This is a clone from official gRPC Go's Quickstart with minor changes. Majority of variables are also renamed so that they make more sense for beginners.
- go 1.14 or later (shouldn't matter much but just in case)
- libprotoc 3.11.4 (for protoc)
protoc -I proto proto/hello.proto --go_out=plugins=grpc:protoA new go file should be generated as proto/hello.pb.go that has the service definition in Go.
The folowing code in server/main.go implements the server interface to serve the request.
package main
import (
"context"
"log"
"net"
pb "../proto"
grpc "google.golang.org/grpc"
)
const (
port = ":50051"
)
type greeterServer struct {
}
func (s *greeterServer) Greet(ctx context.Context, in *pb.HelloRequest) (*pb.HelloReply, error) {
log.Printf("Received request: %v", in.GetName())
return &pb.HelloReply{Message: "Hello " in.GetName()}, nil
}
func main() {
tcpListener, err := net.Listen("tcp", port)
if err != nil {
log.Fatalf("failed to listen: %v", err)
}
grpcServer := grpc.NewServer()
pb.RegisterGreeterServer(grpcServer, &greeterServer{})
if err := grpcServer.Serve(tcpListener); err != nil {
log.Fatalf("failed to serve: %v", err)
}
}Please note that this server type greeterServer struct {} doesn't have an pb.UnimplementedGreeterServer as in the reference document. This is because I don't understand why it's required when greetServer implements type hello.GreetServer anyway.
Compile the server code
go build -o server/main server/main.goThe folowing code in client/main.go implements the server interface to serve the request.
package main
import (
"context"
"log"
"os"
"time"
pb "../proto"
grpc "google.golang.org/grpc"
)
const (
address = "localhost:50051"
defaultName = "nam"
)
func main() {
grpcConn, err := grpc.Dial(address, grpc.WithInsecure(), grpc.WithBlock())
if err != nil {
log.Fatalf("did not connect: %v", err)
}
defer grpcConn.Close()
greeterClient := pb.NewGreeterClient(grpcConn)
name := defaultName
if len(os.Args) > 1 {
name = os.Args[1]
}
ctx, cancel := context.WithTimeout(context.Background(), time.Second)
defer cancel()
response, err := greeterClient.Greet(ctx, &pb.HelloRequest{Name: name})
if err != nil {
log.Fatalf("could not great: %v", err)
}
log.Printf("Received response: %s", response.GetMessage())
}The client takes one command line argument as a name to pass to the request to server or use a default if one is missing. Compile the code.
go build -o client/main client/main.goRun the server (here from zsh)
./server/mainOn another terminal run the client passing in an argument
./client/main worldOn the server side there should be
2020/03/25 22:18:20 Received request: worldAnd on client side
2020/03/25 22:18:20 Received response: Hello worldTo exit the server press Ctrl C.