[TriLUG] How reliable is inotifywait?

[Scott Lambdin via TriLUG]

https://www.linux.com/topic/desktop/systemd-services-monitoring-files-and-directories/

On Mon, Mar 11, 2024, 4:32 PM Scott Lambdin <lopaki at gmail.com> wrote:

> Interesting.  I saw a web page called "Replacing incron with systemd."
> Looks like there may be a new way to do it.  I can't get to the page,
> perhaps because I am at a cigar bar in Mexico.
>
> On Mon, Mar 11, 2024, 4:06 PM Scott Lambdin <lopaki at gmail.com> wrote:
>
>> iNotify/incron has been around like ten years.  If you can find an active
>> incron message board, that would probably be a good place to look for
>> failure reports.
>>
>> On Sun, Mar 10, 2024, 5:24 PM James Toebes via TriLUG <trilug at trilug.org>
>> wrote:
>>
>>> Have you checked out incron?   Similar to cron,  but runs on inodes.
>>> You can easily define script that run when a file is added, deleted....
>>>
>>>
>>> On 3/10/24 18:41, Ken VanDine via TriLUG wrote:
>>> > In my experience it's very reliable.  We use it in Ubuntu to determine
>>> when
>>> > the display server is up before starting the installer.
>>> >
>>> >
>>> https://github.com/canonical/ubuntu-core-desktop-installer/blob/00cb18b0b2512bb81986c6259d5561fc5a9e3976/launcher/launcher#L57
>>> >
>>> > Cheers,
>>> > Ken
>>> >
>>> >
>>> > On Sun, Mar 10, 2024, 6:09 PM Steve Litt via TriLUG <trilug at trilug.org
>>> >
>>> > wrote:
>>> >
>>> >> Hi all,
>>> >>
>>> >> The inotifywait program waits until a specific file event happens in a
>>> >> specific directory or file, and then terminates. So it enables
>>> >> file-driven event driven programs.
>>> >>
>>> >> I'd like to wake up the instant a file appears in a directory.
>>> >> Something like the following:
>>> >>
>>> >> inotifywait -e create -e moved_to -t 30 /tmp/pager
>>> >>
>>> >> The preceding waits 30 seconds, except if a file is created in or
>>> moved
>>> >> to /tmp/pager, it quits waiting and terminates immediately.
>>> >>
>>> >> I use it to combine polling with an event driven, so if for some
>>> reason
>>> >> the event (moved_to or create) doesn't quit and terminate immediately,
>>> >> it will still quit and terminate at the end of 30 seconds.
>>> >>
>>> >> I can significantly simplify my program if I changed -t 30 to t -1,
>>> >> where -1 stands for "forever". False positives aren't a problem: They
>>> >> would just start another cycle. But false negatives, where a file is
>>> >> created or moved into /tmp/pager but fails to quit and terminate,
>>> would
>>> >> really mess me up in this particular situation.
>>> >>
>>> >> So what do you think, is inotifywait reliable?
>>> >>
>>> >> Thanks,
>>> >>
>>> >> SteveT
>>> >>
>>> >> Steve Litt
>>> >>
>>> >> Autumn 2023 featured book: Rapid Learning for the 21st Century
>>> >> http://www.troubleshooters.com/rl21
>>> >> --
>>> >> This message was sent to: Ken VanDine <ken at vandine.org>
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>>> --
>>> This message was sent to: Scott Lambdin <lopaki at gmail.com>
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>>
>>