Merge remote-tracking branch 'upstream/master' into auto-build-example

34 files changed, 290 insertions, 80 deletions

diff --git a/src/core/ext/client_config/channel_connectivity.c b/src/core/ext/client_config/channel_connectivity.c
index 20c01a9a7c..2fd8e0e123 100644
--- a/src/core/ext/client_config/channel_connectivity.c
+++ b/src/core/ext/client_config/channel_connectivity.c
@@ -189,10 +189,10 @@ void grpc_channel_watch_connectivity_state(
   GRPC_API_TRACE(
       "grpc_channel_watch_connectivity_state("
       "channel=%p, last_observed_state=%d, "
-      "deadline=gpr_timespec { tv_sec: %lld, tv_nsec: %d, clock_type: %d }, "
+      "deadline=gpr_timespec { tv_sec: %"PRId64", tv_nsec: %d, clock_type: %d }, "
       "cq=%p, tag=%p)",
-      7, (channel, (int)last_observed_state, (long long)deadline.tv_sec,
-          (int)deadline.tv_nsec, (int)deadline.clock_type, cq, tag));
+      7, (channel, (int)last_observed_state, deadline.tv_sec,
+          deadline.tv_nsec, (int)deadline.clock_type, cq, tag));
 
   grpc_cq_begin_op(cq, tag);
 
diff --git a/src/core/ext/transport/chttp2/transport/chttp2_transport.c b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
index 9c99ff883a..9c125566d4 100644
--- a/src/core/ext/transport/chttp2/transport/chttp2_transport.c
+++ b/src/core/ext/transport/chttp2/transport/chttp2_transport.c
@@ -1557,17 +1557,15 @@ static void close_from_api(grpc_exec_ctx *exec_ctx,
       gpr_slice_buffer_add(&transport_global->qbuf,
                            gpr_slice_ref(*optional_message));
     }
-
     gpr_slice_buffer_add(
         &transport_global->qbuf,
         grpc_chttp2_rst_stream_create(stream_global->id, GRPC_CHTTP2_NO_ERROR,
                                       &stream_global->stats.outgoing));
-
-    if (optional_message) {
-      gpr_slice_ref(*optional_message);
-    }
   }
 
+  if (optional_message) {
+    gpr_slice_ref(*optional_message);
+  }
   grpc_chttp2_fake_status(exec_ctx, transport_global, stream_global, status,
                           optional_message);
   grpc_error *err = GRPC_ERROR_CREATE("Stream closed");
diff --git a/src/core/lib/iomgr/tcp_posix.c b/src/core/lib/iomgr/tcp_posix.c
index 017f52c367..1046b60bcc 100644
--- a/src/core/lib/iomgr/tcp_posix.c
+++ b/src/core/lib/iomgr/tcp_posix.c
@@ -160,7 +160,7 @@ static void call_read_cb(grpc_exec_ctx *exec_ctx, grpc_tcp *tcp,
                          grpc_error *error) {
   grpc_closure *cb = tcp->read_cb;
 
-  if (false && grpc_tcp_trace) {
+  if (grpc_tcp_trace) {
     size_t i;
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "read: error=%s", str);
@@ -394,7 +394,7 @@ static void tcp_write(grpc_exec_ctx *exec_ctx, grpc_endpoint *ep,
   grpc_tcp *tcp = (grpc_tcp *)ep;
   grpc_error *error = GRPC_ERROR_NONE;
 
-  if (false && grpc_tcp_trace) {
+  if (grpc_tcp_trace) {
     size_t i;
 
     for (i = 0; i < buf->count; i++) {
diff --git a/src/core/lib/profiling/basic_timers.c b/src/core/lib/profiling/basic_timers.c
index 50082cd7ee..ee464f310f 100644
--- a/src/core/lib/profiling/basic_timers.c
+++ b/src/core/lib/profiling/basic_timers.c
@@ -141,9 +141,9 @@ static void write_log(gpr_timer_log *log) {
       entry->tm = gpr_time_0(entry->tm.clock_type);
     }
     fprintf(output_file,
-            "{\"t\": %lld.%09d, \"thd\": \"%d\", \"type\": \"%c\", \"tag\": "
+            "{\"t\": %"PRId64".%09d, \"thd\": \"%d\", \"type\": \"%c\", \"tag\": "
             "\"%s\", \"file\": \"%s\", \"line\": %d, \"imp\": %d}\n",
-            (long long)entry->tm.tv_sec, (int)entry->tm.tv_nsec, entry->thd,
+            entry->tm.tv_sec, entry->tm.tv_nsec, entry->thd,
             entry->type, entry->tagstr, entry->file, entry->line,
             entry->important);
   }
diff --git a/src/core/lib/security/credentials/composite/composite_credentials.c b/src/core/lib/security/credentials/composite/composite_credentials.c
index 07db8bfd75..850e41e646 100644
--- a/src/core/lib/security/credentials/composite/composite_credentials.c
+++ b/src/core/lib/security/credentials/composite/composite_credentials.c
@@ -72,11 +72,12 @@ static void composite_call_md_context_destroy(
 static void composite_call_metadata_cb(grpc_exec_ctx *exec_ctx, void *user_data,
                                        grpc_credentials_md *md_elems,
                                        size_t num_md,
-                                       grpc_credentials_status status) {
+                                       grpc_credentials_status status,
+                                       const char *error_details) {
   grpc_composite_call_credentials_metadata_context *ctx =
       (grpc_composite_call_credentials_metadata_context *)user_data;
   if (status != GRPC_CREDENTIALS_OK) {
-    ctx->cb(exec_ctx, ctx->user_data, NULL, 0, status);
+    ctx->cb(exec_ctx, ctx->user_data, NULL, 0, status, error_details);
     return;
   }
 
@@ -101,7 +102,7 @@ static void composite_call_metadata_cb(grpc_exec_ctx *exec_ctx, void *user_data,
 
   /* We're done!. */
   ctx->cb(exec_ctx, ctx->user_data, ctx->md_elems->entries,
-          ctx->md_elems->num_entries, GRPC_CREDENTIALS_OK);
+          ctx->md_elems->num_entries, GRPC_CREDENTIALS_OK, NULL);
   composite_call_md_context_destroy(ctx);
 }
 
diff --git a/src/core/lib/security/credentials/credentials.c b/src/core/lib/security/credentials/credentials.c
index 0eadaec191..029a357261 100644
--- a/src/core/lib/security/credentials/credentials.c
+++ b/src/core/lib/security/credentials/credentials.c
@@ -117,7 +117,7 @@ void grpc_call_credentials_get_request_metadata(
     grpc_credentials_metadata_cb cb, void *user_data) {
   if (creds == NULL || creds->vtable->get_request_metadata == NULL) {
     if (cb != NULL) {
-      cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_OK);
+      cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_OK, NULL);
     }
     return;
   }
diff --git a/src/core/lib/security/credentials/credentials.h b/src/core/lib/security/credentials/credentials.h
index ce235e3a1d..8e9d842ead 100644
--- a/src/core/lib/security/credentials/credentials.h
+++ b/src/core/lib/security/credentials/credentials.h
@@ -156,11 +156,10 @@ void grpc_credentials_md_store_unref(grpc_credentials_md_store *store);
 
 /* --- grpc_call_credentials. --- */
 
-typedef void (*grpc_credentials_metadata_cb)(grpc_exec_ctx *exec_ctx,
-                                             void *user_data,
-                                             grpc_credentials_md *md_elems,
-                                             size_t num_md,
-                                             grpc_credentials_status status);
+/* error_details must be NULL if status is GRPC_CREDENTIALS_OK. */
+typedef void (*grpc_credentials_metadata_cb)(
+    grpc_exec_ctx *exec_ctx, void *user_data, grpc_credentials_md *md_elems,
+    size_t num_md, grpc_credentials_status status, const char *error_details);
 
 typedef struct {
   void (*destruct)(grpc_call_credentials *c);
diff --git a/src/core/lib/security/credentials/fake/fake_credentials.c b/src/core/lib/security/credentials/fake/fake_credentials.c
index ee6d964de1..51cafd986f 100644
--- a/src/core/lib/security/credentials/fake/fake_credentials.c
+++ b/src/core/lib/security/credentials/fake/fake_credentials.c
@@ -100,7 +100,7 @@ static void on_simulated_token_fetch_done(grpc_exec_ctx *exec_ctx,
       (grpc_credentials_metadata_request *)user_data;
   grpc_md_only_test_credentials *c = (grpc_md_only_test_credentials *)r->creds;
   r->cb(exec_ctx, r->user_data, c->md_store->entries, c->md_store->num_entries,
-        GRPC_CREDENTIALS_OK);
+        GRPC_CREDENTIALS_OK, NULL);
   grpc_credentials_metadata_request_destroy(r);
 }
 
@@ -117,7 +117,7 @@ static void md_only_test_get_request_metadata(
         grpc_closure_create(on_simulated_token_fetch_done, cb_arg),
         GRPC_ERROR_NONE);
   } else {
-    cb(exec_ctx, user_data, c->md_store->entries, 1, GRPC_CREDENTIALS_OK);
+    cb(exec_ctx, user_data, c->md_store->entries, 1, GRPC_CREDENTIALS_OK, NULL);
   }
 }
 
diff --git a/src/core/lib/security/credentials/iam/iam_credentials.c b/src/core/lib/security/credentials/iam/iam_credentials.c
index 64d5871844..370a384d0e 100644
--- a/src/core/lib/security/credentials/iam/iam_credentials.c
+++ b/src/core/lib/security/credentials/iam/iam_credentials.c
@@ -55,7 +55,7 @@ static void iam_get_request_metadata(grpc_exec_ctx *exec_ctx,
                                      void *user_data) {
   grpc_google_iam_credentials *c = (grpc_google_iam_credentials *)creds;
   cb(exec_ctx, user_data, c->iam_md->entries, c->iam_md->num_entries,
-     GRPC_CREDENTIALS_OK);
+     GRPC_CREDENTIALS_OK, NULL);
 }
 
 static grpc_call_credentials_vtable iam_vtable = {iam_destruct,
diff --git a/src/core/lib/security/credentials/jwt/jwt_credentials.c b/src/core/lib/security/credentials/jwt/jwt_credentials.c
index 973fb75eaa..6323eb9393 100644
--- a/src/core/lib/security/credentials/jwt/jwt_credentials.c
+++ b/src/core/lib/security/credentials/jwt/jwt_credentials.c
@@ -113,10 +113,11 @@ static void jwt_get_request_metadata(grpc_exec_ctx *exec_ctx,
 
   if (jwt_md != NULL) {
     cb(exec_ctx, user_data, jwt_md->entries, jwt_md->num_entries,
-       GRPC_CREDENTIALS_OK);
+       GRPC_CREDENTIALS_OK, NULL);
     grpc_credentials_md_store_unref(jwt_md);
   } else {
-    cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_ERROR);
+    cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_ERROR,
+       "Could not generate JWT.");
   }
 }
 
@@ -149,10 +150,10 @@ grpc_call_credentials *grpc_service_account_jwt_access_credentials_create(
       "grpc_service_account_jwt_access_credentials_create("
       "json_key=%s, "
       "token_lifetime="
-      "gpr_timespec { tv_sec: %lld, tv_nsec: %d, clock_type: %d }, "
+      "gpr_timespec { tv_sec: %"PRId64", tv_nsec: %d, clock_type: %d }, "
       "reserved=%p)",
       5,
-      (json_key, (long long)token_lifetime.tv_sec, (int)token_lifetime.tv_nsec,
+      (json_key, token_lifetime.tv_sec, token_lifetime.tv_nsec,
        (int)token_lifetime.clock_type, reserved));
   GPR_ASSERT(reserved == NULL);
   return grpc_service_account_jwt_access_credentials_create_from_auth_json_key(
diff --git a/src/core/lib/security/credentials/oauth2/oauth2_credentials.c b/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
index 1102553dd3..c22ea5c468 100644
--- a/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
+++ b/src/core/lib/security/credentials/oauth2/oauth2_credentials.c
@@ -235,10 +235,11 @@ static void on_oauth2_token_fetcher_http_response(grpc_exec_ctx *exec_ctx,
     c->token_expiration =
         gpr_time_add(gpr_now(GPR_CLOCK_REALTIME), token_lifetime);
     r->cb(exec_ctx, r->user_data, c->access_token_md->entries,
-          c->access_token_md->num_entries, status);
+          c->access_token_md->num_entries, GRPC_CREDENTIALS_OK, NULL);
   } else {
     c->token_expiration = gpr_inf_past(GPR_CLOCK_REALTIME);
-    r->cb(exec_ctx, r->user_data, NULL, 0, status);
+    r->cb(exec_ctx, r->user_data, NULL, 0, status,
+          "Error occured when fetching oauth2 token.");
   }
   gpr_mu_unlock(&c->mu);
   grpc_credentials_metadata_request_destroy(r);
@@ -266,7 +267,7 @@ static void oauth2_token_fetcher_get_request_metadata(
   }
   if (cached_access_token_md != NULL) {
     cb(exec_ctx, user_data, cached_access_token_md->entries,
-       cached_access_token_md->num_entries, GRPC_CREDENTIALS_OK);
+       cached_access_token_md->num_entries, GRPC_CREDENTIALS_OK, NULL);
     grpc_credentials_md_store_unref(cached_access_token_md);
   } else {
     c->fetch_func(
@@ -404,7 +405,8 @@ static void access_token_get_request_metadata(
     grpc_polling_entity *pollent, grpc_auth_metadata_context context,
     grpc_credentials_metadata_cb cb, void *user_data) {
   grpc_access_token_credentials *c = (grpc_access_token_credentials *)creds;
-  cb(exec_ctx, user_data, c->access_token_md->entries, 1, GRPC_CREDENTIALS_OK);
+  cb(exec_ctx, user_data, c->access_token_md->entries, 1, GRPC_CREDENTIALS_OK,
+     NULL);
 }
 
 static grpc_call_credentials_vtable access_token_vtable = {
diff --git a/src/core/lib/security/credentials/plugin/plugin_credentials.c b/src/core/lib/security/credentials/plugin/plugin_credentials.c
index 9fb55e8466..824ff081dc 100644
--- a/src/core/lib/security/credentials/plugin/plugin_credentials.c
+++ b/src/core/lib/security/credentials/plugin/plugin_credentials.c
@@ -67,7 +67,8 @@ static void plugin_md_request_metadata_ready(void *request,
       gpr_log(GPR_ERROR, "Getting metadata from plugin failed with error: %s",
               error_details);
     }
-    r->cb(&exec_ctx, r->user_data, NULL, 0, GRPC_CREDENTIALS_ERROR);
+    r->cb(&exec_ctx, r->user_data, NULL, 0, GRPC_CREDENTIALS_ERROR,
+          error_details);
   } else {
     size_t i;
     grpc_credentials_md *md_array = NULL;
@@ -79,7 +80,7 @@ static void plugin_md_request_metadata_ready(void *request,
             gpr_slice_from_copied_buffer(md[i].value, md[i].value_length);
       }
     }
-    r->cb(&exec_ctx, r->user_data, md_array, num_md, GRPC_CREDENTIALS_OK);
+    r->cb(&exec_ctx, r->user_data, md_array, num_md, GRPC_CREDENTIALS_OK, NULL);
     if (md_array != NULL) {
       for (i = 0; i < num_md; i++) {
         gpr_slice_unref(md_array[i].key);
@@ -107,7 +108,7 @@ static void plugin_get_request_metadata(grpc_exec_ctx *exec_ctx,
     c->plugin.get_metadata(c->plugin.state, context,
                            plugin_md_request_metadata_ready, request);
   } else {
-    cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_OK);
+    cb(exec_ctx, user_data, NULL, 0, GRPC_CREDENTIALS_OK, NULL);
   }
 }
 
diff --git a/src/core/lib/security/transport/client_auth_filter.c b/src/core/lib/security/transport/client_auth_filter.c
index 76be2acd72..399b92c8e1 100644
--- a/src/core/lib/security/transport/client_auth_filter.c
+++ b/src/core/lib/security/transport/client_auth_filter.c
@@ -91,14 +91,16 @@ static void bubble_up_error(grpc_exec_ctx *exec_ctx, grpc_call_element *elem,
                             grpc_status_code status, const char *error_msg) {
   call_data *calld = elem->call_data;
   gpr_log(GPR_ERROR, "Client side authentication failure: %s", error_msg);
-  grpc_transport_stream_op_add_cancellation(&calld->op, status);
+  gpr_slice error_slice = gpr_slice_from_copied_string(error_msg);
+  grpc_transport_stream_op_add_close(&calld->op, status, &error_slice);
   grpc_call_next_op(exec_ctx, elem, &calld->op);
 }
 
 static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
                                     grpc_credentials_md *md_elems,
                                     size_t num_md,
-                                    grpc_credentials_status status) {
+                                    grpc_credentials_status status,
+                                    const char *error_details) {
   grpc_call_element *elem = (grpc_call_element *)user_data;
   call_data *calld = elem->call_data;
   grpc_transport_stream_op *op = &calld->op;
@@ -107,7 +109,9 @@ static void on_credentials_metadata(grpc_exec_ctx *exec_ctx, void *user_data,
   reset_auth_metadata_context(&calld->auth_md_context);
   if (status != GRPC_CREDENTIALS_OK) {
     bubble_up_error(exec_ctx, elem, GRPC_STATUS_UNAUTHENTICATED,
-                    "Credentials failed to get metadata.");
+                    (error_details != NULL && strlen(error_details) > 0)
+                        ? error_details
+                        : "Credentials failed to get metadata.");
     return;
   }
   GPR_ASSERT(num_md <= MAX_CREDENTIALS_METADATA_COUNT);
diff --git a/src/core/lib/surface/channel.c b/src/core/lib/surface/channel.c
index 8936e7164f..952a769de1 100644
--- a/src/core/lib/surface/channel.c
+++ b/src/core/lib/surface/channel.c
@@ -223,10 +223,10 @@ grpc_call *grpc_channel_create_call(grpc_channel *channel,
       "grpc_channel_create_call("
       "channel=%p, parent_call=%p, propagation_mask=%x, cq=%p, method=%s, "
       "host=%s, "
-      "deadline=gpr_timespec { tv_sec: %lld, tv_nsec: %d, clock_type: %d }, "
+      "deadline=gpr_timespec { tv_sec: %"PRId64", tv_nsec: %d, clock_type: %d }, "
       "reserved=%p)",
       10, (channel, parent_call, (unsigned)propagation_mask, cq, method, host,
-           (long long)deadline.tv_sec, (int)deadline.tv_nsec,
+           deadline.tv_sec, deadline.tv_nsec,
            (int)deadline.clock_type, reserved));
   GPR_ASSERT(!reserved);
   return grpc_channel_create_call_internal(
@@ -282,11 +282,11 @@ grpc_call *grpc_channel_create_registered_call(
       "grpc_channel_create_registered_call("
       "channel=%p, parent_call=%p, propagation_mask=%x, completion_queue=%p, "
       "registered_call_handle=%p, "
-      "deadline=gpr_timespec { tv_sec: %lld, tv_nsec: %d, clock_type: %d }, "
+      "deadline=gpr_timespec { tv_sec: %"PRId64", tv_nsec: %d, clock_type: %d }, "
       "reserved=%p)",
       9, (channel, parent_call, (unsigned)propagation_mask, completion_queue,
-          registered_call_handle, (long long)deadline.tv_sec,
-          (int)deadline.tv_nsec, (int)deadline.clock_type, reserved));
+          registered_call_handle, deadline.tv_sec,
+          deadline.tv_nsec, (int)deadline.clock_type, reserved));
   GPR_ASSERT(!reserved);
   return grpc_channel_create_call_internal(
       channel, parent_call, propagation_mask, completion_queue, NULL,
diff --git a/src/core/lib/surface/completion_queue.c b/src/core/lib/surface/completion_queue.c
index 2cc6aa74e0..aa35ae02fe 100644
--- a/src/core/lib/surface/completion_queue.c
+++ b/src/core/lib/surface/completion_queue.c
@@ -316,9 +316,9 @@ grpc_event grpc_completion_queue_next(grpc_completion_queue *cc,
   GRPC_API_TRACE(
       "grpc_completion_queue_next("
       "cc=%p, "
-      "deadline=gpr_timespec { tv_sec: %lld, tv_nsec: %d, clock_type: %d }, "
+      "deadline=gpr_timespec { tv_sec: %"PRId64", tv_nsec: %d, clock_type: %d }, "
       "reserved=%p)",
-      5, (cc, (long long)deadline.tv_sec, (int)deadline.tv_nsec,
+      5, (cc, deadline.tv_sec, deadline.tv_nsec,
           (int)deadline.clock_type, reserved));
   GPR_ASSERT(!reserved);
 
@@ -428,9 +428,9 @@ grpc_event grpc_completion_queue_pluck(grpc_completion_queue *cc, void *tag,
   GRPC_API_TRACE(
       "grpc_completion_queue_pluck("
       "cc=%p, tag=%p, "
-      "deadline=gpr_timespec { tv_sec: %lld, tv_nsec: %d, clock_type: %d }, "
+      "deadline=gpr_timespec { tv_sec: %"PRId64", tv_nsec: %d, clock_type: %d }, "
       "reserved=%p)",
-      6, (cc, tag, (long long)deadline.tv_sec, (int)deadline.tv_nsec,
+      6, (cc, tag, deadline.tv_sec, deadline.tv_nsec,
           (int)deadline.clock_type, reserved));
   GPR_ASSERT(!reserved);
 
diff --git a/src/core/lib/surface/version.c b/src/core/lib/surface/version.c
index aca76d2bb7..53f3c43854 100644
--- a/src/core/lib/surface/version.c
+++ b/src/core/lib/surface/version.c
@@ -36,4 +36,4 @@
 
 #include <grpc/grpc.h>
 
-const char *grpc_version_string(void) { return "0.15.0-dev"; }
+const char *grpc_version_string(void) { return "0.16.0-dev"; }
diff --git a/src/core/lib/transport/transport_op_string.c b/src/core/lib/transport/transport_op_string.c
index df04c61127..d8fae7805e 100644
--- a/src/core/lib/transport/transport_op_string.c
+++ b/src/core/lib/transport/transport_op_string.c
@@ -63,8 +63,8 @@ static void put_metadata_list(gpr_strvec *b, grpc_metadata_batch md) {
   }
   if (gpr_time_cmp(md.deadline, gpr_inf_future(md.deadline.clock_type)) != 0) {
     char *tmp;
-    gpr_asprintf(&tmp, " deadline=%lld.%09d", (long long)md.deadline.tv_sec,
-                 (int)md.deadline.tv_nsec);
+    gpr_asprintf(&tmp, " deadline=%"PRId64".%09d", md.deadline.tv_sec,
+                 md.deadline.tv_nsec);
     gpr_strvec_add(b, tmp);
   }
 }
diff --git a/src/csharp/Grpc.Auth/project.json b/src/csharp/Grpc.Auth/project.json
index 1677565824..4c5c960204 100644
--- a/src/csharp/Grpc.Auth/project.json
+++ b/src/csharp/Grpc.Auth/project.json
@@ -1,5 +1,5 @@
 {
-  "version": "0.15.0-dev",
+  "version": "0.16.0-dev",
   "title": "gRPC C# Auth",
   "authors": [ "Google Inc." ],
   "copyright": "Copyright 2015, Google Inc.",
@@ -13,7 +13,7 @@
     "tags": [ "gRPC RPC Protocol HTTP/2 Auth OAuth2" ],
   },
   "dependencies": {
-    "Grpc.Core": "0.15.0-dev",
+    "Grpc.Core": "0.16.0-dev",
     "Google.Apis.Auth": "1.11.1"
   },
   "frameworks": {
diff --git a/src/csharp/Grpc.Core/Grpc.Core.nuspec b/src/csharp/Grpc.Core/Grpc.Core.nuspec
index fa2c1fbff2..47593f787b 100644
--- a/src/csharp/Grpc.Core/Grpc.Core.nuspec
+++ b/src/csharp/Grpc.Core/Grpc.Core.nuspec
@@ -24,11 +24,12 @@
     <file src="bin/ReleaseSigned/Grpc.Core.xml" target="lib/net45" />
     <file src="**\*.cs" target="src" />
     <file src="Grpc.Core.targets" target="\build\net45\Grpc.Core.targets" />
-    <file src="../nativelibs/windows_x86/grpc_csharp_ext.dll" target="/build/native/bin/windows_x86/grpc_csharp_ext.dll" />
-    <file src="../nativelibs/windows_x64/grpc_csharp_ext.dll" target="/build/native/bin/windows_x64/grpc_csharp_ext.dll" />
-    <file src="../nativelibs/linux_x86/libgrpc_csharp_ext.so" target="/build/native/bin/linux_x86/libgrpc_csharp_ext.so" />
-    <file src="../nativelibs/linux_x64/libgrpc_csharp_ext.so" target="/build/native/bin/linux_x64/libgrpc_csharp_ext.so" />
-    <file src="../nativelibs/macosx_x86/libgrpc_csharp_ext.dylib" target="/build/native/bin/macosx_x86/libgrpc_csharp_ext.dylib" />
-    <file src="../nativelibs/macosx_x64/libgrpc_csharp_ext.dylib" target="/build/native/bin/macosx_x64/libgrpc_csharp_ext.dylib" />
+    <!-- without backslashes in the the source path, nuget won't copy the files -->
+    <file src="..\nativelibs\windows_x86\grpc_csharp_ext.dll" target="/build/native/bin/windows_x86/grpc_csharp_ext.dll" />
+    <file src="..\nativelibs\windows_x64\grpc_csharp_ext.dll" target="/build/native/bin/windows_x64/grpc_csharp_ext.dll" />
+    <file src="..\nativelibs\linux_x86\libgrpc_csharp_ext.so" target="/build/native/bin/linux_x86/libgrpc_csharp_ext.so" />
+    <file src="..\nativelibs\linux_x64\libgrpc_csharp_ext.so" target="/build/native/bin/linux_x64/libgrpc_csharp_ext.so" />
+    <file src="..\nativelibs\macosx_x86\libgrpc_csharp_ext.dylib" target="/build/native/bin/macosx_x86/libgrpc_csharp_ext.dylib" />
+    <file src="..\nativelibs\macosx_x64\libgrpc_csharp_ext.dylib" target="/build/native/bin/macosx_x64/libgrpc_csharp_ext.dylib" />
   </files>
 </package>
diff --git a/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs b/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
index 8581302706..014a8db78f 100644
--- a/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
+++ b/src/csharp/Grpc.Core/Internal/ServerSafeHandle.cs
@@ -54,7 +54,10 @@ namespace Grpc.Core.Internal
 
         public void RegisterCompletionQueue(CompletionQueueSafeHandle cq)
         {
-            Native.grpcsharp_server_register_completion_queue(this, cq);
+            using (cq.NewScope())
+            {
+                Native.grpcsharp_server_register_completion_queue(this, cq);
+            }
         }
 
         public int AddInsecurePort(string addr)
@@ -74,16 +77,22 @@ namespace Grpc.Core.Internal
     
         public void ShutdownAndNotify(BatchCompletionDelegate callback, CompletionQueueSafeHandle completionQueue)
         {
-            var ctx = BatchContextSafeHandle.Create();
-            completionQueue.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
-            Native.grpcsharp_server_shutdown_and_notify_callback(this, completionQueue, ctx);
+            using (completionQueue.NewScope())
+            {
+                var ctx = BatchContextSafeHandle.Create();
+                completionQueue.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+                Native.grpcsharp_server_shutdown_and_notify_callback(this, completionQueue, ctx);
+            }
         }
 
         public void RequestCall(BatchCompletionDelegate callback, CompletionQueueSafeHandle completionQueue)
         {
-            var ctx = BatchContextSafeHandle.Create();
-            completionQueue.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
-            Native.grpcsharp_server_request_call(this, completionQueue, ctx).CheckOk();
+            using (completionQueue.NewScope())
+            {
+                var ctx = BatchContextSafeHandle.Create();
+                completionQueue.CompletionRegistry.RegisterBatchCompletion(ctx, callback);
+                Native.grpcsharp_server_request_call(this, completionQueue, ctx).CheckOk();
+            }
         }
 
         protected override bool ReleaseHandle()
diff --git a/src/csharp/Grpc.Core/VersionInfo.cs b/src/csharp/Grpc.Core/VersionInfo.cs
index e1609341d9..cb20967680 100644
--- a/src/csharp/Grpc.Core/VersionInfo.cs
+++ b/src/csharp/Grpc.Core/VersionInfo.cs
@@ -48,11 +48,11 @@ namespace Grpc.Core
         /// <summary>
         /// Current <c>AssemblyFileVersion</c> of gRPC C# assemblies
         /// </summary>
-        public const string CurrentAssemblyFileVersion = "0.15.0.0";
+        public const string CurrentAssemblyFileVersion = "0.16.0.0";
 
         /// <summary>
         /// Current version of gRPC C#
         /// </summary>
-        public const string CurrentVersion = "0.15.0-dev";
+        public const string CurrentVersion = "0.16.0-dev";
     }
 }
diff --git a/src/csharp/Grpc.Core/project.json b/src/csharp/Grpc.Core/project.json
index 7253107e04..4729a9346c 100644
--- a/src/csharp/Grpc.Core/project.json
+++ b/src/csharp/Grpc.Core/project.json
@@ -1,5 +1,5 @@
 {
-  "version": "0.15.0-dev",
+  "version": "0.16.0-dev",
   "title": "gRPC C# Core",
   "authors": [ "Google Inc." ],
   "copyright": "Copyright 2015, Google Inc.",
diff --git a/src/csharp/Grpc.HealthCheck/project.json b/src/csharp/Grpc.HealthCheck/project.json
index eb57608957..c4895c2ad3 100644
--- a/src/csharp/Grpc.HealthCheck/project.json
+++ b/src/csharp/Grpc.HealthCheck/project.json
@@ -1,5 +1,5 @@
 {
-  "version": "0.15.0-dev",
+  "version": "0.16.0-dev",
   "title": "gRPC C# Healthchecking",
   "authors": [ "Google Inc." ],
   "copyright": "Copyright 2015, Google Inc.",
@@ -13,7 +13,7 @@
     "tags": [ "gRPC health check" ]
   },
   "dependencies": {
-    "Grpc.Core": "0.15.0-dev",
+    "Grpc.Core": "0.16.0-dev",
     "Google.Protobuf": "3.0.0-beta3"
   },
   "frameworks": {
diff --git a/src/csharp/build_packages.bat b/src/csharp/build_packages.bat
index 63f8c30bc7..272b30f385 100644
--- a/src/csharp/build_packages.bat
+++ b/src/csharp/build_packages.bat
@@ -30,7 +30,7 @@
 @rem Builds gRPC NuGet packages
 
 @rem Current package versions
-set VERSION=0.15.0-dev
+set VERSION=0.16.0-dev
 set PROTOBUF_VERSION=3.0.0-beta3
 
 @rem Packages that depend on prerelease packages (like Google.Protobuf) need to have prerelease suffix as well.
diff --git a/src/node/ext/node_grpc.cc b/src/node/ext/node_grpc.cc
index f18ce01c6f..ce988f9dfa 100644
--- a/src/node/ext/node_grpc.cc
+++ b/src/node/ext/node_grpc.cc
@@ -31,12 +31,16 @@
  *
  */
 
+#include <list>
+
 #include <node.h>
 #include <nan.h>
 #include <v8.h>
 #include "grpc/grpc.h"
 #include "grpc/grpc_security.h"
 #include "grpc/support/alloc.h"
+#include "grpc/support/log.h"
+#include "grpc/support/time.h"
 
 #include "call.h"
 #include "call_credentials.h"
@@ -45,14 +49,32 @@
 #include "server.h"
 #include "completion_queue_async_worker.h"
 #include "server_credentials.h"
+#include "timeval.h"
 
 using v8::FunctionTemplate;
 using v8::Local;
 using v8::Value;
+using v8::Number;
 using v8::Object;
 using v8::Uint32;
 using v8::String;
 
+typedef struct log_args {
+  gpr_log_func_args core_args;
+  gpr_timespec timestamp;
+} log_args;
+
+typedef struct logger_state {
+  Nan::Callback *callback;
+  std::list<log_args *> *pending_args;
+  uv_mutex_t mutex;
+  uv_async_t async;
+  // Indicates that a logger has been set
+  bool logger_set;
+} logger_state;
+
+logger_state grpc_logger_state;
+
 static char *pem_root_certs = NULL;
 
 void InitStatusConstants(Local<Object> exports) {
@@ -235,6 +257,18 @@ void InitWriteFlags(Local<Object> exports) {
   Nan::Set(write_flags, Nan::New("NO_COMPRESS").ToLocalChecked(), NO_COMPRESS);
 }
 
+void InitLogConstants(Local<Object> exports) {
+  Nan::HandleScope scope;
+  Local<Object> log_verbosity = Nan::New<Object>();
+  Nan::Set(exports, Nan::New("logVerbosity").ToLocalChecked(), log_verbosity);
+  Local<Value> DEBUG(Nan::New<Uint32, uint32_t>(GPR_LOG_SEVERITY_DEBUG));
+  Nan::Set(log_verbosity, Nan::New("DEBUG").ToLocalChecked(), DEBUG);
+  Local<Value> INFO(Nan::New<Uint32, uint32_t>(GPR_LOG_SEVERITY_INFO));
+  Nan::Set(log_verbosity, Nan::New("INFO").ToLocalChecked(), INFO);
+  Local<Value> ERROR(Nan::New<Uint32, uint32_t>(GPR_LOG_SEVERITY_ERROR));
+  Nan::Set(log_verbosity, Nan::New("ERROR").ToLocalChecked(), ERROR);
+}
+
 NAN_METHOD(MetadataKeyIsLegal) {
   if (!info[0]->IsString()) {
     return Nan::ThrowTypeError(
@@ -298,16 +332,101 @@ NAN_METHOD(SetDefaultRootsPem) {
   }
 }
 
+NAUV_WORK_CB(LogMessagesCallback) {
+  Nan::HandleScope scope;
+  std::list<log_args *> args;
+  uv_mutex_lock(&grpc_logger_state.mutex);
+  args.splice(args.begin(), *grpc_logger_state.pending_args);
+  uv_mutex_unlock(&grpc_logger_state.mutex);
+  /* Call the callback with each log message */
+  while (!args.empty()) {
+    log_args *arg = args.front();
+    args.pop_front();
+    Local<Value> file = Nan::New(arg->core_args.file).ToLocalChecked();
+    Local<Value> line = Nan::New<Uint32, uint32_t>(arg->core_args.line);
+    Local<Value> severity = Nan::New(
+        gpr_log_severity_string(arg->core_args.severity)).ToLocalChecked();
+    Local<Value> message = Nan::New(arg->core_args.message).ToLocalChecked();
+    Local<Value> timestamp = Nan::New<v8::Date>(
+        grpc::node::TimespecToMilliseconds(arg->timestamp)).ToLocalChecked();
+    const int argc = 5;
+    Local<Value> argv[argc] = {file, line, severity, message, timestamp};
+    grpc_logger_state.callback->Call(argc, argv);
+    delete[] arg->core_args.message;
+    delete arg;
+  }
+}
+
+void node_log_func(gpr_log_func_args *args) {
+  // TODO(mlumish): Use the core's log formatter when it becomes available
+  log_args *args_copy = new log_args;
+  size_t message_len = strlen(args->message) + 1;
+  char *message = new char[message_len];
+  memcpy(message, args->message, message_len);
+  memcpy(&args_copy->core_args, args, sizeof(gpr_log_func_args));
+  args_copy->core_args.message = message;
+  args_copy->timestamp = gpr_now(GPR_CLOCK_REALTIME);
+
+  uv_mutex_lock(&grpc_logger_state.mutex);
+  grpc_logger_state.pending_args->push_back(args_copy);
+  uv_mutex_unlock(&grpc_logger_state.mutex);
+
+  uv_async_send(&grpc_logger_state.async);
+}
+
+void init_logger() {
+  memset(&grpc_logger_state, 0, sizeof(logger_state));
+  grpc_logger_state.pending_args = new std::list<log_args *>();
+  uv_mutex_init(&grpc_logger_state.mutex);
+  uv_async_init(uv_default_loop(),
+                &grpc_logger_state.async,
+                LogMessagesCallback);
+  uv_unref((uv_handle_t*)&grpc_logger_state.async);
+  grpc_logger_state.logger_set = false;
+
+  gpr_log_verbosity_init();
+}
+
+/* This registers a JavaScript logger for messages from the gRPC core. Because
+   that handler has to be run in the context of the JavaScript event loop, it
+   will be run asynchronously. To minimize the problems that could cause for
+   debugging, we leave core to do its default synchronous logging until a
+   JavaScript logger is set */
+NAN_METHOD(SetDefaultLoggerCallback) {
+  if (!info[0]->IsFunction()) {
+    return Nan::ThrowTypeError(
+        "setDefaultLoggerCallback's argument must be a function");
+  }
+  if (!grpc_logger_state.logger_set) {
+    gpr_set_log_function(node_log_func);
+    grpc_logger_state.logger_set = true;
+  }
+  grpc_logger_state.callback = new Nan::Callback(info[0].As<v8::Function>());
+}
+
+NAN_METHOD(SetLogVerbosity) {
+  if (!info[0]->IsUint32()) {
+    return Nan::ThrowTypeError(
+        "setLogVerbosity's argument must be a number");
+  }
+  gpr_log_severity severity = static_cast<gpr_log_severity>(
+      Nan::To<uint32_t>(info[0]).FromJust());
+  gpr_set_log_verbosity(severity);
+}
+
 void init(Local<Object> exports) {
   Nan::HandleScope scope;
   grpc_init();
   grpc_set_ssl_roots_override_callback(get_ssl_roots_override);
+  init_logger();
+
   InitStatusConstants(exports);
   InitCallErrorConstants(exports);
   InitOpTypeConstants(exports);
   InitPropagateConstants(exports);
   InitConnectivityStateConstants(exports);
   InitWriteFlags(exports);
+  InitLogConstants(exports);
 
   grpc::node::Call::Init(exports);
   grpc::node::CallCredentials::Init(exports);
@@ -333,6 +452,14 @@ void init(Local<Object> exports) {
            Nan::GetFunction(
                Nan::New<FunctionTemplate>(SetDefaultRootsPem)
                             ).ToLocalChecked());
+  Nan::Set(exports, Nan::New("setDefaultLoggerCallback").ToLocalChecked(),
+           Nan::GetFunction(
+               Nan::New<FunctionTemplate>(SetDefaultLoggerCallback)
+                            ).ToLocalChecked());
+  Nan::Set(exports, Nan::New("setLogVerbosity").ToLocalChecked(),
+           Nan::GetFunction(
+               Nan::New<FunctionTemplate>(SetLogVerbosity)
+                            ).ToLocalChecked());
 }
 
 NODE_MODULE(grpc_node, init)
diff --git a/src/node/index.js b/src/node/index.js
index 66664d94b5..9fb6faa5d7 100644
--- a/src/node/index.js
+++ b/src/node/index.js
@@ -46,6 +46,8 @@ var client = require('./src/client.js');
 
 var server = require('./src/server.js');
 
+var common = require('./src/common.js');
+
 var Metadata = require('./src/metadata.js');
 
 var grpc = require('./src/grpc_extension');
@@ -122,6 +124,42 @@ exports.load = function load(filename, format, options) {
   return loadObject(builder.ns, options);
 };
 
+var log_template = _.template(
+    '{severity} {timestamp}\t{file}:{line}]\t{message}',
+    {interpolate: /{([\s\S]+?)}/g});
+
+/**
+ * Sets the logger function for the gRPC module. For debugging purposes, the C
+ * core will log synchronously directly to stdout unless this function is
+ * called. Note: the output format here is intended to be informational, and
+ * is not guaranteed to stay the same in the future.
+ * Logs will be directed to logger.error.
+ * @param {Console} logger A Console-like object.
+ */
+exports.setLogger = function setLogger(logger) {
+  common.logger = logger;
+  grpc.setDefaultLoggerCallback(function(file, line, severity,
+                                         message, timestamp) {
+    logger.error(log_template({
+      file: path.basename(file),
+      line: line,
+      severity: severity,
+      message: message,
+      timestamp: timestamp.toISOString()
+    }));
+  });
+};
+
+/**
+ * Sets the logger verbosity for gRPC module logging. The options are members
+ * of the grpc.logVerbosity map.
+ * @param {Number} verbosity The minimum severity to log
+ */
+exports.setLogVerbosity = function setLogVerbosity(verbosity) {
+  common.logVerbosity = verbosity;
+  grpc.setLogVerbosity(verbosity);
+};
+
 /**
  * @see module:src/server.Server
  */
@@ -153,6 +191,11 @@ exports.callError = grpc.callError;
 exports.writeFlags = grpc.writeFlags;
 
 /**
+ * Log verbosity setting name to code number mapping
+ */
+exports.logVerbosity = grpc.logVerbosity;
+
+/**
  * Credentials factories
  */
 exports.credentials = require('./src/credentials.js');
diff --git a/src/node/src/common.js b/src/node/src/common.js
index 8cf43b7a84..22159dd39f 100644
--- a/src/node/src/common.js
+++ b/src/node/src/common.js
@@ -157,3 +157,24 @@ exports.getProtobufServiceAttrs = function getProtobufServiceAttrs(service,
     }];
   }));
 };
+
+/**
+ * The logger object for the gRPC module. Defaults to console.
+ */
+exports.logger = console;
+
+/**
+ * The current logging verbosity. 0 corresponds to logging everything
+ */
+exports.logVerbosity = 0;
+
+/**
+ * Log a message if the severity is at least as high as the current verbosity
+ * @param {Number} severity A value of the grpc.logVerbosity map
+ * @param {String} message The message to log
+ */
+exports.log = function log(severity, message) {
+  if (severity >= exports.logVerbosity) {
+    exports.logger.error(message);
+  }
+};
diff --git a/src/node/src/credentials.js b/src/node/src/credentials.js
index a12eade4e1..b746d0625d 100644
--- a/src/node/src/credentials.js
+++ b/src/node/src/credentials.js
@@ -69,6 +69,8 @@ var ChannelCredentials = grpc.ChannelCredentials;
 
 var Metadata = require('./metadata.js');
 
+var common = require('./common.js');
+
 /**
  * Create an SSL Credentials object. If using a client-side certificate, both
  * the second and third arguments must be passed.
@@ -120,7 +122,7 @@ exports.createFromGoogleCredential = function(google_credential) {
     var service_url = auth_context.service_url;
     google_credential.getRequestMetadata(service_url, function(err, header) {
       if (err) {
-        console.log('Auth error:', err);
+        common.log(grpc.logVerbosity.INFO, 'Auth error:' + err);
         callback(err);
         return;
       }
diff --git a/src/node/src/server.js b/src/node/src/server.js
index fd5153f124..b3b414969a 100644
--- a/src/node/src/server.js
+++ b/src/node/src/server.js
@@ -735,8 +735,8 @@ Server.prototype.addService = function(service, implementation) {
     }
     var impl;
     if (implementation[name] === undefined) {
-      console.warn('Method handler for %s expected but not provided',
-                   attrs.path);
+      common.log(grpc.logVerbosity.ERROR, 'Method handler for ' +
+          attrs.path + ' expected but not provided');
       impl = defaultHandler[method_type];
     } else {
       impl = _.bind(implementation[name], implementation);
diff --git a/src/node/tools/package.json b/src/node/tools/package.json
index c34b259e2e..7c256d7ba0 100644
--- a/src/node/tools/package.json
+++ b/src/node/tools/package.json
@@ -1,6 +1,6 @@
 {
   "name": "grpc-tools",
-  "version": "0.15.0-dev",
+  "version": "0.16.0-dev",
   "author": "Google Inc.",
   "description": "Tools for developing with gRPC on Node.js",
   "homepage": "http://www.grpc.io/",
diff --git a/src/objective-c/examples/SwiftSample/ViewController.swift b/src/objective-c/examples/SwiftSample/ViewController.swift
index a21ce07978..2a95d2de51 100644
--- a/src/objective-c/examples/SwiftSample/ViewController.swift
+++ b/src/objective-c/examples/SwiftSample/ViewController.swift
@@ -71,7 +71,8 @@ class ViewController: UIViewController {
       NSLog("2. Response trailers: \(RPC.responseTrailers)")
     }
 
-    RPC.requestHeaders["My-Header"] = "My value"
+    // TODO(jcanizales): Revert to using subscript syntax once XCode 8 is released.
+    RPC.requestHeaders.setObject("My value", forKey: "My-Header")
 
     RPC.start()
 
@@ -84,7 +85,7 @@ class ViewController: UIViewController {
 
     let call = GRPCCall(host: RemoteHost, path: method.HTTPPath, requestsWriter: requestsWriter)
 
-    call.requestHeaders["My-Header"] = "My value"
+    call.requestHeaders.setObject("My value", forKey: "My-Header")
 
     call.startWithWriteable(GRXWriteable { response, error in
       if let response = response as? NSData {
diff --git a/src/python/grpcio/grpc_version.py b/src/python/grpcio/grpc_version.py
index 0c13104d9d..0f4db9d972 100644
--- a/src/python/grpcio/grpc_version.py
+++ b/src/python/grpcio/grpc_version.py
@@ -29,4 +29,4 @@
 
 # AUTO-GENERATED FROM `$REPO_ROOT/templates/src/python/grpcio/grpc_version.py.template`!!!
 
-VERSION='0.15.0.dev0'
+VERSION='0.16.0.dev0'
diff --git a/src/ruby/lib/grpc/version.rb b/src/ruby/lib/grpc/version.rb
index 01c8c5ac8f..5e6aaef2eb 100644
--- a/src/ruby/lib/grpc/version.rb
+++ b/src/ruby/lib/grpc/version.rb
@@ -29,5 +29,5 @@
 
 # GRPC contains the General RPC module.
 module GRPC
-  VERSION = '0.15.0.dev'
+  VERSION = '0.16.0.dev'
 end
diff --git a/src/ruby/tools/version.rb b/src/ruby/tools/version.rb
index dca7fd7e72..68c1bf369d 100644
--- a/src/ruby/tools/version.rb
+++ b/src/ruby/tools/version.rb
@@ -29,6 +29,6 @@
 
 module GRPC
   module Tools
-    VERSION = '0.15.0.dev'
+    VERSION = '0.16.0.dev'
   end
 end