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一个基于 gin+ grpc + etcd 等框架开发的小栗子 - M-Anonymous

 1 year ago
source link: https://www.cnblogs.com/M-Anonymous/p/17159371.html
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neoserver,ios ssh client

一、标准的项目结构

首先我们看一个标准的项目结构是什么样子的，github 上给出的一个示例：golang-standards/project-layout

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二、服务注册与发现流程

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 三、示例代码

项目地址：gRPC-GoWeb

1、服务注册

服务注册和发现都可参考 etcd官网 的注册和发现流程，以下是项目的几个步骤的代码，详细的可下载项目查看。

 1、连接etcd注册中心

func New(etcdAddr []string) (*EtcdRegister, error) {
    log.Printf("开始连接etcd注册中心... \n")
    cli, err := clientv3.New(clientv3.Config{
        Endpoints:   etcdAddr,
        DialTimeout: 5 * time.Second,
    })
    if err != nil {
        log.Printf("连接etcd注册中心失败,失败原因是: %v \n", err)
        return nil, err
    }
    log.Printf("连接etcd注册中心成功! \n")
    return &EtcdRegister{
        cli: cli,
    }, nil
}

2、服务注册

func (etcdRegister *EtcdRegister) Register(srvName string, srvAddr string, ttl int64) error {
    etcdRegister.srvName = srvName
    etcdRegister.srvAddr = srvAddr
    log.Printf("开始创建etcd端点管理器... \n")
    em, err := endpoints.NewManager(etcdRegister.cli, srvName)
    if err != nil {
        log.Printf("创建etcd端点管理器失败,失败原因是: %v \n", err)
        return err
    }
    etcdRegister.em = em
    log.Printf("创建etcd端点管理器成功! \n")
    log.Printf("开始创建服务租期... \n")
    lease, err := etcdRegister.cli.Grant(context.TODO(), ttl)
    if err != nil {
        log.Printf("创建服务租期失败,失败原因是: %v", err)
    }
    etcdRegister.ttl = ttl
    etcdRegister.leaseID = lease.ID
    log.Printf("创建服务租期成功! \n")
    log.Printf("开始注册服务,服务名: %s,服务地址: %s \n", srvName, srvAddr)
    em.AddEndpoint(context.TODO(), fmt.Sprintf("%v/%v", srvName, srvAddr), endpoints.Endpoint{Addr: srvAddr}, clientv3.WithLease(lease.ID))
    if err != nil {
        log.Printf("注册服务失败! \n")
        return err
    }
    log.Printf("注册服务成功! \n")
    log.Printf("开始服务定期续租! \n")
    leaseChan, err := etcdRegister.cli.KeepAlive(context.TODO(), etcdRegister.leaseID)
    if err != nil {
        log.Printf("服务定期续租失败! \n")
        return err
    }
    etcdRegister.leaseChan = leaseChan
    log.Printf("服务定期续租成功! \n")
    return nil
}

3、提供服务(需要用到Protobuf)

func init() {
    pb.RegisterUserServiceServer(server.GrpcServer, &UserService{})
}

2、服务发现

1、服务发现

func (etcdDiscovery *etcdDiscovery) Discovery(srvName string) (*grpc.ClientConn, error) {
    target := fmt.Sprintf("etcd:///%s", srvName)
    conn, err := grpc.Dial(target, grpc.WithResolvers(etcdDiscovery.resolver), grpc.WithInsecure())
    if err != nil {
        log.Printf("%s服务发现失败,原因是: %v \n", srvName, err)
        return nil, err
    }
    return conn, nil
}

2、调用服务方法

func UserRegister(ginCtx *gin.Context) {
    etcdDiscovery := serviceDiscovery.EtcdCenter
    //获取用户服务
    conn, _ := etcdDiscovery.Discovery("study-user-service")
    userService := pb.NewUserServiceClient(conn)
    data, err := userService.SayHello(ginCtx, &pb.Request{})
    if err != nil {
        log.Printf("调用用户服务出错了,原因是: %v \n", err)
    }
    ginCtx.JSON(200, gin.H{
        "message": data,
    })
}

备注：api-gateway 和 study-user-service 都使用了空导入的方式，所以主要看空导入的几个 init 函数，main 方法都是空的。

如果对 Go 的代码执行顺序不熟悉的，可以了解一下!

参考文献：

https://etcd.io/docs/v3.5/dev-guide/grpc_naming/

https://gin-gonic.com/zh-cn/docs/quickstart/

https://grpc.io/docs/languages/go/basics/

https://doc.oschina.net/grpc?t=60133

https://devpress.csdn.net/cloud/62f627bac6770329307fc0c9.html


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