Add a way to override channel arguments for server creation

include/grpc++/server.h

@@ -79,6 +79,8 @@ class Server GRPC_FINAL : public ServerInterface, private GrpcLibrary {
   class GlobalCallbacks {
    public:
     virtual ~GlobalCallbacks() {}
+    /// Called before server is created.
+    virtual void UpdateArguments(ChannelArguments* args) {}
     /// Called before application callback for each synchronous server request
     virtual void PreSynchronousRequest(ServerContext* context) = 0;
     /// Called after application callback for each synchronous server request
@@ -108,7 +110,7 @@ class Server GRPC_FINAL : public ServerInterface, private GrpcLibrary {
   /// \param max_message_size Maximum message length that the channel can
   /// receive.
   Server(ThreadPoolInterface* thread_pool, bool thread_pool_owned,
-         int max_message_size, const ChannelArguments& args);
+         int max_message_size, ChannelArguments* args);
 
   /// Register a service. This call does not take ownership of the service.
   /// The service must exist for the lifetime of the Server instance.
@@ -177,7 +179,7 @@ class Server GRPC_FINAL : public ServerInterface, private GrpcLibrary {
   bool has_generic_service_;
 
   // Pointer to the c grpc server.
-  grpc_server* const server_;
+  grpc_server* server_;
 
   ThreadPoolInterface* thread_pool_;
   // Whether the thread pool is created and owned by the server.

src/cpp/server/server.cc

@@ -272,27 +272,25 @@ class Server::SyncRequest GRPC_FINAL : public CompletionQueueTag {
   grpc_completion_queue* cq_;
 };
 
-static grpc_server* CreateServer(const ChannelArguments& args) {
-  grpc_channel_args channel_args;
-  args.SetChannelArgs(&channel_args);
-  return grpc_server_create(&channel_args, nullptr);
-}
-
 static internal::GrpcLibraryInitializer g_gli_initializer;
 Server::Server(ThreadPoolInterface* thread_pool, bool thread_pool_owned,
-               int max_message_size, const ChannelArguments& args)
+               int max_message_size, ChannelArguments* args)
     : max_message_size_(max_message_size),
       started_(false),
       shutdown_(false),
       num_running_cb_(0),
       sync_methods_(new std::list<SyncRequest>),
       has_generic_service_(false),
-      server_(CreateServer(args)),
+      server_(nullptr),
       thread_pool_(thread_pool),
       thread_pool_owned_(thread_pool_owned) {
   g_gli_initializer.summon();
   gpr_once_init(&g_once_init_callbacks, InitGlobalCallbacks);
   global_callbacks_ = g_callbacks;
+  global_callbacks_->UpdateArguments(args);
+  grpc_channel_args channel_args;
+  args->SetChannelArgs(&channel_args);
+  server_ = grpc_server_create(&channel_args, nullptr);
   grpc_server_register_completion_queue(server_, cq_.cq(), nullptr);
 }
 

src/cpp/server/server_builder.cc

@@ -103,7 +103,7 @@ std::unique_ptr<Server> ServerBuilder::BuildAndStart() {
   args.SetInt(GRPC_COMPRESSION_ALGORITHM_STATE_ARG,
               compression_options_.enabled_algorithms_bitset);
   std::unique_ptr<Server> server(
-      new Server(thread_pool.release(), true, max_message_size_, args));
+      new Server(thread_pool.release(), true, max_message_size_, &args));
   for (auto cq = cqs_.begin(); cq != cqs_.end(); ++cq) {
     grpc_server_register_completion_queue(server->server_, (*cq)->cq(),
                                           nullptr);