RabbitMQ - 5 topic模式

前言：direct模式相當於精準匹配，有精準就有模糊，對吧，接下來看看模糊匹配。

Topic exchange

區別：routing_key 必須是一系列的單詞，以逗號分隔；這些單詞可以是任意的，但通常它們會指定一些與信息相關的特性，最多255字節的限制。

routing_key 中兩個特殊的單詞：
	* 可以代替一個單詞
	# 可以代替0個或多個單詞

　　

for example：
----------------------------------------
| routing_key             |  queue     |
----------------------------------------
| quick.orange.rabbit     |  Q1 Q2     |
----------------------------------------
| lazy.orange.elephant    |  Q1 Q2     |    
----------------------------------------
| quick.orange.fox        |  Q1        |
----------------------------------------
| lazy.brown.fox          |  Q2        |
----------------------------------------
| lazy.pink.rabbit        |  Q2        |
----------------------------------------
| quick.brown.fox         |  discarded |
----------------------------------------
| orange                  |  discarded |
----------------------------------------
| quick.orange.male.rabbit|  discarded |
----------------------------------------
| lazy.orange.male.rabbit |  Q2        |
----------------------------------------

Topic 這種交換機制也如其他exchange一樣強大。當 routing_key 爲 '#' 時分發效果和fanout一樣。當 '*' 和 '#' 在routing_key中都沒出現時，分發效果同direct一樣。

Putting it all together

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 = sys.argv[1] if len(sys.argv) > 2 else 'anonymous.info'
message = ' '.join(sys.argv[2:]) or 'Hello World!'
channel.basic_publish(
    exchange='topic_logs', routing_key=routing_key, body=message)
print(" [x] Sent %r:%r" % (routing_key, message))
connection.close()

receive.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')

result = channel.queue_declare('', exclusive=True)
queue_name = result.method.queue

binding_keys = sys.argv[1:]
if not binding_keys:
    sys.stderr.write("Usage: %s [binding_key]...\n" % sys.argv[0])
    sys.exit(1)

for binding_key in binding_keys:
    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(
    queue=queue_name, on_message_callback=callback, auto_ack=True)

channel.start_consuming()