mirror of https://github.com/grpc/grpc-go.git
97 lines
2.7 KiB
Go
97 lines
2.7 KiB
Go
/*
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*
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* Copyright 2018 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 client demonstrates how to cancel in-flight RPCs by canceling the
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// context passed to the RPC.
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package main
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import (
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"context"
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"flag"
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"fmt"
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"log"
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"time"
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"google.golang.org/grpc"
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"google.golang.org/grpc/codes"
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"google.golang.org/grpc/credentials/insecure"
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pb "google.golang.org/grpc/examples/features/proto/echo"
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"google.golang.org/grpc/status"
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)
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var addr = flag.String("addr", "localhost:50051", "the address to connect to")
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func sendMessage(stream pb.Echo_BidirectionalStreamingEchoClient, msg string) error {
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fmt.Printf("sending message %q\n", msg)
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return stream.Send(&pb.EchoRequest{Message: msg})
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}
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func recvMessage(stream pb.Echo_BidirectionalStreamingEchoClient, wantErrCode codes.Code) {
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res, err := stream.Recv()
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if status.Code(err) != wantErrCode {
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log.Fatalf("stream.Recv() = %v, %v; want _, status.Code(err)=%v", res, err, wantErrCode)
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}
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if err != nil {
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fmt.Printf("stream.Recv() returned expected error %v\n", err)
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return
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}
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fmt.Printf("received message %q\n", res.GetMessage())
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}
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func main() {
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flag.Parse()
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// Set up a connection to the server.
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conn, err := grpc.NewClient(*addr, grpc.WithTransportCredentials(insecure.NewCredentials()))
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if err != nil {
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log.Fatalf("did not connect: %v", err)
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}
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defer conn.Close()
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c := pb.NewEchoClient(conn)
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// Initiate the stream with a context that supports cancellation.
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ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
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stream, err := c.BidirectionalStreamingEcho(ctx)
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if err != nil {
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log.Fatalf("error creating stream: %v", err)
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}
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// Send some test messages.
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if err := sendMessage(stream, "hello"); err != nil {
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log.Fatalf("error sending on stream: %v", err)
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}
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if err := sendMessage(stream, "world"); err != nil {
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log.Fatalf("error sending on stream: %v", err)
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}
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// Ensure the RPC is working.
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recvMessage(stream, codes.OK)
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recvMessage(stream, codes.OK)
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fmt.Println("cancelling context")
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cancel()
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// This Send may or may not return an error, depending on whether the
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// monitored context detects cancellation before the call is made.
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sendMessage(stream, "closed")
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// This Recv should never succeed.
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recvMessage(stream, codes.Canceled)
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}
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