Enable adding and removing watches at runtime.

[nkvoll]

It would be great if there was a way to add and remove watches during the controller lifecycle.

Use case: want to be able to get some data from a user-supplied secret, instead of inline:

    credentials:
        secretSource:
            name: name-of-a-secret-containing-some-credentials
        #inline:
        #    username: foo
        #    password: bar

• If secretSource is specified, we want to add a watch for it so we can reconcile when it changes (likely have to provide a custom handler.EventHandler to reconcile the correct object(s)).
• If it is no longer specified, we want to remove the watch for it (if we created it) so we no longer spend resources on having an unused watch.
• This means the resources we would like to have watches for may change over time, so the ability to not only add, but also remove watches becomes important.

[DirectXMan12]

/kind feature
/priority important-longterm

[fejta-bot]

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Mark the issue as fresh with /remove-lifecycle stale.
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/lifecycle stale

[fejta-bot]

Stale issues rot after 30d of inactivity.
Mark the issue as fresh with /remove-lifecycle rotten.
Rotten issues close after an additional 30d of inactivity.

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/lifecycle rotten

[DirectXMan12]

I believe we support this now, closing.

[jcanseco]

How can one actually do this (i.e. dynamically add and remove watches?)

If I understand correctly, I can dynamically add a watch by calling controller.Watch() from within the reonciler.

How can one remove the watch once it is no longer needed?

[jcanseco]

Gentle ping -- still looking for an answer to my question above.

@DirectXMan12 is this something you could help out with?