This repo has examples for configuring AWS Lambda functions. The examples use Lambda function versions and aliases to determine which config values to fetch (i.e. DEV, TEST, PROD).
More details in the following post:
https://www.concurrencylabs.com/blog/configure-your-lambda-function-like-a-champ-sail-smoothly/
In this example, the Lambda function gets config values from Lambda Environment Variables that are configured for the function itself. It gets the right value based on the current stage (DEV, TEST, PROD)
In this example, the Lambda function fetches config files from an S3 bucket defined in index.js. This bucket has one folder per stage (i.e. $LATEST, DEV, TEST, PROD) and each folder contains a config file.
In this example, the Lambda function fetches config values from a DynamoDB table. Each item in the table stores a set of config values. The key for each item consists of a prefix and the actual stage. For example: mykey_$LATEST, mykey_DEV, etc.
In this example, the Lambda function reads config values from a file that is packaged together with the function.