📘 What are AWS Lambda Layers?

AWS Lambda Layers allow you to manage shared libraries, custom runtimes, or configuration files that can be reused across multiple Lambda functions. This provides a modular approach to managing dependencies and common code, enabling easy updates and centralization of resources.

🛠️ Why Use AWS Lambda Layers?

• Reusability: Shared libraries can be reused across multiple Lambda functions.
• Separation of Concerns: Keeps the Lambda codebase smaller by externalizing dependencies.
• Centralized Management: Libraries are maintained in one location and updated easily.
• Version Control: Layers can have multiple versions, allowing fine-grained control over the libraries used by each function.
• Optimized Deployment: By separating dependencies, the core Lambda package size is minimized.

📅 When to Use AWS Lambda Layers?

Use Lambda Layers when:

• Multiple Lambda functions need the same dependencies.
• You need a custom runtime.
• There is a need for efficient dependency management.
• You want to optimize deployment package size and manage shared libraries centrally.

🏗️ How to Create and Use AWS Lambda Layers?

Step-by-Step Process:

1. Create the Folder:

   • On your local machine, create a folder named nodejs (required name for Node.js Lambda layers).

2. Initialize the Node.js Project:

   • Open a terminal in the nodejs folder and run:

    npm init -y
   

3. Install the Required Package:

   • For example, to install the uuid package, run:

    npm install uuid
   

4. Create the Layer Zip File:

   • Zip the contents of the nodejs folder to create the layer:

    zip -r layer.zip nodejs
   

5. Upload the Layer to AWS Lambda:

   • In the AWS Console, go to Lambda → Layers → Create Layer.
   • Upload the layer.zip file, specify the runtime (e.g., Node.js), and click Create.

6. Attach the Layer to Your Lambda Function:

   • In your Lambda function, go to Configuration → Layers → Add a Layer.
   • Select your custom layer and attach it.

7. Use the Layer in Your Lambda Code:

   • In your Lambda function code, require the library from the layer:

    const { v4: uuidv4 } = require('uuid');
   
    exports.handler = async (event) => {
      const id = uuidv4();
      return {
        statusCode: 200,
        body: JSON.stringify({ uuid: id }),
      };
    };
   

⚙️ Best Practices for AWS Lambda Layers

• Keep Layers Small: Only include necessary files to avoid bloated layers.
• Use Versioning: Always track and manage versions of your layers.
• Test Thoroughly: Before deploying in production, test your layers in staging environments.
• Security: Do not include sensitive information (e.g., credentials) in layers.

⭐ Key Takeaways

• What: AWS Lambda Layers allow sharing of libraries and custom runtimes across multiple Lambda functions.
• Why: They promote reusability, efficient dependency management, and optimized package size.
• How: You create a nodejs folder, install the required libraries, zip it, and upload it as a Lambda Layer, which can be attached to multiple Lambda functions.
• When: Use Lambda Layers when managing shared dependencies across functions, creating custom runtimes, or optimizing deployment sizes.