Hey ./manage.py runserver, Y U No Work?

Recently I was working on a Django-based project that integrates with Android and Embedded Linux devices. One day a coworker called me and asked about an error he had encountered. It seemed like he was not able to execute ./manage.py runserver to any port he had previously used. He was careful to use Control + C to stop the server, but for some reason the port was held onto by something. Looking at the output of “ps aux” was not showing any running processes using ./manage.py.

Who’s using that port?

Next instead of looking at processes, I wanted to see what was holding onto that port.  I ran the following command:

netstat -lpn | grep 8000

The output gave me the answer:

tcp    0    0 127.0.0.1:8000        0.0.0.0:*      LISTEN    15902/adb

So ADB was the culprit. A simple kill -9 to the process ID and the issue was fixed (temporarily). The issue keeps occuring, so maybe something in my code may be keeping ADB holding onto that port. I’m using the subprocess module to interact with ADB. I tried adding a call to terminate from the result of my subprocess.Popen call, but that ended very badly and had no effect on the hanging port. I’m sure when I have time to dig deeper (read “After My Looming Deadline”), I’ll try to write some tests to explore this issue more thoroughly.