Node&RabbitMQ系列三 重连

// !应该写断言的。。。下次
import * as assert from 'assert'
import * as amqp from 'amqplib'
import * as consumer from './consumer'


// 连接配置：https://www.squaremobius.net/amqp.node/channel_api.html#connect
// url | config
const config = {
    protocol: 'amqp',
    hostname: 'localhost',
    port: 5672,
    username: 'guest',
    password: 'guest',
    // 最大连接数，0:无限
    // the size in bytes of the maximum frame allowed over the connection. 0 means no limit (but since frames have a size field which is an unsigned 32 bit integer, it’s perforce 2^32 - 1); I default it to 0x1000, i.e. 4kb, which is the allowed minimum, will fit many purposes, and not chug through Node.JS’s buffer pooling.
    frameMax: 0,
    // 心跳周期
    heartbeat: 0,
}

let connect: amqp.Connection;
// 最大连接次数...
let maxConnectTimes = 0;
let isConnect = false;
export const init = async () => {
    try {
        connect = await amqp.connect(config);
        // 监听error\close，重新连接
        connect.on('error', err => {
            reconnect(err, 'error');
        });
        // 什么时候会触发？网络异常、服务异常、管理后台删除
        connect.on('close', err => {
            reconnect(err, 'close');
        });
        console.info('[x]Rabbitmq connect success');
        // !注册执行消费者
        // 可以根据需求，多写几个？
        consumer.run(connect);
        return connect;
    } catch (error) {
        reconnect(error, 'catch');
    }

}

const reconnect = (err, event) => {
    // 因为后台删除连接，会同时触发error、close, 为了不一次创建两个，所以做个限制
    if (!isConnect) {
        isConnect = true;
        maxConnectTimes++;
        console.error(`[x]Lost connection to RMQ. reconnectingCount: ${maxConnectTimes}. Reconnecting in 10 seconds...`);
        console.error('[x]Rabbitmq close: ', event, err);
        // 5秒连接一次
        return setTimeout(init, 1000 * 5);
    }
}

// 公用这个连接
export const connection = () => {
    return connect;
}

import * as http from 'http'
import * as rabbitmq from './rabbitmq';
import * as producer from './producer';

/** 
 * 实现功能
 * 1. 启动node服务 && 初始化rabbitmq <包含：重联、启动消费端>
 * 2. 接口请求：http://127.0.0.1:3000/producer； 触发【生产者生产信息】
 * 3. 【消费端】
 *      1. 监听队列进行消费
 *      2. 限流，其实设置一下参数就行了
 *      3. 待完成：根据业务，扔到死信队列 ？
*/

http.createServer((req, res) => {
    if (req.url === '/producer') {
        producer.publish();
    }
    res.end('hello world')
}).listen(3000, () => {
    rabbitmq.init();
    console.log('开启端口3000')
})

async function consumer(args: {exchange, queue, routingKey, connection}, cb: (msg: any, channel: any) => void){
    // 常规操作
    const channel = await args.connection.createChannel();
    await channel.assertExchange(args.exchange, 'direct', {durable: false});
    const queueA = await channel.assertQueue(args.queue, {exclusive: false});
    await channel.bindQueue(queueA.queue, args.exchange, args.routingKey);
    // !消费端限流
    await channel.prefetch(1, false);
    // 消费队列
    await channel.consume(queueA.queue, msg => {
        cb(msg, channel);
    });
}


export const run = (connection) => {
    consumer({
        exchange: 'order.exchange',
        routingKey: 'order.routingKey',
        queue: 'order.queue',
        connection,
    }, async (msg, channel) => {
        const data = msg.content.toString();
        console.info(`${(new Date()).getMinutes()}:${(new Date()).getSeconds()} consumer msg：%j`, data);
        console.log('msg: ', msg)
        return setTimeout(function () {
            try {
                /**
                 * 针对队列信息进行业务操作
                 * 1. 直接消费
                 * 2. 重回队列
                 * 3. 扔到死信队列
                */
               channel.ack(msg);
                // if(Number(data) < 6) {
                //     // 手动ack
                //     channel.ack(msg);
                // } else {
                //     // !1. 重回队列
                //     channel.nack(msg);
                //     // !2. 扔到死信队列
                //     // 下个demo再整理。
                // }
            } catch (err) {
                console.error('消息 Ack Error：', err)
            }
            // 每隔1s执行一个任务
        }, 1000);
    })
}