I've rarely had occasion to run a python script in the background. I tend to use them for one-off tasks, and if they print to stdout I want the output immediately. I was therefore baffled when my python script to receive workspace info from i3 refused to pipe to Lemonbar. Shouldn't it be as straightforward as piping output from a bash script? After a little toubleshooting I discovered that it is--so long as the script isn't backgrounded. When backgrounded, however, the default behavior is not to print until the process finishes. This is due to Python's output buffering.
Thankfully, the solution to this problem is simple. To enable unbuffered, realtime output, run python with the -u flag:
$ python -u myscript.pyWith that, everything works as expected.