mirror of https://github.com/grpc/grpc-go.git
112 lines
2.7 KiB
Go
112 lines
2.7 KiB
Go
/*
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*
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* Copyright 2023 gRPC authors.
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*
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*/
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// Binary server demonstrates how gRPC flow control block sending when the
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// receiver is not ready.
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package main
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import (
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"flag"
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"fmt"
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"io"
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"log"
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"net"
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"time"
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"google.golang.org/grpc"
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pb "google.golang.org/grpc/examples/features/proto/echo"
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"google.golang.org/grpc/internal/grpcsync"
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)
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var port = flag.Int("port", 50052, "port number")
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var payload = string(make([]byte, 8*1024)) // 8KB
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// server is used to implement EchoServer.
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type server struct {
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pb.UnimplementedEchoServer
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}
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func (s *server) BidirectionalStreamingEcho(stream pb.Echo_BidirectionalStreamingEchoServer) error {
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log.Printf("New stream began.")
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// First, we wait 2 seconds before reading from the stream, to give the
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// client an opportunity to block while sending its requests.
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time.Sleep(2 * time.Second)
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// Next, read all the data sent by the client to allow it to unblock.
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for i := 0; true; i++ {
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if _, err := stream.Recv(); err != nil {
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log.Printf("Read %v messages.", i)
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if err == io.EOF {
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break
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}
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log.Printf("Error receiving data: %v", err)
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return err
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}
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}
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// Finally, send data until we block, then end the stream after we unblock.
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stopSending := grpcsync.NewEvent()
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sentOne := make(chan struct{})
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go func() {
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for !stopSending.HasFired() {
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after := time.NewTimer(time.Second)
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select {
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case <-sentOne:
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after.Stop()
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case <-after.C:
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log.Printf("Sending is blocked.")
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stopSending.Fire()
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<-sentOne
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}
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}
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}()
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i := 0
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for !stopSending.HasFired() {
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i++
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if err := stream.Send(&pb.EchoResponse{Message: payload}); err != nil {
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log.Printf("Error sending data: %v", err)
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return err
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}
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sentOne <- struct{}{}
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}
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log.Printf("Sent %v messages.", i)
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log.Printf("Stream ended successfully.")
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return nil
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}
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func main() {
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flag.Parse()
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address := fmt.Sprintf(":%v", *port)
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lis, err := net.Listen("tcp", address)
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if err != nil {
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log.Fatalf("failed to listen: %v", err)
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}
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grpcServer := grpc.NewServer()
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pb.RegisterEchoServer(grpcServer, &server{})
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if err := grpcServer.Serve(lis); err != nil {
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log.Fatalf("failed to serve: %v", err)
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}
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}
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