So, I need to monitor a fairly large nested directory tree for changes on Linux. It seems like there are a few different watcher modules that I could use – fsnotify and notify being the main ones, both of which use the inotify interface and attempt to set watches on each individual subdirectory and maintain all their watchers as things change. I have way too many directories for that to be a workable approach. It looks like the underlying issue is just that this is a difficult problem on Linux; both inotify and fanotify have some issues which make them difficult for library authors to use to present a clean and useful API.

Long story short - I coded up an fanotify-based solution which seems like a good start of what I need, and I’m planning on sharing it back in the hopes that it’s useful. I guess my question is, did I miss something? Is there already an easy and straightforward way to monitor a big directory for changes?

  • @[email protected]
    3•10 months ago

    Just the other day I wrote something just like this, but I used inotify.

    I have to monitor a fairly small direcotry tho, so I didn’t encounter any problem.

    both of which use the inotify interface and attempt to set watches on each individual subdirectory

    Is this really necessary? Inotify’s man page says it can monitor a whole directory with only one watch, so that’s what I did and it looks like it’s working

    I didn’t make a lot of tests tho, so I might be wrong

    Edit: from the inotify man page:

    Inotify monitoring of directories is not recursive: to monitor subdirectories under a directory, additional watches must be created. This can take a significant amount time for large directory trees.

    Yeah, it is necessary. That’s what I get for not reading the whole thing.