https://github.com/dschep/lambda-decorators

🐍λ✨ - A collection of useful decorators for making AWS Lambda handlers
https://github.com/dschep/lambda-decorators

aws-lambda decorators python serverless

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🐍λ✨ - A collection of useful decorators for making AWS Lambda handlers

• Host: GitHub
• URL: https://github.com/dschep/lambda-decorators
• Owner: dschep
• License: mit
• Created: 2017-12-23T16:25:06.000Z (over 7 years ago)
• Default Branch: master
• Last Pushed: 2023-07-20T14:13:36.000Z (almost 2 years ago)
• Last Synced: 2024-10-19T06:02:55.843Z (6 months ago)
• Topics: aws-lambda, decorators, python, serverless
• Language: Python
• Homepage: http://lambda-decorators.rtfd.io
• Size: 118 KB
• Stars: 247
• Watchers: 4
• Forks: 34
• Open Issues: 18
• Metadata Files:
  • Readme: README.rst
  • License: LICENSE

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README

        

🐍λ✨ - lambda_decorators

=========================

|Version|_ |Docs|_ |Build|_ |SayThanks|_

A collection of useful decorators for making AWS Lambda handlers

``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.

Quick example

-------------

.. code:: python

    # handler.py

    from lambda_decorators import json_http_resp, load_json_body

    @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:

.. code:: shell

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

   {"hello": "world"}

Install

-------

If you are using `the serverless framework `_

I recommend using

`serverless-python-requirements `_

.. code:: shell

    sls plugin install -n serverless-python-requirements

    echo lambda-decorators >> requirements.txt

Or if using some other deployment method to AWS Lambda you can just download

the entire module because it's only one file.

.. code:: shell

    curl -O https://raw.githubusercontent.com/dschep/lambda-decorators/master/lambda_decorators.py

Included Decorators:

--------------------

``lambda_decorators`` includes the following decorators to avoid boilerplate

for common usecases when using AWS Lambda with Python.

* `async_handler `_ - support for async handlers

* `cors_headers `_ - automatic injection of CORS headers

* `dump_json_body `_ - auto-serialization of http body to JSON

* `load_json_body `_ - auto-deserialize of http body from JSON

* `json_http_resp `_ - automatic serialization of python object to HTTP JSON response

* `json_schema_validator `_ - use JSONSchema to validate request&response payloads

* `load_urlencoded_body `_ - auto-deserialize of http body from a querystring encoded body

* `no_retry_on_failure `_ - detect and stop retry attempts for scheduled lambdas

* `ssm_parameter_store `_ - fetch parameters from the AWS SSM Parameter Store

* `secret_manager `_ - fetch secrets from the AWS Secrets Manager

See each individual decorators for specific usage details and the example_

for some more use cases. This library is also meant to serve as an example for how to write

decorators for use as lambda middleware. See the recipes_ page for some more niche examples of

using decorators as middleware for lambda.

.. _example: https://github.com/dschep/lambda-decorators/tree/master/example

.. _recipes: recipes.rst

Writing your own

----------------

``lambda_decorators`` includes utilities to make building your own decorators

easier. The `before `_, `after `_, and `on_exception `_ decorators

can be applied to your own functions to turn them into decorators for your

handlers. For example:

.. code:: python

    import logging

    from lambda_decorators import before

    @before

    def log_event(event, context):

        logging.debug(event)

        return event, context

    @log_event

    def handler(event, context):

        return {}

And if you want to make a decorator that provides two or more of

before/after/on_exception functionality, you can use

`LambdaDecorator `_:

.. code:: python

    import logging

    from lambda_decorators import LambdaDecorator

    class log_everything(LambdaDecorator):

        def before(self, event, context):

            logging.debug(event, context)

            return event, context

        def after(self, retval):

            logging.debug(retval)

            return retval

        def on_exception(self, exception):

            logging.debug(exception)

            return {'statusCode': 500}

    @log_everything

    def handler(event, context):

        return {}

Why

---

Initially, I was inspired by `middy `_ which

I like using in JavaScript. 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 and utilities to build them.

-----

.. |Version| image:: https://img.shields.io/pypi/v/lambda-decorators.svg

.. _Version: https://pypi.org/project/lambda-decorators

.. |Docs| image:: http://readthedocs.org/projects/lambda-decorators/badge/?version=latest

.. _Docs: http://lambda-decorators.readthedocs.org/en/latest

.. |Build| image:: https://img.shields.io/travis/dschep/lambda-decorators/master.svg

.. _Build: https://travis-ci.org/dschep/lambda-decorators

.. |SayThanks| image:: https://img.shields.io/badge/Say%20Thanks-!-1EAEDB.svg

.. _SayThanks: https://saythanks.io/to/dschep

`Full API Documentation `_