grpc-go/examples/features/metadata_interceptor/client/main.go

115 lines
2.7 KiB
Go

/*
*
* Copyright 2022 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 demonstrates how to receive metadata in RPC headers
// and trailers.
package main
import (
"context"
"flag"
"fmt"
"io"
"log"
"time"
"google.golang.org/grpc"
"google.golang.org/grpc/credentials/insecure"
"google.golang.org/grpc/metadata"
pb "google.golang.org/grpc/examples/features/proto/echo"
)
var addr = flag.String("addr", "localhost:50051", "the address to connect to")
func callUnaryEcho(ctx context.Context, client pb.EchoClient) {
var header, trailer metadata.MD
resp, err := client.UnaryEcho(ctx, &pb.EchoRequest{Message: "hello world"}, grpc.Header(&header), grpc.Trailer(&trailer))
if err != nil {
log.Fatalf("UnaryEcho: %v", err)
}
fmt.Println("UnaryEcho: ", resp.Message)
fmt.Println("Received headers:")
for k, v := range header {
fmt.Printf("%s: %v\n", k, v)
}
fmt.Println("Received trailers:")
for k, v := range trailer {
fmt.Printf("%s: %v\n", k, v)
}
}
func callBidiStreamingEcho(ctx context.Context, client pb.EchoClient) {
c, err := client.BidirectionalStreamingEcho(ctx)
if err != nil {
log.Fatalf("BidiStreamingEcho: %v", err)
}
if err := c.Send(&pb.EchoRequest{Message: "hello world"}); err != nil {
log.Fatalf("Sending echo request: %v", err)
}
c.CloseSend()
for {
resp, err := c.Recv()
if err == io.EOF {
break
}
if err != nil {
log.Fatalf("Receiving echo response: %v", err)
}
fmt.Println("BidiStreaming Echo: ", resp.Message)
}
header, err := c.Header()
if err != nil {
log.Fatalf("Receiving headers: %v", err)
}
fmt.Println("Received headers:")
for k, v := range header {
fmt.Printf("%s: %v\n", k, v)
}
trailer := c.Trailer()
fmt.Println("Received tailers:")
for k, v := range trailer {
fmt.Printf("%s: %v\n", k, v)
}
}
func main() {
flag.Parse()
conn, err := grpc.NewClient(*addr, grpc.WithTransportCredentials(insecure.NewCredentials()))
if err != nil {
log.Fatalf("grpc.NewClient(%q): %v", *addr, err)
}
defer conn.Close()
ec := pb.NewEchoClient(conn)
ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
defer cancel()
callUnaryEcho(ctx, ec)
callBidiStreamingEcho(ctx, ec)
}