一 消息队列介绍 1.1 介绍 消息队列就是基础数据结构中的“先进先出”的一种数据机构。想一下,生活中买东西,需要排队,先排的人先买消费,就是典型的“先进先出”
1.2 MQ解决什么问题 MQ是一直存在,不过随着微服务架构的流行,成了解决微服务之间问题的常用工具。
应用解耦 以电商应用为例,应用中有订单系统、库存系统、物流系统、支付系统。用户创建订单后,如果耦合调用库存系统、物流系统、支付系统,任何一个子系统出了故障,都会造成下单操作异常。
当转变成基于消息队列的方式后,系统间调用的问题会减少很多,比如物流系统因为发生故障,需要几分钟来修复。在这几分钟的时间里,物流系统要处理的内存被缓存在消息队列中,用户的下单操作可以正常完成。当物流系统恢复后,继续处理订单信息即可,中单用户感受不到物流系统的故障。提升系统的可用性
流量消峰 举个栗子,如果订单系统最多能处理一万次订单,这个处理能力应付正常时段的下单时绰绰有余,正常时段我们下单一秒后就能返回结果。但是在高峰期,如果有两万次下单操作系统是处理不了的,只能限制订单超过一万后不允许用户下单。
使用消息队列做缓冲,我们可以取消这个限制,把一秒内下的订单分散成一段时间来处理,这事有些用户可能在下单十几秒后才能收到下单成功的操作,但是比不能下单的体验要好。
消息分发 多个服务队数据感兴趣,只需要监听同一类消息即可处理。
例如A产生数据,B对数据感兴趣。如果没有消息的队列A每次处理完需要调用一下B服务。过了一段时间C对数据也感性,A就需要改代码,调用B服务,调用C服务。只要有服务需要,A服务都要改动代码。很不方便。
有了消息队列后,A只管发送一次消息,B对消息感兴趣,只需要监听消息。C感兴趣,C也去监听消息。A服务作为基础服务完全不需要有改动
异步消息
有些服务间调用是异步的,例如A调用B,B需要花费很长时间执行,但是A需要知道B什么时候可以执行完,以前一般有两种方式,A过一段时间去调用B的查询api查询。或者A提供一个callback api,B执行完之后调用api通知A服务。这两种方式都不是很优雅
使用消息总线,可以很方便解决这个问题,A调用B服务后,只需要监听B处理完成的消息,当B处理完成后,会发送一条消息给MQ,MQ会将此消息转发给A服务。
这样A服务既不用循环调用B的查询api,也不用提供callback api。同样B服务也不用做这些操作。A服务还能及时的得到异步处理成功的消息
1.3 常见消息队列及比较
结论:
Kafka在于分布式架构,RabbitMQ基于AMQP协议来实现,RocketMQ/思路来源于kafka,改成了主从结构,在事务性可靠性方面做了优化。广泛来说,电商、金融等对事务性要求很高的,可以考虑RabbitMQ和RocketMQ,对性能要求高的可考虑Kafka
二 Rabbitmq安装 官网:https://www.rabbitmq.com/getstarted.html
2.1 服务端原生安装 1 2 3 4 5
# 安装配置epel源 # 安装erlang yum -y install erlang # 安装RabbitMQ yum -y install rabbitmq-server
2.2 服务端Docker安装 1 2
docker pull rabbitmq:management docker run -di --name Myrabbitmq -e RABBITMQ_DEFAULT_USER=admin -e RABBITMQ_DEFAULT_PASS=admin -p 15672:15672 -p 5672:5672 rabbitmq:managemen
2.3 客户端安装 2.4 设置用户和密码 1 2 3 4 5 6 7 8 9 10
rabbitmqctl add_user lqz 123 # 设置用户为administrator角色 rabbitmqctl set_user_tags lqz administrator # 设置权限 rabbitmqctl set_permissions -p "/" root ".*" ".*" ".*" # 然后重启rabbiMQ服务 systemctl reatart rabbitmq-server # 然后可以使用刚才的用户远程连接rabbitmq server了。
三 基于Queue实现生产者消费者模型 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20
import Queue import threading message = Queue.Queue(10) def producer(i): while True: message.put(i) def consumer(i): while True: msg = message.get() for i in range(12): t = threading.Thread(target=producer, args=(i,)) t.start() for i in range(10): t = threading.Thread(target=consumer, args=(i,)) t.start()
四 基本使用(生产者消费者模型) 对于RabbitMQ来说,生产和消费不再针对内存里的一个Queue对象,而是某台服务器上的RabbitMQ Server实现的消息队列。
生产者 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
import pika # 无密码 # cOnnection= pika.BlockingConnection(pika.ConnectionParameters('127.0.0.1')) # 有密码 credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 声明一个队列(创建一个队列) channel.queue_declare(queue='lqz') channel.basic_publish(exchange='', routing_key='lqz', # 消息队列名称 body='hello world') connection.close()
消费者 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 声明一个队列(创建一个队列) channel.queue_declare(queue='lqz') def callback(ch, method, properties, body): print("消费者接受到了任务: %r" % body) channel.basic_consume(queue='lqz',on_message_callback=callback,auto_ack=True) channel.start_consuming()
五 消息安全之ack 生产者 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
import pika # 无密码 # cOnnection= pika.BlockingConnection(pika.ConnectionParameters('127.0.0.1')) # 有密码 credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 声明一个队列(创建一个队列) channel.queue_declare(queue='lqz') channel.basic_publish(exchange='', routing_key='lqz', # 消息队列名称 body='hello world') connection.close()
消费者 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 声明一个队列(创建一个队列) channel.queue_declare(queue='lqz') def callback(ch, method, properties, body): print("消费者接受到了任务: %r" % body) # 通知服务端,消息取走了,如果auto_ack=False,不加下面,消息会一直存在 # ch.basic_ack(delivery_tag=method.delivery_tag) channel.basic_consume(queue='lqz',on_message_callback=callback,auto_ack=False) channel.start_consuming()
六 消息安全之durable持久化 生产者 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
import pika # 无密码 # cOnnection= pika.BlockingConnection(pika.ConnectionParameters('127.0.0.1')) # 有密码 credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 声明一个队列(创建一个队列),durable=True支持持久化,队列必须是新的才可以 channel.queue_declare(queue='lqz1',durable=True) channel.basic_publish(exchange='', routing_key='lqz1', # 消息队列名称 body='111', properties=pika.BasicProperties( delivery_mode=2, # make message persistent,消息也持久化 ) ) connection.close()
消费者 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 声明一个队列(创建一个队列) channel.queue_declare(queue='lqz1') def callback(ch, method, properties, body): print("消费者接受到了任务: %r" % body) # 通知服务端,消息取走了,如果auto_ack=False,不加下面,消息会一直存在 # ch.basic_ack(delivery_tag=method.delivery_tag) channel.basic_consume(queue='lqz1',on_message_callback=callback,auto_ack=False) channel.start_consuming()
七 闲置消费 正常情况如果有多个消费者,是按照顺序第一个消息给第一个消费者,第二个消息给第二个消费者
但是可能第一个消息的消费者处理消息很耗时,一直没结束,就可以让第二个消费者优先获得闲置的消息
生产者 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19
import pika # 无密码 # cOnnection= pika.BlockingConnection(pika.ConnectionParameters('127.0.0.1')) # 有密码 credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 声明一个队列(创建一个队列),durable=True支持持久化,队列必须是新的才可以 channel.queue_declare(queue='lqz123',durable=True) channel.basic_publish(exchange='', routing_key='lqz123', # 消息队列名称 body='111', properties=pika.BasicProperties( delivery_mode=2, # make message persistent,消息也持久化 ) ) connection.close()
消费者 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 声明一个队列(创建一个队列) # channel.queue_declare(queue='lqz123') def callback(ch, method, properties, body): print("消费者接受到了任务: %r" % body) # 通知服务端,消息取走了,如果auto_ack=False,不加下面,消息会一直存在 ch.basic_ack(delivery_tag=method.delivery_tag) channel.basic_qos(prefetch_count=1) #####就只有这一句话 谁闲置谁获取,没必要按照顺序一个一个来 channel.basic_consume(queue='lqz123',on_message_callback=callback,auto_ack=False) channel.start_consuming()
八 发布订阅 发布者 1 2 3 4 5 6 7 8 9 10 11 12
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() channel.exchange_declare(exchange='m1',exchange_type='fanout') channel.basic_publish(exchange='m1', routing_key='', body='lqz nb') connection.close()
订阅者(启动几次订阅者会生成几个队列) 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # exchange='m1',exchange(秘书)的名称 # exchange_type='fanout' , 秘书工作方式将消息发送给所有的队列 channel.exchange_declare(exchange='m1',exchange_type='fanout') # 随机生成一个队列 result = channel.queue_declare(queue='',exclusive=True) queue_name = result.method.queue print(queue_name) # 让exchange和queque进行绑定. channel.queue_bind(exchange='m1',queue=queue_name) def callback(ch, method, properties, body): print("消费者接受到了任务: %r" % body) channel.basic_consume(queue=queue_name,on_message_callback=callback,auto_ack=True) channel.start_consuming()
九 发布订阅高级之Routing(按关键字匹配) 发布者 1 2 3 4 5 6 7 8 9 10 11 12 13
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() channel.exchange_declare(exchange='m2',exchange_type='direct') channel.basic_publish(exchange='m2', routing_key='bnb', # 多个关键字,指定routing_key body='lqz nb') connection.close()
订阅者1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # exchange='m1',exchange(秘书)的名称 # exchange_type='direct' , 秘书工作方式将消息发送给不同的关键字 channel.exchange_declare(exchange='m2',exchange_type='direct') # 随机生成一个队列 result = channel.queue_declare(queue='',exclusive=True) queue_name = result.method.queue print(queue_name) # 让exchange和queque进行绑定. channel.queue_bind(exchange='m2',queue=queue_name,routing_key='nb') channel.queue_bind(exchange='m2',queue=queue_name,routing_key='bnb') def callback(ch, method, properties, body): print("消费者接受到了任务: %r" % body) channel.basic_consume(queue=queue_name,on_message_callback=callback,auto_ack=True) channel.start_consuming()
订阅者2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # exchange='m1',exchange(秘书)的名称 # exchange_type='direct' , 秘书工作方式将消息发送给不同的关键字 channel.exchange_declare(exchange='m2',exchange_type='direct') # 随机生成一个队列 result = channel.queue_declare(queue='',exclusive=True) queue_name = result.method.queue print(queue_name) # 让exchange和queque进行绑定. channel.queue_bind(exchange='m2',queue=queue_name,routing_key='nb') def callback(ch, method, properties, body): print("消费者接受到了任务: %r" % body) channel.basic_consume(queue=queue_name,on_message_callback=callback,auto_ack=True) channel.start_consuming()
九 发布订阅高级之Topic(按关键字模糊匹配) 发布者 1 2 3 4 5 6 7 8 9 10 11 12 13
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() channel.exchange_declare(exchange='m3',exchange_type='topic') channel.basic_publish(exchange='m3', # routing_key='lqz.handsome', #都能收到 routing_key='lqz.handsome.xx', #只有lqz.#能收到 body='lqz nb') connection.close()
订阅者1 *只能加一个单词
#可以加任意单词字符
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # exchange='m1',exchange(秘书)的名称 # exchange_type='direct' , 秘书工作方式将消息发送给不同的关键字 channel.exchange_declare(exchange='m3',exchange_type='topic') # 随机生成一个队列 result = channel.queue_declare(queue='',exclusive=True) queue_name = result.method.queue print(queue_name) # 让exchange和queque进行绑定. channel.queue_bind(exchange='m3',queue=queue_name,routing_key='lqz.#') def callback(ch, method, properties, body): print("消费者接受到了任务: %r" % body) channel.basic_consume(queue=queue_name,on_message_callback=callback,auto_ack=True) channel.start_consuming()
订阅者2 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # exchange='m1',exchange(秘书)的名称 # exchange_type='topic' , 模糊匹配 channel.exchange_declare(exchange='m3',exchange_type='topic') # 随机生成一个队列 result = channel.queue_declare(queue='',exclusive=True) queue_name = result.method.queue print(queue_name) # 让exchange和queque进行绑定. channel.queue_bind(exchange='m3',queue=queue_name,routing_key='lqz.*') def callback(ch, method, properties, body): queue_name = result.method.queue # 发送的routing_key是什么 print("消费者接受到了任务: %r" % body) channel.basic_consume(queue=queue_name,on_message_callback=callback,auto_ack=True) channel.start_consuming()
十 基于rabbitmq实现rpc 服务端 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22
import pika credentials = pika.PlainCredentials("admin","admin") cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166',credentials=credentials)) channel = connection.channel() # 起翰监听任务队列 channel.queue_declare(queue='rpc_queue') def on_request(ch, method, props, body): n = int(body) respOnse= n + 100 # props.reply_to 要放结果的队列. # props.correlation_id 任务 ch.basic_publish(exchange='', routing_key=props.reply_to, properties=pika.BasicProperties(correlation_id= props.correlation_id), body=str(response)) ch.basic_ack(delivery_tag=method.delivery_tag) channel.basic_qos(prefetch_count=1) channel.basic_consume( queue='rpc_queue',on_message_callback=on_request,) channel.start_consuming()
客户端 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41
import pika import uuid class FibonacciRpcClient(object): def __init__(self): credentials = pika.PlainCredentials("admin", "admin") self.cOnnection= pika.BlockingConnection(pika.ConnectionParameters('101.133.225.166', credentials=credentials)) self.channel = self.connection.channel() # 随机生成一个消息队列(用于接收结果) result = self.channel.queue_declare(queue='',exclusive=True) self.callback_queue = result.method.queue # 监听消息队列中是否有值返回,如果有值则执行 on_response 函数(一旦有结果,则执行on_response) self.channel.basic_consume(queue=self.callback_queue,on_message_callback=self.on_response, auto_ack=True) def on_response(self, ch, method, props, body): if self.corr_id == props.correlation_id: self.respOnse= body def call(self, n): self.respOnse= None self.corr_id = str(uuid.uuid4()) # 客户端 给 服务端 发送一个任务: 任务id = corr_id / 任务内容 = '30' / 用于接收结果的队列名称 self.channel.basic_publish(exchange='', routing_key='rpc_queue', # 服务端接收任务的队列名称 properties=pika.BasicProperties( reply_to = self.callback_queue, # 用于接收结果的队列 correlation_id = self.corr_id, # 任务ID ), body=str(n)) while self.response is None: self.connection.process_data_events() return self.response fibonacci_rpc = FibonacciRpcClient() respOnse= fibonacci_rpc.call(50) print('返回结果:',response)