snapshot of https://github.com/grpc/grpc-go.git (master, 2026-09-15; blobs > 131072B omitted)

server_ext_test.go

@@ -0,0 +1,332 @@
+/*
+ *
+ * Copyright 2023 gRPC authors.
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ *
+ */
+
+package grpc_test
+
+import (
+	"context"
+	"io"
+	"runtime"
+	"sync"
+	"testing"
+	"time"
+
+	"google.golang.org/grpc"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/internal/grpcsync"
+	"google.golang.org/grpc/internal/stubserver"
+	"google.golang.org/grpc/status"
+
+	testgrpc "google.golang.org/grpc/interop/grpc_testing"
+	testpb "google.golang.org/grpc/interop/grpc_testing"
+)
+
+// TestServer_MaxHandlers ensures that no more than MaxConcurrentStreams server
+// handlers are active at one time.
+func (s) TestServer_MaxHandlers(t *testing.T) {
+	started := make(chan struct{})
+	blockCalls := grpcsync.NewEvent()
+
+	// This stub server does not properly respect the stream context, so it will
+	// not exit when the context is canceled.
+	ss := stubserver.StubServer{
+		FullDuplexCallF: func(testgrpc.TestService_FullDuplexCallServer) error {
+			started <- struct{}{}
+			<-blockCalls.Done()
+			return nil
+		},
+	}
+	if err := ss.Start([]grpc.ServerOption{grpc.MaxConcurrentStreams(1)}); err != nil {
+		t.Fatal("Error starting server:", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	// Start one RPC to the server.
+	ctx1, cancel1 := context.WithCancel(ctx)
+	_, err := ss.Client.FullDuplexCall(ctx1)
+	if err != nil {
+		t.Fatal("Error staring call:", err)
+	}
+
+	// Wait for the handler to be invoked.
+	select {
+	case <-started:
+	case <-ctx.Done():
+		t.Fatalf("Timed out waiting for RPC to start on server.")
+	}
+
+	// Cancel it on the client.  The server handler will still be running.
+	cancel1()
+
+	ctx2, cancel2 := context.WithCancel(ctx)
+	defer cancel2()
+	s, err := ss.Client.FullDuplexCall(ctx2)
+	if err != nil {
+		t.Fatal("Error staring call:", err)
+	}
+
+	// After 100ms, allow the first call to unblock.  That should allow the
+	// second RPC to run and finish.
+	select {
+	case <-started:
+		blockCalls.Fire()
+		t.Fatalf("RPC started unexpectedly.")
+	case <-time.After(100 * time.Millisecond):
+		blockCalls.Fire()
+	}
+
+	select {
+	case <-started:
+	case <-ctx.Done():
+		t.Fatalf("Timed out waiting for second RPC to start on server.")
+	}
+	if _, err := s.Recv(); err != io.EOF {
+		t.Fatal("Received unexpected RPC error:", err)
+	}
+}
+
+// Tests the case where the stream worker goroutine option is enabled, and a
+// number of RPCs are initiated around the same time that Stop() is called. This
+// used to result in a write to a closed channel. This test verifies that there
+// is no panic.
+func (s) TestStreamWorkers_RPCsAndStop(t *testing.T) {
+	ss := stubserver.StartTestService(t, nil, grpc.NumStreamWorkers(uint32(runtime.NumCPU())))
+	// This deferred stop takes care of stopping the server when one of the
+	// below grpc.NewClient fail, and the test exits early.
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	const numChannels = 20
+	const numRPCLoops = 20
+
+	// Create a bunch of clientconns and ensure that they are READY by making an
+	// RPC on them.
+	ccs := make([]*grpc.ClientConn, numChannels)
+	for i := 0; i < numChannels; i++ {
+		var err error
+		ccs[i], err = grpc.NewClient(ss.Address, grpc.WithTransportCredentials(insecure.NewCredentials()))
+		if err != nil {
+			t.Fatalf("[iteration: %d] grpc.NewClient(%s) failed: %v", i, ss.Address, err)
+		}
+		defer ccs[i].Close()
+		client := testgrpc.NewTestServiceClient(ccs[i])
+		if _, err := client.EmptyCall(ctx, &testpb.Empty{}); err != nil {
+			t.Fatalf("EmptyCall() failed: %v", err)
+		}
+	}
+
+	// Make a bunch of concurrent RPCs on the above clientconns. These will
+	// eventually race with Stop(), and will start to fail.
+	var wg sync.WaitGroup
+	for i := 0; i < numChannels; i++ {
+		client := testgrpc.NewTestServiceClient(ccs[i])
+		for j := 0; j < numRPCLoops; j++ {
+			wg.Add(1)
+			go func(client testgrpc.TestServiceClient) {
+				defer wg.Done()
+				for {
+					_, err := client.EmptyCall(ctx, &testpb.Empty{})
+					if err == nil {
+						continue
+					}
+					if code := status.Code(err); code == codes.Unavailable {
+						// Once Stop() has been called on the server, we expect
+						// subsequent calls to fail with Unavailable.
+						return
+					}
+					t.Errorf("EmptyCall() failed: %v", err)
+					return
+				}
+			}(client)
+		}
+	}
+
+	// Call Stop() concurrently with the above RPC attempts.
+	ss.Stop()
+	wg.Wait()
+}
+
+// Tests the case where the stream worker goroutine option is enabled, and both
+// Stop() and GracefulStop() care called. This used to result in a close of a
+// closed channel. This test verifies that there is no panic.
+func (s) TestStreamWorkers_GracefulStopAndStop(t *testing.T) {
+	ss := stubserver.StartTestService(t, nil, grpc.NumStreamWorkers(uint32(runtime.NumCPU())))
+	defer ss.Stop()
+
+	if err := ss.StartClient(grpc.WithTransportCredentials(insecure.NewCredentials())); err != nil {
+		t.Fatalf("Failed to create client to stub server: %v", err)
+	}
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+	client := testgrpc.NewTestServiceClient(ss.CC)
+	if _, err := client.EmptyCall(ctx, &testpb.Empty{}); err != nil {
+		t.Fatalf("EmptyCall() failed: %v", err)
+	}
+
+	ss.S.GracefulStop()
+}
+
+// Tests the WaitForHandlers ServerOption by leaving an RPC running while Stop
+// is called, and ensures Stop doesn't return until the handler returns.
+func (s) TestServer_WaitForHandlers(t *testing.T) {
+	started := grpcsync.NewEvent()
+	blockCalls := grpcsync.NewEvent()
+
+	// This stub server does not properly respect the stream context, so it will
+	// not exit when the context is canceled.
+	ss := stubserver.StubServer{
+		FullDuplexCallF: func(testgrpc.TestService_FullDuplexCallServer) error {
+			started.Fire()
+			<-blockCalls.Done()
+			return nil
+		},
+	}
+	if err := ss.Start([]grpc.ServerOption{grpc.WaitForHandlers(true)}); err != nil {
+		t.Fatal("Error starting server:", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	// Start one RPC to the server.
+	ctx1, cancel1 := context.WithCancel(ctx)
+	_, err := ss.Client.FullDuplexCall(ctx1)
+	if err != nil {
+		t.Fatal("Error staring call:", err)
+	}
+
+	// Wait for the handler to be invoked.
+	select {
+	case <-started.Done():
+	case <-ctx.Done():
+		t.Fatalf("Timed out waiting for RPC to start on server.")
+	}
+
+	// Cancel it on the client.  The server handler will still be running.
+	cancel1()
+
+	// Close the connection.  This might be sufficient to allow the server to
+	// return if it doesn't properly wait for outstanding method handlers to
+	// return.
+	ss.CC.Close()
+
+	// Try to Stop() the server, which should block indefinitely (until
+	// blockCalls is fired).
+	stopped := grpcsync.NewEvent()
+	go func() {
+		ss.S.Stop()
+		stopped.Fire()
+	}()
+
+	// Wait 100ms and ensure stopped does not fire.
+	select {
+	case <-stopped.Done():
+		trace := make([]byte, 4096)
+		trace = trace[0:runtime.Stack(trace, true)]
+		blockCalls.Fire()
+		t.Fatalf("Server returned from Stop() illegally.  Stack trace:\n%v", string(trace))
+	case <-time.After(100 * time.Millisecond):
+		// Success; unblock the call and wait for stopped.
+		blockCalls.Fire()
+	}
+
+	select {
+	case <-stopped.Done():
+	case <-ctx.Done():
+		t.Fatalf("Timed out waiting for second RPC to start on server.")
+	}
+}
+
+// Tests that GracefulStop will wait for all method handlers to return by
+// blocking a handler and ensuring GracefulStop doesn't return until after it is
+// unblocked.
+func (s) TestServer_GracefulStopWaits(t *testing.T) {
+	started := grpcsync.NewEvent()
+	blockCalls := grpcsync.NewEvent()
+
+	// This stub server does not properly respect the stream context, so it will
+	// not exit when the context is canceled.
+	ss := stubserver.StubServer{
+		FullDuplexCallF: func(testgrpc.TestService_FullDuplexCallServer) error {
+			started.Fire()
+			<-blockCalls.Done()
+			return nil
+		},
+	}
+	if err := ss.Start(nil); err != nil {
+		t.Fatal("Error starting server:", err)
+	}
+	defer ss.Stop()
+
+	ctx, cancel := context.WithTimeout(context.Background(), defaultTestTimeout)
+	defer cancel()
+
+	// Start one RPC to the server.
+	ctx1, cancel1 := context.WithCancel(ctx)
+	_, err := ss.Client.FullDuplexCall(ctx1)
+	if err != nil {
+		t.Fatal("Error staring call:", err)
+	}
+
+	// Wait for the handler to be invoked.
+	select {
+	case <-started.Done():
+	case <-ctx.Done():
+		t.Fatalf("Timed out waiting for RPC to start on server.")
+	}
+
+	// Cancel it on the client.  The server handler will still be running.
+	cancel1()
+
+	// Close the connection.  This might be sufficient to allow the server to
+	// return if it doesn't properly wait for outstanding method handlers to
+	// return.
+	ss.CC.Close()
+
+	// Try to Stop() the server, which should block indefinitely (until
+	// blockCalls is fired).
+	stopped := grpcsync.NewEvent()
+	go func() {
+		ss.S.GracefulStop()
+		stopped.Fire()
+	}()
+
+	// Wait 100ms and ensure stopped does not fire.
+	select {
+	case <-stopped.Done():
+		trace := make([]byte, 4096)
+		trace = trace[0:runtime.Stack(trace, true)]
+		blockCalls.Fire()
+		t.Fatalf("Server returned from Stop() illegally.  Stack trace:\n%v", string(trace))
+	case <-time.After(100 * time.Millisecond):
+		// Success; unblock the call and wait for stopped.
+		blockCalls.Fire()
+	}
+
+	select {
+	case <-stopped.Done():
+	case <-ctx.Done():
+		t.Fatalf("Timed out waiting for second RPC to start on server.")
+	}
+}