python开发-实现RabbitMQ的消息队列

摘要：最近在研究做消息队列时，顺便看了一下做消息队列的实现。远程连接时需要认证实例化连接对象实例化链接参数对象创建新的通道模式向绑定到指定的中发送消息，消费者从中取出数据，类似于广播模式发布订阅模式。

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：

import pika
        
        
# 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:

from base import channel, connection
        
# 声明exchange, 不声明queue
channel.exchange_declare(exchange="logs", exchange_type="fanout")  # 广播
message = "hello fanout"
channel.basic_publish(
    exchange="logs",
    routing_key="",
    body=message
)
connection.close()

consumer.py：

from base import channel, 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)


def callback(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：

from base import channel, 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：

from base import channel, 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"  
)


def callback(ch, method, properties, body):
    print("body:%s" % body)


channel.basic_consume(
    callback,
    queue=queue_name
)


channel.start_consuming()

consumer02.py：

from base import channel, 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"   
)


def callback(ch, method, properties, bosy):
    print("body:%s" % body)


channel.basic_consume(
    callback,
    queue=queue_name
)


channel.start_consuming()

consumer03.py：

from base import channel, 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"]
for key in key_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  
    )


def callback(ch, method, properties, body):
    print("body:%s" % body)


channel.basic_consume(
    callback,
    queue=queue_name
)


channel.start_consuming()

执行:

python producer.py
python consumer01.py
python consumer02.py
python consumer03.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：

import sys
from base import channel, connection


# 声明exchange
channel.exchange_declare(exchange="topic_test", exchange_type="topic")

# 待发送消息
message = " ".join(sys.argv[1:]) or "hello topic"

# 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:

from base import channel, 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
)


def callback(ch, method, properties, body):
    print("body:%s" % body)


channel.basic_consume(
    callback,
    queue=queue_name,
    no_ack=True
)


channel.start_consuming()

consumer02.py:

from base import channel, 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
)


def callback(ch, method, properties, body):
    print("body:%s" % body)


channel.basic_consume(
    callback,
    queue=queue_name,
    no_ack=True
)


channel.start_consuming()

执行:

python publisher02.py "this is a topic test"
python consumer01.py
python consumer02.py

结果:

consumer01.py的结果: body:b"this is a topic test"
consumer02.py的结果: body:b"this is a topic test"

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:

python publisher02.py "this is a topic test"
python consumer01.py
python consumer02.py

结果:

consumer01.py没收到结果
consumer02.py的结果: body:b"this is a topic test"

通过这个例子我们就能明白topic的运行方式了。

参考自： https://blog.csdn.net/fgf00/a...

今天就说到这里，如有问题，欢迎交流指正！