CDK Python Lambda Function

This module provides a self-building Python Lambda module that generates a layer for the dependent packages from your requirements.txt dynamically. It will automatically compile the libraries using the correct version of python as you have specified. Usage is almost identical to a regular lambda except the asset source/build dir is defined automatically using Code.fromAsset.

Requirements:

• The source for the Lambda must be in src/${name}, where ${name} is the name used in creation of the CDK construct
• build/* must be in git ignore.
• Docker installed and running (it is used to build against the correct Python version)

Usage

new PythonLambda(this, "function1", {
  handler: "index.lambda_handler",
  runtime: lambda.Runtime.PYTHON_3_8,
});

With the following file structure:

root
|-- src
|   |-- index.py <-- Contains a "lambda_handler" function that is called upon execution by Lambda
|   |-- requirements.txt <-- All of your requirements defined here as usual
|-- build <-- This is in gitignore, doesn't have to exist otherwise; Just contains the layer cache for the required packages

From the above:

• Any packages listed in requirements.txt will be automatically bundled up in to a layer
• The packages will be installed via the correctly versioned docker container (provided by lambda.Runtime.*.bundlingDockerImage)
• The layer will be assigned to the Lambda function that is created
• The output object will be a regular Lambda function
• There is an additional property of requirementsLayer on the function if you need to interact with it for some reason