python使用redis实现消息队列（异步实现）完整例程

python使用redis实现消息队列(异步编程)

最近在用fastapi框架开发web后端，由于近几年python异步编程大火，fastapi凭借高性能也火了起来。本篇介绍了在异步环境下实现redis消息队列的方法，代码可以直接拷贝到fastapi中使用。

安装相关库

pip install aioredis

消息队列实现及使用

我们使用redis的stream类型作为消息队列的载体

首先我们创建一个目录作为项目目录：works/

创建配置文件

在项目根目录下新建文件works/.env
在文件中写入

export APP_ENV=development

export REDIS_URL="192.168.70.130/"
export REDIS_USER=
export REDIS_PASSWORD=
export REDIS_HOST="192.168.70.130"
export REDIS_PORT=6379

代码实现

在项目目录下创建py文件works/main.py

import os
from dotenv import load_dotenv
import aioredis
import asyncio

load_dotenv()

class Redis():
    def __init__(self):
        """initialize  connection """
        self.REDIS_URL = os.environ['REDIS_URL']
        self.REDIS_PASSWORD = os.environ['REDIS_PASSWORD']
        self.REDIS_USER = os.environ['REDIS_USER']
        self.connection_url = f"redis://{self.REDIS_USER}:{self.REDIS_PASSWORD}@{self.REDIS_URL}"
        self.REDIS_HOST = os.environ['REDIS_HOST']
        self.REDIS_PORT = os.environ['REDIS_PORT']
        
    async def create_connection(self):
        self.connection = aioredis.from_url(
            self.connection_url, db=0)

        return self.connection


class Producer:
    def __init__(self, redis_client):
        self.redis_client = redis_client

    async def add_to_stream(self,  data: dict, stream_channel):
        """将一条数据添加到队列

        Args:
            data (dict): _description_
            stream_channel (_type_): _description_

        Returns:
            _type_: _description_
        """
        try:
            msg_id = await self.redis_client.xadd(name=stream_channel, id="*", fields=data)
            print(f"Message id {msg_id} added to {stream_channel} stream")
            return msg_id

        except Exception as e:
            raise Exception(f"Error sending msg to stream => {e}")



class StreamConsumer:
    def __init__(self, redis_client):
        self.redis_client = redis_client

    async def consume_stream(self, count: int, block: int,  stream_channel):
        """读取队列中的消息，但是并不删除

        Args:
            count (int): _description_
            block (int): _description_
            stream_channel (_type_): _description_

        Returns:
            _type_: _description_
        """
        response = await self.redis_client.xread(
            streams={stream_channel:  '0-0'}, count=count, block=block)

        return response

    async def delete_message(self, stream_channel, message_id):
        """成功消费数据后，调用此函数删除队列数据

        Args:
            stream_channel (_type_): _description_
            message_id (_type_): _description_
        """
        await self.redis_client.xdel(stream_channel, message_id)


async def main():
    redis_conn = await Redis().create_connection()
    produce = Producer(redis_conn)
    consumer = StreamConsumer(redis_conn)
    # 添加一个消息到队列中
    data = {'xiaoming4':123}
    await produce.add_to_stream(data=data,stream_channel='message_channel')
    
    # 从队列中拿出最新的1条数据
    data = await consumer.consume_stream(1,block=0,stream_channel='message_channel')
    print(data)
    
    # 轮询等待队列中的新消息
    response = await consumer.consume_stream(stream_channel="message_channel", count=1, block=0)
    if response:
        for stream, messagees in response:
            print('stream:',stream)
            for message in messagees:
                print('message: ',message)
                message_id = message[0]
                print('message_id: ',message_id)
                message_content = message[1]
                print('message_content: ',message_content)
                print('注意里面的键、值都变成了byte类型，需要进行解码:')
                message_content:dict
                print('message_content_decode: ',{k.decode('utf-8'):v.decode('utf-8') for k,v in message_content.items()})

    # 消费成功后删除队列中的消息
    await consumer.delete_message(
        stream_channel='message_channel',message_id=message_id
    )    

if __name__ == '__main__':
    asyncio.run(main())

非常简单好用，启动一下看看吧