Added a channel argument to set the maximum reconnect backoff duration....

Added a channel argument to set the maximum reconnect backoff duration. Extended the interop test to test the custom reconnect backoffs.

This closes #5377.

include/grpc/impl/codegen/grpc_types.h

@@ -142,6 +142,8 @@ typedef struct {
 /** Secondary user agent: goes at the end of the user-agent metadata
     sent on each request */
 #define GRPC_ARG_SECONDARY_USER_AGENT_STRING "grpc.secondary_user_agent"
+/** The maximum time between subsequent connection attempts, in ms */
+#define GRPC_ARG_MAX_RECONNECT_BACKOFF_MS "grpc.max_reconnect_backoff_ms"
 /* The caller of the secure_channel_create functions may override the target
    name used for SSL host name checking using this channel argument which is of
    type GRPC_ARG_STRING. This *should* be used for testing only.

src/core/client_config/subchannel.c

@@ -603,6 +603,20 @@ static void update_reconnect_parameters(grpc_subchannel *c) {
             gpr_time_from_millis(c->args->args[i].value.integer, GPR_TIMESPAN));
         return;
       }
+      if (0 ==
+          strcmp(c->args->args[i].key, GRPC_ARG_MAX_RECONNECT_BACKOFF_MS)) {
+        if (c->args->args[i].type == GRPC_ARG_INTEGER) {
+          if (c->args->args[i].value.integer >= 0) {
+            max_backoff_millis = c->args->args[i].value.integer;
+          } else {
+            gpr_log(GPR_ERROR, GRPC_ARG_MAX_RECONNECT_BACKOFF_MS
+                    " : must be non-negative");
+          }
+        } else {
+          gpr_log(GPR_ERROR,
+                  GRPC_ARG_MAX_RECONNECT_BACKOFF_MS " : must be an integer");
+        }
+      }
     }
   }
 

src/proto/grpc/testing/messages.proto

 
-// Copyright 2015, Google Inc.
+// Copyright 2015-2016, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -158,6 +158,12 @@ message StreamingOutputCallResponse {
   Payload payload = 1;
 }
 
+// For reconnect interop test only.
+// Client tells server what reconnection parameters it used.
+message ReconnectParams {
+  int32 max_reconnect_backoff_ms = 1;
+}
+
 // For reconnect interop test only.
 // Server tells client whether its reconnects are following the spec and the
 // reconnect backoffs it saw.

src/proto/grpc/testing/test.proto

 
-// Copyright 2015, Google Inc.
+// Copyright 2015-2016, Google Inc.
 // All rights reserved.
 //
 // Redistribution and use in source and binary forms, with or without
@@ -80,6 +80,6 @@ service UnimplementedService {
 
 // A service used to control reconnect server.
 service ReconnectService {
-  rpc Start(grpc.testing.Empty) returns (grpc.testing.Empty);
+  rpc Start(grpc.testing.ReconnectParams) returns (grpc.testing.Empty);
   rpc Stop(grpc.testing.Empty) returns (grpc.testing.ReconnectInfo);
 }

test/core/util/reconnect_server.c

@@ -60,8 +60,12 @@ static void pretty_print_backoffs(reconnect_server *server) {
             i, backoff / 1000.0, expected_backoff / 1000.0,
             (backoff - expected_backoff) * 100.0 / expected_backoff);
     expected_backoff *= 1.6;
-    if (expected_backoff > 120 * 1000) {
-      expected_backoff = 120 * 1000;
+    int max_reconnect_backoff_ms = 120 * 1000;
+    if (server->max_reconnect_backoff_ms > 0) {
+      max_reconnect_backoff_ms = server->max_reconnect_backoff_ms;
+    }
+    if (expected_backoff > max_reconnect_backoff_ms) {
+      expected_backoff = max_reconnect_backoff_ms;
     }
   }
 }
@@ -108,6 +112,7 @@ void reconnect_server_init(reconnect_server *server) {
   server->head = NULL;
   server->tail = NULL;
   server->peer = NULL;
+  server->max_reconnect_backoff_ms = 0;
 }
 
 void reconnect_server_start(reconnect_server *server, int port) {

test/core/util/reconnect_server.h

 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -52,6 +52,7 @@ typedef struct reconnect_server {
   timestamp_list *head;
   timestamp_list *tail;
   char *peer;
+  int max_reconnect_backoff_ms;
 } reconnect_server;
 
 void reconnect_server_init(reconnect_server *server);

test/cpp/interop/reconnect_interop_client.cc

@@ -39,6 +39,7 @@
 #include <gflags/gflags.h>
 #include <grpc++/channel.h>
 #include <grpc++/client_context.h>
+#include <grpc++/support/channel_arguments.h>
 #include "test/cpp/util/create_test_channel.h"
 #include "test/cpp/util/test_config.h"
 #include "src/proto/grpc/testing/test.grpc.pb.h"
@@ -48,13 +49,18 @@
 DEFINE_int32(server_control_port, 0, "Server port for control rpcs.");
 DEFINE_int32(server_retry_port, 0, "Server port for testing reconnection.");
 DEFINE_string(server_host, "127.0.0.1", "Server host to connect to");
+DEFINE_int32(max_reconnect_backoff_ms, 0,
+             "Maximum backoff time, or 0 for default.");
 
+using grpc::CallCredentials;
 using grpc::Channel;
+using grpc::ChannelArguments;
 using grpc::ClientContext;
 using grpc::CreateTestChannel;
 using grpc::Status;
 using grpc::testing::Empty;
 using grpc::testing::ReconnectInfo;
+using grpc::testing::ReconnectParams;
 using grpc::testing::ReconnectService;
 
 int main(int argc, char** argv) {
@@ -68,17 +74,25 @@ int main(int argc, char** argv) {
       ReconnectService::NewStub(
           CreateTestChannel(server_address.str(), false)));
   ClientContext start_context;
-  Empty empty_request;
+  ReconnectParams reconnect_params;
+  reconnect_params.set_max_reconnect_backoff_ms(FLAGS_max_reconnect_backoff_ms);
   Empty empty_response;
   Status start_status =
-      control_stub->Start(&start_context, empty_request, &empty_response);
+      control_stub->Start(&start_context, reconnect_params, &empty_response);
   GPR_ASSERT(start_status.ok());
 
   gpr_log(GPR_INFO, "Starting connections with retries.");
   server_address.str("");
   server_address << FLAGS_server_host << ':' << FLAGS_server_retry_port;
+  ChannelArguments channel_args;
+  if (FLAGS_max_reconnect_backoff_ms > 0) {
+    channel_args.SetInt(GRPC_ARG_MAX_RECONNECT_BACKOFF_MS,
+                        FLAGS_max_reconnect_backoff_ms);
+  }
   std::shared_ptr<Channel> retry_channel =
-      CreateTestChannel(server_address.str(), true);
+      CreateTestChannel(server_address.str(), "foo.test.google.fr", true, false,
+                        std::shared_ptr<CallCredentials>(), channel_args);
+
   // About 13 retries.
   const int kDeadlineSeconds = 540;
   // Use any rpc to test retry.
@@ -88,15 +102,15 @@ int main(int argc, char** argv) {
   retry_context.set_deadline(std::chrono::system_clock::now() +
                              std::chrono::seconds(kDeadlineSeconds));
   Status retry_status =
-      retry_stub->Start(&retry_context, empty_request, &empty_response);
+      retry_stub->Start(&retry_context, reconnect_params, &empty_response);
   GPR_ASSERT(retry_status.error_code() == grpc::StatusCode::DEADLINE_EXCEEDED);
   gpr_log(GPR_INFO, "Done retrying, getting final data from server");
 
   ClientContext stop_context;
   ReconnectInfo response;
-  Status stop_status =
-      control_stub->Stop(&stop_context, empty_request, &response);
+  Status stop_status = control_stub->Stop(&stop_context, Empty(), &response);
   GPR_ASSERT(stop_status.ok());
   GPR_ASSERT(response.passed() == true);
+  gpr_log(GPR_INFO, "Passed");
   return 0;
 }

test/cpp/interop/reconnect_interop_server.cc

@@ -69,6 +69,7 @@ using grpc::Status;
 using grpc::testing::Empty;
 using grpc::testing::ReconnectService;
 using grpc::testing::ReconnectInfo;
+using grpc::testing::ReconnectParams;
 
 static bool got_sigint = false;
 
@@ -90,7 +91,8 @@ class ReconnectServiceImpl : public ReconnectService::Service {
 
   void Poll(int seconds) { reconnect_server_poll(&tcp_server_, seconds); }
 
-  Status Start(ServerContext* context, const Empty* request, Empty* response) {
+  Status Start(ServerContext* context, const ReconnectParams* request,
+               Empty* response) {
     bool start_server = true;
     std::unique_lock<std::mutex> lock(mu_);
     while (serving_ && !shutdown_) {
@@ -103,6 +105,8 @@ class ReconnectServiceImpl : public ReconnectService::Service {
     if (server_started_) {
       start_server = false;
     } else {
+      tcp_server_.max_reconnect_backoff_ms =
+          request->max_reconnect_backoff_ms();
       server_started_ = true;
     }
     lock.unlock();
@@ -131,7 +135,9 @@ class ReconnectServiceImpl : public ReconnectService::Service {
     const double kTransmissionDelay = 100.0;
     const double kBackoffMultiplier = 1.6;
     const double kJitterFactor = 0.2;
-    const int kMaxBackoffMs = 120 * 1000;
+    const int kMaxBackoffMs = tcp_server_.max_reconnect_backoff_ms
+                                  ? tcp_server_.max_reconnect_backoff_ms
+                                  : 120 * 1000;
     bool passed = true;
     for (timestamp_list* cur = tcp_server_.head; cur && cur->next;
          cur = cur->next) {

test/cpp/util/create_test_channel.cc

 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -58,8 +58,9 @@ namespace grpc {
 std::shared_ptr<Channel> CreateTestChannel(
     const grpc::string& server, const grpc::string& override_hostname,
     bool enable_ssl, bool use_prod_roots,
-    const std::shared_ptr<CallCredentials>& creds) {
-  ChannelArguments channel_args;
+    const std::shared_ptr<CallCredentials>& creds,
+    const ChannelArguments& args) {
+  ChannelArguments channel_args(args);
   if (enable_ssl) {
     const char* roots_certs = use_prod_roots ? "" : test_root_cert;
     SslCredentialsOptions ssl_opts = {roots_certs, "", ""};
@@ -81,6 +82,14 @@ std::shared_ptr<Channel> CreateTestChannel(
   }
 }
 
+std::shared_ptr<Channel> CreateTestChannel(
+    const grpc::string& server, const grpc::string& override_hostname,
+    bool enable_ssl, bool use_prod_roots,
+    const std::shared_ptr<CallCredentials>& creds) {
+  return CreateTestChannel(server, override_hostname, enable_ssl,
+                           use_prod_roots, creds, ChannelArguments());
+}
+
 std::shared_ptr<Channel> CreateTestChannel(
     const grpc::string& server, const grpc::string& override_hostname,
     bool enable_ssl, bool use_prod_roots) {

test/cpp/util/create_test_channel.h

 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -53,6 +53,12 @@ std::shared_ptr<Channel> CreateTestChannel(
     bool enable_ssl, bool use_prod_roots,
     const std::shared_ptr<CallCredentials>& creds);
 
+std::shared_ptr<Channel> CreateTestChannel(
+    const grpc::string& server, const grpc::string& override_hostname,
+    bool enable_ssl, bool use_prod_roots,
+    const std::shared_ptr<CallCredentials>& creds,
+    const ChannelArguments& args);
+
 }  // namespace grpc
 
 #endif  // GRPC_TEST_CPP_UTIL_CREATE_TEST_CHANNEL_H