AWS lambda layers error when call API "cannot find module"

Question

I try to use layers of AWS Lambda, watched a tutorial about it, but I get an error "cannot find module ..."

service: aws-nodejs 

package:
  exclude:
    - .gitignore
    - package.json
    - .git/**

provider:
  name: aws
  profile: sandbox
  runtime: nodejs12.x

layers:
  testLayer:
    path: testLayer
    compatibleRuntimes:
      - nodejs12.x
    allowedAccounts:
      - '*'

functions:
  hello:
    handler: handler.hello
    layers:
      -  arn:aws:lambda:us-east-1:*:layer:testLayer:15
    events:
      - http:
          path: test
          method: get
          cors: true

When i deploy it, i don't have any errors in my terminal, and on AWS, i see my layer and when i download it, i have my package.json with moment dependency, and the node_modules folder with moment

my handler.js looks like this :

'use strict';
module.exports.hello = async (event, context) => {
    const moment = require('moment')
    const a = moment('2016-01-01')
  return {
    statusCode: 200,
    body: JSON.stringify({
      message: 'Hey' + a
    }),
  };
};

My files structure :

testLayer/
   node_modules/
      moment/
   package.json
serverless.yml
handler.js
package.json

Do you have any idea of what i doing wrong ?

toraritte · Accepted Answer · 2021-10-11 10:39:44Z

16

Yes, it's possible that your node modules are there in your lambda layer and yet lambda is throwing error of "cannot find module..".

This may be happening because the zip that you have created is not as per directory structure mentioned in AWS documentation.

As per official documentation :

Including Library Dependencies in a Layer You can move runtime dependencies out of your function code by placing them in a layer. Lambda runtimes include paths in the /opt directory to ensure that your function code has access to libraries that are included in layers.

To include libraries in a layer, place them in one of the folders supported by your runtime.

Node.js – nodejs/node_modules, nodejs/node8/node_modules (NODE_PATH)

Example AWS X-Ray SDK for Node.js
nodejs/node_modules/aws-xray-sdk

Make sure your zip contains correct directory structure else try importing your modules from /opt/your_node_module_directory

edited Oct 11, 2021 at 10:39

toraritte

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answered Apr 20, 2020 at 18:25

Rahul Goel

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2 Comments

dc-mpo Over a year ago

Thanks for your answer, i've add a nodejs folder in my testLayer, and i've add package.json and node_modules into it, and it works Thanks for your help

Rahul Goel Over a year ago

I am glad, I was able to help.

hahuaz · Accepted Answer · 2022-06-09 06:54:17Z

4

You can check node paths that provided by lambda with:

console.log(process.env.NODE_PATH);

After seeing the absolute path, you should set your import according to it. In my case it was:

import axios from '/opt/nodejs/node_modules/axios/index.js';

answered Jun 9, 2022 at 6:54

hahuaz

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