提示用户配置服务提供

service providers

第一步：编写提供端的服务

1. 编写需要被编码的结构体，由于使用 Hessian2 作为编码协议，User 需要实现 JavaClassName 方法，它的返回值在dubbo中对应User类的类名。

   type User struct {
   	Id   string
   	Name string
   	Age  int32
   	Time time.Time
   }
   
   func (u User) JavaClassName() string {
   	return "org.apache.dubbo.User"
   }

2. 编写业务逻辑，UserProvider 相当于dubbo中的一个服务实现。需要实现 Reference 方法，返回值是这个服务的唯一标识，对应dubbo的 beans 和 path 字段。
   

   type UserProvider struct {
   }
   
   func (u *UserProvider) GetUser(ctx context.Context, req []interface{}) (*User, error) {
   	println("req:%#v", req)
   	rsp := User{"A001", "hellowworld", 18, time.Now()}
   	println("rsp:%#v", rsp)
   	return &rsp, nil
   }
   
   func (u *UserProvider) Reference() string {
   	return "UserProvider"
   }

3. 注册服务和对象

   func init() {
   	config.SetProviderService(new(UserProvider))
   	// ------for hessian2------
   	hessian.RegisterPOJO(&User{})
   }

第二步：编写主程序

1. 引入必需的dubbo-go包

   import (
   	hessian "github.com/apache/dubbo-go-hessian2"
   	_ "github.com/apache/dubbo-go/cluster/cluster_impl"
   	_ "github.com/apache/dubbo-go/cluster/loadbalance"
   	"github.com/apache/dubbo-go/common/logger"
   	_ "github.com/apache/dubbo-go/common/proxy/proxy_factory"
   	"github.com/apache/dubbo-go/config"
   	_ "github.com/apache/dubbo-go/filter/filter_impl"
   	_ "github.com/apache/dubbo-go/protocol/dubbo"
   	_ "github.com/apache/dubbo-go/registry/protocol"
   	_ "github.com/apache/dubbo-go/registry/zookeeper"
   )

2. main 函数

   func main() {
     config.Load()
   }

第三步：编写配置文件并配置环境变量

1. 设置配置文件 log.yml, server.yml
   log.yml
   

   level: "error"
   development: true
   disableCaller: false
   disableStacktrace: false
   sampling:
   encoding: "console"
   
   # encoder
   encoderConfig:
     messageKey: "message"
     levelKey: "level"
     timeKey: "time"
     nameKey: "logger"
     callerKey: "caller"
     stacktraceKey: "stacktrace"
     lineEnding: ""
     levelEncoder: "capital"
     timeEncoder: "iso8601"
     durationEncoder: "seconds"
     callerEncoder: "short"
     nameEncoder: ""
   
   outputPaths:
     - "stderr"
   errorOutputPaths:
     - "stderr"
   initialFields:

   server.yml

   # dubbo server yaml configure file
   
   # application config
   application:
     organization: "dubbo.io"
     name: "UserInfoServer"
     module: "dubbo-go user-info server"
     version: "0.0.1"
     environment: "dev"
   
   # registry config
   registries:
     "demoZk":
       protocol: "zookeeper"
       timeout: "3s"
       address: "127.0.0.1:2181"
   
   # service config
   services:
     "UserProvider":
       registry: "demoZk"
       protocol: "dubbo"
       interface: "org.apache.dubbo.UserProvider"
       loadbalance: "random"
       warmup: "100"
       cluster: "failover"
       methods:
         - name: "GetUser"
           retries: 1
           loadbalance: "random"
   
   # protocol config
   protocols:
     "dubbo":
       name: "dubbo"
       port: 20000
   
   protocol_conf:
     dubbo:
       session_number: 700
       session_timeout: "180s"
       getty_session_param:
         compress_encoding: false
         tcp_no_delay: true
         tcp_keep_alive: true
         keep_alive_period: "120s"
         tcp_r_buf_size: 262144
         tcp_w_buf_size: 65536
         pkg_rq_size: 1024
         pkg_wq_size: 512
         tcp_read_timeout: "1s"
         tcp_write_timeout: "5s"
         wait_timeout: "1s"
         max_msg_len: 1024000
         session_name: "server"

   主要编辑以下部分：
   registries 结点下需要配置zk的数量和地址
   services 结点下配置服务的具体信息，需要配置 interface 配置，修改为对应服务的接口名，服务的key对应第一步中 
   Provider 的 Reference 返回值
2. 把上面的两个配置文件分别配置为环境变量
   

   export CONF_PROVIDER_FILE_PATH="xxx"
   export APP_LOG_CONF_FILE="xxx"

本文章源码详情见git：https://github.com/apache/dubbo-go-samples/tree/1.5/helloworld/go-server