Fix module reconciler not being able to watch for ConfigMaps error

[mresvanis]

This fix adds the watch permission for ConfigMaps to the Module reconciler, in order to be able to successfully client.Get() the build Dockerfile ConfigMap. This client.Get() fails because the contoller-runtime client reads from its cache, instead of directly from the API server. The client needs the watch permission, in order to be able to build its cache.

• client.Get() requires watch permission controller-runtime#1156

Signed-off-by: Michail Resvanis [email protected]

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[k8s-ci-robot]

Hi @mresvanis. Thanks for your PR.

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[qbarrand]

/lgtm
/ok-to-test
/assign @yevgeny-shnaidman

[yevgeny-shnaidman]

@mresvanis we have an e2e test that is runs the build flow with configmap, and it has been passing successfully since the ConfigMap has been added. What has changed that we need the watch permission ( get and list previously was enough)?

[yevgeny-shnaidman]

@mresvanis we have an e2e test that is runs the build flow with configmap, and it has been passing successfully since the ConfigMap has been added. What has changed that we need the watch permission ( get and list previously was enough)?
I am going to lgtm , but we need to better understand what's going on there: we are not watching ConfigMaps in any of our controllers, only Getting it, but not having permissions to watch interefers with our watch for Builds..

[yevgeny-shnaidman]

/lgtm

[yevgeny-shnaidman]

/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: mresvanis, yevgeny-shnaidman

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[mresvanis]

@mresvanis we have an e2e test that is runs the build flow with configmap, and it has been passing successfully since the ConfigMap has been added. What has changed that we need the watch permission ( get and list previously was enough)?
I am going to lgtm , but we need to better understand what's going on there: we are not watching ConfigMaps in any of our controllers, only Getting it, but not having permissions to watch interefers with our watch for Builds..

@yevgeny-shnaidman I apologize for the misunderstanding, this PR was about fixing the reconciler error regarding its client's cache watch permission on ConfigMaps. The module build flow is and was working correctly without this PR's change, i.e. without the Module reconciler's watch permission on ConfigMaps.

Context

The cause of this error is based on the internals of the cache of the controller-runtime/client. By default this client when reading resources, e.g. when Get()-ing or List()-ing, tries to read from its cache first. If there is no cache for the resource we're trying to read, then it creates a new cached client and then tries to build the respective cache. The cache setup includes setting up informers for the resource we're trying to read and those informers watch for such resources, in order to keep the cache as fresh as possible.

Possible Solutions

In order to resolve this reconciler cache watch permission error (and only this error, as the build flow is anyway working as expected), we have 2 options:

1. setup a new client for this ConfigMap client.Get() call, with its cache disabled, so that no informers will be setup and no watch permission is needed
2. add the watch permission to ConfigMaps, so that the existing client can leverage caching on ConfigMaps

This PR's solution

This PR followed option 2, but we can definitely revisit this if we would like to get rid of the watch permission on ConfigMaps.

Does this help?

[yevgeny-shnaidman]

@mresvanis Thank you for explanation, very helpful