Create Lambda Layer

Create Lambda Layer

Creating a Lambda Layer can be both an efficient and organized way to manage external dependencies in AWS Lambda functions. Lambda Layers were introduced to simplify the distribution of libraries and other dependencies across multiple functions. They are especially useful when you have common libraries or modules that are shared across multiple Lambda functions.

Understanding Lambda Layers

A Lambda Layer is an archive containing libraries, custom runtimes, or other dependencies that you can import into your Lambda function. It makes code modular and reusable. You can include either your libraries or third-party libraries that your function requires.

Advantages of Using Lambda Layers

• Avoids redundant code
• Improves code manageability
• Facilitates version control for dependencies
• Reduces deployment package size

Creating a Lambda Layer

Before creating a Lambda layer, ensure that you have the necessary tools installed, like the AWS CLI and zip utility. Below are the steps you’ll follow to create a Lambda layer from scratch.

Step 1: Prepare Your Library

Let’s use a Python library as an example. Assume you need the ‘requests’ library in your Lambda function. First, create a directory to store the library:

mkdir pythonpip install requests -t ./python

The above commands will create a python directory and install the ‘requests’ library into it.

Step 2: Package the Library

Next, you package the directory into a zip file. The zip file format is required by AWS Lambda.

zip -r layer.zip python

This will create a file named layer.zip that contains the directory with the installed ‘requests’ library.

Step 3: Create the Layer in AWS Lambda

Using AWS CLI, you can create the Lambda layer. You’ll need to have AWS credentials configured on your computer. Run the following command to publish the Lambda layer:

aws lambda publish-layer-version \--layer-name requests-layer \--description A layer with requests library \--zip-file fileb://layer.zip \--compatible-runtimes python3.8

This command creates a new layer version with the name ‘requests-layer’, sets a description, specifies the path to the zip file, and sets compatible runtimes.

Step 4: Using the Layer in a Lambda Function

Now that you’ve created the layer, you can add it to your Lambda function. This can be done from the AWS Management Console:

1. Go to the Lambda Management Console.
2. Select the function where you want to add the layer.
3. In the Designer section, click Layers.
4. Click on Add a layer.
5. Select Provide a layer version ARN and input the ARN of your created layer.

You can find the ARN in the output of the `aws lambda publish-layer-version` command or from the Layers section in the AWS Management Console.

Step 5: Updating and Managing Layers

Updating a layer is straightforward. To update, simply repackage the zip file with your updated libraries or dependencies and publish a new version. Run the following command:

aws lambda publish-layer-version \--layer-name requests-layer \--description Updated requests library version \--zip-file fileb://layer.zip \--compatible-runtimes python3.8

This command creates a new version of the layer. You will need to update your Lambda functions to use the new layer version.

Advanced Use Cases

Multiple Libraries

If your Lambda function requires multiple libraries, install all of them in the created directory before zipping it. Example:

mkdir pythonpip install requests -t ./pythonpip install pandas -t ./pythonzip -r layer.zip python

Custom Packages

You can also include custom packages or scripts in your layer. Place your custom code in the appropriate directory, package it, and create a layer. For example:

mkdir -p python/my_modulecp my_script.py python/my_module/zip -r layer.zip python

Ensure your Lambda function’s code correctly references the custom modules included in the layer.

Configuration Files

You can include configuration files within your layers. Ensure that paths are correctly referenced within your Lambda function:

mkdir -p configecho config data > config/my_config.confzip -r layer.zip config

Reference these files within your Lambda function based on the directory structure set during layer creation.

Best Practices for Lambda Layers

Optimizing Layer Size

Larger layers can significantly slow down the initial loading of your Lambda function. Optimize the libraries included in your layers by removing unnecessary files. Use tools like pipreqs to include only required dependencies:

pipreqs ./pythonzip -r layer.zip python

Version Management

Manage versions meticulously by naming layer versions clearly and maintaining a changelog. This helps track changes and roll back if necessary. Example naming convention:

aws lambda publish-layer-version \--layer-name requests-layer-v1.0.1 \--description Updated to requests 2.25.1 \--zip-file fileb://layer.zip \--compatible-runtimes python3.8

Security Practices

Regularly audit included layers for vulnerabilities using tools like AWS Lambda Layers insights or third-party vulnerability scanners. Keep dependencies up-to-date to avoid security risks.

Real-World Examples

Data Processing Tasks

For data processing, multiple functions might share data transformation libraries. Create a layer with necessary libraries like pandas, numpy, and custom scripts and apply it to all related functions.

mkdir pythonpip install pandas numpy -t ./pythonzip -r data-processing-layer.zip pythonaws lambda publish-layer-version \--layer-name data-processing-layer \--description Layer with pandas and numpy for data processing \--zip-file fileb://data-processing-layer.zip \--compatible-runtimes python3.8

Custom Logic Shared Across Functions

When multiple Lambda functions need to utilize a shared custom logic, encapsulate this logic in scripts and add them to a Lambda layer. This avoids duplication and eases updates. Example:

mkdir -p python/custom_logiccp shared_logic.py python/custom_logic/zip -r custom-logic-layer.zip pythonaws lambda publish-layer-version \--layer-name custom-logic-layer \--description Layer with shared custom logic \--zip-file fileb://custom-logic-layer.zip \--compatible-runtimes python3.8

Custom Runtimes

For custom runtimes not offered by AWS, build a layer that includes these runtimes, allowing Lambda functions to execute with custom environments.

mkdir layer# Install or build your custom runtime here (e.g., custom node.js version)zip -r runtime-layer.zip layeraws lambda publish-layer-version \--layer-name custom-runtime-layer \--description Layer with custom runtime \--zip-file fileb://runtime-layer.zip \--compatible-runtimes provided