X-Lambda Helper (Python version)

A Python library to help handle warm-up requests generated by X-Lambda.

X-Lambda predicts AWS Lambda demand and keeps a fleet of containers warm to mitigate cold-start latency. Warm invocations sent by X-Lambda are received by a Lambda function, which needs to respond accordingly.

This X-Lambda Helper project helps to handle warm invocations in Python functions.

Requirements

• Python 3.6+
• AWS account

Quick start

1. Install X-Lambda Helper: pip install xlambda_helper.
2. Decorate your Lambda handler following the example below:
3. Deploy your code in AWS Lambda.

Usage example

import xlambda_helper


@xlambda_helper.warm()
def handler(event, context):
    # Your original code goes here
    x_men = [
        {'Charles': 'Professor Xavier'},
        {'Logan': 'Wolverine'},
        {'Jean': 'Phoenix'},
        {'Scott': 'Cyclops'}
    ]

    return x_men

About

X-Lambda Helper will be executed every time your handler is invoked by AWS Lambda. It will check whether the invocation is a warming request coming from X-Lambda. If not, it will run your handler code normally. If yes, it will short-circuit to return a default answer and will not execute the handler function.

When handling warm requests, X-Lambda Helper will automatically adjust your function behavior:

• Check whether it was a cold start
• Sleep for a period of time, if needed
• Defer to your original handler function, if invocation is not a warm request