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  • RabbitMQ广播模式

    广播模式:1对多,produce发送一则消息多个consumer同时收到。
    注意:广播是实时的,produce只负责发出去,不会管对端是否收到,若发送的时刻没有对端接收,那消息就没了,因此在广播模式下设置消息持久化是无效的。

    三种广播模式:

    fanout: 所有bind到此exchange的queue都可以接收消息(纯广播,绑定到RabbitMQ的接受者都能收到消息);
    direct: 通过routingKey和exchange决定的那个唯一的queue可以接收消息;
    topic:所有符合routingKey(此时可以是一个表达式)的routingKey所bind的queue可以接收消息;

    原理:

    fanout:接受者会在RabbitMQ中创建一个queue用来接收消息,发送者往queue中发送消息。(发送给全员)

    direct:队列绑定关键字,发送者将数据根据关键字发送到消息exchange,exchange根据 关键字 判定应该将数据发送至指定队列。(发送给指定人)

    topic:接受者可以收取指定内容的消息


    代码饭粒1:fanout广播模式

    # publisher发送者

    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
    channel = connection.channel()
    channel.exchange_declare(exchange='broadcast', exchange_type='fanout')
    message = 'big bang!'
    channel.basic_publish(
        exchange='broadcast',
        routing_key='',
        body=message,
    )
    print("[v] Send %r" % message)
    connection.close()

     # subscriber接收者

    import pika
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
    channel = connection.channel()
    channel.exchange_declare(exchange='broadcast', exchange_type='fanout')
    
    result = channel.queue_declare(exclusive=True)
    # 不指定queue名字,Rabbit会随机分配一个名字,并在使用此queue的消费者断开后,自动将queue删除
    queue_name = result.method.queue
    channel.queue_bind(exchange='broadcast',queue=queue_name)
    print(" [*] Waiting for broadcast. To exit press Ctrl+C")
    
    def callback(ch, method, properties, body):
        print(" [v] Get broadcast:",body)
    
    channel.basic_consume(
        callback,
        queue=queue_name,
    )
    channel.start_consuming()

    代码饭粒2:direct广播模式

    # publisher发送者

    import pika
    import sys
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
    channel = connection.channel()
    
    channel.exchange_declare(exchange='direct_logs', exchange_type='direct')
    severity = sys.argv[1] if len(sys.argv) > 1 else 'info'
    message = ' '.join(sys.argv[2:]) or 'Hello World!'
    channel.basic_publish(
        exchange='direct_logs',
        routing_key=severity,
        body=message
    )
    print(" [x] Sent %r:%r" % (severity, message))
    connection.close()

    # subscriber接收者

     
    import pika
    import sys
    connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
    channel = connection.channel()
    
    channel.exchange_declare(exchange='direct_logs', exchange_type='direct')
    result = channel.queue_declare(exclusive=True)
    queue_name = result.method.queue
    
    severities = sys.argv[1:]
    if not severities:
        sys.stderr.write("Usage: %s [info] [warning] [error]
    " % sys.argv[0])
        sys.exit(1)
    
    for severity in severities:
        channel.queue_bind(
            exchange='direct_logs',
            queue=queue_name,
            routing_key=severity
        )
    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()
     

    代码饭粒3:topic广播模式

    # publisher发送者

     
    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) > 1 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()
     

    # subscriber接收者

     
    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]...
    " % 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(
        callback,
        queue=queue_name,
        no_ack=True
    )
    channel.start_consuming()
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  • 原文地址:https://www.cnblogs.com/zqyanywn/p/10115478.html
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