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