配置定时工作
定时工作也就是由工夫触发的执行过程，属于很常见的业务逻辑。Unix 在晚期版本就提供了定时任务调度模块 Cron，并在各类 Linux 零碎上沿用至今。Cron 的配置文件 crontab 具备全面却清晰的格局，可能解决大多数场景下的定时工作配置问题，企业级服务器能够应用类 crontab 的格局灵便配置的各种定时工作逻辑，以下为 crontab 的格局：
# Example of job definition:# .---------------- minute (0 - 59)# | .------------- hour (0 - 23)# | | .---------- day of month (1 - 31)# | | | .------- month (1 - 12) OR jan,feb,mar,apr ...# | | | | .---- day of week (0 - 6) (Sunday=0 or 7) OR sun,mon,tue,wed,thu,fri,sat# | | | | |# * * * * * user-name command to be executed本章将基于上一章已实现的工程 host1-tech/nodejs-server-examples - 10-log 通过 node-schedule 以相似 crontab 的形式配置定时工作，检测可能含有网络攻击的店铺信息并通过 nodemailer 将可疑店铺信息邮件发送给管理员。在工程根目录执行 node-schedule 与 nodemailer 的装置命令：
$ yarn add node-schedule nodemailer # 本地装置 node-schedule、nodemailer# ...info Direct dependencies├─ node-schedule@1.3.2└─ nodemailer@6.4.11# ...网络攻击巡检
当初实现对网络攻击信息的定时检测与报警的逻辑。先补充服务层逻辑：
// src/services/shop.jsconst { Shop } = require('../models');class ShopService { async init() {}- async find({ id, pageIndex = 0, pageSize = 10, logging }) {+ async find({ id, pageIndex = 0, pageSize = 10, where, logging }) { if (id) { return [await Shop.findByPk(id, { logging })]; } return await Shop.findAll({ offset: pageIndex * pageSize, limit: pageSize,+ where, logging, }); } // ...}// ...// src/services/mail.jsconst { promisify } = require('util');const nodemailer = require('nodemailer');const { mailerOptions } = require('../config');class MailService { mailer; async init() { this.mailer = nodemailer.createTransport(mailerOptions); await promisify(this.mailer.verify)(); } async sendMail(params) { return await this.mailer.sendMail({ from: mailerOptions.auth.user, ...params, }); }}let service;module.exports = async () => { if (!service) { service = new MailService(); await service.init(); } return service;};// src/config/index.jsconst merge = require('lodash.merge');const logger = require('../utils/logger');const { logging } = logger;const config = { // 默认配置 default: { // ...+ mailerOptions: {+ host: 'smtp.126.com',+ port: 465,+ secure: true,+ logger: logger.child({ type: 'mail' }),+ auth: {+ user: process.env.MAILER_USER,+ pass: process.env.MAILER_PASS,+ },+ }, }, // ...};// ...# .env.localGITHUB_CLIENT_ID='b8ada004c6d682426cfb'GITHUB_CLIENT_SECRET='0b13f2ab5651f33f879a535fc2b316c6c731a041'++MAILER_USER='ht_nse@126.com'+MAILER_PASS='CAEJHSTBWNOKHRVL'留神因为利用节点可能不止 1 个，执行巡检时将应用分布式锁限度执行节点数量以防止反复报警，这里借助数据库来实现分布式锁：
$ # 生成定时工作锁的 model 文件与 schema 迁徙文件$ yarn sequelize model:generate --name scheduleLock --attributes name:string,counter:integer$ # 将 src/models/schedulelock.js 命名为 src/models/scheduleLock.js$ mv src/models/schedulelock.js src/models/scheduleLock.js$ tree src/models # 展现 src/models 目录内容构造src/models├── config│ └── index.js├── index.js├── migrate│ ├── 20200725045100-create-shop.js│ ├── 20200727025727-create-session.js│ └── 20200801120113-create-schedule-lock.js├── scheduleLock.js├── seed│ └── 20200725050230-first-shop.js└── shop.js调整 src/models/scheduleLock.js 与 src/models/migrate/20200801120113-create-schedule-lock.js：
// src/models/scheduleLock.jsconst { Model } = require('sequelize');module.exports = (sequelize, DataTypes) => { class scheduleLock extends Model { /** * Helper method for defining associations. * This method is not a part of Sequelize lifecycle. * The `models/index` file will call this method automatically. */ static associate(models) { // define association here } } scheduleLock.init( { name: DataTypes.STRING, counter: DataTypes.INTEGER, }, { sequelize, modelName: 'ScheduleLock', tableName: 'schedule_lock', } ); return scheduleLock;};// src/models/migrate/20200801120113-create-schedule-lock.jsmodule.exports = { up: async (queryInterface, Sequelize) => { await queryInterface.createTable('schedule_lock', { id: { allowNull: false, autoIncrement: true, primaryKey: true, type: Sequelize.INTEGER, }, name: { type: Sequelize.STRING, }, counter: { type: Sequelize.INTEGER, }, created_at: { allowNull: false, type: Sequelize.DATE, }, updated_at: { allowNull: false, type: Sequelize.DATE, }, }); }, down: async (queryInterface, Sequelize) => { await queryInterface.dropTable('schedule_lock'); },};而后写入巡检逻辑：
$ mkdir src/schedules # 新建 src/schedules 寄存定时工作$ tree src -L 1 # 展现 src 目录内容构造src├── config├── controllers├── middlewares├── models├── moulds├── schedules├── server.js├── services└── utils// src/schedules/inspectAttack.jsconst { basename } = require('path');const schedule = require('node-schedule');const { sequelize, ScheduleLock, Sequelize } = require('../models');const mailService = require('../services/mail');const shopService = require('../services/shop');const escapeHtmlInObject = require('../utils/escape-html-in-object');const logger = require('../utils/logger');const { Op } = Sequelize;// 当前任务的锁名称const LOCK_NAME = basename(__dirname);// 锁的最长占用工夫const LOCK_TIMEOUT = 15 * 60 * 1000;// 分布式工作并发数const CONCURRENCY = 1;// 报警邮件发送对象const MAIL_RECEIVER = 'licg9999@126.com';class InspectAttack { mailService; shopService; async init() { this.mailService = await mailService(); this.shopService = await shopService(); // 每到 15 分时巡检一次 schedule.scheduleJob('*/15 * * * *', this.findAttackedShopInfoAndSendMail); } findAttackedShopInfoAndSendMail = async () => { // 上锁 const lockUpT = await sequelize.transaction(); try { const [lock] = await ScheduleLock.findOrCreate({ where: { name: LOCK_NAME }, defaults: { name: LOCK_NAME, counter: 0 }, transaction: lockUpT, }); if (lock.counter >= CONCURRENCY) { if (Date.now() - lock.updatedAt.valueOf() > LOCK_TIMEOUT) { lock.counter--; await lock.save({ transaction: lockUpT }); } await lockUpT.commit(); return; } lock.counter++; await lock.save({ transaction: lockUpT }); await lockUpT.commit(); } catch (err) { logger.error(err); await lockUpT.rollback(); return; } try { // 寻找异样数据 const shops = await this.shopService.find({ pageSize: 100, where: { name: { [Op.or]: [{ [Op.like]: '<%' }, { [Op.like]: '%>' }] }, }, }); // 发送报警邮件 if (shops.length) { const subject = '平安正告，发现可疑店铺信息！'; const html = ` <div>以下是服务器巡检发现的疑似含有网络攻击的店铺信息：</div> <pre> ${shops .map((shop) => JSON.stringify(escapeHtmlInObject(shop), null, 2)) .join('\n')} </pre>`; await this.mailService.sendMail({ to: MAIL_RECEIVER, subject, html }); } } catch {} // 解锁 const lockDownT = await sequelize.transaction(); try { const lock = await ScheduleLock.findOne({ where: { name: LOCK_NAME }, transaction: lockDownT, }); if (lock.counter > 0) { lock.counter--; await lock.save({ transaction: lockDownT }); } await lockDownT.commit(); } catch { await lockDownT.rollback(); } };}module.exports = async () => { const s = new InspectAttack(); await s.init();};// src/schedules/index.jsconst inspectAttackSchedule = require('./inspectAttack');module.exports = async function initSchedules() { await inspectAttackSchedule();};// src/server.jsconst express = require('express');const { resolve } = require('path');const { promisify } = require('util');const initMiddlewares = require('./middlewares');const initControllers = require('./controllers');+const initSchedules = require('./schedules');const logger = require('./utils/logger');const server = express();const port = parseInt(process.env.PORT || '9000');const publicDir = resolve('public');const mouldsDir = resolve('src/moulds');async function bootstrap() { server.use(await initMiddlewares()); server.use(express.static(publicDir)); server.use('/moulds', express.static(mouldsDir)); server.use(await initControllers()); server.use(errorHandler);+ await initSchedules(); await promisify(server.listen.bind(server, port))(); logger.info(`> Started on port ${port}`);}// ...查看报警
在新增两个含有网络攻击的店铺信息之后，即可在分钟数为 15 的倍数时收到一则正告邮件：
本章源码
host1-tech/nodejs-server-examples - 11-schedule
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