How do I properly redirect stdout/stderr from a systemd service on Raspbian?

Question

I set up a service on Raspbian (Jessie) using systemd to make it start after boot. The daemon config looks like this:

[Unit]
After=multi-user.target

[Service]
Type=idle
User=root
ExecStart=/bin/sh -c "exec /home/pi/sources/mydaemon.py >> /home/pi/mydaemon.log 2>&1"

[Install]
WantedBy=multi-user.target

That redirection >> isn't working. I have tried most of the options available to the StandardOutput and StandardError but they never end up printing my script's output to /var/log/daemon.log and journalctl -u mydaemon.service only shows messages about the service being started and stopped.

I'm not doing anything funny with file descriptors from within the script currently. I just want my print() or logging.info() statements to show up somewhere I can read them. Any ideas?

(Just to be clear, the daemon does have to run as root. Could that have something to do with my printing problem?)

Answer 1

I needed to run python with the -u parameter to ensure messages were not buffered.

With these lines, the print lines gets added to the journal immediately:

StandardOutput=journal+console
ExecStart=/home/pengman/scripts/mqtt_monitor/venv/bin/python -u home/pengman/scripts/mqtt_monitor/src/mqtt_monitor.py

(I am running inside a virtualenv, but that shouldn't matter)