Running Python through FastCGI with nginx on Ubuntu

Question

I've already looked at other threads on this, but most don't go into enough setup detail which is where I need help.

I have an Ubuntu based VPS running with nginx, serving PHP sites through php-cgi on port 9000.

I'd like to start doing more with Python, so I've written a deployment script which I essentially want to use as a post-receive hook on my local GitLab server as my first python script. I can run this script successfully by running python script.py on the command line but in order to use this as a post-receive hook I need it be able to access it via http.

I looked at this guide on the nginx wiki but partway down is says to:

And start the django fastcgi process:

python ./manage.py runfcgi host=127.0.0.1 port=8080

Now, like I said I am pretty new to python, and I have never used the Django framework. Can anyone assit on how I am supposed to start the fastcgi server? Do I replace ./manage.py with the name of my script? Any help would be appriciated as everything I've found online refers to working with Django.

Answer 1

Do I replace ./manage.py with the name of my script?

No. It's highly unlikely your script is a FastCGI server, or that it can accept HTTP requests of any kind since you mention running it over the command line. (From what little I know of FastCGI , an app supporting it has to be able to handle a stream of requests coming in over stdin in a specific format, so there's definitely some plumbing involved.)

I'd say the easiest approach would be to use some web framework just to act as HTTP/FastCGI middleware. For your use a "microframework" like Flask (or even Paste but I found the documentation inscrutable) sounds like it'd work fine. The idea would be to have two interfaces to your main code, one that can handle command line arguments, and one that can handle a HTTP request, ultimately both would just call one function that actually does the work. (If you want to keep the command-line version of the app.)

The Flask documentation also mentions using uWSGI or standalone workers as deployment options. I'm not familiar with the former; the latter I wouldn't recommend for a simple, low-traffic app for the same reasons as the approach in the next paragraph.

Considering you use a VPS, you might even be able to just run the app as a standalone server process using the http.server module , but I'm not sure that's the better choice unless you absolutely want to avoid using any sort of framework. You'd have to make sure the app starts up if the server is rebooted or that it restarts when it crashes and it seems easier to just have nginx do the job of the supervisor.

UPDATE: Scratch that, it seems that nginx won't handle supervising a FastCGI worker process for you, which would've been the main advantage of the approach. In light of that it doesn't matter which of the three approaches you use since you'll have to set up a service supervisor one way or the other. I'd say go with uWSGI since flup (which is needed for Flask+FastCGI ) seems abandoned since 2011, and the uWSGI protocol is apparently supported in nginx natively. Otherwise you'd need to use a different webserver than nginx, one that will manage a FastCGI worker for you. If this is an option, I'd consider Cherokee , which can be configured using a web GUI.

tl;dr: you need to write a (very simple) webapp. While it is feasible to do this without a web framework of any kind, in my opinion using one is easier, since you some (nontrivial) plumbing for free and there's a lot of guidance available on how to deploy them.