How to Work with AWS Lambda Layers Using AWS CDK with TypeScript

Developers can share resources or code across several Lambda functions with AWS Lambda Layers. Layer management is made considerably easier and more efficient with TypeScript and the AWS Cloud Development Kit (CDK). This post examines real-world use cases and walks you through building and deploying Lambda Layers using AWS CDK in TypeScript.

What are AWS Lambda Layers?

You can manage shared setups, libraries, and dependencies independently of your Lambda functions with Lambda Layers. This makes it possible to reuse code, cut down on duplication, and make upgrades easier. An infrastructure-as-code method for programmatically managing Lambda Layers is offered by the AWS CDK with TypeScript.

Setting Up Lambda Layers with AWS CDK in TypeScript

1. Create a CDK Project

If you don’t have a CDK project yet, initialize one:

mkdir my-lambda-layer-cdk
cd my-lambda-layer-cdk
cdk init app --language=typescript

Install necessary dependencies:

npm install @aws-cdk/aws-lambda

2. Add Layer Content

Create a directory for your layer content:

mkdir -p layer/python

Add dependencies or shared code. For Python dependencies:

pip install requests -t layer/python

1. Define the Layer in CDK

In your CDK stack (e.g., lib/my-stack.ts), define a Lambda Layer:

import * as cdk from 'aws-cdk-lib';
import * as lambda from 'aws-cdk-lib/aws-lambda';
import { Construct } from 'constructs';

export class MyStack extends cdk.Stack {
  constructor(scope: Construct, id: string, props?: cdk.StackProps) {
    super(scope, id, props);

    // Define the Lambda Layer
    const myLayer = new lambda.LayerVersion(this, 'MyLayer', {
      code: lambda.Code.fromAsset('layer'),
      compatibleRuntimes: [lambda.Runtime.PYTHON_3_8],
      description: 'A layer for shared dependencies',
    });

    // Define a Lambda function using the layer
    const myFunction = new lambda.Function(this, 'MyFunction', {
      runtime: lambda.Runtime.PYTHON_3_8,
      handler: 'index.handler',
      code: lambda.Code.fromAsset('lambda'),
      layers: [myLayer], // Attach the layer
    });
  }
}

4. Deploy the Stack

Deploy the stack to AWS:

cdk deploy

5. Update Layers with New Versions

To update the content of a layer, modify the files in your layer directory and redeploy:

cdk deploy

Use Cases for AWS Lambda Layers

1️⃣ Shared Code Libraries:

Reuse utility functions, error handling, or validation logic across functions.

2️⃣ Third-Party Dependencies:

Package libraries like requests or axios in the layer and share them across functions.

3️⃣ Custom Runtimes:

Add tools like FFmpeg for video processing or Puppeteer for browser automation.

4️⃣ AI/ML Models:

Deploy pre-trained models to handle inference tasks efficiently.

5️⃣ Configuration Files:

Share environment-specific configurations to ensure consistency across functions.

6️⃣ Logging and Monitoring:

Include custom logging frameworks or integrations with monitoring tools like Datadog.

7️⃣ Security Libraries:

Share encryption libraries or standardized security tools across functions.

Best Practices with AWS CDK and Lambda Layers

👉🏻 Use CDK Constructs:
Organize code by creating reusable constructs for layers and functions.

👉🏻 Leverage Versioning:
CDK automatically handles versioning of layers. Deploy updates safely.

👉🏻 Minimize Layer Size:
Keep layers small to reduce deployment package size and avoid hitting Lambda’s size limits.

👉🏻 Permissions:
Use IAM permissions in CDK to control access to your layers.