This sample project demonstrates how to deploy a Lambda Function that has a layer added to it.

The SAM template provided deploys two Lambda functions. Both Lambda functions attempt to import the PyMySQL package.

However, only one of the Lambda functions has the PyMySQL layer which allows it to import the package successfully.

This pattern tests both Lambda functions to illustrate the difference when there is a layer added to a Lambda function.

One use case for Lambda layers is to have packages like PyMySQL shared across various Lambda functions that require connections to RDS MySQL.

Using layers reduces the size of uploaded deployment archives and makes it faster to deploy your code.