话题模式 Topic

话题模式（Topic）基本思想和路由模式是一样的，只不过路由键支持模糊匹配，符号“#”匹配一个或多个词，符号“*”匹配不多不少一个词

话题模式相当于消息的模糊匹配，或者按照正则匹配。其中

# 是通配符，匹配一个或者多个单词

* 代表匹配一个单词

• send.py

#!/usr/bin/env python
import pika
import sys

connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channel = connection.channel()

channel.exchange_declare(exchange='topic_logs',
                         exchange_type='topic')

routing_key = ['#', "kern.critical", "A critical kernel error"]
for i in range(10):
    message = '{} msg at : routing key {}'.format(i, routing_key[i % 3])
    channel.basic_publish(exchange='topic_logs',
                          routing_key=routing_key[i % 3],
                          body=message)
    print(" [x] Sent :%r" % (message))
connection.close()

• receiver.py

import pika
import sys

connection = pika.BlockingConnection(pika.ConnectionParameters(host='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_key = "#"

channel.queue_bind(exchange='topic_logs',
                   queue=queue_name,
                   routing_key=binding_key)

print(' [*] Waiting for logs. To exit press CTRL+C')

def callback(ch, method, properties, body):
    print(" [x] %r:%r" % (method.routing_key, body))

channel.basic_consume(callback,
                      queue=queue_name,
                      no_ack=True)

channel.start_consuming()