一、模式介绍
路由模式，与发布-订阅模式一样，消息发送到exchange中，消费者把队列绑定到exchange上。
这种模式在exchange上添加添加了一个路由键（routing-key），生产者发布消息的时候添加路由键（routing-key），消费者绑定队列到交换机时添加键值（routing-key），这样就可以接收到对应的消息。
路由模式的direct exchange。
队列模型：
与发布-订阅模式不同的是，每个消费者队列接收的消息不同，根据消息的routing-key把消息发送到不同的队列中。
当所有的消费队列绑定的routing-key一样时，路由模式行为与发布-订阅模式一样。
二、代码示意
发布者：不再创建队列，发送消息到exchange（交换机）中。exchange_type为direct。
1 import pika 2 import sys 3 4 connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost')) 5 channel = connection.channel() 6 7 channel.exchange_declare(exchange='direct_logs', 8 exchange_type='direct') 9 10 severity = ['info', 'warning', 'error'] 11 for i in range(20): 12 message = '{} Hello World! {}'.format(i, severity[i % 3]) 13 channel.basic_publish(exchange='direct_logs', 14 routing_key=severity[i % 3], 15 body=message) 16 print(" [x] Sent: {}".format(message)) 17 connection.close()
每个消费者绑定的队列定义不同的routing-key，接收到不同的消息。
以info为示例：
1 import pika 2 import sys 3 4 connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost')) 5 channel = connection.channel() 6 7 channel.exchange_declare(exchange='direct_logs', 8 exchange_type='direct') 9 10 result = channel.queue_declare(exclusive=True) 11 queue_name = result.method.queue 12 13 channel.queue_bind(exchange='direct_logs', 14 queue=queue_name, 15 routing_key='info') 16 17 print(' [*] Waiting for logs. To exit press CTRL+C') 18 19 def callback(ch, method, properties, body): 20 print(" [x] %r:%r" % (method.routing_key, body)) 21 22 channel.basic_consume(callback, 23 queue=queue_name, 24 no_ack=True) 25 26 channel.start_consuming()
执行结果输出：
发布者：
[x] Sent: 0 Hello World! info [x] Sent: 1 Hello World! warning [x] Sent: 2 Hello World! error [x] Sent: 3 Hello World! info [x] Sent: 4 Hello World! warning [x] Sent: 5 Hello World! error [x] Sent: 6 Hello World! info [x] Sent: 7 Hello World! warning [x] Sent: 8 Hello World! error [x] Sent: 9 Hello World! info [x] Sent: 10 Hello World! warning [x] Sent: 11 Hello World! error [x] Sent: 12 Hello World! info [x] Sent: 13 Hello World! warning [x] Sent: 14 Hello World! error [x] Sent: 15 Hello World! info [x] Sent: 16 Hello World! warning [x] Sent: 17 Hello World! error [x] Sent: 18 Hello World! info [x] Sent: 19 Hello World! warning
Info输出：
[*] Waiting for logs. To exit press CTRL+C [x] 'info':b'0 Hello World! info' [x] 'info':b'3 Hello World! info' [x] 'info':b'6 Hello World! info' [x] 'info':b'9 Hello World! info' [x] 'info':b'12 Hello World! info' [x] 'info':b'15 Hello World! info' [x] 'info':b'18 Hello World! info'
Warning输出：
[*] Waiting for logs. To exit press CTRL+C [x] 'warning':b'1 Hello World! warning' [x] 'warning':b'4 Hello World! warning' [x] 'warning':b'7 Hello World! warning' [x] 'warning':b'10 Hello World! warning' [x] 'warning':b'13 Hello World! warning' [x] 'warning':b'16 Hello World! warning' [x] 'warning':b'19 Hello World! warning'
Error输出：
[*] Waiting for logs. To exit press CTRL+C [x] 'error':b'2 Hello World! error' [x] 'error':b'5 Hello World! error' [x] 'error':b'8 Hello World! error' [x] 'error':b'11 Hello World! error' [x] 'error':b'14 Hello World! error' [x] 'error':b'17 Hello World! error'
可以看到，不同的消费者收到不同级别的日志信息。
三、队列信息
管理页面，exchange页面，点击“direct_logs”上查看队列情况，可以看到三个不同routing_key的队列
routing key列展示了对应的key。