AWS CDK NodejsFunction: import a module exported as "export ="

Question

Is there any way to use modules (e.g. sharp) exported as export = someModule in a Lambda function defined using NodejsFunction in the aws-cdk-lib?
The require statement(const xxx = require('module')) does not seem to work with the Lambda TypeScript code that CDK bundles.

Both of the following import writing methods resulted in the error.

import sharp from 'sharp'
import * as sharp from 'sharp'
import sharp = require('sharp')

Something went wrong installing the \"sharp\" module
Cannot find module '../build/Release/sharp-linux-x64.node'
Require stack:
- /var/task/index.js
- /var/runtime/index.mjs

The CDK code defines the Lambda function as follows.

import { aws_lambda_nodejs as lambda } from 'aws-cdk-lib'

const fn = new lambda.NodejsFunction(scope, 'fn-id', {
  entry: 'lib/lambda/my-fn.ts',
  functionName: 'fn-name'
})

Answer 1

If you're introducing node_modules or external modules for your NodejsFunction, you'll need to specify this in your CDK Stack.

Look at bundling options to learn more.

Here's an example that uses externalModules, nodeModules and layers to access resources.

this.lambdaFunctionExample= new NodejsFunction(this, `lambdaFunctionExample`, {
  runtime: Runtime.NODEJS_18_X,
  handler: "handler",
  bundling: { minify: false, nodeModules: ["@aws-sdk/client-sfn", "axios", "axios-retry"], externalModules: ["aws-sdk", "crypto-js"] },
  layers: [lambdaLayerStack.getSecrets, lambdaLayerStack.generateMagentoAuthorisationHeader]
});

Answer 2

If you are building on M1 you have to install sharp via

npm install --platform=linux --arch=x64 sharp

otherwise you will get the following error on lambda execution:

Could not load the \"sharp\" module using the linux-x64 runtime\

After you installed sharp you can import it like this:

import sharp from 'sharp' // typescript

const sharp = require("sharp") // javascript

If you encounter this error on cdk deploy

[ERROR] No loader is configured for ".node" files: asset-input/node_modules/sharp/build/Release/sharp-linux-x64.node

add the following option to your NodejsFunction to define sharp as a module that should be installed instead of bundled

const fn = new lambda.NodejsFunction(scope, 'fn-id', {
  entry: 'lib/lambda/my-fn.ts',
  functionName: 'fn-name',
  bundling: {
    nodeModules: ['sharp'],
  }
})