RabbitMQ 入门教程
介绍
RabbitMQ 是一个开源的消息代理和队列服务器，实现了 AMQP 0-9-1 标准。它支持多种消息协议，并且可以在各种环境中运行。
安装与配置
1. 安装 RabbitMQ
Linux (Ubuntu/Debian)
```bash
sudo apt update
sudo apt install rabbitmq-server
```
Windows
- 下载并安装 [RabbitMQ Server](https://www.rabbitmq.com/download.html)
2. 启动服务
```bash
sudo service rabbitmq-server start
```
3. 配置管理插件
```bash
sudo rabbitmq-plugins enable rabbitmq_management
```
4. 访问管理界面
- 浏览器访问: http://localhost:15672/
- 默认账号密码: guest/guest
发布/订阅模式
发布/订阅模式中，消息发布者将消息发送到交换器（Exchange），交换器根据规则将消息转发给绑定的队列（Queue）。
代码示例 (Python)
安装依赖
```bash
pip install pika
```
生产者 (producer.py)
```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()
```
消费者 (consumer.py)
```python
import pika
def callback(ch, method, properties, body):
print(" [x] Received %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()
```
工作队列模式
工作队列模式是实现任务分配的基础，其中消息被发送到队列，消费者从队列中取出消息进行处理。
代码示例 (Python)
生产者 (task_queue_producer.py)
```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 (task_queue_consumer.py)
```python
import pika
import time
def callback(ch, method, properties, body):
print(" [x] Received %r" % body.decode())
time.sleep(body.count(b'.'))
print(" [x] Done")
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()
```
路由模式
路由模式中，交换器可以根据特定的键来决定消息应该发往哪些队列。
代码示例 (Python)
生产者 (direct_sender.py)
```python
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.exchange_declare(exchange='direct_logs', exchange_type='direct')
severity = 'info'
message = 'Info level log'
channel.basic_publish(
exchange='direct_logs', routing_key=severity, body=message)
print(" [x] Sent %r:%r" % (severity, message))
connection.close()
```
消费者 (direct_receiver.py)
```python
import pika
def callback(ch, method, properties, body):
print(" [x] Received %r" % 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 = ['info', '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 logs. To exit press CTRL+C')
channel.start_consuming()