- https://grpc.io/docs/languages/go/quickstart/
- https://github.com/grpc/grpc-go/tree/master/examples/helloworld
protocのインストール
$ mkdir protoc
$ cd protoc
$ curl -o protoc.zip -L https://github.com/protocolbuffers/protobuf/releases/download/v3.17.3/protoc-3.17.3-osx-x86_64.zip
$ unzip protoc.zip
$ cp bin/protoc ~/bin/
$ cd ..
プラグインのインストール
$ go install google.golang.org/protobuf/cmd/protoc-gen-go@v1.26
$ go install google.golang.org/grpc/cmd/protoc-gen-go-grpc@v1.1
$ go install github.com/pseudomuto/protoc-gen-doc/cmd/protoc-gen-doc@latest
grpc-hello の作成
$ mkdir grpc-hello
$ cd grpc-hello
$ go mod init example.com/grpc-hello
protoファイルの作成
$ mkdir protos
protos/hello.proto
$ cat > protos/hello.proto << 'EOS'
syntax = "proto3";
option go_package = "example.com/grpc-hello/pb";
package helloworld;
service Greeter {
rpc SayHello (HelloRequest) returns (HelloReply) {}
}
message HelloRequest {
string name = 1;
}
message HelloReply {
string message = 1;
}
EOS
ProtocolBufferとgRPCコードの生成
$ mkdir pb
protocの実行
$ protoc \
--proto_path=./protos \
--go_out=./pb \
--go_opt=paths=source_relative \
--go-grpc_out=./pb \
--go-grpc_opt=paths=source_relative \
hello.proto
サーバの作成
$ mkdir server
server/server.go
$ cat > server/server.go << 'EOS'
package main
import (
"context"
"log"
"net"
"google.golang.org/grpc"
pb "example.com/grpc-hello/pb"
)
const (
port = ":50051"
)
type server struct {
pb.UnimplementedGreeterServer
}
func (s *server) SayHello(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
log.Printf("Received: %v", in.GetName())
return &pb.HelloReply{Message: "Hello " + in.GetName()}, nil
}
func main() {
lis, err := net.Listen("tcp", port)
if err != nil {
log.Fatalf("failed to listen: %v", err)
}
s := grpc.NewServer()
pb.RegisterGreeterServer(s, &server{})
log.Printf("server listening at %v", lis.Addr())
if err := s.Serve(lis); err != nil {
log.Fatalf("failed to serve: %v", err)
}
}
EOS
クライアントの作成
$ mkdir client
client/client.go
$ cat > client/client.go << 'EOS'
package main
import (
"context"
"log"
"os"
"time"
"google.golang.org/grpc"
pb "example.com/grpc-hello/pb"
)
const (
address = "localhost:50051"
defaultName = "world"
)
func main() {
conn, err := grpc.Dial(address, grpc.WithInsecure(), grpc.WithBlock())
if err != nil {
log.Fatalf("did not connect: %v", err)
}
defer conn.Close()
c := pb.NewGreeterClient(conn)
name := defaultName
if len(os.Args) > 1 {
name = os.Args[1]
}
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
r, err := c.SayHello(ctx, &pb.HelloRequest{Name: name})
if err != nil {
log.Fatalf("could not greet: %v", err)
}
log.Printf("Greeting: %s", r.GetMessage())
}
EOS
ライブラリの取得
$ go mod vendor
サーバの起動
$ go run ./server/
別ターミナルでクライアントの実行
$ go run ./client/