golang rabbitmq實踐 (二 實現簡單的訊息收發)

這是一個建立於 的文章，其中的資訊可能已經有所發展或是發生改變。

1:驅動

　　本來打算自己寫一個驅動的，後來發現github上面已經有了，那我就直接拿現成的了， 驅動採用 github.com/streadway/amqp ，直接import就可以啦！

 2:exchange and queue

　　在上一篇文章中，我們已經建立好virtualhost 、exchange and queue，所以我們先定義這些常量

　　

const (    queueName = "push.msg.q"    exchange  = "t.msg.ex"    mqurl ="amqp://shi:123@192.168.232.130:5672/test")

var conn *amqp.Connection
var channel *amqp.Channel

3：錯誤處理

　　

func failOnErr(err error, msg string) {if err != nil {log.Fatalf("%s:%s", msg, err)panic(fmt.Sprintf("%s:%s", msg, err))}}

4：串連mq

func mqConnect() {    var err error    conn, err = amqp.Dial(mqurl)    failOnErr(err, "failed to connect tp rabbitmq")    channel, err = conn.Channel()    failOnErr(err, "failed to open a channel")}

 

5：push

　　先上代碼：

func push() {    if channel == nil {        mqConnect()    }    msgContent := "hello world!"    channel.Publish(exchange, queueName, false, false, amqp.Publishing{        ContentType: "text/plain",        Body:        []byte(msgContent),    })}

　　其實是很簡單的，調用 channel函數的Publish方法，傳入exchange name 和 queue name，最後一個參數是訊息內容，ContentType我們設定為text/plain， 為文本類型，body是訊息內容，要傳入位元組數組，這樣就完成了一條訊息的push，接下來我們再看receive

6：receive

 代碼：

func receive() {    if channel == nil {        mqConnect()    }    msgs, err := channel.Consume(queueName, "", true, false, false, false, nil)    failOnErr(err, "")    forever := make(chan bool)    go func() {        //fmt.Println(*msgs)        for d := range msgs {            s := BytesToString(&(d.Body))            count++            fmt.Printf("receve msg is :%s -- %d\n", *s, count)        }    }()    fmt.Printf(" [*] Waiting for messages. To exit press CTRL+C\n")    <-forever}

　　通過調用channel.Consume函數返回一個接受訊息的chan類型管道，然後range 這個chan，接收到的資料是[]byte,轉換為string後輸出

　　<-forever  這個是為了控制當前線程不退出

7：入口main

　　

func main() {    go func() {        for {            push()            time.Sleep(1 * time.Second)        }    }()    receive()    fmt.Println("end")    close()}

　　for 迴圈保證每秒發送一條訊息到mq，這個地方採用協程保證不阻塞主線程。receive函數不能採用協程，不然主線程就退出了。close函數是釋放連線物件，但是在這個例子中是沒有起效的，因為線程永遠都不會自動結束，只能認為的CTRL+C 或者程式死掉，系統重啟

 

8：執行：

切換到go檔案目錄執行

go run main.go
//作業記錄receve msg is :hello world! -- 1246
receve msg is :hello world! -- 1247
receve msg is :hello world! -- 1248
receve msg is :hello world! -- 1249
receve msg is :hello world! -- 1250
receve msg is :hello world! -- 1251
receve msg is :hello world! -- 1252
receve msg is :hello world! -- 1253
receve msg is :hello world! -- 1254
receve msg is :hello world! -- 1255
receve msg is :hello world! -- 1256
receve msg is :hello world! -- 1257
receve msg is :hello world! -- 1258
receve msg is :hello world! -- 1259
receve msg is :hello world! -- 1260
receve msg is :hello world! -- 1261
receve msg is :hello world! -- 1262
receve msg is :hello world! -- 1263
receve msg is :hello world! -- 1264
receve msg is :hello world! -- 1265
receve msg is :hello world! -- 1266

9：全部代碼

package mainimport (    "fmt"    "log"    "bytes"    "time"    "github.com/streadway/amqp")var conn *amqp.Connectionvar channel *amqp.Channelvar count = 0const (    queueName = "push.msg.q"    exchange  = "t.msg.ex"    mqurl ="amqp://shi:123@192.168.232.130:5672/test")func main() {    go func() {        for {            push()            time.Sleep(1 * time.Second)        }    }()    receive()    fmt.Println("end")    close()}func failOnErr(err error, msg string) {    if err != nil {        log.Fatalf("%s:%s", msg, err)        panic(fmt.Sprintf("%s:%s", msg, err))    }}func mqConnect() {    var err error    conn, err = amqp.Dial(mqurl)    failOnErr(err, "failed to connect tp rabbitmq")    channel, err = conn.Channel()    failOnErr(err, "failed to open a channel")}func close() {    channel.Close()    conn.Close()}//串連rabbitmq serverfunc push() {    if channel == nil {        mqConnect()    }    msgContent := "hello world!"    channel.Publish(exchange, queueName, false, false, amqp.Publishing{        ContentType: "text/plain",        Body:        []byte(msgContent),    })}func receive() {    if channel == nil {        mqConnect()    }    msgs, err := channel.Consume(queueName, "", true, false, false, false, nil)    failOnErr(err, "")    forever := make(chan bool)    go func() {        //fmt.Println(*msgs)        for d := range msgs {            s := BytesToString(&(d.Body))            count++            fmt.Printf("receve msg is :%s -- %d\n", *s, count)        }    }()    fmt.Printf(" [*] Waiting for messages. To exit press CTRL+C\n")    <-forever}func BytesToString(b *[]byte) *string {    s := bytes.NewBuffer(*b)    r := s.String()    return &r}