RabbitMQ 入门教程
引言
RabbitMQ 是一个开源的消息代理和队列服务器，实现高级消息队列协议 (AMQP) 0-9-1。它能帮助开发者构建可靠、可扩展的应用程序，通过消息传递来解耦组件。
安装与配置
安装 RabbitMQ
1. 下载安装包:
- [RabbitMQ Download Page](https://www.rabbitmq.com/download.html)
2. 安装:
- Follow the installation instructions for your platform.
3. 启动服务:
```bash
sudo service rabbitmq-server start
```
配置管理插件
1. 启用管理插件:
```bash
sudo rabbitmq-plugins enable rabbitmq_management
```
2. 重启服务:
```bash
sudo service rabbitmq-server restart
```
3. 访问管理界面:
- Open `http://localhost:15672/` in your web browser.
- Default credentials: `guest/guest`.
快速入门
创建生产者
Python 示例
```python
import pika
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
channel.queue_declare(queue='hello')
channel.basic_publish(exchange='',
routing_key='hello',
body='Hello World!')
print(" [x] Sent 'Hello World!'")
connection.close()
```
创建消费者
Python 示例
```python
import pika
def callback(ch, method, properties, body):
print(" [x] Received %r" % body)
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()
```
基本概念
- Exchange: Routes messages to queues.
- Queue: Stores messages until they are sent to consumers.
- Binding: Connects an exchange to a queue.
- Message: Unit of information sent between applications.
模式
发布订阅模式
生产者
```python
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)
```
消费者
```python
result = channel.queue_declare(queue='', exclusive=True)
queue_name = result.method.queue
channel.queue_bind(exchange='logs', queue=queue_name)
print(' [*] Waiting for logs. To exit press CTRL+C')
def callback(ch, method, properties, body):
print(" [x] %r" % body)
channel.basic_consume(queue=queue_name, on_message_callback=callback, auto_ack=True)
channel.start_consuming()
```
工作队列模式
生产者
```python
channel.queue_declare(queue='task_queue', durable=True)
message = "Hello, world!"
channel.basic_publish(exchange='',
routing_key='task_queue',
body=message,
properties=pika.BasicProperties(delivery_mode=2,))
print(" [x] Sent %r" % message)
```
消费者
```python
channel.queue_declare(queue='task_queue', durable=True)
print(' [*] Waiting for messages. To exit press CTRL+C')
def callback(ch, method, properties, body):
print(" [x] Received %r" % body)
ch.basic_ack(delivery_tag=method.delivery_tag)
channel.basic_qos(prefetch_count=1)
channel.basic_consume(queue='task_queue', on_message_callback=callback)
channel.start_consuming()
```
高级特性
- 持久化: Ensure messages are not lost if RabbitMQ crashes.
- 公平调度: Distribute tasks evenly among workers.
- 确认机制: Confirm that messages have been delivered.
总结
RabbitMQ is a powerful tool for building robust messaging systems. By mastering its basic and advanced features, you can create highly scalable and fault-tolerant applications.