AppSet with plugin generator are always refreshed when using webhook endpoint

[dacofr]

Hello Argo members,

We are currently facing an unexpected behaviour with ApplicationSet configured with plugin generator, and the fact that we trigger the webhook endpoint via Github on every commit.

We have ~80 appsets using matrix generator with two child generators: git and plugin. All this appsets generates ~4K apps.
Every time GitHub calls our /api/webhook endpoint, all ApplicationSet are always refreshed.
So even for a small appset that generate few applications, each time a commit is done inside git repository all 4k apps are regenerated.

After some debugging iterations, we think it's this function:

func shouldRefreshPluginGenerator(gen *v1alpha1.PluginGenerator) bool { return gen != nil
    return gen != nil
}

There is no specific condition, just having a plugin generator spec is enough to trigger a refresh.

Could this be considered a bug or is this the expected behaviour? I will be happy to contribute to fix or improve it.

In our case, we only want to refresh one ApplicationSet, the one where repoUrl defined in the git generator matches the URL coming from the webhook payload.

Thanks for your feedback 🙏