gRPC是Google开源的一个高性能、跨语言的RPC框架,基于HTTP2协议,基于protobuf 3.x,基于Netty 4.x +。

gRPC与thrift、avro-rpc、WCF等其实在总体原理上并没有太大的区别,简而言之GRPC并没有太多突破性的创新。

protobuf相对于用Json方式传输,效率有很大提高,Kubernetes也从最初的Json转换成了gRPC

gRPC GoLang Test

gRPC 在服务端提供一个 gRPC Server,客户端的库是 gRPC Stub。

典型的场景是客户端发送请求,同步或异步调用服务端的接口。

gRPC在服务端和客户端可以使用多种语言,包括Go, Python, Java or Ruby等。

 

下面以GoLang为例,展示一个gRPC Client调用gRPC Server的整个过程: 

1. 准备gRPC环境

1) 安装Go语言环境,gRPC要求Go 1.5或以上。

2) 安装gRPC

$ go get google.golang.org/grpc

3) 安装Protocol Buffers v3

下载protoc-3.0.0-linux-x86_64.zip:https://github.com/google/protobuf/releases

解压并拷贝bin/protoc$GOPATH (/usr/local/go/bin)

4) 安装protoc plugin for Go

$ go get -u github.com/golang/protobuf/protoc-gen-go

拷贝bin/protoc-gen-go$GOPATH (/usr/local/go/bin) 

2. 编写helloworld.proto协议文件,简单完成一个加法运算

syntax = "proto3";

package helloworld;

// The greeting service definition.
service Greeter {
  // Sends a greeting
  rpc SayAdd (AddRequest) returns (AddReply) {}
}

// The request message containing the a+b.
message AddRequest {
  uint32 a = 1;
  uint32 b =2;
}

// The response message containing the c.
message AddReply {
  uint32 c = 1;
}

3. 使用protoc-gen-go生成gRPC服务端和客户端代理文件helloworld.pb.go

$ protoc -I helloworld/ helloworld/helloworld.proto --go_out=plugins=grpc:helloworld

4. 编写gRPC服务端文件greeter_server/main.go

package main

import (
    "log"
    "net"

    "golang.org/x/net/context"
    "google.golang.org/grpc"
    pb "google.golang.org/grpc/examples/helloworld/helloworld"
    "google.golang.org/grpc/reflection"
)

const (
    port = ":50051"
)

// server is used to implement helloworld.GreeterServer.
type server struct{}

// SayAdd implements helloworld.GreeterServer
func (s *server) SayAdd(ctx context.Context, in *pb.AddRequest) (*pb.AddReply, error) {
    return &pb.AddReply{C: in.A + in.B}, 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{})
    // Register reflection service on gRPC server.
    reflection.Register(s)
    if err := s.Serve(lis); err != nil {
        log.Fatalf("failed to serve: %v", err)
    }
}

 5. 编写gRPC客户端文件greeter_client/main.go

package main

import (
    "log"
    "os"

    "golang.org/x/net/context"
    "google.golang.org/grpc"
    pb "google.golang.org/grpc/examples/helloworld/helloworld"
)

const (
    address     = "localhost:50051"
)

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

    // Contact the server and print out its response.
    rs, errs := c.SayAdd(context.Background(), &pb.AddRequest{A: 1, B:2})
    if errs != nil {
        log.Fatalf("could not greet: %v", errs)
    }
    log.Printf("Add: %d", rs.C)
}

6. 运行gRPC服务端

$ go run greeter_server/main.go

7. 运行gRPC客户端

$ go run greeter_client/main.go

输出结果: Add: 3

 Demo下载地址:https://files.cnblogs.com/files/edisonxiang/helloworld.zip

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