RabbitMQ - 6 rpc
作者:互联网
消息属性 AMQP 0-9-1协议预定义了消息附带的14个属性集。除以下内容外,大多数属性很少使用: delivery_mode:将消息标记为持久性(值为2)或瞬态(任何其他值)。可能还记得第二个教程中的此属性。 content_type:用于描述编码的mime类型。例如,对于经常使用的JSON编码,将此属性设置为application / json是一个好习惯。 reply_to:通常用于命名回调队列。 related_id:用于将RPC响应与请求相关联。在队列中收到响应后,尚不清楚响应属于哪个请求。那就是使用correlation_id属性的时候。每个请求的唯一值。
Putting it all together
server.py
#!/usr/bin/env python import pika connection = pika.BlockingConnection( pika.ConnectionParameters(host='localhost')) channel = connection.channel() channel.queue_declare(queue='rpc_queue') def fib(n): if n == 0: return 0 elif n == 1: return 1 else: return fib(n - 1) + fib(n - 2) def on_request(ch, method, props, body): n = int(body) print(" [.] fib(%s)" % n) response = fib(n) 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) print(" [x] Awaiting RPC requests") channel.start_consuming()
- 我们可能要运行多个服务器进程。为了将负载平均分配到多个服务器上,我们需要设置 prefetch_count设置。
client.py
#!/usr/bin/env python import pika import uuid class FibonacciRpcClient(object): def __init__(self): self.connection = pika.BlockingConnection( pika.ConnectionParameters(host='localhost')) self.channel = self.connection.channel() result = self.channel.queue_declare(queue='', exclusive=True) self.callback_queue = result.method.queue 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()) self.channel.basic_publish( exchange='', routing_key='rpc_queue', properties=pika.BasicProperties( reply_to=self.callback_queue, correlation_id=self.corr_id, ), body=str(n)) while self.response is None: self.connection.process_data_events() # 该方法定时自动向RabbitMQ的消息代理发送心跳包来维持当前连接 return int(self.response) fibonacci_rpc = FibonacciRpcClient() print(" [x] Requesting fib(30)") response = fibonacci_rpc.call(30) print(" [.] Got %r" % response)
标签:pika,self,RabbitMQ,id,queue,rpc,response,channel 来源: https://www.cnblogs.com/liuwei0824/p/14736377.html