C++ context propagation

2 files changed, 15 insertions, 3 deletions

diff --git a/src/cpp/client/channel.cc b/src/cpp/client/channel.cc
index 1912e5e4c8..5f54e7fcc1 100644
--- a/src/cpp/client/channel.cc
+++ b/src/cpp/client/channel.cc
@@ -63,10 +63,12 @@ Call Channel::CreateCall(const RpcMethod& method, ClientContext* context,
   const char* host_str = host_.empty() ? NULL : host_.c_str();
   auto c_call = method.channel_tag() && context->authority().empty()
                     ? grpc_channel_create_registered_call(
-                          c_channel_, NULL, GRPC_PROPAGATE_DEFAULTS, cq->cq(),
+                          c_channel_, context->propagate_from_call_,
+                          context->propagation_options_.c_bitmask(), cq->cq(),
                           method.channel_tag(), context->raw_deadline())
                     : grpc_channel_create_call(
-                          c_channel_, NULL, GRPC_PROPAGATE_DEFAULTS, cq->cq(),
+                          c_channel_, context->propagate_from_call_,
+                          context->propagation_options_.c_bitmask(), cq->cq(),
                           method.name(), context->authority().empty()
                                              ? host_str
                                              : context->authority().c_str(),
diff --git a/src/cpp/client/client_context.cc b/src/cpp/client/client_context.cc
index c38d0c1df6..80b6393f01 100644
--- a/src/cpp/client/client_context.cc
+++ b/src/cpp/client/client_context.cc
@@ -37,6 +37,7 @@
 #include <grpc/support/alloc.h>
 #include <grpc/support/string_util.h>
 #include <grpc++/credentials.h>
+#include <grpc++/server_context.h>
 #include <grpc++/time.h>
 
 #include "src/core/channel/compress_filter.h"
@@ -48,7 +49,8 @@ ClientContext::ClientContext()
     : initial_metadata_received_(false),
       call_(nullptr),
       cq_(nullptr),
-      deadline_(gpr_inf_future(GPR_CLOCK_REALTIME)) {}
+      deadline_(gpr_inf_future(GPR_CLOCK_REALTIME)),
+      propagate_from_call_(nullptr) {}
 
 ClientContext::~ClientContext() {
   if (call_) {
@@ -64,6 +66,14 @@ ClientContext::~ClientContext() {
   }
 }
 
+ClientContext ClientContext::FromServerContext(const ServerContext& context,
+                                               PropagationOptions options) {
+  ClientContext ctx;
+  ctx.propagate_from_call_ = context.call_;
+  ctx.propagation_options_ = options;
+  return ctx;
+}
+
 void ClientContext::AddMetadata(const grpc::string& meta_key,
                                 const grpc::string& meta_value) {
   send_initial_metadata_.insert(std::make_pair(meta_key, meta_value));