介绍
RabbitMQ 是一个消息代理和队列服务器，实现了 AMQP (Advanced Message Queuing Protocol)。它能够接收、存储并转发消息数据。本教程将带你了解如何使用 RabbitMQ，并提供一些基本的示例。
安装和配置
安装 RabbitMQ
1. Ubuntu:
```bash
sudo apt update
sudo apt install rabbitmq-server
```
2. MacOS:
```bash
brew install rabbitmq
```
3. Windows:
- 下载安装包并运行。
- 配置环境变量 `RABBITMQ_SERVER` 指向安装目录。
启动服务
```bash
rabbitmq-server
```
管理插件
```bash
rabbitmq-plugins enable rabbitmq_management
```
访问管理界面: `http://localhost:15672/`
创建用户
```bash
rabbitmqctl add_user myuser mypassword
rabbitmqctl set_permissions -p / myuser ".*" ".*" ".*"
```
发布/订阅模型
发布者(Publisher)发送消息到交换器(Exchange)，交换器根据规则把消息路由到一个或多个队列(Queue)。
Python 示例
发布者
```python
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='logs', exchange_type='fanout')
message = "Hello World!"
channel.basic_publish(exchange='logs', routing_key='', body=message)
print(" [x] Sent %r" % message)
connection.close()
```
订阅者
```python
import pika
def callback(ch, method, properties, body):
print(" [x] %r" % body)
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='logs', exchange_type='fanout')
result = channel.queue_declare(queue='', exclusive=True)
queue_name = result.method.queue
channel.queue_bind(exchange='logs', queue=queue_name)
channel.basic_consume(queue=queue_name, on_message_callback=callback, auto_ack=True)
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()
```
工作队列
工作队列允许你分配任务给多个工作者(worker)。
Python 示例
生产者
```python
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.queue_declare(queue='task_queue', durable=True)
message = "A new task"
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()
```
消费者
```python
import pika
def callback(ch, method, properties, body):
print(" [x] Received %r" % body)
ch.basic_ack(delivery_tag=method.delivery_tag)
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.queue_declare(queue='task_queue', durable=True)
channel.basic_qos(prefetch_count=1)
channel.basic_consume(queue='task_queue', on_message_callback=callback)
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()
```
路由
通过路由键(routing key)和绑定(binding)来决定消息的去向。
Python 示例
生产者
```python
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='direct_logs', exchange_type='direct')
severity = 'info'
message = 'This is an info message'
channel.basic_publish(
exchange='direct_logs',
routing_key=severity,
body=message)
print(" [x] Sent %r:%r" % (severity, message))
connection.close()
```
消费者
```python
import pika
def callback(ch, method, properties, body):
print(" [x] %r:%r" % (method.routing_key, body))
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='direct_logs', exchange_type='direct')
result = channel.queue_declare(queue='', exclusive=True)
queue_name = result.method.queue
severities = ['error', 'warning']
for severity in severities:
channel.queue_bind(
exchange='direct_logs',
queue=queue_name,
routing_key=severity)
channel.basic_consume(queue=queue_name, on_message_callback=callback, auto_ack=True)
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()
```
主题交换
主题交换允许使用通配符。
Python 示例
生产者
```python
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='topic_logs', exchange_type='topic')
routing_key = 'kern.critical'
message = 'A critical kernel error'
channel.basic_publish(
exchange='topic_logs',
routing_key=routing_key,
body=message)
print(" [x] Sent %r:%r" % (routing_key, message))
connection.close()
```
消费者
```python
import pika
def callback(ch, method, properties, body):
print(" [x] %r:%r" % (method.routing_key, body))
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='topic_logs', exchange_type='topic')
result = channel.queue_declare(queue='', exclusive=True)
queue_name = result.method.queue
binding_keys = ['kern.*', '*.critical']
for binding_key in binding_keys:
channel.queue_bind(
exchange='topic_logs',
queue=queue_name,
routing_key=binding_key)
channel.basic_consume(queue=queue_name, on_message_callback=callback, auto_ack=True)
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()
```