golang redigo 发布订阅使用

之前用go-redis 实现的订阅，接收到的消息类型只能是字符串，不支持二进制。今天找到这个redigo实现方式，在此记录下来。
redigo 对redis 的发布订阅机制放在pubsub.go 中
订阅主题后 通过Receive() 函数接受发布订阅主题的消息文章来源地址:https://www.yii666.com/blog/52944.html

// Receive returns a pushed message as a Subscription, Message, Pong or error.
// The return value is intended to be used directly in a type switch as
// illustrated in the PubSubConn example.
func (c PubSubConn) Receive() interface{} {
    return c.receiveInternal(c.Conn.Receive())
}

返回的是一个空类型的interface{} , 由于空接口没有方法， 因此所有的类型都实现了空接口， 也就是说可以返回任意类型。

具体返回的类型 在receiveInternal（） 方法里面可以看到文章来源地址https://www.yii666.com/blog/52944.html文章地址https://www.yii666.com/blog/52944.html

func (c PubSubConn) receiveInternal(replyArg interface{}, errArg error) interface{} {
    reply, err := Values(replyArg, errArg)
    if err != nil {
        return err
    }

    var kind string
    reply, err = Scan(reply, &kind)
    if err != nil {
        return err
    }

    switch kind {
    case "message":
        var m Message
        if _, err := Scan(reply, &m.Channel, &m.Data); err != nil {
            return err
        }
        return m
    case "pmessage":
        var m Message
        if _, err := Scan(reply, &m.Pattern, &m.Channel, &m.Data); err != nil {
            return err
        }
        return m
    case "subscribe", "psubscribe", "unsubscribe", "punsubscribe":
        s := Subscription{Kind: kind}
        if _, err := Scan(reply, &s.Channel, &s.Count); err != nil {
            return err
        }
        return s
    case "pong":
        var p Pong
        if _, err := Scan(reply, &p.Data); err != nil {
            return err
        }
        return p
    }
    return errors.New("redigo: unknown pubsub notification")
}

目前返回 Message Subscription Pone

订阅的主题
收到消息之后通过注册的回调函数处理的方式， 所以代码中多了长map存放回调函数网址:yii666.com

package main

import (
    //"github.com/go-redis/redis"
    "fmt"
    "github.com/labstack/gommon/log"
    "github.com/gomodule/redigo/redis"
    "time"

    //"reflect"
    "unsafe"
)

type SubscribeCallback func (channel, message string)

type Subscriber struct {
    client redis.PubSubConn
    cbMap map[string]SubscribeCallback
}

func (c *Subscriber) Connect(ip string, port uint16) {
    conn, err := redis.Dial("tcp", "127.0.0.1:6379", redis.DialDatabase(0), redis.DialPassword("123456"))
    if err != nil {
        log.Error("redis dial failed.")
    }

    c.client = redis.PubSubConn{conn}
    c.cbMap = make(map[string]SubscribeCallback)

    go func() {
        for {
            log.Info("wait...")
            switch res := c.client.Receive().(type) {
            case redis.Message:
                channel := (*string)(unsafe.Pointer(&res.Channel))
                message := (*string)(unsafe.Pointer(&res.Data))
                c.cbMap[*channel](*channel, *message)
            case redis.Subscription:
                fmt.Printf("%s: %s %d\n", res.Channel, res.Kind, res.Count)
            case error:
                log.Error("error handle...")
                continue
            }
        }
    }()

}

func (c *Subscriber) Close() {
    err := c.client.Close()
    if err != nil{
        log.Error("redis close error.")
    }
}

func (c *Subscriber) Subscribe(channel interface{}, cb SubscribeCallback) {
    err := c.client.Subscribe(channel)
    if err != nil{
        log.Error("redis Subscribe error.")
    }

    c.cbMap[channel.(string)] = cb
}

func TestCallback1(chann, msg string){
    log.Info("TestCallback1 channel : ", chann, " message : ", msg)
}

func TestCallback2(chann, msg string){
    log.Info("TestCallback2 channel : ", chann, " message : ", msg)
}

func TestCallback3(chann, msg string){
    log.Info("TestCallback3 channel : ", chann, " message : ", msg)
}

func main() {

    log.Info("===========main start============")

    var sub Subscriber
    sub.Connect("127.0.0.1", 6397)
    sub.Subscribe("test_chan1", TestCallback1)
    sub.Subscribe("test_chan2", TestCallback2)
    sub.Subscribe("test_chan3", TestCallback3)

    for{ // 这段代码的作用就是 阻止线程结束
        time.Sleep(1 * time.Second)
    }
}

运行main 文件 然后 看到

image.png

在redis 客户端 执行 发布信息

image.png

在控制台 看到监控结果 回调函数 执行的结果

image.png

发布

上面是订阅的代码和 代码要处理 的回调函数
发布直接使用默认的 Conn来Send Publish 就可以
redigo 的管道使用方法设计到三个函数 Do 函数也是下面这个函数的合并

• c.Send()
• c.Flush()
• c.Receive()

解释：
send() 方法吧命令写到缓冲区， flush() 把缓冲区的命令刷新到redis 服务器 receive() 函数接受redis 给予的 回应， 三个操作共同完成一套命令流程。

代码

package main

import(
  //"github.com/go-redis/redis"
  "github.com/gomodule/redigo/redis"
  log "github.com/astaxie/beego/logs"
)

func main() {

  client, err := redis.Dial("tcp", "127.0.0.1:6379")
  if err != nil {
      log.Critical("redis dial failed.")
  }
  defer client.Close()

  _, err = client.Do("Publish", "test_chan1", "hello")
  if err != nil {
    log.Critical("redis Publish failed.")
  }

  _, err = client.Do("Publish", "test_chan2", "hello")
  if err != nil {
    log.Critical("redis Publish failed.")
  }

  _, err = client.Do("Publish", "test_chan3", "hello")
  if err != nil {
    log.Critical("redis Publish failed.")
  }

}