RabbitMQ中交换机的消息分发机制

时间：2018-12-29 19:37:59 阅读：128 评论：0 收藏：0 [点我收藏+]

RabbitMQ是一个消息代理，它接受和转发消息，是一个由 Erlang 语言开发的遵循AMQP协议的开源实现。在RabbitMQ中生产者不会将消息直接发送到队列当中，而是将消息直接发送到交换机(exchange)，交换机用来接受生产者发送的消息并将这些消息发送给绑定的队列，即：生产者-->交换机-->队列。

在RabbitMQ中最主要的三种交换机：1. fanout(广播交换机) 2. direct(直连交换机) 3. topic(话题交换机)

1. fanout(广播交换机)

fanout会将接受到的所有消息广播到它所绑定的所有队列当中(每个消费者都会收到所有的消息)，对于广播交换机，消息路由键routing_key和队列绑定键routing_key的作用都会被忽略。

fanout生产者：

 1 import pika
 2 
 3 
 4 class RabbitProducer(object):
 5     """
 6     与RabbitMq服务器建立连接
 7     """
 8 
 9     def __init__(self):
10         self.conn = pika.BlockingConnection(
11             pika.ConnectionParameters(host=‘localhost‘, port=5672)
12         )
13         self.channel = self.conn.channel()
14 
15         # 声明一个exchange交换机,交换机的类型为fanout广播.
16         self.channel.exchange_declare(
17             exchange=‘fanout_exchange‘, exchange_type=‘fanout‘, durable=True
18         )
19 
20     def send_msg(self, message):
21         """
22         routing_key:绑定的key
23         :param message:
24         :return:
25         """
26         self.channel.basic_publish(
27             exchange=‘fanout_exchange‘,
28             routing_key=‘‘,  # 因为exchange的类型为fanout,所以routing_key的数值在这里将被忽略
29             body=message,
30             properties=pika.BasicProperties(
31                 delivery_mode=2,
32                 # 消息进行持久化(防止服务器挂掉.)===> 如果没有queue绑定到这个exchange交换机,这个参数是没有的.
33             ))
34 
35     def close(self):
36         self.conn.close()
37 
38 
39 if __name__ == "__main__":
40     rabbit_producer = RabbitProducer()
41     for i in range(10):
42         message = ‘hello world {}!‘.format(i)
43         rabbit_producer.send_msg(message)

View Code

消费者consumer1：

 1 import pika
 2 import uuid
 3 
 4 
 5 class RabbitConsumer(object):
 6     """
 7     fanout 消费者1
 8     """
 9 
10     def __init__(self):
11         self.conn = pika.BlockingConnection(
12             pika.ConnectionParameters(host=‘localhost‘, port=5672)
13         )
14         self.channel = self.conn.channel()
15 
16         # 声明一个队列queue_consumer1,并进行持久化(防止服务器挂掉),exclusive设置为false
17         self.channel.queue_declare(
18             exclusive=False, durable=True, queue=‘queue_consumer1‘
19         )
20 
21         # 声明一个exhange交换机,其类型为fanout广播类型  与生产者的交换机一致
22         self.channel.exchange_declare(
23             exchange=‘fanout_exchange‘, exchange_type=‘fanout‘, durable=True
24         )
25 
26         # 将队列queue_consumer1与该exchange交换机进行绑定
27         self.channel.queue_bind(exchange=‘fanout_exchange‘, queue=‘queue_consumer1‘)
28 
29     def call_back(self, method, body):
30         """
31         消费者对消息进行确认,防止消费者挂掉.
32         :param method:
33         :param body:
34         :return:
35         """
36         self.channel.basic_ack(delivery_tag=method.delivery_tag)
37         print(‘接收到的消息为:{}‘.format(str(body)))
38 
39     def receive_msg(self):
40         print(‘consumer1开始接受消息...‘)
41         # 当上一条消息未确认时，会告知RabbitMQ不要再发送消息给这个消费者了 可以控制流量
42         self.channel.basic_qos(prefetch_count=1)
43         self.channel.basic_consume(
44             consumer_callback=self.call_back,
45             queue=‘queue_consumer1‘,
46             no_ack=False,  # 消费者对消息进行确认,防止消费者挂掉
47             consumer_tag=str(uuid.uuid4())
48         )
49 
50     def consume(self):
51         self.receive_msg()
52         self.channel.start_consuming()
53 
54 
55 if __name__ == ‘__main__‘:
56     rabbit_consumer = RabbitConsumer()
57     rabbit_consumer.consume()

View Code

消费者consumer2：

 1 import pika
 2 import uuid
 3 
 4 
 5 class RabbitConsumer(object):
 6     def __init__(self):
 7         self.conn = pika.BlockingConnection(
 8             pika.ConnectionParameters(host=‘localhost‘, port=5672)
 9         )
10         self.channel = self.conn.channel()
11 
12         # 声明一个队列queue_consumer2,并进行持久化(防止服务器挂掉),exclusive设置为false
13         self.channel.queue_declare(
14             exclusive=False, durable=True, queue=‘queue_consumer2‘
15         )
16 
17         # T声明一个exhange交换机,其类型为fanout广播类型
18         self.channel.exchange_declare(
19             exchange=‘fanout_exchange‘, exchange_type=‘fanout‘, durable=True
20         )
21 
22         # 将队列queue_consumer2与该exchange交换机进行绑定
23         self.channel.queue_bind(exchange=‘fanout_exchange‘, queue=‘queue_consumer2‘)
24 
25     def call_back(self, method, body):
26         """
27         消费者对消息进行确认,防止消费者挂掉.
28         :param method:
29         :param body:
30         :return:
31         """
32         self.channel.basic_ack(delivery_tag=method.delivery_tag)
33         print(‘接收到的消息为:{}‘.format(str(body)))
34 
35     def receive_msg(self):
36         print(‘consumer2开始接受消息...‘)
37         self.channel.basic_consume(
38             consumer_callback=self.call_back,
39             queue=‘queue_consumer2‘,
40             no_ack=False,
41             consumer_tag=str(uuid.uuid4())
42         )
43 
44     def consume(self):
45         self.receive_msg()
46         self.channel.start_consuming()
47 
48 
49 if __name__ == ‘__main__‘:
50     rabbit_consumer = RabbitConsumer()
51     rabbit_consumer.consume()

View Code


fanout会将接受到的所有消息广播到消费者consumer1和消费者consumer2，交换机的缺陷：它只能无意识的播放，不够灵活地控制消息广播给指定的消费者

2. direct(直连交换机)

对于direct，根据绑定键判定应该将数据发送至哪个队列，消息进入队列，其绑定秘钥（routing_key）与消息的路由秘钥要完全匹配，当exchange使用相同的绑定秘钥（routing_key）去绑定多个队列也是合法的，在这种情况下direct exchange的效果等同于fanout exchange，交换机会将消息广播到所有匹配的队列当中。

direct生产者：

 1 import pika
 2 
 3 
 4 class RabbitProducer(object):
 5     """
 6     与RabbitMq服务器建立连接
 7     """
 8 
 9     def __init__(self):
10         self.conn = pika.BlockingConnection(
11             pika.ConnectionParameters(host=‘localhost‘, port=5672)
12         )
13         self.channel = self.conn.channel()
14 
15         # 声明一个exchange交换机,交换机的类型为direct
16         self.channel.exchange_declare(
17             exchange=‘direct_exchange‘, exchange_type=‘direct‘, durable=True
18         )
19 
20     def send_msg(self, routing_key, message):
21         """
22         :param routing_key: 消息的路由键 本例中为routing_info
23         :param message: 生成者发送的消息
24         :return:
25         """
26         self.channel.basic_publish(
27             exchange=‘direct_exchange‘,
28             routing_key=routing_key,
29             body=message,
30             properties=pika.BasicProperties(
31                 delivery_mode=2,
32                 # 消息进行持久化(防止服务器挂掉.)===> 如果没有queue绑定到这个exchange交换机,这个参数是没有的.
33             ))
34 
35     def close(self):
36         self.conn.close()
37 
38 
39 if __name__ == "__main__":
40     rabbit_producer = RabbitProducer()
41     routing_key = ‘routing_info‘
42     for i in range(10):
43         message = ‘hello world {}!‘.format(i)
44         print(‘生产者发送的消息为:{}‘.format(message))
45         rabbit_producer.send_msg(routing_key, message)

View Code

direct消费者：

 1 import pika
 2 import uuid
 3 
 4 
 5 class RabbitConsumer(object):
 6     """
 7     消费者(订阅者)
 8     """
 9 
10     def __init__(self):
11         self.conn = pika.BlockingConnection(
12             pika.ConnectionParameters(host=‘localhost‘, port=5672)
13         )
14         self.channel = self.conn.channel()
15 
16         # 消息持久化
17         self.channel.queue_declare(
18             exclusive=False, durable=True, queue=‘task_queue‘
19         )
20 
21         # 交换机类型为direct.
22         self.channel.exchange_declare(
23             exchange=‘direct_exchange‘, exchange_type=‘direct‘, durable=True
24         )
25 
26         # 将队列与该exchange交换机进行绑定
27         routing_keys = [‘routing_info‘, ‘aaa‘]
28         for routing_key in routing_keys:
29             self.channel.queue_bind(
30                 exchange=‘direct_exchange‘, queue=‘task_queue‘, routing_key=routing_key
31             )  # 如果生产者发生消息的routing_key与消费者绑定队列的routing_key相同则成功发送
32 
33     def call_back(self, channel, method, properties, body):
34         """
35         消费者对消息进行确认,防止消费者挂掉
36         :param channel:
37         :param method:
38         :param properties:
39         :param body:
40         :return:
41         """
42         self.channel.basic_ack(delivery_tag=method.delivery_tag)
43         print(‘接收到的消息为:{}‘.format(str(body)))
44 
45     def receive_msg(self):
46         print(‘开始接受消息...‘)
47         self.channel.basic_qos(prefetch_count=1)  # TODO 告诉RabbitMQ,不要向我发送新的消息.
48         self.channel.basic_consume(
49             consumer_callback=self.call_back,
50             queue=‘task_queue‘,
51             no_ack=False,
52             consumer_tag=str(uuid.uuid4())
53         )
54 
55     def consume(self):
56         self.receive_msg()
57         self.channel.start_consuming()
58 
59 
60 if __name__ == ‘__main__‘:
61     rabbit_consumer = RabbitConsumer()
62     rabbit_consumer.consume()

View Code


direct直连交换机相当于是fanout的升级版，当消费者的队列绑定的秘钥routing_key与生产者的routing_key相同时，消费者就会收到消息；当所有消费者的队列所绑定的routing_key都一样且与生产者相同时，就相当于fanout交换机

3. topic(话题交换机)

direct(直连交换机)虽然相当于fanout的升级版，但它仍然有局限性，它不能根据多个标准进行路由;topic(话题交换机)可以很好地解决这一问题：
(1) 如果消息的路由秘钥与队列的绑定秘钥符合匹配规则，topic就会将消息发送到相应的队列当中

(2) 对于绑定键(routing_key)有两个特殊的情况： * （星号）可以代替一个单词，＃（散列）可以替代零个或多个单词

(3) 对于发送到topic交换机消息的routing_key如果包含特殊字符，只能是由"."分割的单词表，如("zhangsan.lisi")

topic 生产者：

 1 import pika
 2 
 3 
 4 class RabbitProducer(object):
 5     def __init__(self):
 6         self.conn = pika.BlockingConnection(
 7             pika.ConnectionParameters(host=‘localhost‘, port=5672)
 8         )
 9         self.channel = self.conn.channel()
10 
11         # 声明交换机,交换机的类型为topic
12         self.channel.exchange_declare(
13             exchange=‘logs_topic‘, exchange_type=‘topic‘, durable=True
14         )
15 
16     def send_msg(self, routing_key, message):
17         """
18         :param routing_key: 消息的路由键
19         :param message: 生成者发送的消息
20         :return:
21         """
22         self.channel.basic_publish(
23             exchange=‘logs_topic‘,
24             routing_key=routing_key,
25             body=message,
26             properties=pika.BasicProperties(
27                 delivery_mode=2,
28                 # 消息进行持久化
29             ))
30 
31     def close(self):
32         self.conn.close()
33 
34 
35 if __name__ == "__main__":
36     rabbit_producer = RabbitProducer()
37     routing_keys = [‘info‘, "debug", "a.debug.b", "a.info.b"]
38     for routing_key in routing_keys:
39         message = ‘hello world! {}‘.format(routing_key)
40         print(‘生产者发送的消息为:{}‘.format(message))
41         rabbit_producer.send_msg(routing_key, message)

View Code

topic 消费者1 --> 实现fanout交换机：

 1 """
 2 当topic交换机使用#绑定键绑定队列时，此时topic交换机就会将消息广播到所有的队列当中，
 3 不管消息的路由秘钥如何，此时topic交换机的效果等同于fanout:发送所有消息都会接受到
 4 """
 5 import pika
 6 import uuid
 7 
 8 
 9 class RabbitConsumer(object):
10     def __init__(self):
11         self.conn = pika.BlockingConnection(
12             pika.ConnectionParameters(host=‘localhost‘, port=5672)
13         )
14         self.channel = self.conn.channel()
15 
16         # 消息持久化
17         self.channel.queue_declare(
18             exclusive=False, durable=True, queue=‘task_queue‘
19         )
20 
21         # 声明交换机,其类型为topic
22         self.channel.exchange_declare(
23             exchange=‘logs_topic‘, exchange_type=‘topic‘, durable=True
24         )
25 
26         # 将队列与该交换机进行绑定
27         routing_keys = [‘#‘]  # 使用#绑定键时,它将接受所有的消息,同fanout效果一样.
28         for routing_key in routing_keys:
29             self.channel.queue_bind(
30                 exchange=‘logs_topic‘, queue=‘task_queue‘, routing_key=routing_key
31             )
32 
33     def call_back(self, channel, method, properties, body):
34         """
35         消费者对消息进行确认,防止消费者挂掉
36         :param channel:
37         :param method:
38         :param properties:
39         :param body:
40         :return:
41         """
42         self.channel.basic_ack(delivery_tag=method.delivery_tag)
43         print(‘接收到的消息为:{}‘.format(str(body)))
44 
45     def receive_msg(self):
46         print(‘开始接受消息...‘)
47         self.channel.basic_qos(prefetch_count=1)
48         self.channel.basic_consume(
49             consumer_callback=self.call_back,
50             queue=‘task_queue‘,
51             no_ack=False,  # 消费者对消息进行确认
52             consumer_tag=str(uuid.uuid4())
53         )
54 
55     def consume(self):
56         self.receive_msg()
57         self.channel.start_consuming()
58 
59 
60 if __name__ == ‘__main__‘:
61     rabbit_consumer = RabbitConsumer()
62     rabbit_consumer.consume()

View Code

topic 消费者2 --> 实现direct交换机：

 1 """
 2 当topic交换机没有使用*和#匹配符绑定键绑定队列时，此时topic交换机的效果等同于direct，
 3 会收到key相匹配的消息  如：info debug
 4 """
 5 import pika
 6 import uuid
 7 
 8 
 9 class RabbitConsumer(object):
10     def __init__(self):
11         self.conn = pika.BlockingConnection(
12             pika.ConnectionParameters(host=‘localhost‘, port=5672)
13         )
14         self.channel = self.conn.channel()
15 
16         # 消息持久化
17         self.channel.queue_declare(
18             exclusive=False, durable=True, queue=‘work_queue‘
19         )
20 
21         #
22         # 声明交换机,其类型为topic
23         self.channel.exchange_declare(
24             exchange=‘logs_topic‘, exchange_type=‘topic‘, durable=True
25         )
26 
27         # 将队列与交换机进行绑定
28         routing_keys = [‘info‘, ‘debug‘]
29         for routing_key in routing_keys:
30             self.channel.queue_bind(
31                 exchange=‘logs_topic‘, queue=‘work_queue‘, routing_key=routing_key
32             )
33 
34     def call_back(self, channel, method, properties, body):
35         """
36         消费者对消息进行确认,防止消费者挂掉
37         :param channel:
38         :param method:
39         :param properties:
40         :param body:
41         :return:
42         """
43         self.channel.basic_ack(delivery_tag=method.delivery_tag)
44         print(‘接收到的消息为:{}‘.format(str(body)))
45 
46     def receive_msg(self):
47         print(‘开始接受消息...‘)
48         self.channel.basic_qos(prefetch_count=1)
49         self.channel.basic_consume(
50             consumer_callback=self.call_back,
51             queue=‘work_queue‘,
52             no_ack=False,  # 消费者对消息进行确认
53             consumer_tag=str(uuid.uuid4())
54         )
55 
56     def consume(self):
57         self.receive_msg()
58         self.channel.start_consuming()
59 
60 
61 if __name__ == ‘__main__‘:
62     rabbit_consumer = RabbitConsumer()
63     rabbit_consumer.consume()

View Code

topic 消费者3 --> 实现*.x.* 消息匹配：

 1 """
 2 匹配任意点分割的单词 生产者发送的：a.debug.b 则匹配了‘*.debug.*‘
 3 生产者发送的：a.info.b 则匹配了‘*.info.*‘
 4 """
 5 import pika
 6 import uuid
 7 
 8 
 9 class RabbitConsumer(object):
10     def __init__(self):
11         self.conn = pika.BlockingConnection(
12             pika.ConnectionParameters(host=‘localhost‘, port=5672)
13         )
14         self.channel = self.conn.channel()
15 
16         # 消息持久化
17         self.channel.queue_declare(
18             exclusive=False, durable=True, queue=‘other_queue‘
19         )
20 
21         # 声明交换机,其类型为topic
22         self.channel.exchange_declare(
23             exchange=‘logs_topic‘, exchange_type=‘topic‘, durable=True
24         )
25 
26         # 将队列与交换机进行绑定
27         routing_keys = [‘*.info.*‘, ‘*.debug.*‘, ‘dfdf*‘]
28         for routing_key in routing_keys:
29             self.channel.queue_bind(
30                 exchange=‘logs_topic‘, queue=‘other_queue‘, routing_key=routing_key
31             )
32 
33     def call_back(self, channel, method, properties, body):
34         """
35         消费者对消息进行确认,防止消费者挂掉
36         :param channel:
37         :param method:
38         :param properties:
39         :param body:
40         :return:
41         """
42         self.channel.basic_ack(delivery_tag=method.delivery_tag)
43         print(‘接收到的消息为:{}‘.format(str(body)))
44 
45     def receive_msg(self):
46         print(‘开始接受消息...‘)
47         self.channel.basic_qos(prefetch_count=1)
48         self.channel.basic_consume(
49             consumer_callback=self.call_back,
50             queue=‘other_queue‘,
51             no_ack=False,  # 消费者对消息进行确认
52             consumer_tag=str(uuid.uuid4())
53         )
54 
55     def consume(self):
56         self.receive_msg()
57         self.channel.start_consuming()
58 
59 
60 if __name__ == ‘__main__‘:
61     rabbit_consumer = RabbitConsumer()
62     rabbit_consumer.consume()