Loader

// 应用配置
// package.json
{
  "dependencies": {
    "egg": "^2.0.0",
    "egg-mysql": "^3.0.0"
  }
}

// config/plugin.js
module.exports = {
  mysql: {
    enable: true,
    package: 'egg-mysql',
  },
}

// 框架配置
// package.json
{
  "name": "framework1",
  "version": "1.0.0",
  "dependencies": {
    "egg-mysql": "^3.0.0",
    "egg-view-nunjucks": "^2.0.0"
  }
}

// config/plugin.js
module.exports = {
  mysql: {
    enable: false,
    package: 'egg-mysql',
  },
  view: {
    enable: false,
    package: 'egg-view-nunjucks',
  }
}

// 应用配置
// package.json
{
  "dependencies": {
    "framework1": "^1.0.0",
  }
}

// config/plugin.js
module.exports = {
  // 开启插件
  mysql: true,
  view: true,
}

// app.js
console.time('app before start 200ms');
console.time('app before start 100ms');

app.beforeStart(async () => {
  await sleep(200);
  console.timeEnd('app before start 200ms');
});

app.beforeStart(async () => {
  await sleep(100);
  console.timeEnd('app before start 100ms');
});

app.on('server', () => {
  console.log('server is ready');
});

app.ready(() => {
  console.log('app ready');
  cp.execSync(`kill ${process.ppid}`);
  console.time('app before close 100ms');
  console.time('app before close 200ms');
});

app.beforeClose(async () => {
  await sleep(200);
  console.timeEnd('app before close 200ms');
});

app.beforeClose(async () => {
  await sleep(100);
  console.timeEnd('app before close 100ms');
});

// agent.js
console.time('agent before start 200ms');
console.time('agent before start 100ms');

agent.beforeStart(async () => {
  await sleep(200);
  console.timeEnd('agent before start 200ms');
});

agent.beforeStart(async () => {
  await sleep(100);
  console.timeEnd('agent before start 100ms');
});

agent.ready(() => {
  console.log('agent ready');
  console.time('agent before close 200ms');
  console.time('agent before close 100ms');
});

agent.beforeClose(async () => {
  await sleep(200);
  console.timeEnd('agent before close 200ms');
});

agent.beforeClose(async () => {
  await sleep(100);
  console.timeEnd('agent before close 100ms');
});

// 自定义 AppWorkerLoader
// lib/framework.js
const path = require('path');
const egg = require('egg');
const EGG_PATH = Symbol.for('egg#eggPath');

class YadanAppWorkerLoader extends egg.AppWorkerLoader {
  constructor(opt) {
    super(opt);
    // 自定义初始化
  }

  loadConfig() {
    super.loadConfig();
    // 对 config 进行处理
  }

  load() {
    super.load();
    // 自定义加载其他目录
    // 或对已加载的文件进行处理
  }
}

class Application extends egg.Application {
  get [EGG_PATH]() {
    return path.dirname(__dirname);
  }
  // 覆盖 Egg 的 Loader，启动时使用这个 Loader
  get [EGG_LOADER]() {
    return YadanAppWorkerLoader;
  }
}

module.exports = Object.assign(egg, {
  Application,
  // 自定义的 Loader 也需要 export，上层框架需要基于这个扩展
  AppWorkerLoader: YadanAppWorkerLoader,
});

// app/xx.js
module.exports = app => {
  console.log(app.config);
};

// app.js
// 以 app/xx.js 为例，我们可以在 app.js 加载这个文件
const path = require('path');
module.exports = app => {
  app.loader.loadFile(path.join(app.config.baseDir, 'app/xx.js'));
};

// app.js
// 以下只是示例，加载 controller 请用 loadController
module.exports = app => {
  const directory = path.join(app.config.baseDir, 'app/controller');
  app.loader.loadToApp(directory, 'controller');
};

// 以下为示例，请使用 loadService
// app/service/user.js
const Service = require('egg').Service;
class UserService extends Service {

}
module.exports = UserService;

// app.js
// 获取所有的 loadUnit
const servicePaths = app.loader.getLoadUnits().map(unit => path.join(unit.path, 'app/service'));

app.loader.loadToContext(servicePaths, 'service', {
  // service 需要继承 app.Service，所以要拿到 app 参数
  // 设置 call 在加载时会调用函数返回 UserService
  call: true,
  // 将文件加载到 app.serviceClasses
  fieldClass: 'serviceClasses',
});

app.loader.loadToApp(directory, 'controller', {
  // 忽略 app/controller/util 下的文件
  ignore: 'util/**',
});

// app/model/user.js
module.exports = class User {
  constructor(app, path) {}
}

// 从 app/model 目录加载，加载时可做一些初始化处理
const directory = path.join(app.config.baseDir, 'app/model');
app.loader.loadToApp(directory, 'model', {
  initializer(model, opt) {
    // 第一个参数为 export 的对象
    // 第二个参数为一个对象，只包含当前文件的路径
    return new model(app, opt.path);
  },
});