微信云函数底层实现的合理乱猜

import * as vm from 'vm';

/**
 * 运行云函数
 */
async function runCloudFunction(sourceCode: string, args: Record<string, any>) {
  // 在虚拟机中解析云函数的源码
  const script = new vm.Script(sourceCode);

  // 执行云函数
  const cloudFn = await script.runInThisContext();
  const fnResult = await cloudFn(args);

  // 返回云函数的执行结果
  return fnResult;
}

/**
 * 执行云函数
 */
async function invokeCloudFunction(
  fnName: string,
  fnArgs: Record<string, any>
) {
  try {
    const fnUrl = `https://cdn.xxx.com/xxx/assets/${fnName}/index.js`;
    const fnCode = await fetch(fnUrl).then(res => res.text());
    const fnResult = await runCloudFunction(fnCode, fnArgs);

    return { success: true, message: 'success', result: fnResult };
  } catch (e) {
    return { success: false, message: e.message, result: null };
  }
}

(async function () {
  // DEMO：
  // HelloWorld → exports.main = () => 'HelloWorld';
  const result = await invokeCloudFunction('HelloWorld');

  // result → { success: true, message: 'success', result: 'HelloWorld' }
  console.log('result', result);
})();

// 引入 npm 开源库
const log4js = require('log4js');

// 引入数据库操作模型
const User = require('../models/user');

// 日志打印
const logger = log4js.getLogger();

exports.main = async function () {
  const allUsers = await User.findMany();
  logger.debug('User.allUsers = ', allUsers);
  return allUsers;
};

import * as vm from 'vm';

/**
 * 运行云函数
 */
async function runCloudFunction(
  files: Record<string, string>,
  entryFile: string,
  args: Record<string, any>
) {
  // 在虚拟机中解析云函数的源码
  const script = new vm.Script(files[entryFile] || '');

  // 在代码的上下文注入 Node.js 的全局变量和方法
  const context = vm.createContext({
    module,
    console,
    process,
    exports,
    __dirname: __dirname,
    __filename: __filename,

    // 手动处理
    require: (moduleOrFile: string) => {
      switch (moduleOrFile) {
        case 'wx-server-sdk': {
          // 处理自定义引入的报名
          return require('./wx-server-sdk');
        }
        case moduleOrFile.startWith('.'): {
          // 处理内联引入的文件
          // 处理场景： const User = require('../models/user')
          const name = moduleOrFile.replace(/^\.\/+/, '/');
          const code = files[name];

          // 仅为讨论，该代码实际不可用
          return new vm.Script(code);
        }
        default: {
          // 处理导入的模块
          // 处理场景： const lodash = require('lodash')
          // if (CloudFunctionDependencies[moduleOrFile]) {
          //   return CloudFunctionDependencies[moduleOrFile];
          // }

          throw new Error(`require('${moduleOrFile}') is not defined.`);
        }
      }
    },
  });

  // 执行云函数
  const cloudFn = await script.runInContext(context); // [!code++]
  const fnResult = await cloudFn(args);

  // 返回云函数的执行结果
  return fnResult;
}

import Docker from 'dockerode';

// 创建 Docker 引用的实例
const docker = new Docker();

// 读取本地安装的 Docker 版本号
docker.version().then(version => {
  // version → { Platform: { Name: 'Docker Desktop 4.6.0' } }
  console.log('version', version);
});