Golang RabbitMQ: 高可用性メッセージ キュー システムのアーキテクチャ設計と実装

         Consumer A                 Consumer B                 Consumer C

         +---------+                 +---------+                 +---------+
         |   App   |   ---------->   |   App   |   ---------->   |   App   |
        /+---------+                 +---------+                 +---------+
       /
      /
     /
   +----+        +------+        +------+
   | P1 | <----> | Node | <----> | Node |
   +----+        +------+        +------+
   | P2 | <----> | Node | <----> | Node |
   +----+        +------+        +------+
   | P3 | <----> | Node | <----> | Node |
   +----+        +------+        +------+

package main

import (
    "fmt"
    "log"

    "github.com/streadway/amqp"
)

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

func main() {
    conn, err := amqp.Dial("amqp://guest:guest@localhost:5672/")
    failOnError(err, "Failed to connect to RabbitMQ")
    defer conn.Close()

    ch, err := conn.Channel()
    failOnError(err, "Failed to open a channel")
    defer ch.Close()

    q, err := ch.QueueDeclare(
        "hello", // 队列名
        false,   // 是否持久化
        false,   // 是否自动删除 when unused
        false,   // 是否独占连接
        false,   // 是否阻塞等待
        nil,     // 额外的属性
    )
    failOnError(err, "Failed to declare a queue")

    body := "Hello RabbitMQ!"
    err = ch.Publish(
        "",     // exchange
        q.Name, // routing key
        false,  // mandatory
        false,  // immediate
        amqp.Publishing{
            ContentType: "text/plain",
            Body:        []byte(body),
        })
    failOnError(err, "Failed to publish a message")

    log.Printf(" [x] Sent %s", body)
}

package main

import (
    "fmt"
    "log"
    "os"
    "os/signal"
    "syscall"

    "github.com/streadway/amqp"
)

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

func main() {
    conn, err := amqp.Dial("amqp://guest:guest@localhost:5672/")
    failOnError(err, "Failed to connect to RabbitMQ")
    defer conn.Close()

    ch, err := conn.Channel()
    failOnError(err, "Failed to open a channel")
    defer ch.Close()

    q, err := ch.QueueDeclare(
        "hello", // 队列名
        false,   // 是否持久化
        false,   // 是否自动删除 when unused
        false,   // 是否独占连接
        false,   // 是否阻塞等待
        nil,     // 额外的属性
    )
    failOnError(err, "Failed to declare a queue")

    msgs, err := ch.Consume(
        q.Name, // 队列名
        "",     // consumer
        true,   // 自动应答
        false,  // 独占连接
        false,  // 阻塞等待时是否自动取消
        false,  // 额外属性
        nil,
    )
    failOnError(err, "Failed to register a consumer")

    forever := make(chan bool)

    go func() {
        for d := range msgs {
            log.Printf("Received a message: %s", d.Body)
        }
    }()

    log.Println(" [*] Waiting for messages. To exit press CTRL+C")
    // Handle SIGINT and SIGTERM.
    sigchan := make(chan os.Signal, 1)
    signal.Notify(sigchan, syscall.SIGINT, syscall.SIGTERM)
    <-sigchan

    <-forever
}