前言

由于工作需要，设计到了阿里云的函数计算，便记录下来

• 技术栈
  • node.js
  • postgresql
  • nodemailer

controller + services

• 编写postgresql lib

  不管异常还是正常都返回resolve，在resolve中处理结果，通过success字段去处理

  const { Pool } = require('pg');const config = require('../config/default.js');const {  database: {    HOST,    PORT,    DATABASE,    USERNAME,    PASSWORD,  },} = config;const pool = new Pool({  port: PORT,  host: HOST,  user: USERNAME,  password: PASSWORD,  database: DATABASE,});/** *  * @param sql 接收的sql语句 * @param {Array} values sql语句参数 * @return { Object } { success: boolean, err || data  } */const query = async function( sql = 'select NOW()', values = []) {  return new Promise(resolve => {    pool.connect((err, client, release) => {      if (err) {        return console.error('Error acquiring client', err.stack)      }      const params = Array.isArray(values) ? [...values] : [values];      client.query(sql, params, (error, result) => {        release();        if (error) {          console.error('Error executing query', error.stack);          resolve({            success: false,            error,          });        }        resolve({          success: true,          data: result.rows,        });      });    });  });}module.exports = {  query,}复制代码

  • config配置文件如下

    const config = {  // 数据库配置  database: {    DATABASE: 'databasename',    USERNAME: 'root',    PASSWORD: '123456',    PORT: '3433',    HOST: 'localhost',  },};module.exports = config;复制代码

• Controller

  • BaseController

  首先编写一个基类，用于封装一些通用的方法

  const pool = require('../lib/postgre'); // 导入封装好的mysql库const { query } = pool; // 导入query方法class BaseController {  constructor() {  }  // 查询表内所有数据（非删除）  async list() {    const sql = `select * from ${
         this.table}`;    return await query(sql);  }  // 执行方法  async excute(sql, vals = []) {    return await query(sql, vals);  }  // log 方法  log({func, err}) {    console.log(`excute function[${func}] occured error : ${err.message || err}`);  }}module.exports = BaseController;复制代码

  • InqueryController

  具体的业务逻辑Controller类

  const BaseController = require('./BaseController'); // 获得基类// 继承基类class InqueryController extends BaseController {  constructor() {    super();    this.table = 'data_table'; // 赋值table  }  // 可以重写基类的方法，如果有业务需要  async list() {    const sql = `select * from ${
         this.table} ORDER BY created_at DESC `;    return await this.excute(sql);  }  async getUnsendCustomer(vals) {    const sql = `select * from ${
         this.table} where created_at > $1 ORDER BY created_at DESC`;    // 统一在基类调用sql参数    return await this.excute(sql, vals);  }  }module.exports = InqueryController;复制代码

• Service

  • BaseService

  统一封装的方法，基类

  // 需要绑定this的方法const funcs = [  'list',]class BaseService {  constructor() {    this.controller = null;    // 循环遍历绑定this, 在koa绑定route的时可用到    funcs.forEach(item => {      this[item] = this[item].bind(this)    });  }  // 查询方法  async list(ctx) {    if (!ctx) {      return await this.controller.list();    }    // controller返回的是一个对象，success(成功为true， 失败为false), data(成功则有此数据), err(失败则有此对象)    const { success: flag, data, error } = await this.controller.list();    if (flag) {      // success      ctx.body = {        data,        code: 200,      }    } else {      // failed      ctx.body = {        code: 500,        error,      };    }  }}module.exports = BaseService复制代码

  • InqueryService

  具体的业务逻辑

  // 导入基类const BaseService = require('./BaseService');// 导入对应的controllerconst Controller = require('../controller/InqueryController');// 获取MailSender Serviceconst MailService = require('./MailSender');const Helper = require('../util/Helper');const funcs = [  'unsendUser',];// 生成一次controllerconst controller = new Controller();class InqueryService extends BaseService {  constructor() {    super()    // 绑定对应的controller    this.controller = controller;    funcs.forEach(item => {      this[item] = this[item].bind(this);    });  }  getMailOpts(i) {    // you can use the data from database to combine the message    const message = 'Hello world!';    return return {        message,        // 可以从配置文件读取或者oss        to: 'xxxx@gmail.com',        subject: 'Hello World',    };  }    async unsendUser() {    const list = await this.controller.list();    if (list.length > 0) {      const mailer = new MailService();      const errorList = [];      iterateList.forEach(async i => {        const mailerOption = this.getMailOpts(i);        const { success, ...rest } = await mailer.sendToAuitAdmin(mailerOption);        if (!success) {          errorList.push(rest);        }      });      const lastestTime = iterateList[0].created_at;      if (errorList.length === 0) {        return {            code: 200,            message: 'Success',        };      }    } else {      return {        code: 204,        message: 'No user found',      };    }  }}module.exports = new InqueryService();复制代码

• index.js

函数计算的逻辑

const inqueryService = require('./services/InqueryService'); exports.handler = async function(event, context, callback) {   const result = await inqueryService.unsendUser();   callback(null, result);};复制代码