feature request: composite triggers

[s-urbaniak]

Hello and thank you for this great project! :-)

As of today locutus supports three types of triggers (interval, oneoff, and resource) which can be used exclusively but not in combination.

To be used as an operator replacement I could think of yet another trigger type, namely a composite type which could leverage existing "primitive" triggers.

I am thinking of the following use cases. If locutus is started as a long running process it should:

• reconcile immediately after startup (essentially oneoff)
• additionally reconcile every x minutes (essentially interval)
• additionally reconcile on resource events (essentially resource)

UX:
Suggested command line option could be --trigger=composite with comma-separated list of triggers --trigger.composite=oneoff,interval,resource and the existing trigger specific configurations.

Another idea would be to allow multiple --trigger declarations, i.e. --trigger=oneoff --trigger=interval --trigger=resource.

Does that make any sense or is it actually preferable to have dedicated triggers only?

cc @paulfantom

[paulfantom]

I think that if we treat locutus as a library for building a solution, then having a composite trigger can be solved on the higher level.

[s-urbaniak]

Hmm, but then each consuming project would have to implement the trigger interface separately for compositing 🤔

[brancz]

reconcile immediately after startup (essentially oneoff)

I believe this is already the case, as filling the informer triggers reconciles for each of the initial objects.

Happy with introducing the option to do both interval and resource together!

[s-urbaniak]

self-assigning to this one.

[brancz]

Actually I could think of a useful case for one-off with resource together. Essentially this would mean that we stop the process after all items are worked off that were added to the informers on the initial list of the ListWatch. I have no idea whether this would be possible to do, but it would certainly be super useful in development.

[bwplotka]

That would be super awesome to see indeed 👍🏽