Revert "Revert "Fold opencensus into grpc_impl namespace""

BUILD

@@ -2283,6 +2283,7 @@ grpc_cc_library(
     ],
     hdrs = [
         "include/grpcpp/opencensus.h",
+        "include/grpcpp/opencensus_impl.h",
         "src/cpp/ext/filters/census/channel_filter.h",
         "src/cpp/ext/filters/census/client_filter.h",
         "src/cpp/ext/filters/census/context.h",

include/grpcpp/opencensus.h

@@ -19,30 +19,6 @@
 #ifndef GRPCPP_OPENCENSUS_H
 #define GRPCPP_OPENCENSUS_H
 
-#include "opencensus/trace/span.h"
-
-namespace grpc {
-// These symbols in this file will not be included in the binary unless
-// grpc_opencensus_plugin build target was added as a dependency. At the moment
-// it is only setup to be built with Bazel.
-
-// Registers the OpenCensus plugin with gRPC, so that it will be used for future
-// RPCs. This must be called before any views are created.
-void RegisterOpenCensusPlugin();
-
-// RPC stats definitions, defined by
-// https://github.com/census-instrumentation/opencensus-specs/blob/master/stats/gRPC.md
-
-// Registers the cumulative gRPC views so that they will be exported by any
-// registered stats exporter. For on-task stats, construct a View using the
-// ViewDescriptors below.
-void RegisterOpenCensusViewsForExport();
-
-class ServerContext;
-
-// Returns the tracing Span for the current RPC.
-::opencensus::trace::Span GetSpanFromServerContext(ServerContext* context);
-
-}  // namespace grpc
+#include "grpcpp/opencensus_impl.h"
 
 #endif  // GRPCPP_OPENCENSUS_H

include/grpcpp/opencensus_impl.h

@@ -0,0 +1,51 @@
+/*
+ *
+ * Copyright 2019 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+#ifndef GRPCPP_OPENCENSUS_IMPL_H
+#define GRPCPP_OPENCENSUS_IMPL_H
+
+#include "opencensus/trace/span.h"
+
+namespace grpc {
+
+class ServerContext;
+}
+namespace grpc_impl {
+// These symbols in this file will not be included in the binary unless
+// grpc_opencensus_plugin build target was added as a dependency. At the moment
+// it is only setup to be built with Bazel.
+
+// Registers the OpenCensus plugin with gRPC, so that it will be used for future
+// RPCs. This must be called before any views are created.
+void RegisterOpenCensusPlugin();
+
+// RPC stats definitions, defined by
+// https://github.com/census-instrumentation/opencensus-specs/blob/master/stats/gRPC.md
+
+// Registers the cumulative gRPC views so that they will be exported by any
+// registered stats exporter. For on-task stats, construct a View using the
+// ViewDescriptors below.
+void RegisterOpenCensusViewsForExport();
+
+// Returns the tracing Span for the current RPC.
+::opencensus::trace::Span GetSpanFromServerContext(
+    grpc::ServerContext* context);
+
+}  // namespace grpc_impl
+
+#endif  // GRPCPP_OPENCENSUS_IMPL_H

src/cpp/ext/filters/census/grpc_plugin.cc

@@ -30,35 +30,6 @@
 
 namespace grpc {
 
-void RegisterOpenCensusPlugin() {
-  RegisterChannelFilter<CensusChannelData, CensusClientCallData>(
-      "opencensus_client", GRPC_CLIENT_CHANNEL, INT_MAX /* priority */,
-      nullptr /* condition function */);
-  RegisterChannelFilter<CensusChannelData, CensusServerCallData>(
-      "opencensus_server", GRPC_SERVER_CHANNEL, INT_MAX /* priority */,
-      nullptr /* condition function */);
-
-  // Access measures to ensure they are initialized. Otherwise, creating a view
-  // before the first RPC would cause an error.
-  RpcClientSentBytesPerRpc();
-  RpcClientReceivedBytesPerRpc();
-  RpcClientRoundtripLatency();
-  RpcClientServerLatency();
-  RpcClientSentMessagesPerRpc();
-  RpcClientReceivedMessagesPerRpc();
-
-  RpcServerSentBytesPerRpc();
-  RpcServerReceivedBytesPerRpc();
-  RpcServerServerLatency();
-  RpcServerSentMessagesPerRpc();
-  RpcServerReceivedMessagesPerRpc();
-}
-
-::opencensus::trace::Span GetSpanFromServerContext(ServerContext* context) {
-  return reinterpret_cast<const CensusContext*>(context->census_context())
-      ->Span();
-}
-
 // These measure definitions should be kept in sync across opencensus
 // implementations--see
 // https://github.com/census-instrumentation/opencensus-java/blob/master/contrib/grpc_metrics/src/main/java/io/opencensus/contrib/grpc/metrics/RpcMeasureConstants.java.
@@ -126,5 +97,39 @@ ABSL_CONST_INIT const absl::string_view
 
 ABSL_CONST_INIT const absl::string_view kRpcServerServerLatencyMeasureName =
     "grpc.io/server/server_latency";
-
 }  // namespace grpc
+namespace grpc_impl {
+
+void RegisterOpenCensusPlugin() {
+  grpc::RegisterChannelFilter<grpc::CensusChannelData,
+                              grpc::CensusClientCallData>(
+      "opencensus_client", GRPC_CLIENT_CHANNEL, INT_MAX /* priority */,
+      nullptr /* condition function */);
+  grpc::RegisterChannelFilter<grpc::CensusChannelData,
+                              grpc::CensusServerCallData>(
+      "opencensus_server", GRPC_SERVER_CHANNEL, INT_MAX /* priority */,
+      nullptr /* condition function */);
+
+  // Access measures to ensure they are initialized. Otherwise, creating a view
+  // before the first RPC would cause an error.
+  grpc::RpcClientSentBytesPerRpc();
+  grpc::RpcClientReceivedBytesPerRpc();
+  grpc::RpcClientRoundtripLatency();
+  grpc::RpcClientServerLatency();
+  grpc::RpcClientSentMessagesPerRpc();
+  grpc::RpcClientReceivedMessagesPerRpc();
+
+  grpc::RpcServerSentBytesPerRpc();
+  grpc::RpcServerReceivedBytesPerRpc();
+  grpc::RpcServerServerLatency();
+  grpc::RpcServerSentMessagesPerRpc();
+  grpc::RpcServerReceivedMessagesPerRpc();
+}
+
+::opencensus::trace::Span GetSpanFromServerContext(
+    grpc::ServerContext* context) {
+  return reinterpret_cast<const grpc::CensusContext*>(context->census_context())
+      ->Span();
+}
+
+}  // namespace grpc_impl

src/cpp/ext/filters/census/grpc_plugin.h

@@ -22,12 +22,14 @@
 #include <grpc/support/port_platform.h>
 
 #include "absl/strings/string_view.h"
-#include "include/grpcpp/opencensus.h"
+#include "include/grpcpp/opencensus_impl.h"
 #include "opencensus/stats/stats.h"
 
-namespace grpc {
+namespace grpc_impl {
 
 class ServerContext;
+}
+namespace grpc {
 
 // The tag keys set when recording RPC stats.
 ::opencensus::stats::TagKey ClientMethodTagKey();

src/cpp/ext/filters/census/views.cc

@@ -25,6 +25,23 @@
 #include "opencensus/stats/internal/set_aggregation_window.h"
 #include "opencensus/stats/stats.h"
 
+namespace grpc_impl {
+
+void RegisterOpenCensusViewsForExport() {
+  grpc::ClientSentMessagesPerRpcCumulative().RegisterForExport();
+  grpc::ClientSentBytesPerRpcCumulative().RegisterForExport();
+  grpc::ClientReceivedMessagesPerRpcCumulative().RegisterForExport();
+  grpc::ClientReceivedBytesPerRpcCumulative().RegisterForExport();
+  grpc::ClientRoundtripLatencyCumulative().RegisterForExport();
+  grpc::ClientServerLatencyCumulative().RegisterForExport();
+
+  grpc::ServerSentMessagesPerRpcCumulative().RegisterForExport();
+  grpc::ServerSentBytesPerRpcCumulative().RegisterForExport();
+  grpc::ServerReceivedMessagesPerRpcCumulative().RegisterForExport();
+  grpc::ServerReceivedBytesPerRpcCumulative().RegisterForExport();
+  grpc::ServerServerLatencyCumulative().RegisterForExport();
+}
+}  // namespace grpc_impl
 namespace grpc {
 
 using ::opencensus::stats::Aggregation;
@@ -71,21 +88,6 @@ ViewDescriptor HourDescriptor() {
 
 }  // namespace
 
-void RegisterOpenCensusViewsForExport() {
-  ClientSentMessagesPerRpcCumulative().RegisterForExport();
-  ClientSentBytesPerRpcCumulative().RegisterForExport();
-  ClientReceivedMessagesPerRpcCumulative().RegisterForExport();
-  ClientReceivedBytesPerRpcCumulative().RegisterForExport();
-  ClientRoundtripLatencyCumulative().RegisterForExport();
-  ClientServerLatencyCumulative().RegisterForExport();
-
-  ServerSentMessagesPerRpcCumulative().RegisterForExport();
-  ServerSentBytesPerRpcCumulative().RegisterForExport();
-  ServerReceivedMessagesPerRpcCumulative().RegisterForExport();
-  ServerReceivedBytesPerRpcCumulative().RegisterForExport();
-  ServerServerLatencyCumulative().RegisterForExport();
-}
-
 // client cumulative
 const ViewDescriptor& ClientSentBytesPerRpcCumulative() {
   const static ViewDescriptor descriptor =

test/cpp/ext/filters/census/stats_plugin_end2end_test.cc

@@ -58,7 +58,7 @@ class EchoServer final : public EchoTestService::Service {
 
 class StatsPluginEnd2EndTest : public ::testing::Test {
  protected:
-  static void SetUpTestCase() { RegisterOpenCensusPlugin(); }
+  static void SetUpTestCase() { grpc_impl::RegisterOpenCensusPlugin(); }
 
   void SetUp() {
     // Set up a synchronous server on a different thread to avoid the asynch

test/cpp/microbenchmarks/bm_opencensus_plugin.cc

@@ -29,7 +29,9 @@
 #include "test/cpp/microbenchmarks/helpers.h"
 
 absl::once_flag once;
-void RegisterOnce() { absl::call_once(once, grpc::RegisterOpenCensusPlugin); }
+void RegisterOnce() {
+  absl::call_once(once, grpc_impl::RegisterOpenCensusPlugin);
+}
 
 class EchoServer final : public grpc::testing::EchoTestService::Service {
   grpc::Status Echo(grpc::ServerContext* context,
@@ -99,7 +101,7 @@ static void BM_E2eLatencyCensusEnabled(benchmark::State& state) {
   RegisterOnce();
   // This we can safely repeat, and doing so clears accumulated data to avoid
   // initialization costs varying between runs.
-  grpc::RegisterOpenCensusViewsForExport();
+  grpc_impl::RegisterOpenCensusViewsForExport();
 
   EchoServerThread server;
   std::unique_ptr<grpc::testing::EchoTestService::Stub> stub =