2023-03-17Go操作consul

一 Go操作consul

1.1 注册服务

搭建好conusl集群后，用户或者程序就能到consul中去查询或者注册服务。可以通过提供服务定义文件或者调用 HTTP API 来注册一个服务。

启动consul开发模式：

consul agent -dev
# 访问可视化界面
http://127.0.0.1:8500/ui/dc1/nodes

1.2 服务端

package main
import (
    "fmt"
    consular "github.com/hashicorp/consul/api"
    "io"
    "log"
    "net"
    "net/http"
)
func registerServer() {
    config := consular.DefaultConfig()
    client, err := consular.NewClient(config)
    if err != nil {
        log.Fatal("consul client error: ", err)
        return
    }
    checkPort := 8080
    registration := new(consular.AgentServiceRegistration)
    registration.ID = "node01"
    registration.Name = "serverNode"
    registration.Port = 9527
    registration.Tags = []string{"serverNode"}
    registration.Address = "127.0.0.1"
    registration.Check = &consular.AgentServiceCheck{
        HTTP: fmt.Sprintf("http://%s:%d%s", registration.Address, checkPort, "/check"),
        Timeout: "3s",
        Interval: "5s",
        DeregisterCriticalServiceAfter: "30s", //check失败后30秒删除本服务
    }
    err = client.Agent().ServiceRegister(registration)
    if err != nil {
        log.Fatal("register server error : ", err)
        return
    }
    http.HandleFunc("/check", func (w http.ResponseWriter, r *http.Request) {
        fmt.Println( "consulCheck: ", w)
    })
    http.ListenAndServe(fmt.Sprintf(":%d", checkPort), nil)
}
func main() {
    // 注册服务
    go registerServer()
    // 生成一个服务：服务1
    ln, err := net.Listen("tcp", "0.0.0.0:9527")
    if err != nil {
        panic("error：" + err.Error())
    }
    for {
        conn, err := ln.Accept()
        if err != nil {
            panic("error：" + err.Error())
        }
        go EchoServer(conn)
    }
}
func EchoServer(conn net.Conn) {
    buf := make([]byte, 1024)
    defer conn.Close()
    for {
        n, err := conn.Read(buf)
        switch err {
        case nil:
            log.Println("get and echo:", "EchoServer "+string(buf[0:n]))
            conn.Write(append([]byte("EchoServer "), buf[0:n]...))
        case io.EOF:
            log.Printf("Warning: End of data: %s\n", err)
            return
        default:
            log.Printf("Error: Reading data: %s\n", err)
            return
        }
    }
}

1.3 客户端

package main
import (
    "fmt"
    "log"
    "net"
    "time"
    consular "github.com/hashicorp/consul/api"
)
func main() {
    client, err := consular.NewClient(consular.DefaultConfig())
    if err != nil {
        log.Fatal("consul client error : ", err)
    }
    for {
        time.Sleep(time.Second * 3)
        var services map[string]*consular.AgentService
        var err error
        services, err = client.Agent().Services()
        if nil != err {
            log.Println("in consual list Services:", err)
            continue
        }
        if _, found := services["node01"]; !found {
            log.Println("node01 not found")
            continue
        }
        sendData(services["node01"])
    }
}
func sendData(service *consular.AgentService) {
    conn, err := net.Dial("tcp", fmt.Sprintf("%s:%d", service.Address, service.Port))
    if err != nil {
        log.Println(err)
        return
    }
    defer conn.Close()
    buf := make([]byte, 1024)
    i := 0
    for {
        i++
        msg := fmt.Sprintf("Hello World, %03d", i)
        n, err := conn.Write([]byte(msg))
        if err != nil {
            println("Write Buffer Error:", err.Error())
            break
        }
        n, err = conn.Read(buf)
        if err != nil {
            println("Read Buffer Error:", err.Error())
            break
        }
        log.Println("get:", string(buf[0:n]))
        //等一秒钟
        time.Sleep(time.Second)
    }
}