[Koha-bugs] [Bug 15032] [Plack] Scripts that fork (like stage-marc-import.pl) don't work as expected

[bugzilla-daemon at bugs.koha-community.org]

https://bugs.koha-community.org/bugzilla3/show_bug.cgi?id=15032

--- Comment #37 from David Cook <dcook at prosentient.com.au> ---
(In reply to Tomás Cohen Arazi from comment #36)
> I need to implement a way to hook record/item updates so changes are pushed
> to an external service. Ideally through the use of plugins so a more generic
> job queue was the first thing to consider. Then if we replace (say)
> rebuild_zebra.pl -d with this, we should add a way to inject new 'tasks'
> derived from this events (so a record update should trigger a zebra/ES
> indexing step, and also look for things (plugins) that would require
> actions. It felt simpler if it just sent broadcast messages through a socket
> to any service listening there.
> I like ZeroMQ because it doesn't need a server, you just use your own
> service.
> 
> So, one event => multiple actions.

I've been wanting a hook for record/item creation/update/deletion as well, so
it sounds like our desire is similar there! I'm sure many people have a variety
of external services which would like event-driven updates from Koha. 

I read about ZeroMQ a while ago, but I didn't realize it doesn't need a
dedicated broker (ie server). That's interesting! It would be fun to play with
that.

In the context of #15032, would you still want to use a message queue? I could
see Koha sending a message to an importer service (in a pub/sub pattern), but
I'm not sure how Koha would know when the import task is finished without
having a result store. I suppose we could have a result store though. We could
send a message to the importer service, and then asynchronously poll the result
store to see when the task is done? I suppose that has disadvantages in that if
the task fails, you're polling forever. And if you're polling, you also lose
any sort of progress meter (although I always assumed we faked the progress
with our current background implementation anyway). I guess those are just
implementation details though.

(With #10662, the Koha web UI connects to the OAI-PMH harvester demon through a
Unix socket. It has bidirectional communication though as it has a
request-reply relationship.)

-- 
You are receiving this mail because:
You are watching all bug changes.