RabbitMQ-RPC

RPC：Client向Server发送消息，Server收到后回复确认报文。即两边都同时是生产者和消费者。

代码饭粒：client发送请求第？个斐波那契数，server接到请求后返回相应的斐波那契数
# Client

import pika
import uuid
import time
class FibonacciRpcClient(object):
    def __init__(self):
        self.connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
        self.channel = self.connection.channel()
        result = self.channel.queue_declare(exclusive=True)   # 自动创建queue
        self.callback_queue = result.method.queue
        self.channel.basic_consume(   # 接收消息
            self.on_response,   # 只要一收到消息就调用on_response
            no_ack=True,
            queue=self.callback_queue
        )

    def on_response(self, ch, method, props, body):
        if self.corr_id == props.correlation_id:
            # 判断server返回的correlation_id与刚刚发送过去的corr_id是否相等,若相等则为刚刚发送消息的ACK
            self.response = body

    def call(self, n):
        self.response = None
        self.corr_id = str(uuid.uuid1())   # uuid.uuid1()：基于时间戳生成唯一ID
        self.channel.basic_publish(exchange='',   # 发送消息
                                   routing_key='rpc_queue',
                                   properties=pika.BasicProperties(
                                       reply_to=self.callback_queue,
                                       correlation_id=self.corr_id,
                                   ),
                                   body=str(n))   # 不能发送数字，所以要转成str
        while self.response is None:
            self.connection.process_data_events()   # 相当于非阻塞版的start_consuming()
            print("no message...")
            time.sleep(0.5)
        return int(self.response)

fibonacci_rpc = FibonacciRpcClient()
print(" [x] Requesting fib(10)")
response = fibonacci_rpc.call(10)
print(" [.] Got %r" % response)

# Server

import pika
import time
connection = pika.BlockingConnection(pika.ConnectionParameters(host='localhost'))
channel = connection.channel()
channel.queue_declare(queue='rpc_queue')

def fib(n):   # 生成斐波那契数
    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='',   # 发送消息
                     routing_key=props.reply_to,   # 发送到client发过来的reply队列
                     properties=pika.BasicProperties(correlation_id= \
                                                         props.correlation_id),
                     # 将client发送过来的corr_id发回去,用于client验证消息对应的ACK
                     body=str(response))
    ch.basic_ack(delivery_tag=method.delivery_tag)

channel.basic_consume(on_request,    # 只要一收到消息就调用on_request
                      queue='rpc_queue')
print(" [x] Awaiting RPC requests")
channel.start_consuming()