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)
Use pip:
python -m pip install apig-wsgi
Python 3.5 to 3.8 supported.
Deploying a Django Project? Check out my book Speed Up Your Django Tests which covers loads of best practices so you can write faster, more accurate tests.
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.
An example application with Ansible deployment is provided in the example/
directory in the repository. See the README.rst
there for guidance.