request support for the non-blocking apply method

[zxbyoyoyo]

We use fluxcd to implement gitops, one application corresponds to one yaml. In use, we found that kustomize-controller will perform dry-run verification on each yaml when executing manifest apply. Once there is a problem with yaml, it will return an error directly. As a result, other normal yaml cannot be executed. See: github.com/fluxcd/pkg/ssa/manager_apply.go:125

We expect that an application yaml has a problem without affecting other application yaml to be applied。
my implementation：

[stefanprodan]

Each application should be reconciled by its own Kustomization, ignoring invalid definitions is not something that I would consider for Flux. You may want to reach out to the others maintainers during Flux dev meetings, write an RFC for this proposal and if the majority of the maintainers vote in favor I will comply with their decision even though I strongly appose it.

[aw185176]

While slightly off-topic, it would be fantastic if all the dry run results were collected and returned. Currently our human operators and controllers that leverage fluxcd/pkg/ssa all have to deal with remediations one at a time, then wait for a reconcile or apply loop to finish with the next error.

[stefanprodan]

@aw185176 is flux diff bailing out at first error? If so then please fill a an issue on the flux2 please.

[aw185176]

@stefanprodan flux diff works fine, but the dry-run apply that is done by fluxcd/pkg/ssa does bail out on the first dry-run apply erorr: https://github.com/fluxcd/pkg/blob/main/ssa/manager_apply.go#L88. This results in the Kustomization object status only reporting one problem at a time (as well as any of the code that we write using fluxcd/pkg/ssa)

Definitely happy to file a separate issue for that if that is helpful.