Merge pull request grpc#21597 from yang-g/max_message_size

Allow plugin/global_callback to override max_recv_message_size

include/grpcpp/server_impl.h

@@ -163,9 +163,6 @@ class Server : public grpc::ServerInterface, private grpc::GrpcLibraryCodegen {
   ///
   /// Server constructors. To be used by \a ServerBuilder only.
   ///
-  /// \param max_message_size Maximum message length that the channel can
-  /// receive.
-  ///
   /// \param args The channel args
   ///
   /// \param sync_server_cqs The completion queues to use if the server is a
@@ -182,7 +179,7 @@ class Server : public grpc::ServerInterface, private grpc::GrpcLibraryCodegen {
   ///
   /// \param sync_cq_timeout_msec The timeout to use when calling AsyncNext() on
   /// server completion queues passed via sync_server_cqs param.
-  Server(int max_message_size, ChannelArguments* args,
+  Server(ChannelArguments* args,
          std::shared_ptr<std::vector<std::unique_ptr<ServerCompletionQueue>>>
              sync_server_cqs,
          int min_pollers, int max_pollers, int sync_cq_timeout_msec,
@@ -306,7 +303,7 @@ class Server : public grpc::ServerInterface, private grpc::GrpcLibraryCodegen {
       std::unique_ptr<grpc::experimental::ServerInterceptorFactoryInterface>>
       interceptor_creators_;
 
-  const int max_receive_message_size_;
+  int max_receive_message_size_;
 
   /// The following completion queues are ONLY used in case of Sync API
   /// i.e. if the server has any services with sync methods. The server uses

src/cpp/server/server_builder.cc

@@ -26,6 +26,7 @@
 
 #include <utility>
 
+#include "src/core/lib/channel/channel_args.h"
 #include "src/core/lib/gpr/string.h"
 #include "src/core/lib/gpr/useful.h"
 #include "src/cpp/server/external_connection_acceptor_impl.h"
@@ -218,20 +219,24 @@ ServerBuilder& ServerBuilder::AddListeningPort(
 
 std::unique_ptr<grpc::Server> ServerBuilder::BuildAndStart() {
   grpc::ChannelArguments args;
+
   for (const auto& option : options_) {
     option->UpdateArguments(&args);
     option->UpdatePlugins(&plugins_);
   }
-
-  for (const auto& plugin : plugins_) {
-    plugin->UpdateServerBuilder(this);
-    plugin->UpdateChannelArguments(&args);
-  }
-
   if (max_receive_message_size_ >= -1) {
+    grpc_channel_args c_args = args.c_channel_args();
+    const grpc_arg* arg =
+        grpc_channel_args_find(&c_args, GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH);
+    // Some option has set max_receive_message_length and it is also set
+    // directly on the ServerBuilder.
+    if (arg != nullptr) {
+      gpr_log(
+          GPR_ERROR,
+          "gRPC ServerBuilder receives multiple max_receive_message_length");
+    }
     args.SetInt(GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH, max_receive_message_size_);
   }
-
   // The default message size is -1 (max), so no need to explicitly set it for
   // -1.
   if (max_send_message_size_ >= 0) {
@@ -254,6 +259,11 @@ std::unique_ptr<grpc::Server> ServerBuilder::BuildAndStart() {
                               grpc_resource_quota_arg_vtable());
   }
 
+  for (const auto& plugin : plugins_) {
+    plugin->UpdateServerBuilder(this);
+    plugin->UpdateChannelArguments(&args);
+  }
+
   // == Determine if the server has any syncrhonous methods ==
   bool has_sync_methods = false;
   for (const auto& value : services_) {
@@ -332,10 +342,10 @@ std::unique_ptr<grpc::Server> ServerBuilder::BuildAndStart() {
   }
 
   std::unique_ptr<grpc::Server> server(new grpc::Server(
-      max_receive_message_size_, &args, sync_server_cqs,
-      sync_server_settings_.min_pollers, sync_server_settings_.max_pollers,
-      sync_server_settings_.cq_timeout_msec, std::move(acceptors_),
-      resource_quota_, std::move(interceptor_creators_)));
+      &args, sync_server_cqs, sync_server_settings_.min_pollers,
+      sync_server_settings_.max_pollers, sync_server_settings_.cq_timeout_msec,
+      std::move(acceptors_), resource_quota_,
+      std::move(interceptor_creators_)));
 
   grpc_impl::ServerInitializer* initializer = server->initializer();
 

src/cpp/server/server_cc.cc

@@ -23,6 +23,7 @@
 #include <utility>
 
 #include <grpc/grpc.h>
+#include <grpc/impl/codegen/grpc_types.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpcpp/completion_queue.h>
@@ -964,7 +965,7 @@ class Server::SyncRequestThreadManager : public grpc::ThreadManager {
 
 static grpc::internal::GrpcLibraryInitializer g_gli_initializer;
 Server::Server(
-    int max_receive_message_size, grpc::ChannelArguments* args,
+    grpc::ChannelArguments* args,
     std::shared_ptr<std::vector<std::unique_ptr<grpc::ServerCompletionQueue>>>
         sync_server_cqs,
     int min_pollers, int max_pollers, int sync_cq_timeout_msec,
@@ -976,7 +977,7 @@ Server::Server(
         interceptor_creators)
     : acceptors_(std::move(acceptors)),
       interceptor_creators_(std::move(interceptor_creators)),
-      max_receive_message_size_(max_receive_message_size),
+      max_receive_message_size_(INT_MIN),
       sync_server_cqs_(std::move(sync_server_cqs)),
       started_(false),
       shutdown_(false),
@@ -1026,10 +1027,12 @@ Server::Server(
             static_cast<grpc::HealthCheckServiceInterface*>(
                 channel_args.args[i].value.pointer.p));
       }
-      break;
+    }
+    if (0 ==
+        strcmp(channel_args.args[i].key, GRPC_ARG_MAX_RECEIVE_MESSAGE_LENGTH)) {
+      max_receive_message_size_ = channel_args.args[i].value.integer;
     }
   }
-
   server_ = grpc_server_create(&channel_args, nullptr);
 }