一、模式介紹

路由模式，與釋出-訂閱模式一樣，訊息傳送到exchange中，消費者把佇列繫結到exchange上。

這種模式在exchange上新增添加了一個路由鍵（routing-key），生產者釋出訊息的時候新增路由鍵（routing-key），消費者繫結佇列到交換機時新增鍵值（routing-key），這樣就可以接收到對應的訊息。

路由模式的direct exchange。

佇列模型：

與釋出-訂閱模式不同的是，每個消費者佇列接收的訊息不同，根據訊息的routing-key把訊息傳送到不同的佇列中。

當所有的消費佇列繫結的routing-key一樣時，路由模式行為與釋出-訂閱模式一樣。

二、程式碼示意 

釋出者：不再建立佇列，傳送訊息到exchange（交換機）中。exchange_type為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()

每個消費者繫結的佇列定義不同的routing-key，接收到不同的訊息。

以info為示例：

 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()

執行結果輸出：

釋出者：

[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輸出：

[*] 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輸出：

[*] 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輸出：

[*] 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，不同的消費者收到不同級別的日誌資訊。

三、佇列資訊

管理頁面，exchange頁面，點選“direct_logs”上檢視佇列情況，可以看到三個不同routing_key的佇列

routing key列展示了對應的key。