Is there a way for a user or a task to send something to the scheduler log? cylc message appears to be tied to jobs, but I was thinking about just wanting to log something in the scheduler log for tracking purposes, not for Cylc itself to make use of.
The cylc message command is the way to do this, however, it is tied to jobs as you say.
You can still use it outside of jobs, and it will appear in the scheduler log, but as an “undeliverable task messages received and ignored” warning.
What type of event are you attempting to feed into the log?