Merge pull request #21747 from vjpai/synced_alarm

Make use of alarm in test service more robust

test/cpp/end2end/test_service_impl.cc

@@ -19,6 +19,7 @@
 #include "test/cpp/end2end/test_service_impl.h"
 
 #include <grpc/support/log.h>
+#include <grpcpp/alarm.h>
 #include <grpcpp/security/credentials.h>
 #include <grpcpp/server_context.h>
 #include <gtest/gtest.h>
@@ -120,7 +121,8 @@ void ServerTryCancel(ServerContext* context) {
 void ServerTryCancelNonblocking(experimental::CallbackServerContext* context) {
   EXPECT_FALSE(context->IsCancelled());
   context->TryCancel();
-  gpr_log(GPR_INFO, "Server called TryCancel() to cancel the request");
+  gpr_log(GPR_INFO,
+          "Server called TryCancelNonblocking() to cancel the request");
 }
 
 }  // namespace
@@ -451,9 +453,9 @@ experimental::ServerUnaryReactor* CallbackTestServiceImpl::Echo(
                          gpr_time_from_micros(req_->param().server_sleep_us(),
                                               GPR_TIMESPAN)),
             [this](bool ok) { NonDelayed(ok); });
-      } else {
-        NonDelayed(true);
+        return;
       }
+      NonDelayed(true);
     }
     void OnSendInitialMetadataDone(bool ok) override {
       EXPECT_TRUE(ok);
@@ -462,10 +464,9 @@ experimental::ServerUnaryReactor* CallbackTestServiceImpl::Echo(
     void OnCancel() override {
       EXPECT_TRUE(started_);
       EXPECT_TRUE(ctx_->IsCancelled());
-      // do the actual finish in the main handler only but use this as a chance
-      // to cancel any alarms.
-      alarm_.Cancel();
       on_cancel_invoked_ = true;
+      std::lock_guard<std::mutex> l(cancel_mu_);
+      cancel_cv_.notify_one();
     }
     void OnDone() override {
       if (req_->has_param() && req_->param().echo_metadata_initially()) {
@@ -476,6 +477,9 @@ experimental::ServerUnaryReactor* CallbackTestServiceImpl::Echo(
       if (rpc_wait_thread_.joinable()) {
         rpc_wait_thread_.join();
       }
+      if (finish_when_cancelled_.joinable()) {
+        finish_when_cancelled_.join();
+      }
       delete this;
     }
 
@@ -506,7 +510,7 @@ experimental::ServerUnaryReactor* CallbackTestServiceImpl::Echo(
         EXPECT_FALSE(ctx_->IsCancelled());
         ctx_->TryCancel();
         gpr_log(GPR_INFO, "Server called TryCancel() to cancel the request");
-        LoopUntilCancelled(1000);
+        FinishWhenCancelledAsync();
         return;
       }
       gpr_log(GPR_DEBUG, "Request message was %s", req_->message().c_str());
@@ -520,7 +524,7 @@ experimental::ServerUnaryReactor* CallbackTestServiceImpl::Echo(
           std::unique_lock<std::mutex> lock(service_->mu_);
           service_->signal_client_ = true;
         }
-        LoopUntilCancelled(req_->param().client_cancel_after_us());
+        FinishWhenCancelledAsync();
         return;
       } else if (req_->has_param() && req_->param().server_cancel_after_us()) {
         alarm_.experimental().Set(
@@ -578,20 +582,12 @@ experimental::ServerUnaryReactor* CallbackTestServiceImpl::Echo(
       }
       Finish(Status::OK);
     }
-    void LoopUntilCancelled(int loop_delay_us) {
-      if (!ctx_->IsCancelled()) {
-        alarm_.experimental().Set(
-            gpr_time_add(gpr_now(GPR_CLOCK_REALTIME),
-                         gpr_time_from_micros(loop_delay_us, GPR_TIMESPAN)),
-            [this, loop_delay_us](bool ok) {
-              if (!ok) {
-                EXPECT_TRUE(ctx_->IsCancelled());
-              }
-              LoopUntilCancelled(loop_delay_us);
-            });
-      } else {
+    void FinishWhenCancelledAsync() {
+      finish_when_cancelled_ = std::thread([this] {
+        std::unique_lock<std::mutex> l(cancel_mu_);
+        cancel_cv_.wait(l, [this] { return ctx_->IsCancelled(); });
         Finish(Status::CANCELLED);
-      }
+      });
     }
 
     CallbackTestServiceImpl* const service_;
@@ -599,11 +595,14 @@ experimental::ServerUnaryReactor* CallbackTestServiceImpl::Echo(
     const EchoRequest* const req_;
     EchoResponse* const resp_;
     Alarm alarm_;
-    bool initial_metadata_sent_{false};
-    bool started_{false};
-    bool on_cancel_invoked_{false};
+    std::mutex cancel_mu_;
+    std::condition_variable cancel_cv_;
+    bool initial_metadata_sent_ = false;
+    bool started_ = false;
+    bool on_cancel_invoked_ = false;
     std::thread async_cancel_check_;
     std::thread rpc_wait_thread_;
+    std::thread finish_when_cancelled_;
   };
 
   return new Reactor(this, context, request, response);

test/cpp/end2end/test_service_impl.h

@@ -23,7 +23,6 @@
 #include <mutex>
 
 #include <grpc/grpc.h>
-#include <grpcpp/alarm.h>
 #include <grpcpp/server_context.h>
 
 #include "src/proto/grpc/testing/echo.grpc.pb.h"