RabbitMQ 入门教程

介绍

RabbitMQ 是一个消息中间件，它实现了 AMQP (Advanced Message Queuing Protocol) 协议。本教程将引导你通过几个简单的步骤来学习如何使用 RabbitMQ 发送和接收消息。

环境准备

1. 安装 RabbitMQ

- 在你的系统上安装 RabbitMQ: https://www.rabbitmq.com/download.html

- 启动服务: `sudo rabbitmq-server`

2. 安装客户端库

- Python 示例将使用 `pika` 库: `pip install pika`

第一步: 创建生产者

创建一个简单的生产者，用于发送消息到 RabbitMQ 服务器。

```python

import pika

def main():

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='hello')

message = "Hello World!"

channel.basic_publish(exchange='',

routing_key='hello',

body=message)

print(" [x] Sent %r" % message)

connection.close()

if __name__ == '__main__':

main()

```

第二步: 创建消费者

创建一个简单的消费者，用于接收来自 RabbitMQ 服务器的消息。

```python

import pika

def callback(ch, method, properties, body):

print(" [x] Received %r" % body)

def main():

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='hello')

channel.basic_consume(queue='hello',

on_message_callback=callback,

auto_ack=True)

print(' [*] Waiting for messages. To exit press CTRL+C')

channel.start_consuming()

if __name__ == '__main__':

main()

```

第三步: 使用持久化消息

确保消息在 RabbitMQ 重启后仍然存在。

生产者代码修改

```python

import pika

def main():

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='hello', durable=True)

message = "Hello World!"

channel.basic_publish(exchange='',

routing_key='hello',

body=message,

properties=pika.BasicProperties(

delivery_mode=2, # make message persistent

))

print(" [x] Sent %r" % message)

connection.close()

if __name__ == '__main__':

main()

```

消费者代码修改

```python

import pika

def callback(ch, method, properties, body):

print(" [x] Received %r" % body)

def main():

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='hello', durable=True)

channel.basic_qos(prefetch_count=1)

channel.basic_consume(queue='hello',

on_message_callback=callback,

auto_ack=False)

print(' [*] Waiting for messages. To exit press CTRL+C')

channel.start_consuming()

if __name__ == '__main__':

main()

```

第四步: 使用工作队列

实现一个简单的工作队列，可以分发任务给多个工作者。

生产者

```python

import pika

import sys

import random

def main():

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='task_queue', durable=True)

message = ' '.join(sys.argv[1:]) or "Hello World!"

message += f" {random.randint(1, 10)}"

channel.basic_publish(

exchange='',

routing_key='task_queue',

body=message,

properties=pika.BasicProperties(delivery_mode=2)) # make message persistent

print(" [x] Sent %r" % message)

connection.close()

if __name__ == '__main__':

main()

```

工作者

```python

import pika

import time

def callback(ch, method, properties, body):

print(" [x] Received %r" % body)

time.sleep(body.count(b'.'))

print(" [x] Done")

ch.basic_ack(delivery_tag=method.delivery_tag)

def main():

connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))

channel = connection.channel()

channel.queue_declare(queue='task_queue', durable=True)

print(' [*] Waiting for messages. To exit press CTRL+C')

channel.basic_qos(prefetch_count=1)

channel.basic_consume(queue='task_queue',

on_message_callback=callback)

channel.start_consuming()

if __name__ == '__main__':

main()

```