Revert "Revert "Revert "Fold opencensus into grpc_impl namespace"""

This reverts commit f66b654.

Author: karthikravis

BUILD

@@ -2322,7 +2322,6 @@ 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

@@ -19,7 +19,31 @@
 #ifndef GRPCPP_OPENCENSUS_H
 #define GRPCPP_OPENCENSUS_H
 
-#include "grpcpp/opencensus_impl.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
 
 namespace grpc {
 

include/grpcpp/opencensus_impl.h

@@ -31,6 +31,35 @@
 
 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.
@@ -98,39 +127,5 @@ 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
+}  // namespace grpc

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

@@ -25,23 +25,6 @@
 #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;
@@ -88,6 +71,21 @@ 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 =