examples/features/metadata/client/main.go - third_party/grpc/grpc-go - Git at Google

 /*
  *
  * 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"
 	"io"
 	"log"
 	"time"

 	"google.golang.org/grpc"
 	pb "google.golang.org/grpc/examples/features/proto/echo"
 	"google.golang.org/grpc/metadata"
 )

 var addr = flag.String("addr", "localhost:50051", "the address to connect to")

 const (
 	timestampFormat = time.StampNano // "Jan _2 15:04:05.000"
 	streamingCount  = 10
 )

 func unaryCallWithMetadata(c pb.EchoClient, message string) {
 	fmt.Printf("--- unary ---\n")
 	// Create metadata and context.
 	md := metadata.Pairs("timestamp", time.Now().Format(timestampFormat))
 	ctx := metadata.NewOutgoingContext(context.Background(), md)

 	// Make RPC using the context with the metadata.
 	var header, trailer metadata.MD
 	r, err := c.UnaryEcho(ctx, &pb.EchoRequest{Message: message}, grpc.Header(&header), grpc.Trailer(&trailer))
 	if err != nil {
 		log.Fatalf("failed to call UnaryEcho: %v", err)
 	}

 	if t, ok := header["timestamp"]; ok {
 		fmt.Printf("timestamp from header:\n")
 		for i, e := range t {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("timestamp expected but doesn't exist in header")
 	}
 	if l, ok := header["location"]; ok {
 		fmt.Printf("location from header:\n")
 		for i, e := range l {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("location expected but doesn't exist in header")
 	}
 	fmt.Printf("response:\n")
 	fmt.Printf(" - %s\n", r.Message)

 	if t, ok := trailer["timestamp"]; ok {
 		fmt.Printf("timestamp from trailer:\n")
 		for i, e := range t {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("timestamp expected but doesn't exist in trailer")
 	}
 }

 func serverStreamingWithMetadata(c pb.EchoClient, message string) {
 	fmt.Printf("--- server streaming ---\n")
 	// Create metadata and context.
 	md := metadata.Pairs("timestamp", time.Now().Format(timestampFormat))
 	ctx := metadata.NewOutgoingContext(context.Background(), md)

 	// Make RPC using the context with the metadata.
 	stream, err := c.ServerStreamingEcho(ctx, &pb.EchoRequest{Message: message})
 	if err != nil {
 		log.Fatalf("failed to call ServerStreamingEcho: %v", err)
 	}

 	// Read the header when the header arrives.
 	header, err := stream.Header()
 	if err != nil {
 		log.Fatalf("failed to get header from stream: %v", err)
 	}
 	// Read metadata from server's header.
 	if t, ok := header["timestamp"]; ok {
 		fmt.Printf("timestamp from header:\n")
 		for i, e := range t {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("timestamp expected but doesn't exist in header")
 	}
 	if l, ok := header["location"]; ok {
 		fmt.Printf("location from header:\n")
 		for i, e := range l {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("location expected but doesn't exist in header")
 	}

 	// Read all the responses.
 	var rpcStatus error
 	fmt.Printf("response:\n")
 	for {
 		r, err := stream.Recv()
 		if err != nil {
 			rpcStatus = err
 			break
 		}
 		fmt.Printf(" - %s\n", r.Message)
 	}
 	if rpcStatus != io.EOF {
 		log.Fatalf("failed to finish server streaming: %v", rpcStatus)
 	}

 	// Read the trailer after the RPC is finished.
 	trailer := stream.Trailer()
 	// Read metadata from server's trailer.
 	if t, ok := trailer["timestamp"]; ok {
 		fmt.Printf("timestamp from trailer:\n")
 		for i, e := range t {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("timestamp expected but doesn't exist in trailer")
 	}
 }

 func clientStreamWithMetadata(c pb.EchoClient, message string) {
 	fmt.Printf("--- client streaming ---\n")
 	// Create metadata and context.
 	md := metadata.Pairs("timestamp", time.Now().Format(timestampFormat))
 	ctx := metadata.NewOutgoingContext(context.Background(), md)

 	// Make RPC using the context with the metadata.
 	stream, err := c.ClientStreamingEcho(ctx)
 	if err != nil {
 		log.Fatalf("failed to call ClientStreamingEcho: %v\n", err)
 	}

 	// Read the header when the header arrives.
 	header, err := stream.Header()
 	if err != nil {
 		log.Fatalf("failed to get header from stream: %v", err)
 	}
 	// Read metadata from server's header.
 	if t, ok := header["timestamp"]; ok {
 		fmt.Printf("timestamp from header:\n")
 		for i, e := range t {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("timestamp expected but doesn't exist in header")
 	}
 	if l, ok := header["location"]; ok {
 		fmt.Printf("location from header:\n")
 		for i, e := range l {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("location expected but doesn't exist in header")
 	}

 	// Send all requests to the server.
 	for i := 0; i < streamingCount; i++ {
 		if err := stream.Send(&pb.EchoRequest{Message: message}); err != nil {
 			log.Fatalf("failed to send streaming: %v\n", err)
 		}
 	}

 	// Read the response.
 	r, err := stream.CloseAndRecv()
 	if err != nil {
 		log.Fatalf("failed to CloseAndRecv: %v\n", err)
 	}
 	fmt.Printf("response:\n")
 	fmt.Printf(" - %s\n\n", r.Message)

 	// Read the trailer after the RPC is finished.
 	trailer := stream.Trailer()
 	// Read metadata from server's trailer.
 	if t, ok := trailer["timestamp"]; ok {
 		fmt.Printf("timestamp from trailer:\n")
 		for i, e := range t {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("timestamp expected but doesn't exist in trailer")
 	}
 }

 func bidirectionalWithMetadata(c pb.EchoClient, message string) {
 	fmt.Printf("--- bidirectional ---\n")
 	// Create metadata and context.
 	md := metadata.Pairs("timestamp", time.Now().Format(timestampFormat))
 	ctx := metadata.NewOutgoingContext(context.Background(), md)

 	// Make RPC using the context with the metadata.
 	stream, err := c.BidirectionalStreamingEcho(ctx)
 	if err != nil {
 		log.Fatalf("failed to call BidirectionalStreamingEcho: %v\n", err)
 	}

 	go func() {
 		// Read the header when the header arrives.
 		header, err := stream.Header()
 		if err != nil {
 			log.Fatalf("failed to get header from stream: %v", err)
 		}
 		// Read metadata from server's header.
 		if t, ok := header["timestamp"]; ok {
 			fmt.Printf("timestamp from header:\n")
 			for i, e := range t {
 				fmt.Printf(" %d. %s\n", i, e)
 			}
 		} else {
 			log.Fatal("timestamp expected but doesn't exist in header")
 		}
 		if l, ok := header["location"]; ok {
 			fmt.Printf("location from header:\n")
 			for i, e := range l {
 				fmt.Printf(" %d. %s\n", i, e)
 			}
 		} else {
 			log.Fatal("location expected but doesn't exist in header")
 		}

 		// Send all requests to the server.
 		for i := 0; i < streamingCount; i++ {
 			if err := stream.Send(&pb.EchoRequest{Message: message}); err != nil {
 				log.Fatalf("failed to send streaming: %v\n", err)
 			}
 		}
 		stream.CloseSend()
 	}()

 	// Read all the responses.
 	var rpcStatus error
 	fmt.Printf("response:\n")
 	for {
 		r, err := stream.Recv()
 		if err != nil {
 			rpcStatus = err
 			break
 		}
 		fmt.Printf(" - %s\n", r.Message)
 	}
 	if rpcStatus != io.EOF {
 		log.Fatalf("failed to finish server streaming: %v", rpcStatus)
 	}

 	// Read the trailer after the RPC is finished.
 	trailer := stream.Trailer()
 	// Read metadata from server's trailer.
 	if t, ok := trailer["timestamp"]; ok {
 		fmt.Printf("timestamp from trailer:\n")
 		for i, e := range t {
 			fmt.Printf(" %d. %s\n", i, e)
 		}
 	} else {
 		log.Fatal("timestamp expected but doesn't exist in trailer")
 	}

 }

 const message = "this is examples/metadata"

 func main() {
 	flag.Parse()
 	// Set up a connection to the server.
 	conn, err := grpc.Dial(*addr, grpc.WithInsecure())
 	if err != nil {
 		log.Fatalf("did not connect: %v", err)
 	}
 	defer conn.Close()

 	c := pb.NewEchoClient(conn)

 	unaryCallWithMetadata(c, message)
 	time.Sleep(1 * time.Second)

 	serverStreamingWithMetadata(c, message)
 	time.Sleep(1 * time.Second)

 	clientStreamWithMetadata(c, message)
 	time.Sleep(1 * time.Second)

 	bidirectionalWithMetadata(c, message)
 }
	/*
	*
	* 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"
	"io"
	"log"
	"time"

	"google.golang.org/grpc"
	pb "google.golang.org/grpc/examples/features/proto/echo"
	"google.golang.org/grpc/metadata"
	)

	var addr = flag.String("addr", "localhost:50051", "the address to connect to")

	const (
	timestampFormat = time.StampNano // "Jan _2 15:04:05.000"
	streamingCount = 10
	)

	func unaryCallWithMetadata(c pb.EchoClient, message string) {
	fmt.Printf("--- unary ---\n")
	// Create metadata and context.
	md := metadata.Pairs("timestamp", time.Now().Format(timestampFormat))
	ctx := metadata.NewOutgoingContext(context.Background(), md)

	// Make RPC using the context with the metadata.
	var header, trailer metadata.MD
	r, err := c.UnaryEcho(ctx, &pb.EchoRequest{Message: message}, grpc.Header(&header), grpc.Trailer(&trailer))
	if err != nil {
	log.Fatalf("failed to call UnaryEcho: %v", err)
	}

	if t, ok := header["timestamp"]; ok {
	fmt.Printf("timestamp from header:\n")
	for i, e := range t {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("timestamp expected but doesn't exist in header")
	}
	if l, ok := header["location"]; ok {
	fmt.Printf("location from header:\n")
	for i, e := range l {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("location expected but doesn't exist in header")
	}
	fmt.Printf("response:\n")
	fmt.Printf(" - %s\n", r.Message)

	if t, ok := trailer["timestamp"]; ok {
	fmt.Printf("timestamp from trailer:\n")
	for i, e := range t {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("timestamp expected but doesn't exist in trailer")
	}
	}

	func serverStreamingWithMetadata(c pb.EchoClient, message string) {
	fmt.Printf("--- server streaming ---\n")
	// Create metadata and context.
	md := metadata.Pairs("timestamp", time.Now().Format(timestampFormat))
	ctx := metadata.NewOutgoingContext(context.Background(), md)

	// Make RPC using the context with the metadata.
	stream, err := c.ServerStreamingEcho(ctx, &pb.EchoRequest{Message: message})
	if err != nil {
	log.Fatalf("failed to call ServerStreamingEcho: %v", err)
	}

	// Read the header when the header arrives.
	header, err := stream.Header()
	if err != nil {
	log.Fatalf("failed to get header from stream: %v", err)
	}
	// Read metadata from server's header.
	if t, ok := header["timestamp"]; ok {
	fmt.Printf("timestamp from header:\n")
	for i, e := range t {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("timestamp expected but doesn't exist in header")
	}
	if l, ok := header["location"]; ok {
	fmt.Printf("location from header:\n")
	for i, e := range l {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("location expected but doesn't exist in header")
	}

	// Read all the responses.
	var rpcStatus error
	fmt.Printf("response:\n")
	for {
	r, err := stream.Recv()
	if err != nil {
	rpcStatus = err
	break
	}
	fmt.Printf(" - %s\n", r.Message)
	}
	if rpcStatus != io.EOF {
	log.Fatalf("failed to finish server streaming: %v", rpcStatus)
	}

	// Read the trailer after the RPC is finished.
	trailer := stream.Trailer()
	// Read metadata from server's trailer.
	if t, ok := trailer["timestamp"]; ok {
	fmt.Printf("timestamp from trailer:\n")
	for i, e := range t {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("timestamp expected but doesn't exist in trailer")
	}
	}

	func clientStreamWithMetadata(c pb.EchoClient, message string) {
	fmt.Printf("--- client streaming ---\n")
	// Create metadata and context.
	md := metadata.Pairs("timestamp", time.Now().Format(timestampFormat))
	ctx := metadata.NewOutgoingContext(context.Background(), md)

	// Make RPC using the context with the metadata.
	stream, err := c.ClientStreamingEcho(ctx)
	if err != nil {
	log.Fatalf("failed to call ClientStreamingEcho: %v\n", err)
	}

	// Read the header when the header arrives.
	header, err := stream.Header()
	if err != nil {
	log.Fatalf("failed to get header from stream: %v", err)
	}
	// Read metadata from server's header.
	if t, ok := header["timestamp"]; ok {
	fmt.Printf("timestamp from header:\n")
	for i, e := range t {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("timestamp expected but doesn't exist in header")
	}
	if l, ok := header["location"]; ok {
	fmt.Printf("location from header:\n")
	for i, e := range l {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("location expected but doesn't exist in header")
	}

	// Send all requests to the server.
	for i := 0; i < streamingCount; i++ {
	if err := stream.Send(&pb.EchoRequest{Message: message}); err != nil {
	log.Fatalf("failed to send streaming: %v\n", err)
	}
	}

	// Read the response.
	r, err := stream.CloseAndRecv()
	if err != nil {
	log.Fatalf("failed to CloseAndRecv: %v\n", err)
	}
	fmt.Printf("response:\n")
	fmt.Printf(" - %s\n\n", r.Message)

	// Read the trailer after the RPC is finished.
	trailer := stream.Trailer()
	// Read metadata from server's trailer.
	if t, ok := trailer["timestamp"]; ok {
	fmt.Printf("timestamp from trailer:\n")
	for i, e := range t {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("timestamp expected but doesn't exist in trailer")
	}
	}

	func bidirectionalWithMetadata(c pb.EchoClient, message string) {
	fmt.Printf("--- bidirectional ---\n")
	// Create metadata and context.
	md := metadata.Pairs("timestamp", time.Now().Format(timestampFormat))
	ctx := metadata.NewOutgoingContext(context.Background(), md)

	// Make RPC using the context with the metadata.
	stream, err := c.BidirectionalStreamingEcho(ctx)
	if err != nil {
	log.Fatalf("failed to call BidirectionalStreamingEcho: %v\n", err)
	}

	go func() {
	// Read the header when the header arrives.
	header, err := stream.Header()
	if err != nil {
	log.Fatalf("failed to get header from stream: %v", err)
	}
	// Read metadata from server's header.
	if t, ok := header["timestamp"]; ok {
	fmt.Printf("timestamp from header:\n")
	for i, e := range t {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("timestamp expected but doesn't exist in header")
	}
	if l, ok := header["location"]; ok {
	fmt.Printf("location from header:\n")
	for i, e := range l {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("location expected but doesn't exist in header")
	}

	// Send all requests to the server.
	for i := 0; i < streamingCount; i++ {
	if err := stream.Send(&pb.EchoRequest{Message: message}); err != nil {
	log.Fatalf("failed to send streaming: %v\n", err)
	}
	}
	stream.CloseSend()
	}()

	// Read all the responses.
	var rpcStatus error
	fmt.Printf("response:\n")
	for {
	r, err := stream.Recv()
	if err != nil {
	rpcStatus = err
	break
	}
	fmt.Printf(" - %s\n", r.Message)
	}
	if rpcStatus != io.EOF {
	log.Fatalf("failed to finish server streaming: %v", rpcStatus)
	}

	// Read the trailer after the RPC is finished.
	trailer := stream.Trailer()
	// Read metadata from server's trailer.
	if t, ok := trailer["timestamp"]; ok {
	fmt.Printf("timestamp from trailer:\n")
	for i, e := range t {
	fmt.Printf(" %d. %s\n", i, e)
	}
	} else {
	log.Fatal("timestamp expected but doesn't exist in trailer")
	}

	}

	const message = "this is examples/metadata"

	func main() {
	flag.Parse()
	// Set up a connection to the server.
	conn, err := grpc.Dial(*addr, grpc.WithInsecure())
	if err != nil {
	log.Fatalf("did not connect: %v", err)
	}
	defer conn.Close()

	c := pb.NewEchoClient(conn)

	unaryCallWithMetadata(c, message)
	time.Sleep(1 * time.Second)

	serverStreamingWithMetadata(c, message)
	time.Sleep(1 * time.Second)

	clientStreamWithMetadata(c, message)
	time.Sleep(1 * time.Second)

	bidirectionalWithMetadata(c, message)
	}