python实现RabbitMQ的消息队列的示例代码
最近在研究redis做消息队列时，顺便看了一下RabbitMQ做消息队列的实现。以下是总结的RabbitMQ中三种exchange模式的实现，分别是fanout,direct和topic。
base.py：
importpika
#获取认证对象，参数是用户名、密码。远程连接时需要认证
credentials=pika.PlainCredentials("admin","admin")
#BlockingConnection():实例化连接对象
#ConnectionParameters():实例化链接参数对象
connection=pika.BlockingConnection(pika.ConnectionParameters(
"192.168.0.102",5672,"/",credentials))
#创建新的channel(通道)
channel=connection.channel()
fanout模式：向绑定到指定exchange的queue中发送消息，消费者从queue中取出数据，类似于广播模式、发布订阅模式。
绑定方式:在接收端channel.queue_bind(exchange="logs",queue=queue_name)
代码：
publisher.py:
frombaseimportchannel,connection #声明exchange,不声明queue channel.exchange_declare(exchange="logs",exchange_type="fanout")#广播 message="hellofanout" channel.basic_publish( exchange="logs", routing_key="", body=message ) connection.close()
consumer.py：
frombaseimportchannel,connection
#声明exchange
channel.exchange_declare(exchange="logs",exchange_type="fanout")
#不指定queue名字,rabbitmq会随机分配一个名字,消息处理完成后queue会自动删除
result=channel.queue_declare(exclusive=True)
#获取queue名字
queue_name=result.method.queue
#绑定exchange和queue
channel.queue_bind(exchange="logs",queue=queue_name)
defcallback(ch,method,properties,body):
print("body:%s"%body)
channel.basic_consume(
callback,
queue=queue_name
)
channel.start_consuming()
direct模式：发送端绑定一个routing_key1,queue中绑定若干个routing_key2,若key1与key2相等，或者key1在key2中，则消息就会发送到这个queue中，再由相应的消费者去queue中取数据。
publisher.py：
frombaseimportchannel,connection channel.exchange_declare(exchange="direct_test",exchange_type="direct") message="hello" channel.basic_publish( exchange="direct_test", routing_key="info",#绑定key body=message ) connection.close()
consumer01.py：
frombaseimportchannel,connection
channel.exchange_declare(exchange="direct_test",exchange_type="direct")
result=channel.queue_declare(exclusive=True)
queue_name=result.method.queue
channel.queue_bind(
exchange="direct_test",
queue=queue_name,
#绑定的key,与publisher中的相同
routing_key="info"
)
defcallback(ch,method,properties,body):
print("body:%s"%body)
channel.basic_consume(
callback,
queue=queue_name
)
channel.start_consuming()
consumer02.py：
frombaseimportchannel,connection
channel.exchange_declare(exchange="direct_test",exchange_type="direct")
result=channel.queue_declare(exclusive=True)
queue_name=result.method.queue
channel.queue_bind(
exchange="direct_test",
queue=queue_name,
#绑定的key
routing_key="error"
)
defcallback(ch,method,properties,bosy):
print("body:%s"%body)
channel.basic_consume(
callback,
queue=queue_name
)
channel.start_consuming()
consumer03.py：
frombaseimportchannel,connection
channel.exchange_declare(exchange="direct_test",exchange_type="direct")
result=channel.queue_declare(exclusive=True)
queue_name=result.method.queue
key_list=["info","warning"]
forkeyinkey_list:
channel.queue_bind(
exchange="direct_test",
queue=queue_name,
#一个queue同时绑定多个key，有一个key满足条件时就可以收到数据
routing_key=key
)
defcallback(ch,method,properties,body):
print("body:%s"%body)
channel.basic_consume(
callback,
queue=queue_name
)
channel.start_consuming()
执行:
pythonproducer.py pythonconsumer01.py pythonconsumer02.py pythonconsumer03.py
结果:
consumer01.py:body:b'hello'
consumer02.py没收到结果
consumer03.py:body:b'hello'
topic模式不是太好理解，我的理解如下:
对于发送端绑定的routing_key1，queue绑定若干个routing_key2；若routing_key1满足任意一个routing_key2，则该消息就会通过exchange发送到这个queue中，然后由接收端从queue中取出其实就是direct模式的扩展。
绑定方式:
发送端绑定:
channel.basic_publish( exchange="topic_logs", routing_key=routing_key, body=message )
接收端绑定:
channel.queue_bind( exchange="topic_logs", queue=queue_name, routing_key=binding_key )
publisher.py：
importsys frombaseimportchannel,connection #声明exchange channel.exchange_declare(exchange="topic_test",exchange_type="topic") #待发送消息 message="".join(sys.argv[1:])or"hellotopic" #发布消息 channel.basic_publish( exchange="topic_test", routing_key="mysql.error",#绑定的routing_key body=message ) connection.close()
consumer01.py:
frombaseimportchannel,connection
channel.exchange_declare(exchange="topic_test",exchange_type="topic")
result=channel.queue_declare(exclusive=True)
queue_name=result.method.queue
channel.queue_bind(
exchange="topic_test",
queue=queue_name,
routing_key="*.error"#绑定的routing_key
)
defcallback(ch,method,properties,body):
print("body:%s"%body)
channel.basic_consume(
callback,
queue=queue_name,
no_ack=True
)
channel.start_consuming()
consumer02.py:
frombaseimportchannel,connection
channel.exchange_declare(exchange="topic_test",exchange_type="topic")
result=channel.queue_declare(exclusive=True)
queue_name=result.method.queue
channel.queue_bind(
exchange="topic_test",
queue=queue_name,
routing_key="mysql.*"#绑定的routing_key
)
defcallback(ch,method,properties,body):
print("body:%s"%body)
channel.basic_consume(
callback,
queue=queue_name,
no_ack=True
)
channel.start_consuming()
执行:
pythonpublisher02.py"thisisatopictest" pythonconsumer01.py pythonconsumer02.py
结果:
consumer01.py的结果:body:b'thisisatopictest'
consumer02.py的结果:body:b'thisisatopictest'
说明通过绑定相应的routing_key，两个消费者都收到了消息
将publisher.py的routing_key改成"mysql.info"
再此执行:
pythonpublisher02.py"thisisatopictest" pythonconsumer01.py pythonconsumer02.py
结果:
consumer01.py没收到结果
consumer02.py的结果:body:b'thisisatopictest'
通过这个例子我们就能明白topic的运行方式了。
参考自：https://www.nhooo.com/article/150386.htm
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