An event emitter for stream related events
@@ -407,7 +457,9 @@ function makeServerStreamRequestFunction(method, serialize, deserialize) {
     /* jshint validthis: true */
     var call = getCall(this.channel, method, options);
     if (metadata === null || metadata === undefined) {
-      metadata = {};
+      metadata = new Metadata();
+    } else {
+      metadata = metadata.clone();
     }
     var stream = new ClientReadableStream(call, deserialize);
     this.updateMetadata(this.auth_uri, metadata, function(error, metadata) {
@@ -421,7 +473,8 @@ function makeServerStreamRequestFunction(method, serialize, deserialize) {
       if (options) {
         message.grpcWriteFlags = options.flags;
       }
-      start_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
+      start_batch[grpc.opType.SEND_INITIAL_METADATA] =
+          metadata._getCoreRepresentation();
       start_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
       start_batch[grpc.opType.SEND_MESSAGE] = message;
       start_batch[grpc.opType.SEND_CLOSE_FROM_CLIENT] = true;
@@ -431,11 +484,14 @@ function makeServerStreamRequestFunction(method, serialize, deserialize) {
           // in the other batch.
           return;
         }
-        stream.emit('metadata', response.metadata);
+        stream.emit('metadata', Metadata._fromCoreRepresentation(
+            response.metadata));
       });
       var status_batch = {};
       status_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
       call.startBatch(status_batch, function(err, response) {
+        response.status.metadata = Metadata._fromCoreRepresentation(
+              response.status.metadata);
         stream.emit('status', response.status);
         if (response.status.code !== grpc.status.OK) {
           var error = new Error(response.status.details);
@@ -470,7 +526,7 @@ function makeBidiStreamRequestFunction(method, serialize, deserialize) {
   /**
    * Make a bidirectional stream request with this method on the given channel.
    * @this {SurfaceClient} Client object. Must have a channel member.
-   * @param {array=} metadata Array of metadata key/value pairs to add to the
+   * @param {Metadata=} metadata Array of metadata key/value pairs to add to the
    *     call
    * @param {Options} options Options map
    * @return {EventEmitter} An event emitter for stream related events
@@ -479,7 +535,9 @@ function makeBidiStreamRequestFunction(method, serialize, deserialize) {
     /* jshint validthis: true */
     var call = getCall(this.channel, method, options);
     if (metadata === null || metadata === undefined) {
-      metadata = {};
+      metadata = new Metadata();
+    } else {
+      metadata = metadata.clone();
     }
     var stream = new ClientDuplexStream(call, serialize, deserialize);
     this.updateMetadata(this.auth_uri, metadata, function(error, metadata) {
@@ -489,7 +547,8 @@ function makeBidiStreamRequestFunction(method, serialize, deserialize) {
         return;
       }
       var start_batch = {};
-      start_batch[grpc.opType.SEND_INITIAL_METADATA] = metadata;
+      start_batch[grpc.opType.SEND_INITIAL_METADATA] =
+          metadata._getCoreRepresentation();
       start_batch[grpc.opType.RECV_INITIAL_METADATA] = true;
       call.startBatch(start_batch, function(err, response) {
         if (err) {
@@ -497,11 +556,14 @@ function makeBidiStreamRequestFunction(method, serialize, deserialize) {
           // in the other batch.
           return;
         }
-        stream.emit('metadata', response.metadata);
+        stream.emit('metadata', Metadata._fromCoreRepresentation(
+            response.metadata));
       });
       var status_batch = {};
       status_batch[grpc.opType.RECV_STATUS_ON_CLIENT] = true;
       call.startBatch(status_batch, function(err, response) {
+        response.status.metadata = Metadata._fromCoreRepresentation(
+              response.status.metadata);
         stream.emit('status', response.status);
         if (response.status.code !== grpc.status.OK) {
           var error = new Error(response.status.details);
diff --git a/src/node/src/metadata.js b/src/node/src/metadata.js
new file mode 100644
index 0000000000..c1da70b197
--- /dev/null
+++ b/src/node/src/metadata.js
@@ -0,0 +1,181 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+/**
+ * Metadata module
+ * @module
+ */
+
+'use strict';
+
+var _ = require('lodash');
+
+/**
+ * Class for storing metadata. Keys are normalized to lowercase ASCII.
+ * @constructor
+ */
+function Metadata() {
+  this._internal_repr = {};
+}
+
+function normalizeKey(key) {
+  if (!(/^[A-Za-z\d_-]+$/.test(key))) {
+    throw new Error('Metadata keys must be nonempty strings containing only ' +
+        'alphanumeric characters and hyphens');
+  }
+  return key.toLowerCase();
+}
+
+function validate(key, value) {
+  if (_.endsWith(key, '-bin')) {
+    if (!(value instanceof Buffer)) {
+      throw new Error('keys that end with \'-bin\' must have Buffer values');
+    }
+  } else {
+    if (!_.isString(value)) {
+      throw new Error(
+          'keys that don\'t end with \'-bin\' must have String values');
+    }
+    if (!(/^[\x20-\x7E]*$/.test(value))) {
+      throw new Error('Metadata string values can only contain printable ' +
+          'ASCII characters and space');
+    }
+  }
+}
+
+/**
+ * Sets the given value for the given key, replacing any other values associated
+ * with that key. Normalizes the key.
+ * @param {String} key The key to set
+ * @param {String|Buffer} value The value to set. Must be a buffer if and only
+ *     if the normalized key ends with '-bin'
+ */
+Metadata.prototype.set = function(key, value) {
+  key = normalizeKey(key);
+  validate(key, value);
+  this._internal_repr[key] = [value];
+};
+
+/**
+ * Adds the given value for the given key. Normalizes the key.
+ * @param {String} key The key to add to.
+ * @param {String|Buffer} value The value to add. Must be a buffer if and only
+ *     if the normalized key ends with '-bin'
+ */
+Metadata.prototype.add = function(key, value) {
+  key = normalizeKey(key);
+  validate(key, value);
+  if (!this._internal_repr[key]) {
+    this._internal_repr[key] = [];
+  }
+  this._internal_repr[key].push(value);
+};
+
+/**
+ * Remove the given key and any associated values. Normalizes the key.
+ * @param {String} key The key to remove
+ */
+Metadata.prototype.remove = function(key) {
+  key = normalizeKey(key);
+  if (Object.prototype.hasOwnProperty.call(this._internal_repr, key)) {
+    delete this._internal_repr[key];
+  }
+};
+
+/**
+ * Gets a list of all values associated with the key. Normalizes the key.
+ * @param {String} key The key to get
+ * @return {Array.<String|Buffer>} The values associated with that key
+ */
+Metadata.prototype.get = function(key) {
+  key = normalizeKey(key);
+  if (Object.prototype.hasOwnProperty.call(this._internal_repr, key)) {
+    return this._internal_repr[key];
+  } else {
+    return [];
+  }
+};
+
+/**
+ * Get a map of each key to a single associated value. This reflects the most
+ * common way that people will want to see metadata.
+ * @return {Object.<String,String|Buffer>} A key/value mapping of the metadata
+ */
+Metadata.prototype.getMap = function() {
+  var result = {};
+  _.forOwn(this._internal_repr, function(values, key) {
+    if(values.length > 0) {
+      result[key] = values[0];
+    }
+  });
+  return result;
+};
+
+/**
+ * Clone the metadata object.
+ * @return {Metadata} The new cloned object
+ */
+Metadata.prototype.clone = function() {
+  var copy = new Metadata();
+  _.forOwn(this._internal_repr, function(value, key) {
+    copy._internal_repr[key] = _.clone(value);
+  });
+  return copy;
+};
+
+/**
+ * Gets the metadata in the format used by interal code. Intended for internal
+ * use only. API stability is not guaranteed.
+ * @private
+ * @return {Object.<String, Array.<String|Buffer>>} The metadata
+ */
+Metadata.prototype._getCoreRepresentation = function() {
+  return this._internal_repr;
+};
+
+/**
+ * Creates a Metadata object from a metadata map in the internal format.
+ * Intended for internal use only. API stability is not guaranteed.
+ * @private
+ * @param {Object.<String, Array.<String|Buffer>>} The metadata
+ * @return {Metadata} The new Metadata object
+ */
+Metadata._fromCoreRepresentation = function(metadata) {
+  var newMetadata = new Metadata();
+  if (metadata) {
+    newMetadata._internal_repr = _.cloneDeep(metadata);
+  }
+  return newMetadata;
+};
+
+module.exports = Metadata;
diff --git a/src/node/src/server.js b/src/node/src/server.js
index 137f60ed12..b6f162adf8 100644
--- a/src/node/src/server.js
+++ b/src/node/src/server.js
@@ -44,6 +44,8 @@ var grpc = require('bindings')('grpc.node');
 
 var common = require('./common');
 
+var Metadata = require('./metadata');
+
 var stream = require('stream');
 
 var Readable = stream.Readable;
@@ -60,10 +62,10 @@ var EventEmitter = require('events').EventEmitter;
  * @param {Object} error The error object
  */
 function handleError(call, error) {
+  var statusMetadata = new Metadata();
   var status = {
     code: grpc.status.UNKNOWN,
-    details: 'Unknown Error',
-    metadata: {}
+    details: 'Unknown Error'
   };
   if (error.hasOwnProperty('message')) {
     status.details = error.message;
@@ -75,11 +77,13 @@ function handleError(call, error) {
     }
   }
   if (error.hasOwnProperty('metadata')) {
-    status.metadata = error.metadata;
+    statusMetadata = error.metadata;
   }
+  status.metadata = statusMetadata._getCoreRepresentation();
   var error_batch = {};
   if (!call.metadataSent) {
-    error_batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+    error_batch[grpc.opType.SEND_INITIAL_METADATA] =
+        (new Metadata())._getCoreRepresentation();
   }
   error_batch[grpc.opType.SEND_STATUS_FROM_SERVER] = status;
   call.startBatch(error_batch, function(){});
@@ -114,22 +118,24 @@ function waitForCancel(call, emitter) {
  * @param {*} value The value to respond with
  * @param {function(*):Buffer=} serialize Serialization function for the
  *     response
- * @param {Object=} metadata Optional trailing metadata to send with status
+ * @param {Metadata=} 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, flags) {
   var end_batch = {};
+  var statusMetadata = new Metadata();
   var status = {
     code: grpc.status.OK,
-    details: 'OK',
-    metadata: {}
+    details: 'OK'
   };
   if (metadata) {
-    status.metadata = metadata;
+    statusMetadata = metadata;
   }
+  status.metadata = statusMetadata._getCoreRepresentation();
   if (!call.metadataSent) {
-    end_batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+    end_batch[grpc.opType.SEND_INITIAL_METADATA] =
+        (new Metadata())._getCoreRepresentation();
     call.metadataSent = true;
   }
   var message = serialize(value);
@@ -151,14 +157,19 @@ function setUpWritable(stream, serialize) {
   stream.status = {
     code : grpc.status.OK,
     details : 'OK',
-    metadata : {}
+    metadata : new Metadata()
   };
   stream.serialize = common.wrapIgnoreNull(serialize);
   function sendStatus() {
     var batch = {};
     if (!stream.call.metadataSent) {
       stream.call.metadataSent = true;
-      batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+      batch[grpc.opType.SEND_INITIAL_METADATA] =
+          (new Metadata())._getCoreRepresentation();
+    }
+
+    if (stream.status.metadata) {
+      stream.status.metadata = stream.status.metadata._getCoreRepresentation();
     }
     batch[grpc.opType.SEND_STATUS_FROM_SERVER] = stream.status;
     stream.call.startBatch(batch, function(){});
@@ -173,7 +184,7 @@ function setUpWritable(stream, serialize) {
   function setStatus(err) {
     var code = grpc.status.UNKNOWN;
     var details = 'Unknown Error';
-    var metadata = {};
+    var metadata = new Metadata();
     if (err.hasOwnProperty('message')) {
       details = err.message;
     }
@@ -203,7 +214,7 @@ function setUpWritable(stream, serialize) {
   /**
    * Override of Writable#end method that allows for sending metadata with a
    * success status.
-   * @param {Object=} metadata Metadata to send with the status
+   * @param {Metadata=} metadata Metadata to send with the status
    */
   stream.end = function(metadata) {
     if (metadata) {
@@ -266,7 +277,8 @@ function _write(chunk, encoding, callback) {
   /* jshint validthis: true */
   var batch = {};
   if (!this.call.metadataSent) {
-    batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+    batch[grpc.opType.SEND_INITIAL_METADATA] =
+        (new Metadata())._getCoreRepresentation();
     this.call.metadataSent = true;
   }
   var message = this.serialize(chunk);
@@ -289,15 +301,15 @@ ServerWritableStream.prototype._write = _write;
 
 /**
  * Send the initial metadata for a writable stream.
- * @param {Object<String, Array<(String|Buffer)>>} responseMetadata Metadata
- *   to send
+ * @param {Metadata} responseMetadata Metadata to send
  */
 function sendMetadata(responseMetadata) {
   /* jshint validthis: true */
   if (!this.call.metadataSent) {
     this.call.metadataSent = true;
     var batch = [];
-    batch[grpc.opType.SEND_INITIAL_METADATA] = responseMetadata;
+    batch[grpc.opType.SEND_INITIAL_METADATA] =
+        responseMetadata._getCoreRepresentation();
     this.call.startBatch(batch, function(err) {
       if (err) {
         this.emit('error', err);
@@ -422,7 +434,7 @@ ServerDuplexStream.prototype.getPeer = getPeer;
  * @access private
  * @param {grpc.Call} call The call to handle
  * @param {Object} handler Request handler object for the method that was called
- * @param {Object} metadata Metadata from the client
+ * @param {Metadata} metadata Metadata from the client
  */
 function handleUnary(call, handler, metadata) {
   var emitter = new EventEmitter();
@@ -430,7 +442,8 @@ function handleUnary(call, handler, metadata) {
     if (!call.metadataSent) {
       call.metadataSent = true;
       var batch = {};
-      batch[grpc.opType.SEND_INITIAL_METADATA] = responseMetadata;
+      batch[grpc.opType.SEND_INITIAL_METADATA] =
+          responseMetadata._getCoreRepresentation();
       call.startBatch(batch, function() {});
     }
   };
@@ -478,7 +491,7 @@ function handleUnary(call, handler, metadata) {
  * @access private
  * @param {grpc.Call} call The call to handle
  * @param {Object} handler Request handler object for the method that was called
- * @param {Object} metadata Metadata from the client
+ * @param {Metadata} metadata Metadata from the client
  */
 function handleServerStreaming(call, handler, metadata) {
   var stream = new ServerWritableStream(call, handler.serialize);
@@ -507,7 +520,7 @@ function handleServerStreaming(call, handler, metadata) {
  * @access private
  * @param {grpc.Call} call The call to handle
  * @param {Object} handler Request handler object for the method that was called
- * @param {Object} metadata Metadata from the client
+ * @param {Metadata} metadata Metadata from the client
  */
 function handleClientStreaming(call, handler, metadata) {
   var stream = new ServerReadableStream(call, handler.deserialize);
@@ -515,7 +528,8 @@ function handleClientStreaming(call, handler, metadata) {
     if (!call.metadataSent) {
       call.metadataSent = true;
       var batch = {};
-      batch[grpc.opType.SEND_INITIAL_METADATA] = responseMetadata;
+      batch[grpc.opType.SEND_INITIAL_METADATA] =
+          responseMetadata._getCoreRepresentation();
       call.startBatch(batch, function() {});
     }
   };
@@ -542,7 +556,7 @@ function handleClientStreaming(call, handler, metadata) {
  * @access private
  * @param {grpc.Call} call The call to handle
  * @param {Object} handler Request handler object for the method that was called
- * @param {Object} metadata Metadata from the client
+ * @param {Metadata} metadata Metadata from the client
  */
 function handleBidiStreaming(call, handler, metadata) {
   var stream = new ServerDuplexStream(call, handler.serialize,
@@ -599,7 +613,7 @@ function Server(options) {
       var details = event.new_call;
       var call = details.call;
       var method = details.method;
-      var metadata = details.metadata;
+      var metadata = Metadata._fromCoreRepresentation(details.metadata);
       if (method === null) {
         return;
       }
@@ -609,7 +623,8 @@ function Server(options) {
         handler = handlers[method];
       } else {
         var batch = {};
-        batch[grpc.opType.SEND_INITIAL_METADATA] = {};
+        batch[grpc.opType.SEND_INITIAL_METADATA] =
+            (new Metadata())._getCoreRepresentation();
         batch[grpc.opType.SEND_STATUS_FROM_SERVER] = {
           code: grpc.status.UNIMPLEMENTED,
           details: 'This method is not available on this server.',
diff --git a/src/node/test/metadata_test.js b/src/node/test/metadata_test.js
new file mode 100644
index 0000000000..86383f1bad
--- /dev/null
+++ b/src/node/test/metadata_test.js
@@ -0,0 +1,193 @@
+/*
+ *
+ * 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.
+ *
+ */
+
+'use strict';
+
+var Metadata = require('../src/metadata.js');
+
+var assert = require('assert');
+
+describe('Metadata', function() {
+  var metadata;
+  beforeEach(function() {
+    metadata = new Metadata();
+  });
+  describe('#set', function() {
+    it('Only accepts string values for non "-bin" keys', function() {
+      assert.throws(function() {
+        metadata.set('key', new Buffer('value'));
+      });
+      assert.doesNotThrow(function() {
+        metadata.set('key', 'value');
+      });
+    });
+    it('Only accepts Buffer values for "-bin" keys', function() {
+      assert.throws(function() {
+        metadata.set('key-bin', 'value');
+      });
+      assert.doesNotThrow(function() {
+        metadata.set('key-bin', new Buffer('value'));
+      });
+    });
+    it('Rejects invalid keys', function() {
+      assert.throws(function() {
+        metadata.set('key$', 'value');
+      });
+      assert.throws(function() {
+        metadata.set('', 'value');
+      });
+    });
+    it('Rejects values with non-ASCII characters', function() {
+      assert.throws(function() {
+        metadata.set('key', 'résumé');
+      });
+    });
+    it('Saves values that can be retrieved', function() {
+      metadata.set('key', 'value');
+      assert.deepEqual(metadata.get('key'), ['value']);
+    });
+    it('Overwrites previous values', function() {
+      metadata.set('key', 'value1');
+      metadata.set('key', 'value2');
+      assert.deepEqual(metadata.get('key'), ['value2']);
+    });
+    it('Normalizes keys', function() {
+      metadata.set('Key', 'value1');
+      assert.deepEqual(metadata.get('key'), ['value1']);
+      metadata.set('KEY', 'value2');
+      assert.deepEqual(metadata.get('key'), ['value2']);
+    });
+  });
+  describe('#add', function() {
+    it('Only accepts string values for non "-bin" keys', function() {
+      assert.throws(function() {
+        metadata.add('key', new Buffer('value'));
+      });
+      assert.doesNotThrow(function() {
+        metadata.add('key', 'value');
+      });
+    });
+    it('Only accepts Buffer values for "-bin" keys', function() {
+      assert.throws(function() {
+        metadata.add('key-bin', 'value');
+      });
+      assert.doesNotThrow(function() {
+        metadata.add('key-bin', new Buffer('value'));
+      });
+    });
+    it('Rejects invalid keys', function() {
+      assert.throws(function() {
+        metadata.add('key$', 'value');
+      });
+      assert.throws(function() {
+        metadata.add('', 'value');
+      });
+    });
+    it('Saves values that can be retrieved', function() {
+      metadata.add('key', 'value');
+      assert.deepEqual(metadata.get('key'), ['value']);
+    });
+    it('Combines with previous values', function() {
+      metadata.add('key', 'value1');
+      metadata.add('key', 'value2');
+      assert.deepEqual(metadata.get('key'), ['value1', 'value2']);
+    });
+    it('Normalizes keys', function() {
+      metadata.add('Key', 'value1');
+      assert.deepEqual(metadata.get('key'), ['value1']);
+      metadata.add('KEY', 'value2');
+      assert.deepEqual(metadata.get('key'), ['value1', 'value2']);
+    });
+  });
+  describe('#remove', function() {
+    it('clears values from a key', function() {
+      metadata.add('key', 'value');
+      metadata.remove('key');
+      assert.deepEqual(metadata.get('key'), []);
+    });
+    it('Normalizes keys', function() {
+      metadata.add('key', 'value');
+      metadata.remove('KEY');
+      assert.deepEqual(metadata.get('key'), []);
+    });
+  });
+  describe('#get', function() {
+    beforeEach(function() {
+      metadata.add('key', 'value1');
+      metadata.add('key', 'value2');
+      metadata.add('key-bin', new Buffer('value'));
+    });
+    it('gets all values associated with a key', function() {
+      assert.deepEqual(metadata.get('key'), ['value1', 'value2']);
+    });
+    it('Normalizes keys', function() {
+      assert.deepEqual(metadata.get('KEY'), ['value1', 'value2']);
+    });
+    it('returns an empty list for non-existent keys', function() {
+      assert.deepEqual(metadata.get('non-existent-key'), []);
+    });
+    it('returns Buffers for "-bin" keys', function() {
+      assert(metadata.get('key-bin')[0] instanceof Buffer);
+    });
+  });
+  describe('#getMap', function() {
+    it('gets a map of keys to values', function() {
+      metadata.add('key1', 'value1');
+      metadata.add('Key2', 'value2');
+      metadata.add('KEY3', 'value3');
+      assert.deepEqual(metadata.getMap(),
+                       {key1: 'value1',
+                        key2: 'value2',
+                        key3: 'value3'});
+    });
+  });
+  describe('#clone', function() {
+    it('retains values from the original', function() {
+      metadata.add('key', 'value');
+      var copy = metadata.clone();
+      assert.deepEqual(copy.get('key'), ['value']);
+    });
+    it('Does not see newly added values', function() {
+      metadata.add('key', 'value1');
+      var copy = metadata.clone();
+      metadata.add('key', 'value2');
+      assert.deepEqual(copy.get('key'), ['value1']);
+    });
+    it('Does not add new values to the original', function() {
+      metadata.add('key', 'value1');
+      var copy = metadata.clone();
+      copy.add('key', 'value2');
+      assert.deepEqual(metadata.get('key'), ['value1']);
+    });
+  });
+});
diff --git a/src/node/test/surface_test.js b/src/node/test/surface_test.js
index 6e45871fc8..7c2a8d7258 100644
--- a/src/node/test/surface_test.js
+++ b/src/node/test/surface_test.js
@@ -262,6 +262,7 @@ describe('Generic client and server', function() {
 describe('Echo metadata', function() {
   var client;
   var server;
+  var metadata;
   before(function() {
     var test_proto = ProtoBuf.loadProtoFile(__dirname + '/test_service.proto');
     var test_service = test_proto.lookup('TestService');
@@ -294,6 +295,8 @@ describe('Echo metadata', function() {
     var Client = surface_client.makeProtobufClientConstructor(test_service);
     client = new Client('localhost:' + port, grpc.Credentials.createInsecure());
     server.start();
+    metadata = new grpc.Metadata();
+    metadata.set('key', 'value');
   });
   after(function() {
     server.forceShutdown();
@@ -301,35 +304,35 @@ describe('Echo metadata', function() {
   it('with unary call', function(done) {
     var call = client.unary({}, function(err, data) {
       assert.ifError(err);
-    }, {key: ['value']});
+    }, metadata);
     call.on('metadata', function(metadata) {
-      assert.deepEqual(metadata.key, ['value']);
+      assert.deepEqual(metadata.get('key'), ['value']);
       done();
     });
   });
   it('with client stream call', function(done) {
     var call = client.clientStream(function(err, data) {
       assert.ifError(err);
-    }, {key: ['value']});
+    }, metadata);
     call.on('metadata', function(metadata) {
-      assert.deepEqual(metadata.key, ['value']);
+      assert.deepEqual(metadata.get('key'), ['value']);
       done();
     });
     call.end();
   });
   it('with server stream call', function(done) {
-    var call = client.serverStream({}, {key: ['value']});
+    var call = client.serverStream({}, metadata);
     call.on('data', function() {});
     call.on('metadata', function(metadata) {
-      assert.deepEqual(metadata.key, ['value']);
+      assert.deepEqual(metadata.get('key'), ['value']);
       done();
     });
   });
   it('with bidi stream call', function(done) {
-    var call = client.bidiStream({key: ['value']});
+    var call = client.bidiStream(metadata);
     call.on('data', function() {});
     call.on('metadata', function(metadata) {
-      assert.deepEqual(metadata.key, ['value']);
+      assert.deepEqual(metadata.get('key'), ['value']);
       done();
     });
     call.end();
@@ -337,9 +340,10 @@ describe('Echo metadata', function() {
   it('shows the correct user-agent string', function(done) {
     var version = require('../package.json').version;
     var call = client.unary({}, function(err, data) { assert.ifError(err); },
-                            {key: ['value']});
+                            metadata);
     call.on('metadata', function(metadata) {
-      assert(_.startsWith(metadata['user-agent'], 'grpc-node/' + version));
+      assert(_.startsWith(metadata.get('user-agent')[0],
+                          'grpc-node/' + version));
       done();
     });
   });
@@ -354,13 +358,15 @@ describe('Other conditions', function() {
     var test_proto = ProtoBuf.loadProtoFile(__dirname + '/test_service.proto');
     test_service = test_proto.lookup('TestService');
     server = new grpc.Server();
+    var trailer_metadata = new grpc.Metadata();
+    trailer_metadata.add('trailer-present', 'yes');
     server.addProtoService(test_service, {
       unary: function(call, cb) {
         var req = call.request;
         if (req.error) {
-          cb(new Error('Requested error'), null, {trailer_present: ['yes']});
+          cb(new Error('Requested error'), null, trailer_metadata);
         } else {
-          cb(null, {count: 1}, {trailer_present: ['yes']});
+          cb(null, {count: 1}, trailer_metadata);
         }
       },
       clientStream: function(stream, cb){
@@ -369,14 +375,14 @@ describe('Other conditions', function() {
         stream.on('data', function(data) {
           if (data.error) {
             errored = true;
-            cb(new Error('Requested error'), null, {trailer_present: ['yes']});
+            cb(new Error('Requested error'), null, trailer_metadata);
           } else {
             count += 1;
           }
         });
         stream.on('end', function() {
           if (!errored) {
-            cb(null, {count: count}, {trailer_present: ['yes']});
+            cb(null, {count: count}, trailer_metadata);
           }
         });
       },
@@ -384,13 +390,13 @@ describe('Other conditions', function() {
         var req = stream.request;
         if (req.error) {
           var err = new Error('Requested error');
-          err.metadata = {trailer_present: ['yes']};
+          err.metadata = trailer_metadata;
           stream.emit('error', err);
         } else {
           for (var i = 0; i < 5; i++) {
             stream.write({count: i});
           }
-          stream.end({trailer_present: ['yes']});
+          stream.end(trailer_metadata);
         }
       },
       bidiStream: function(stream) {
@@ -398,10 +404,8 @@ describe('Other conditions', function() {
         stream.on('data', function(data) {
           if (data.error) {
             var err = new Error('Requested error');
-            err.metadata = {
-              trailer_present: ['yes'],
-              count: ['' + count]
-            };
+            err.metadata = trailer_metadata.clone();
+            err.metadata.add('count', '' + count);
             stream.emit('error', err);
           } else {
             stream.write({count: count});
@@ -409,7 +413,7 @@ describe('Other conditions', function() {
           }
         });
         stream.on('end', function() {
-          stream.end({trailer_present: ['yes']});
+          stream.end(trailer_metadata);
         });
       }
     });
@@ -510,7 +514,7 @@ describe('Other conditions', function() {
         assert.ifError(err);
       });
       call.on('status', function(status) {
-        assert.deepEqual(status.metadata.trailer_present, ['yes']);
+        assert.deepEqual(status.metadata.get('trailer-present'), ['yes']);
         done();
       });
     });
@@ -519,7 +523,7 @@ describe('Other conditions', function() {
         assert(err);
       });
       call.on('status', function(status) {
-        assert.deepEqual(status.metadata.trailer_present, ['yes']);
+        assert.deepEqual(status.metadata.get('trailer-present'), ['yes']);
         done();
       });
     });
@@ -531,7 +535,7 @@ describe('Other conditions', function() {
       call.write({error: false});
       call.end();
       call.on('status', function(status) {
-        assert.deepEqual(status.metadata.trailer_present, ['yes']);
+        assert.deepEqual(status.metadata.get('trailer-present'), ['yes']);
         done();
       });
     });
@@ -543,7 +547,7 @@ describe('Other conditions', function() {
       call.write({error: true});
       call.end();
       call.on('status', function(status) {
-        assert.deepEqual(status.metadata.trailer_present, ['yes']);
+        assert.deepEqual(status.metadata.get('trailer-present'), ['yes']);
         done();
       });
     });
@@ -552,7 +556,7 @@ describe('Other conditions', function() {
       call.on('data', function(){});
       call.on('status', function(status) {
         assert.strictEqual(status.code, grpc.status.OK);
-        assert.deepEqual(status.metadata.trailer_present, ['yes']);
+        assert.deepEqual(status.metadata.get('trailer-present'), ['yes']);
         done();
       });
     });
@@ -560,7 +564,7 @@ describe('Other conditions', function() {
       var call = client.serverStream({error: true});
       call.on('data', function(){});
       call.on('error', function(error) {
-        assert.deepEqual(error.metadata.trailer_present, ['yes']);
+        assert.deepEqual(error.metadata.get('trailer-present'), ['yes']);
         done();
       });
     });
@@ -572,7 +576,7 @@ describe('Other conditions', function() {
       call.on('data', function(){});
       call.on('status', function(status) {
         assert.strictEqual(status.code, grpc.status.OK);
-        assert.deepEqual(status.metadata.trailer_present, ['yes']);
+        assert.deepEqual(status.metadata.get('trailer-present'), ['yes']);
         done();
       });
     });
@@ -583,7 +587,7 @@ describe('Other conditions', function() {
       call.end();
       call.on('data', function(){});
       call.on('error', function(error) {
-        assert.deepEqual(error.metadata.trailer_present, ['yes']);
+        assert.deepEqual(error.metadata.get('trailer-present'), ['yes']);
         done();
       });
     });
diff --git a/src/php/README.md b/src/php/README.md
index f432935fde..afa09d79a1 100644
--- a/src/php/README.md
+++ b/src/php/README.md
@@ -32,10 +32,10 @@ $ sudo php -d detect_unicode=0 go-pear.phar
 
 **Linux (Debian):**
 
-Add [Debian unstable][] to your `sources.list` file. Example:
+Add [Debian testing][] to your `sources.list` file. Example:
 
 ```sh
-echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+echo "deb http://ftp.us.debian.org/debian testing main contrib non-free" | \
 sudo tee -a /etc/apt/sources.list
 ```
 
@@ -73,29 +73,24 @@ This will download and run the [gRPC install script][] and compile the gRPC PHP
 
 Clone this repository
 
-```
+```sh
 $ git clone https://github.com/grpc/grpc.git
 ```
 
-Build and install the Protocol Buffers compiler (protoc)
+Build and install the gRPC C core libraries
 
-```
+```sh
 $ cd grpc
 $ git pull --recurse-submodules && git submodule update --init --recursive
-$ cd third_party/protobuf
-$ ./autogen.sh
-$ ./configure
 $ make
-$ make check
 $ sudo make install
 ```
 
-Build and install the gRPC C core libraries
+Note: you may encounter a warning about the Protobuf compiler `protoc` 3.0.0+ not being installed. The following might help, and will be useful later on when we need to compile the `protoc-gen-php` tool.
 
 ```sh
-$ cd grpc
-$ make
-$ sudo make install
+$ cd grpc/third_party/protobuf
+$ sudo make install   # 'make' should have been run by core grpc
 ```
 
 Install the gRPC PHP extension
@@ -172,4 +167,4 @@ $ ./bin/run_gen_code_test.sh
 [homebrew]:http://brew.sh
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
 [Node]:https://github.com/grpc/grpc/tree/master/src/node/examples
-[Debian unstable]:https://www.debian.org/releases/sid/
+[Debian testing]:https://www.debian.org/releases/stretch/
diff --git a/src/php/ext/grpc/credentials.c b/src/php/ext/grpc/credentials.c
index 0eba6608bb..8e3b7ff212 100644
--- a/src/php/ext/grpc/credentials.c
+++ b/src/php/ext/grpc/credentials.c
@@ -170,7 +170,7 @@ PHP_METHOD(Credentials, createComposite) {
  * @return Credentials The new GCE credentials object
  */
 PHP_METHOD(Credentials, createGce) {
-  grpc_credentials *creds = grpc_compute_engine_credentials_create(NULL);
+  grpc_credentials *creds = grpc_google_compute_engine_credentials_create(NULL);
   zval *creds_object = grpc_php_wrap_credentials(creds);
   RETURN_DESTROY_ZVAL(creds_object);
 }
diff --git a/src/python/README.md b/src/python/README.md
index affce64884..a21deb33ef 100644
--- a/src/python/README.md
+++ b/src/python/README.md
@@ -16,10 +16,10 @@ INSTALLATION
 
 **Linux (Debian):**
 
-Add [Debian unstable][] to your `sources.list` file. Example:
+Add [Debian testing][] to your `sources.list` file. Example:
 
 ```sh
-echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+echo "deb http://ftp.us.debian.org/debian testing main contrib non-free" | \
 sudo tee -a /etc/apt/sources.list
 ```
 
@@ -92,4 +92,4 @@ $ ../../tools/distrib/python/submit.py
 [gRPC install script]:https://raw.githubusercontent.com/grpc/homebrew-grpc/master/scripts/install
 [Quick Start]:http://www.grpc.io/docs/tutorials/basic/python.html
 [detailed example]:http://www.grpc.io/docs/installation/python.html
-[Debian unstable]:https://www.debian.org/releases/sid/
+[Debian testing]:https://www.debian.org/releases/stretch/
diff --git a/src/python/grpcio/grpc/_adapter/_c/types.h b/src/python/grpcio/grpc/_adapter/_c/types.h
index f6ff957baa..ec0687a9fd 100644
--- a/src/python/grpcio/grpc/_adapter/_c/types.h
+++ b/src/python/grpcio/grpc/_adapter/_c/types.h
@@ -57,8 +57,6 @@ ClientCredentials *pygrpc_ClientCredentials_composite(
     PyTypeObject *type, PyObject *args, PyObject *kwargs);
 ClientCredentials *pygrpc_ClientCredentials_compute_engine(
     PyTypeObject *type, PyObject *ignored);
-ClientCredentials *pygrpc_ClientCredentials_service_account(
-    PyTypeObject *type, PyObject *args, PyObject *kwargs);
 ClientCredentials *pygrpc_ClientCredentials_jwt(
     PyTypeObject *type, PyObject *args, PyObject *kwargs);
 ClientCredentials *pygrpc_ClientCredentials_refresh_token(
diff --git a/src/python/grpcio/grpc/_adapter/_c/types/client_credentials.c b/src/python/grpcio/grpc/_adapter/_c/types/client_credentials.c
index 36fd207464..90652b7b47 100644
--- a/src/python/grpcio/grpc/_adapter/_c/types/client_credentials.c
+++ b/src/python/grpcio/grpc/_adapter/_c/types/client_credentials.c
@@ -48,8 +48,6 @@ PyMethodDef pygrpc_ClientCredentials_methods[] = {
      METH_CLASS|METH_KEYWORDS, ""},
     {"compute_engine", (PyCFunction)pygrpc_ClientCredentials_compute_engine,
      METH_CLASS|METH_NOARGS, ""},
-    {"service_account", (PyCFunction)pygrpc_ClientCredentials_service_account,
-     METH_CLASS|METH_KEYWORDS, ""},
     {"jwt", (PyCFunction)pygrpc_ClientCredentials_jwt,
      METH_CLASS|METH_KEYWORDS, ""},
     {"refresh_token", (PyCFunction)pygrpc_ClientCredentials_refresh_token,
@@ -173,7 +171,7 @@ ClientCredentials *pygrpc_ClientCredentials_composite(
 ClientCredentials *pygrpc_ClientCredentials_compute_engine(
     PyTypeObject *type, PyObject *ignored) {
   ClientCredentials *self = (ClientCredentials *)type->tp_alloc(type, 0);
-  self->c_creds = grpc_compute_engine_credentials_create(NULL);
+  self->c_creds = grpc_google_compute_engine_credentials_create(NULL);
   if (!self->c_creds) {
     Py_DECREF(self);
     PyErr_SetString(PyExc_RuntimeError,
@@ -183,29 +181,6 @@ ClientCredentials *pygrpc_ClientCredentials_compute_engine(
   return self;
 }
 
-ClientCredentials *pygrpc_ClientCredentials_service_account(
-    PyTypeObject *type, PyObject *args, PyObject *kwargs) {
-  ClientCredentials *self;
-  const char *json_key;
-  const char *scope;
-  double lifetime;
-  static char *keywords[] = {"json_key", "scope", "token_lifetime", NULL};
-  if (!PyArg_ParseTupleAndKeywords(args, kwargs, "ssd:service_account", keywords,
-        &json_key, &scope, &lifetime)) {
-    return NULL;
-  }
-  self = (ClientCredentials *)type->tp_alloc(type, 0);
-  self->c_creds = grpc_service_account_credentials_create(
-      json_key, scope, pygrpc_cast_double_to_gpr_timespec(lifetime), NULL);
-  if (!self->c_creds) {
-    Py_DECREF(self);
-    PyErr_SetString(PyExc_RuntimeError,
-                    "couldn't create service account credentials");
-    return NULL;
-  }
-  return self;
-}
-
 /* TODO: Rename this credentials to something like service_account_jwt_access */
 ClientCredentials *pygrpc_ClientCredentials_jwt(
     PyTypeObject *type, PyObject *args, PyObject *kwargs) {
@@ -239,7 +214,7 @@ ClientCredentials *pygrpc_ClientCredentials_refresh_token(
   }
   self = (ClientCredentials *)type->tp_alloc(type, 0);
   self->c_creds =
-      grpc_refresh_token_credentials_create(json_refresh_token, NULL);
+      grpc_google_refresh_token_credentials_create(json_refresh_token, NULL);
   if (!self->c_creds) {
     Py_DECREF(self);
     PyErr_SetString(PyExc_RuntimeError,
@@ -260,8 +235,8 @@ ClientCredentials *pygrpc_ClientCredentials_iam(
     return NULL;
   }
   self = (ClientCredentials *)type->tp_alloc(type, 0);
-  self->c_creds = grpc_iam_credentials_create(authorization_token,
-                                              authority_selector, NULL);
+  self->c_creds = grpc_google_iam_credentials_create(authorization_token,
+                                                     authority_selector, NULL);
   if (!self->c_creds) {
     Py_DECREF(self);
     PyErr_SetString(PyExc_RuntimeError, "couldn't create IAM credentials");
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx b/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx
index 2d74702fbd..dc40a7a611 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/credentials.pyx
@@ -106,26 +106,6 @@ def client_credentials_compute_engine():
   credentials.c_credentials = grpc.grpc_compute_engine_credentials_create()
   return credentials
 
-def client_credentials_service_account(
-    json_key, scope, records.Timespec token_lifetime not None):
-  if isinstance(json_key, bytes):
-    pass
-  elif isinstance(json_key, basestring):
-    json_key = json_key.encode()
-  else:
-    raise TypeError("expected json_key to be str or bytes")
-  if isinstance(scope, bytes):
-    pass
-  elif isinstance(scope, basestring):
-    scope = scope.encode()
-  else:
-    raise TypeError("expected scope to be str or bytes")
-  cdef ClientCredentials credentials = ClientCredentials()
-  credentials.c_credentials = grpc.grpc_service_account_credentials_create(
-      json_key, scope, token_lifetime.c_time)
-  credentials.references.extend([json_key, scope])
-  return credentials
-
 #TODO rename to something like client_credentials_service_account_jwt_access.
 def client_credentials_jwt(json_key, records.Timespec token_lifetime not None):
   if isinstance(json_key, bytes):
diff --git a/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxd b/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxd
index c793774c8d..8b46972490 100644
--- a/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxd
+++ b/src/python/grpcio/grpc/_cython/_cygrpc/grpc.pxd
@@ -311,8 +311,6 @@ cdef extern from "grpc/grpc_security.h":
   grpc_credentials *grpc_composite_credentials_create(grpc_credentials *creds1,
                                                       grpc_credentials *creds2)
   grpc_credentials *grpc_compute_engine_credentials_create()
-  grpc_credentials *grpc_service_account_credentials_create(
-      const char *json_key, const char *scope, gpr_timespec token_lifetime)
   grpc_credentials *grpc_service_account_jwt_access_credentials_create(const char *json_key,
                                                 gpr_timespec token_lifetime)
   grpc_credentials *grpc_refresh_token_credentials_create(
diff --git a/src/python/grpcio/grpc/_cython/adapter_low.py b/src/python/grpcio/grpc/_cython/adapter_low.py
index 2bb468eece..4f24da330f 100644
--- a/src/python/grpcio/grpc/_cython/adapter_low.py
+++ b/src/python/grpcio/grpc/_cython/adapter_low.py
@@ -60,10 +60,6 @@ class ClientCredentials(object):
     raise NotImplementedError()
 
   @staticmethod
-  def service_account():
-    raise NotImplementedError()
-
-  @staticmethod
   def jwt():
     raise NotImplementedError()
 
diff --git a/src/python/grpcio/grpc/_links/service.py b/src/python/grpcio/grpc/_links/service.py
index 10634e43b5..c5ecc47cd9 100644
--- a/src/python/grpcio/grpc/_links/service.py
+++ b/src/python/grpcio/grpc/_links/service.py
@@ -316,9 +316,8 @@ class _Kernel(object):
         call.status(status, call)
         self._rpc_states.pop(call, None)
 
-  def add_port(self, port, server_credentials):
+  def add_port(self, address, server_credentials):
     with self._lock:
-      address = '[::]:%d' % port
       if self._server is None:
         self._completion_queue = _intermediary_low.CompletionQueue()
         self._server = _intermediary_low.Server(self._completion_queue)
@@ -337,10 +336,13 @@ class _Kernel(object):
       self._server.start()
       self._server.service(None)
 
-  def graceful_stop(self):
+  def begin_stop(self):
     with self._lock:
       self._server.stop()
       self._server = None
+
+  def end_stop(self):
+    with self._lock:
       self._completion_queue.stop()
       self._completion_queue = None
       pool = self._pool
@@ -348,11 +350,6 @@ class _Kernel(object):
       self._rpc_states = None
     pool.shutdown(wait=True)
 
-  def immediate_stop(self):
-    # TODO(nathaniel): Implementation.
-    raise NotImplementedError(
-        'TODO(nathaniel): after merge of rewritten lower layers')
-
 
 class ServiceLink(links.Link):
   """A links.Link for use on the service-side of a gRPC connection.
@@ -362,17 +359,20 @@ class ServiceLink(links.Link):
   """
 
   @abc.abstractmethod
-  def add_port(self, port, server_credentials):
+  def add_port(self, address, server_credentials):
     """Adds a port on which to service RPCs after this link has been started.
 
     Args:
-      port: The port on which to service RPCs, or zero to request that a port
-        be automatically selected and used.
+      address: The address on which to service RPCs with a port number of zero
+        requesting that a port number be automatically selected and used.
       server_credentials: An _intermediary_low.ServerCredentials object, or
         None for insecure service.
 
     Returns:
-      A port on which RPCs will be serviced after this link has been started.
+      A integer port on which RPCs will be serviced after this link has been
+        started. This is typically the same number as the port number contained
+        in the passed address, but will likely be different if the port number
+        contained in the passed address was zero.
     """
     raise NotImplementedError()
 
@@ -386,18 +386,20 @@ class ServiceLink(links.Link):
     raise NotImplementedError()
 
   @abc.abstractmethod
-  def stop_gracefully(self):
-    """Stops this link.
+  def begin_stop(self):
+    """Indicate imminent link stop and immediate rejection of new RPCs.
 
     New RPCs will be rejected as soon as this method is called, but ongoing RPCs
-    will be allowed to continue until they terminate. This method blocks until
-    all RPCs have terminated.
+    will be allowed to continue until they terminate. This method does not
+    block.
     """
     raise NotImplementedError()
 
   @abc.abstractmethod
-  def stop_immediately(self):
-    """Stops this link.
+  def end_stop(self):
+    """Finishes stopping this link.
+
+    begin_stop must have been called exactly once before calling this method.
 
     All in-progress RPCs will be terminated immediately.
     """
@@ -417,19 +419,18 @@ class _ServiceLink(ServiceLink):
   def join_link(self, link):
     self._relay.set_behavior(link.accept_ticket)
 
-  def add_port(self, port, server_credentials):
-    return self._kernel.add_port(port, server_credentials)
+  def add_port(self, address, server_credentials):
+    return self._kernel.add_port(address, server_credentials)
 
   def start(self):
     self._relay.start()
     return self._kernel.start()
 
-  def stop_gracefully(self):
-    self._kernel.graceful_stop()
-    self._relay.stop()
+  def begin_stop(self):
+    self._kernel.begin_stop()
 
-  def stop_immediately(self):
-    self._kernel.immediate_stop()
+  def end_stop(self):
+    self._kernel.end_stop()
     self._relay.stop()
 
 
diff --git a/src/python/grpcio/grpc/framework/core/_end.py b/src/python/grpcio/grpc/framework/core/_end.py
index fb2c532df6..5ef2f6d3a3 100644
--- a/src/python/grpcio/grpc/framework/core/_end.py
+++ b/src/python/grpcio/grpc/framework/core/_end.py
@@ -30,7 +30,6 @@
 """Implementation of base.End."""
 
 import abc
-import enum
 import threading
 import uuid
 
@@ -75,7 +74,7 @@ def _abort(operations):
 
 def _cancel_futures(futures):
   for future in futures:
-    futures.cancel()
+    future.cancel()
 
 
 def _future_shutdown(lock, cycle, event):
@@ -83,8 +82,6 @@ def _future_shutdown(lock, cycle, event):
     with lock:
       _abort(cycle.operations.values())
       _cancel_futures(cycle.futures)
-      pool = cycle.pool
-    cycle.pool.shutdown(wait=True)
   return in_future
 
 
@@ -113,6 +110,7 @@ def _termination_action(lock, stats, operation_id, cycle):
         cycle.idle_actions = []
         if cycle.grace:
           _cancel_futures(cycle.futures)
+          cycle.pool.shutdown(wait=False)
   return termination_action
 
 
diff --git a/src/python/grpcio_test/grpc_interop/methods.py b/src/python/grpcio_test/grpc_interop/methods.py
index 642458e892..52b800af7a 100644
--- a/src/python/grpcio_test/grpc_interop/methods.py
+++ b/src/python/grpcio_test/grpc_interop/methods.py
@@ -346,20 +346,6 @@ def _compute_engine_creds(stub, args):
                                           response.username))
 
 
-def _service_account_creds(stub, args):
-  json_key_filename = os.environ[
-      oauth2client_client.GOOGLE_APPLICATION_CREDENTIALS]
-  wanted_email = json.load(open(json_key_filename, 'rb'))['client_email']
-  response = _large_unary_common_behavior(stub, True, True)
-  if wanted_email != response.username:
-    raise ValueError(
-        'expected username %s, got %s' % (wanted_email, response.username))
-  if args.oauth_scope.find(response.oauth_scope) == -1:
-    raise ValueError(
-        'expected to find oauth scope "%s" in received "%s"' %
-            (response.oauth_scope, args.oauth_scope))
-
-
 def _oauth2_auth_token(stub, args):
   json_key_filename = os.environ[
       oauth2client_client.GOOGLE_APPLICATION_CREDENTIALS]
@@ -383,7 +369,6 @@ class TestCase(enum.Enum):
   CANCEL_AFTER_BEGIN = 'cancel_after_begin'
   CANCEL_AFTER_FIRST_RESPONSE = 'cancel_after_first_response'
   COMPUTE_ENGINE_CREDS = 'compute_engine_creds'
-  SERVICE_ACCOUNT_CREDS = 'service_account_creds'
   OAUTH2_AUTH_TOKEN = 'oauth2_auth_token'
   TIMEOUT_ON_SLEEPING_SERVER = 'timeout_on_sleeping_server'
 
@@ -406,8 +391,6 @@ class TestCase(enum.Enum):
       _timeout_on_sleeping_server(stub)
     elif self is TestCase.COMPUTE_ENGINE_CREDS:
       _compute_engine_creds(stub, args)
-    elif self is TestCase.SERVICE_ACCOUNT_CREDS:
-      _service_account_creds(stub, args)
     elif self is TestCase.OAUTH2_AUTH_TOKEN:
       _oauth2_auth_token(stub, args)
     else:
diff --git a/src/python/grpcio_test/grpc_test/_core_over_links_base_interface_test.py b/src/python/grpcio_test/grpc_test/_core_over_links_base_interface_test.py
index 7fa90fe35f..9112c34190 100644
--- a/src/python/grpcio_test/grpc_test/_core_over_links_base_interface_test.py
+++ b/src/python/grpcio_test/grpc_test/_core_over_links_base_interface_test.py
@@ -45,11 +45,7 @@ from grpc_test.framework.common import test_constants
 from grpc_test.framework.interfaces.base import test_cases
 from grpc_test.framework.interfaces.base import test_interfaces
 
-_INVOCATION_INITIAL_METADATA = ((b'0', b'abc'), (b'1', b'def'), (b'2', b'ghi'),)
-_SERVICE_INITIAL_METADATA = ((b'3', b'jkl'), (b'4', b'mno'), (b'5', b'pqr'),)
-_SERVICE_TERMINAL_METADATA = ((b'6', b'stu'), (b'7', b'vwx'), (b'8', b'yza'),)
 _CODE = _intermediary_low.Code.OK
-_MESSAGE = b'test message'
 
 
 class _SerializationBehaviors(
@@ -95,7 +91,7 @@ class _Implementation(test_interfaces.Implementation):
     service_grpc_link = service.service_link(
         serialization_behaviors.request_deserializers,
         serialization_behaviors.response_serializers)
-    port = service_grpc_link.add_port(0, None)
+    port = service_grpc_link.add_port('[::]:0', None)
     channel = _intermediary_low.Channel('localhost:%d' % port, None)
     invocation_grpc_link = invocation.invocation_link(
         channel, b'localhost',
@@ -114,19 +110,22 @@ class _Implementation(test_interfaces.Implementation):
   def destantiate(self, memo):
     invocation_grpc_link, service_grpc_link = memo
     invocation_grpc_link.stop()
-    service_grpc_link.stop_gracefully()
+    service_grpc_link.begin_stop()
+    service_grpc_link.end_stop()
 
   def invocation_initial_metadata(self):
-    return _INVOCATION_INITIAL_METADATA
+    return grpc_test_common.INVOCATION_INITIAL_METADATA
 
   def service_initial_metadata(self):
-    return _SERVICE_INITIAL_METADATA
+    return grpc_test_common.SERVICE_INITIAL_METADATA
 
   def invocation_completion(self):
     return utilities.completion(None, None, None)
 
   def service_completion(self):
-    return utilities.completion(_SERVICE_TERMINAL_METADATA, _CODE, _MESSAGE)
+    return utilities.completion(
+        grpc_test_common.SERVICE_TERMINAL_METADATA, _CODE,
+        grpc_test_common.DETAILS)
 
   def metadata_transmitted(self, original_metadata, transmitted_metadata):
     return original_metadata is None or grpc_test_common.metadata_transmitted(
@@ -146,14 +145,6 @@ class _Implementation(test_interfaces.Implementation):
       return True
 
 
-def setUpModule():
-  logging.warn('setUpModule!')
-
-
-def tearDownModule():
-  logging.warn('tearDownModule!')
-
-
 def load_tests(loader, tests, pattern):
   return unittest.TestSuite(
       tests=tuple(
diff --git a/src/python/grpcio_test/grpc_test/_crust_over_core_over_links_face_interface_test.py b/src/python/grpcio_test/grpc_test/_crust_over_core_over_links_face_interface_test.py
index 25b99cbbaf..1401536503 100644
--- a/src/python/grpcio_test/grpc_test/_crust_over_core_over_links_face_interface_test.py
+++ b/src/python/grpcio_test/grpc_test/_crust_over_core_over_links_face_interface_test.py
@@ -39,11 +39,10 @@ from grpc.framework.core import implementations as core_implementations
 from grpc.framework.crust import implementations as crust_implementations
 from grpc.framework.foundation import logging_pool
 from grpc.framework.interfaces.links import utilities
-from grpc_test import test_common
+from grpc_test import test_common as grpc_test_common
 from grpc_test.framework.common import test_constants
 from grpc_test.framework.interfaces.face import test_cases
 from grpc_test.framework.interfaces.face import test_interfaces
-from grpc_test.framework.interfaces.links import test_utilities
 
 
 class _SerializationBehaviors(
@@ -85,7 +84,7 @@ class _Implementation(test_interfaces.Implementation):
     service_grpc_link = service.service_link(
         serialization_behaviors.request_deserializers,
         serialization_behaviors.response_serializers)
-    port = service_grpc_link.add_port(0, None)
+    port = service_grpc_link.add_port('[::]:0', None)
     channel = _intermediary_low.Channel('localhost:%d' % port, None)
     invocation_grpc_link = invocation.invocation_link(
         channel, b'localhost',
@@ -121,8 +120,9 @@ class _Implementation(test_interfaces.Implementation):
      service_end_link, pool) = memo
     invocation_end_link.stop(0).wait()
     invocation_grpc_link.stop()
-    service_grpc_link.stop_gracefully()
+    service_grpc_link.begin_stop()
     service_end_link.stop(0).wait()
+    service_grpc_link.end_stop()
     invocation_end_link.join_link(utilities.NULL_LINK)
     invocation_grpc_link.join_link(utilities.NULL_LINK)
     service_grpc_link.join_link(utilities.NULL_LINK)
@@ -130,19 +130,19 @@ class _Implementation(test_interfaces.Implementation):
     pool.shutdown(wait=True)
 
   def invocation_metadata(self):
-    return test_common.INVOCATION_INITIAL_METADATA
+    return grpc_test_common.INVOCATION_INITIAL_METADATA
 
   def initial_metadata(self):
-    return test_common.SERVICE_INITIAL_METADATA
+    return grpc_test_common.SERVICE_INITIAL_METADATA
 
   def terminal_metadata(self):
-    return test_common.SERVICE_TERMINAL_METADATA
+    return grpc_test_common.SERVICE_TERMINAL_METADATA
 
   def code(self):
     return _intermediary_low.Code.OK
 
   def details(self):
-    return test_common.DETAILS
+    return grpc_test_common.DETAILS
 
   def metadata_transmitted(self, original_metadata, transmitted_metadata):
     return original_metadata is None or grpc_test_common.metadata_transmitted(
diff --git a/src/python/grpcio_test/grpc_test/_links/_transmission_test.py b/src/python/grpcio_test/grpc_test/_links/_transmission_test.py
index db011bca66..c114cef6a6 100644
--- a/src/python/grpcio_test/grpc_test/_links/_transmission_test.py
+++ b/src/python/grpcio_test/grpc_test/_links/_transmission_test.py
@@ -50,7 +50,7 @@ class TransmissionTest(test_cases.TransmissionTest, unittest.TestCase):
     service_link = service.service_link(
         {self.group_and_method(): self.deserialize_request},
         {self.group_and_method(): self.serialize_response})
-    port = service_link.add_port(0, None)
+    port = service_link.add_port('[::]:0', None)
     service_link.start()
     channel = _intermediary_low.Channel('localhost:%d' % port, None)
     invocation_link = invocation.invocation_link(
@@ -62,7 +62,8 @@ class TransmissionTest(test_cases.TransmissionTest, unittest.TestCase):
 
   def destroy_transmitting_links(self, invocation_side_link, service_side_link):
     invocation_side_link.stop()
-    service_side_link.stop_gracefully()
+    service_side_link.begin_stop()
+    service_side_link.end_stop()
 
   def create_invocation_initial_metadata(self):
     return (
@@ -116,7 +117,7 @@ class RoundTripTest(unittest.TestCase):
         identity_transformation, identity_transformation)
     service_mate = test_utilities.RecordingLink()
     service_link.join_link(service_mate)
-    port = service_link.add_port(0, None)
+    port = service_link.add_port('[::]:0', None)
     service_link.start()
     channel = _intermediary_low.Channel('localhost:%d' % port, None)
     invocation_link = invocation.invocation_link(
@@ -140,7 +141,8 @@ class RoundTripTest(unittest.TestCase):
     invocation_mate.block_until_tickets_satisfy(test_cases.terminated)
 
     invocation_link.stop()
-    service_link.stop_gracefully()
+    service_link.begin_stop()
+    service_link.end_stop()
 
     self.assertIs(
         service_mate.tickets()[-1].termination,
@@ -160,7 +162,7 @@ class RoundTripTest(unittest.TestCase):
         {(test_group, test_method): scenario.serialize_response})
     service_mate = test_utilities.RecordingLink()
     service_link.join_link(service_mate)
-    port = service_link.add_port(0, None)
+    port = service_link.add_port('[::]:0', None)
     service_link.start()
     channel = _intermediary_low.Channel('localhost:%d' % port, None)
     invocation_link = invocation.invocation_link(
@@ -206,7 +208,8 @@ class RoundTripTest(unittest.TestCase):
     invocation_mate.block_until_tickets_satisfy(test_cases.terminated)
 
     invocation_link.stop()
-    service_link.stop_gracefully()
+    service_link.begin_stop()
+    service_link.end_stop()
 
     observed_requests = tuple(
         ticket.payload for ticket in service_mate.tickets()
diff --git a/src/python/grpcio_test/grpc_test/test_common.py b/src/python/grpcio_test/grpc_test/test_common.py
index f8e1f1e43f..44284be88b 100644
--- a/src/python/grpcio_test/grpc_test/test_common.py
+++ b/src/python/grpcio_test/grpc_test/test_common.py
@@ -31,6 +31,11 @@
 
 import collections
 
+INVOCATION_INITIAL_METADATA = ((b'0', b'abc'), (b'1', b'def'), (b'2', b'ghi'),)
+SERVICE_INITIAL_METADATA = ((b'3', b'jkl'), (b'4', b'mno'), (b'5', b'pqr'),)
+SERVICE_TERMINAL_METADATA = ((b'6', b'stu'), (b'7', b'vwx'), (b'8', b'yza'),)
+DETAILS = b'test details'
+
 
 def metadata_transmitted(original_metadata, transmitted_metadata):
   """Judges whether or not metadata was acceptably transmitted.
diff --git a/src/ruby/README.md b/src/ruby/README.md
index f8902e34c5..7f75c0e313 100644
--- a/src/ruby/README.md
+++ b/src/ruby/README.md
@@ -19,10 +19,10 @@ INSTALLATION
 
 **Linux (Debian):**
 
-Add [Debian unstable][] to your `sources.list` file. Example:
+Add [Debian testing][] to your `sources.list` file. Example:
 
 ```sh
-echo "deb http://ftp.us.debian.org/debian unstable main contrib non-free" | \
+echo "deb http://ftp.us.debian.org/debian testing main contrib non-free" | \
 sudo tee -a /etc/apt/sources.list
 ```
 
@@ -99,4 +99,4 @@ Directory structure is the layout for [ruby extensions][]
 [ruby extensions]:http://guides.rubygems.org/gems-with-extensions/
 [rubydoc]: http://www.rubydoc.info/gems/grpc
 [grpc.io]: http://www.grpc.io/docs/installation/ruby.html
-[Debian unstable]:https://www.debian.org/releases/sid/
+[Debian testing]:https://www.debian.org/releases/stretch/
diff --git a/src/ruby/ext/grpc/rb_credentials.c b/src/ruby/ext/grpc/rb_credentials.c
index ac3804df6f..ae757f6986 100644
--- a/src/ruby/ext/grpc/rb_credentials.c
+++ b/src/ruby/ext/grpc/rb_credentials.c
@@ -154,7 +154,7 @@ static VALUE grpc_rb_default_credentials_create(VALUE cls) {
     Creates the default credential instances. */
 static VALUE grpc_rb_compute_engine_credentials_create(VALUE cls) {
   grpc_rb_credentials *wrapper = ALLOC(grpc_rb_credentials);
-  wrapper->wrapped = grpc_compute_engine_credentials_create(NULL);
+  wrapper->wrapped = grpc_google_compute_engine_credentials_create(NULL);
   if (wrapper->wrapped == NULL) {
     rb_raise(rb_eRuntimeError,
              "could not create composite engine credentials, not sure why");