So, I was messing around with this project, right? And I ran into this “resource run monopoly” thing. Basically, I wanted to make sure only one instance of my script was running at a time. You know, to avoid all sorts of weird conflicts and stuff.
First, I thought, “Okay, I’ll just use a lock file.” Super simple, right? I created a file at the start of my script and tried to get exclusive access. If it worked, great! The script was running solo. If not, I knew another instance was already going, and my script would just bail out.
My First Go
- Created a lock file: I used
open("my_lock_*", "w"). Nothing fancy, just a plain old text file. - Tried to lock it: I used whatever library to flock() it.
- Checked the result: If flock return successed, I was good to go. If not, I printed a message like, “Another instance is already running,” and exited.
It seemed to work… most of the time. But I started noticing some weirdness. Sometimes, the lock file would get left behind, even if the script crashed or something. That meant the next time I tried to run it, it would think another instance was still going, even though it wasn’t. Frustrating!
Getting Fancier
So, I did some digging and realized I needed a more robust solution.I need to implement these.
- Error Handling: I added some
tryandfinallyblocks (or whatever your language uses) to make sure the lock file got deleted even if the script crashed. - Timeout: I also added some timeout when try to lock the resource.
With these tweaks, things got a lot more reliable. The lock file was always cleaned up, and the script only ran when it was supposed to. I could finally rest easy knowing my script wasn’t going to cause any resource run monopoly problems.
It was a bit of a learning curve, but hey, that’s how we grow, right? Now I’ve got this neat little trick in my toolbox for any time I need to make sure only one instance of something is running.
