中间件_RabbitMQ五种消息模型

在RabbitMQ中，有五种消息模型，分别是简单模型（Simple）、工作队列模型（Work Queue）、发布/订阅模型（Publish/Subscribe）、路由模型（Routing）和主题模型（Topics）。

1. 简单模型（Simple）：一个生产者，一个消费者。

生产者代码：

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!'")

消费者代码：

import pika
 
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
 
channel.queue_declare(queue='hello')
 
def callback(ch, method, properties, body):
    print(f" [x] Received {body}")
 
channel.basic_consume(queue='hello', on_message_callback=callback, auto_ack=True)
 
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()

2. 工作队列模型（Work Queue）：多个消费者竞争从队列中获取任务。

与简单模型的区别在于，需要在队列中声明basic_qos(prefetch_count=1)，以保证一条消息只会被一个消费者接收处理。

生产者与简单模型相同。

消费者代码：

import pika
 
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
 
channel.queue_declare(queue='hello')
 
def callback(ch, method, properties, body):
    print(f" [x] Received {body}")
 
channel.basic_qos(prefetch_count=1)
channel.basic_consume(queue='hello', on_message_callback=callback, auto_ack=True)
 
print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()

3. 发布/订阅模型（Publish/Subscribe）：一个生产者，多个消费者，生产者发送的消息，所有订阅的消费者都可以接收到。

生产者代码：

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(f" [x] Sent {message}")

消费者代码：

import pika
 
connection = pika.BlockingConnection(pika.ConnectionParameters('localhost'))
channel = connection.channel()
 
channel.exchange_declare(exchange='logs', exchange_type='fanout')
 
result = channel.queue_declare(exclusive=True)
queue_name = result.method.queue
 
channel.queue_bind(excha