I need to be able to log the times that an Ubuntu 10.04 Desktop system is suspended and resumed.
I can detect when the system is resumed via a DBus signal (org.freedesktop.UPower.Resuming()) but the corresponding "org.freedesktop.UPower.Sleeping()" signal is never fired. Ideally, I'd like to use DBus, but given the lack of success I'm having, I'd be happy with any solution providing it can be called from the command line.
I've discovered one way to do it:
tail -f /var/log/pm-suspend.log | grep "performing suspend"
This simply listens on one of the pm logs for the suspend logging. Although this works, it's probably rather brittle. I've found relying on log parsing to be rather problematic in the past due to changes in the log statements.
Ideally I'd like a more robust mechanism. The service that invokes this will be ran as root.