redigo 对 发布订阅的使用

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

// 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

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

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")
	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

在redis 客户端 执行 发布信息

在控制台 看到监控结果 回调函数 执行的结果

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.")
  }

}