api-gateway-reverse-proxy-python-flask

A simple API Gateway (reverse proxy) implementation in python using requests and Flask

Note that there are certain HTTP functions which have not been handled in this simple implementation (e.g.forwarding client headers).

~$ flask --app gateway run --port 5000 &
~$ curl --location 'http://localhost:5000/does_not_exist/v1'
endpoint '/does_not_exist/v1' not found
~$ curl -X POST --location 'http://localhost:5000/test_post_request/v1' --header 'Content-Type: application/json' --data '{"test": 123}'
<returns response from https://httpbin.org/post>
~$ pkill -f flask -SIGTERM

Because an API-Gateway is by nature I/O-bound (i.e. it spends most of it's time waiting, as opposed to doing computation), it will strongly benefit from asynchronous workers, for example using gevent:

pip install gunicorn
pip install gevent
gunicorn --bind :8000 --workers 3 --worker-class=gevent --worker-connections=999 main:gateway

(refer to gunicorn design docs for more information)

Here is a more complete gateway example:

# start local flask servers (in the background) #
flask --app gateway run --port 5000 &
flask --app endpoints run --port 8000 &

# send some requests through the gateway #
curl -X POST --location 'http://localhost:5000/return_to_sender/v1?key=test' --header 'Content-Type: application/json' --data '{"test": 123}'

# stop local flask servers #
pkill -f flask -SIGTERM