gRPC is a high-performance, open-source framework for building remote procedure call (RPC) APIs. It uses Protocol Buffers (Protobuf) as its default data serialization format and supports bidirectional streaming, making it an ideal choice for building real-time applications.
In this tutorial, we will explore how to use gRPC and Protobuf to stream data in Golang. We will build a simple chat application that allows clients to join a chat room and send messages to each other in real-time using bidirectional streaming.
Prerequisite
You need to install the gRPC and Protobuf packages for Golang. You can do this by running the following command:
go get -u google.golang.org/grpc
go get -u github.com/golang/protobuf/protoc-gen-go
Step 1: Define Protobuf Message
Next, you need to define your gRPC service and messages in a .proto file. Here’s an example:
syntax = "proto3";
option go_package = "./;pb";
service ChatService {
rpc JoinChat (stream JoinRequest) returns (stream ChatMessage);
}
message JoinRequest {
string username = 1;
}
message ChatMessage {
string username = 1;
string message = 2;
}
This defines a ChatService
with a JoinChat
method that takes a stream of JoinRequest
messages and returns a stream of ChatMessage
messages.
Step 2: Generate Go code
Once you have defined your message types, you need to generate Go code from the .proto
file.
Here’s an example command:
protoc --go_out=. \
--go_opt=paths=source_relative \
--go-grpc_out=. \
--go-grpc_opt=paths=source_relative \
path/to/your.proto
This will generate two files: message.pb.go
and message_grpc.pb.go
.
Step 3: Create a gRPC Serve
Now you can implement your gRPC server
package main
import (
"fmt"
"log"
"net"
"google.golang.org/grpc"
pb "github.com/grpc-streaming/pb"
)
type server struct {
pb.UnimplementedChatServiceServer
}
func (s *server) JoinChat(stream pb.ChatService_JoinChatServer) error…