This patch makes the worker reject the incoming frame for putting the
message back in the queue, in the event the job id doesn't exist yet.
Which is the case when some actions are being triggered inside a
transaction which hasn't been commited to the DB yet.
To test you will need 3 KTD shells
(a) mysql:
$ ktd --shell
k$ sudo koha-mysql kohadev
(b) logs:
$ ktd --shell
# for restarting the worker and looking at the logs
k$ sudo koha-worker --restart kohadev ; tail -f /var/log/koha/kohadev/worker-*.log
(c) running the test:
$ ktd --shell
1. Have (a), (b) and (c) terminals ready
2. On (c), run:
$ perl -MKoha::Database -MKoha::BackgroundJob::BatchUpdateBiblioHoldsQueue -e 'Koha::Database->schema->txn_do( sub { Koha::BackgroundJob::BatchUpdateBiblioHoldsQueue->new->enqueue({ biblio_ids => [ 1 ] }); sleep 1; } );'
=> FAIL:
* (b) shows (once) an error about a job not existing
3. On (a) run:
> SELECT * FROM background_jobs;
=> FAIL: Notice the job ID mentioned on 2 stands as 'new'.
4. Apply this patch
5. Ctrl+c on (b), and re-run to launch the worker with the patch applied
6. Repeat 2
=> SUCCESS (partial): The error about the job not existing is displayed
many times
7. Repeat 3
=> SUCCESS: The job ID mentioned on 6 stands as 'finished'.
8. Sign off :-D
Discussion:
* The `requeue` header I added is correct, but it is the default
behavior anyway. I prefered to make it explicit, though.
* To avoid that bunch of retries, we should requeue with some delay. I
didn't manage to make it work (yet) but there's a 'delay' plugin for
rabbit [1]. We already install the 'stomp' plugin in
koha-common.postinst. But this plugin requires downloading it. Which
would require further investigation.
* As Nick and Marcel pointed, we need to revisit the whole architecture,
the need of a MQ (DB polling wouldn't have this problem), etc. But
that's for another place.
[1] https://hevodata.com/learn/rabbitmq-delayed-message/#:~:text=To%20delay%20a%20message%2C%20the,to%20queues%20or%20other%20exchanges.
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Tomas Cohen Arazi <tomascohen@theke.io>
Signed-off-by: Marcel de Rooy <m.de.rooy@rijksmuseum.nl>
Signed-off-by: Katrin Fischer <katrin.fischer@bsz-bw.de>
(cherry picked from commit 1a51c2e973)
Signed-off-by: Fridolin Somers <fridolin.somers@biblibre.com>
83fb050b2f