python rabbitmq实践

sudo apt install erlang -y
sudo apt update && sudo apt install wget -y
sudo apt install apt-transport-https -y
wget -O- https://dl.bintray.com/rabbitmq/Keys/rabbitmq-release-signing-key.asc | sudo apt-key add -
wget -O- https://www.rabbitmq.com/rabbitmq-release-signing-key.asc | sudo apt-key add -

echo "deb https://dl.bintray.com/rabbitmq-erlang/debian focal erlang-22.x" | sudo tee /etc/apt/sources.list.d/rabbitmq.list

echo "deb https://dl.bintray.com/rabbitmq-erlang/debian bionic erlang-22.x" | sudo tee /etc/apt/sources.list.d/rabbitmq.list

sudo apt install rabbitmq-server -y
pip install pika

实际应用的一个例子，可参考

RabbitMQ 简介及例子，可以运行。

send.py

#!/usr/bin/env python
import pika

connection = pika.BlockingConnection(
    pika.ConnectionParameters(host='localhost'))
channel = connection.channel()

channel.queue_declare(queue='hello')

channel.basic_publish(exchange='', routing_key='hello', body='Hello World!')
print(" [x] Sent 'Hello World!'")
connection.close()

receive.py

#!/usr/bin/env python
import pika

connection = pika.BlockingConnection(
    pika.ConnectionParameters(host='localhost'))
channel = connection.channel()

channel.queue_declare(queue='hello')


def callback(ch, method, properties, body):
    print(" [x] Received %r" % body)


channel.basic_consume(
    queue='hello', on_message_callback=callback, auto_ack=True)

print(' [*] Waiting for messages. To exit press CTRL+C')
channel.start_consuming()

参考 Python使用RabbitMQ(AMQP)极简例子，可以通过网页来监视rabbitmq。

Python使用RabbitMQ实现RPC调用示例，我已经验证通过，不过rpcclient.py在sublime中正常，在命令行下有错，暂时找不到原因。

rpcserver.py

#!/usr/bin/env python3
# -*- coding: utf-8 -*-

import pika


def fib(n):
    if(n == 0):
        return 0
    if(n == 1):
        return 1
    return fib(n - 1) + fib(n - 2)


def on_request(ch, method, props, body):
    # 执行方法
    n = int(body)
    print(" [.] fib(%s)" % n)
    response = fib(n)

    # 返回消息给客户端
    ch.basic_publish(
        exchange='',
        routing_key=props.reply_to,  # 消息发送队列
        body=str(response),
        properties=pika.BasicProperties(
            correlation_id=props.correlation_id
        )
    )
    ch.basic_ack(delivery_tag=method.delivery_tag)  # 任务完成，告诉客户端


if __name__ == "__main__":
    params = pika.ConnectionParameters(host='localhost')
    connection = pika.BlockingConnection(params)
    channel = connection.channel()
    channel.queue_declare(queue='rpc_queue')  # 指定一个队列
    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()

rpcclient.py:

# coding=utf-8
import pika
import uuid
# import settings


class RPCClient:
    def __init__(self):
        params = pika.ConnectionParameters(host='localhost')
        self.connection = pika.BlockingConnection(params)
        self.channel = self.connection.channel()
        result = self.channel.queue_declare(  # 定义接收返回值队列
            queue=str(uuid.uuid4()),
            exclusive=True
        )
        self.callback_queue = result.method.queue
        self.channel.basic_consume(
            queue=self.callback_queue,
            on_message_callback=self.on_response
        )

    # 调用远程方法
    def call(self, n):
        self.response = None

        # 调用远程方法
        self.corr_id = str(uuid.uuid4())  # 调用唯一标识
        self.channel.basic_publish(
            exchange='',
            routing_key='rpc_queue',  # 消息发送队列
            properties=pika.BasicProperties(
                correlation_id=self.corr_id,
                reply_to=self.callback_queue
            ),
            body=str(n)
        )

        # 等待响应
        while self.response is None:
            self.connection.process_data_events()  # 非阻塞版的start_consuming()

        return int(self.response)

    # 接收到消息后调用

    def on_response(self, ch, method, props, body):
        # 如果收到的ID和本机生成的相同，则返回的结果就是我想要的指令返回的结果
        if(self.corr_id == props.correlation_id):
            self.response = body


if __name__ == "__main__":
    client = RPCClient()

    print(" [x] Requesting fib(7)")
    response = client.call(7)
    print(" [.] Got %r" % response)