AWS Lambda+Layer环境下Node.js ES6导入aws-sdk模块报错问题

问题背景 #

在AWS Lambda中使用Node.js（ES6语法），将node_modules打包为AWS Layer实现依赖管理，需向SNS发布消息。使用CommonJS语法时代码运行正常，但切换到ES6的import语法后，因模块导入方式问题报错。

当前package.json配置：

{
  "name": "test",
  "version": "1.0.0",
  "dependencies": {
    "@aws-sdk/client-sns": "^3.370.0"
  },
  "type": "module"
}

相关情况：

• 代码与AWS官方文档示例一致
• Node Modules已放入nodejs目录并打包为Layer
• 已按文档创建../lib/snsClient.js
• 测试过nodejs16.x、nodejs18.x、nodejs20.x版本及.mjs扩展名
• 因业务依赖必须使用ES6语法

报错信息 #

2024-05-05T20:50:31.064Z    undefined   ERROR   Uncaught Exception  
{
    "errorType": "Runtime.UserCodeSyntaxError",
    "errorMessage": "SyntaxError: Named export 'AWS' not found. The requested module 'aws-sdk' is a CommonJS module, which may not support all module.exports as named exports.
CommonJS modules can always be imported via the default export, for example using:

import pkg from 'aws-sdk';
const { AWS } = pkg;
",
    "stack": [
        "Runtime.UserCodeSyntaxError: SyntaxError: Named export 'AWS' not found. The requested module 'aws-sdk' is a CommonJS module, which may not support all module.exports as named exports.",
        "CommonJS modules can always be imported via the default export, for example using:",
        "",
        "import pkg from 'aws-sdk';",
        "const { AWS } = pkg;",
        "",
        "    at _loadUserApp (file:///var/runtime/index.mjs:1084:17)",
        "    at async UserFunction.js.module.exports.load (file:///var/runtime/index.mjs:1119:21)",
        "    at async start (file:///var/runtime/index.mjs:1282:23)",
        "    at async file:///var/runtime/index.mjs:1288:1"
    ]
}

已尝试的无效方案 #

尝试过以下导入方式，问题仍未解决：

import pkg from 'aws-sdk'; 
const { AWS } = pkg;

核心原因与解决方案 #

核心原因 #

你的package.json中依赖的是AWS SDK v3的@aws-sdk/client-sns，但代码中却在导入AWS SDK v2的aws-sdk模块。两者的导入逻辑完全不同，且v2的aws-sdk是CommonJS模块，在ES6模块环境下无法按v2的方式导入。

正确解决方案 #

1. 修正模块导入逻辑，使用AWS SDK v3的ES6语法导入对应模块：

   • 编辑../lib/snsClient.js，创建SNS客户端：

     import { SNSClient } from "@aws-sdk/client-sns";
     // 替换为你的AWS区域
     const snsClient = new SNSClient({ region: "us-east-1" });
     export default snsClient;
     

   • Lambda主函数中导入客户端与发布命令：

     import { PublishCommand } from "@aws-sdk/client-sns";
     import snsClient from "./lib/snsClient.js";
     
     export const handler = async (event) => {
       const publishParams = {
         Message: "测试SNS消息内容",
         TopicArn: "arn:aws:sns:us-east-1:123456789012:your-topic-name"
       };
     
       try {
         const response = await snsClient.send(new PublishCommand(publishParams));
         return {
           statusCode: 200,
           body: JSON.stringify({ messageId: response.MessageId })
         };
       } catch (error) {
         console.error("发布SNS消息失败:", error);
         return {
           statusCode: 500,
           body: JSON.stringify({ error: error.message })
         };
       }
     };
     

2. 确认Layer结构正确性：
   打包Layer时，确保node_modules放在nodejs目录下，最终结构为：

   nodejs/
     node_modules/
       @aws-sdk/
         client-sns/
   

3. 保持package.json配置：
   保留"type": "module"配置，确保Node.js以ES6模块方式解析代码。

内容的提问来源于stack exchange，提问作者Mayur