FLock question

[cjboat]

Hey. I have in built FLock in my scripts to prevent duplicate runnings, and have a couple of questions/concerns:

• Does Cronicle have anything already built in to handle this?
• I have noticed that after a timeout the FLock isn't released. Is this something that I can change?

[jhuckaby]

I have no idea what FLock is.

In Cronicle you can set Event Concurrency to control this.

However, the default is 1 (only 1 concurrent job allowed at a time), so I have no idea what is going on with your setup.

[cjboat]

FLock is file locking, preventing this particular script from running a second time. Would Cronicle be able to release the hold if I have the timeout set for say 55 minutes on a job that runs every hour? Does it kill the script (which runs a MySQL query) automatically? I'm noticing the timeout that currently runs doesn't always release the file lock, which would keep the NEW one from running.

[jhuckaby]

I apologize, but you're talking about things that are way outside of my area of expertise, and outside the scope of Cronicle. I don't know if I can help you here. Cronicle doesn't use FLocking. It doesn't "hold" anything to be released.

Cronicle just launches a job by spawning a child process. When that process is complete, it exits. If you set an Event Timeout and the job runs longer, a SIGTERM signal is sent to the outermost process. If the job still doesn't exit within child_kill_timeout seconds, then a SIGKILL signal is sent to the outermost process.

If you need to run a cleanup routine in your job, such as releasing a custom lock that you implemented, then you need to trap the SIGTERM signal. If you are using the Shell Plugin then you can use some shell code to trap it. See this issue for details:

#838

Make sure your shutdown / cleanup process doesn't take longer than 10 seconds, or whatever you have child_kill_timeout set to, because a SIGKILL is not trappable.