Prefer using Gunicorn or uWSGI with gevent workers rather than using gevent directly. Gunicorn and uWSGI provide much more configurable and production-tested servers.
gevent allows writing asynchronous, coroutine-based code that looks
like standard synchronous Python. It uses greenlet to enable task
switching without writing
async/await or using
eventlet is another library that does the same thing. Certain dependencies you have, or other considerations, may affect which of the two you choose to use.
gevent provides a WSGI server that can handle many connections at once instead of one per worker process. You must actually use gevent in your own code to see any benefit to using the server.
When using gevent, greenlet>=1.0 is required, otherwise context locals
request will not work as expected. When using PyPy,
PyPy>=7.3.7 is required.
Create a virtualenv, install your application, then install
$ cd hello-app $ python -m venv .venv $ . .venv/bin/activate $ pip install . # install your application $ pip install gevent
To use gevent to serve your application, write a script that imports its
WSGIServer, as well as your app or app factory.
from gevent.pywsgi import WSGIServer from hello import create_app app = create_app() http_server = WSGIServer(("127.0.0.1", 8000), app) http_server.serve_forever()
$ python wsgi.py
No output is shown when the server starts.
gevent should not be run as root because it would cause your application code to run as root, which is not secure. However, this means it will not be possible to bind to port 80 or 443. Instead, a reverse proxy such as nginx or Apache httpd should be used in front of gevent.
You can bind to all external IPs on a non-privileged port by using
0.0.0.0 in the server arguments shown in the previous section. Don’t
do this when using a reverse proxy setup, otherwise it will be possible
to bypass the proxy.
0.0.0.0 is not a valid address to navigate to, you’d use a specific
IP address in your browser.