lambda-decorators 0.1a4

A collection of useful decorators for making AWS Lambda handlers

A collection of useful decorators for making AWS Lambda handlers

NOTE: this is in very early stages of development.

lambda_decorators is a collection of useful decorators for writing Python handlers for AWS Lambda. They allow you to avoid boiler plate for common things such as CORS headers, JSON serialization, etc.

These can be used as a library or simply copied and adapted to your needs. If you want to write your own “middlewares” it’s as easy as writing a decorator. The documentation has links to the source of each decorator. They also serve as handy examples for implemenenting your own boilerplate-reducing decorators.

Quick example

# handler.py

from lambda_decorators import cors_headers, json_http_resp, load_json_body

@cors_headers
@json_http_resp
@load_json_body
def handler(event, context):
    return {'hello': event['body']['name']}

When deployed to Lambda behind API Gateway and cURL’d:

$ curl -d '{"name": "world"}' https://example.execute-api.us-east-1.amazonaws.com/dev/hello
{"hello": "world"}

Install

pip install lambda-decorators

Why

Initially, I was inspired by middy which I’ve tried out in JavaScript and was happy with it. So naturally, I thought I’d like to have something similar in Python too. But then as I thought about it more, it seemed that when thinking of functions as the compute unit, when using python, decorators pretty much are middleware! So instead of building a middleware engine and a few middlewares, I just built a few useful decorators.

Included Decorators:

• async_handler - support for async handlers

• cors_headers - automatic injection of CORS headers

• dump_json_body - auto-serialization of http body to JSON

• json_http_resp - automatic serialization of python object to HTTP JSON response

• load_json_body - auto-deserialize of http body from JSON

• no_retry_on_failure - detect and stop retry attempts for scheduled lambdas

See each individual decorators for specific usage details and the example for some more use cases.

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Full API Documentation