Python: Using pdb with Flask application

Question

I'm using Flask 0.9 with Python 2.7.1 within a virtualenv, and starting my app with foreman start

In other apps I've built when I add the following line to my app:

import pdb; pdb.set_trace()

then reload the browser window, my terminal window displays the pdb interactive debugger:

(pdb)

However in my app when I add those lines nothing happens. The browser window hangs and shows a constant state of loading yet nothing shows in the console.

Is there some magic that needs to happen?

Answer 1

This is because you're using Foreman, which captures the standard output.

To debug your app with pdb, you'll need to "manually" run it, using python app.py or whatever you use.

Alternatively, you can use WinPDB (which, despite the name, has nothing to do with the operating system), which will let you remotely debug a Python process. You can even use it when the program is running on another server.