apig-wsgi 2.8.0

Wrap a WSGI application in an AWS Lambda handler function for running on API Gateway or an ALB.

Wrap a WSGI application in an AWS Lambda handler function for running on API Gateway or an ALB.

A quick example:

from apig_wsgi import make_lambda_handler
from myapp.wsgi import app

# Configure this as your entry point in AWS Lambda
lambda_handler = make_lambda_handler(app)

Installation

Use pip:

python -m pip install apig-wsgi

Python 3.5 to 3.8 supported.

Usage

make_lambda_handler(app, binary_support=False, non_binary_content_type_prefixes=None)

app should be a WSGI app, for example from Django’s wsgi.py or Flask’s Flask() object.

If you want to support sending binary responses, set binary_support to True. ALB’s support binary responses by default, but on API Gateway you need to make sure you have '*/*' in the ‘binary media types’ configuration on your Rest API. You will need to configure this through API Gateway directly, CloudFormation, SAM, or whatever tool your project is using. Whilst API Gateway supports a list of binary media types, using '*/*' is the best way to configure this, since it is used to match the request ‘Accept’ header as well, which WSGI applications are likely to ignore.

Note that binary responses aren’t sent if your response has a ‘Content-Type’ starting ‘text/’, ‘application/json’ or ‘application/vnd.api+json’ - this is to support sending larger text responses. To support other content types than the ones specified above, you can set non_binary_content_type_prefixes to a list of content type prefixes of your choice.

If the event from API Gateway contains the requestContext key, for example from custom request authorizers, this will be available in the WSGI environ at the key apig_wsgi.request_context.

If you want to inspect the full event from API Gateway, it’s available in the WSGI environ at the key apig_wsgi.full_event.

If you need the Lambda Context object, it’s available in the WSGI environ at the key apig_wsgi.context.

Multiple values for request and response headers and query parameters are supported. They are enabled automatically on API Gateway but need explict activation on ALB’s. If you need to determine from within your application if multiple header values are enabled, you can can check the apgi_wsgi.multi_value_headers key in the WSGI environ, which is True if they are enabled and False otherwise.

Example

An example application with Ansible deployment is provided in the example/ directory in the repository. See the README.rst there for guidance.