controller: ignore deleted PVs

[pohly]

It is normal that a volume is still in the work queue after it was
deleted, which used to trigger an unnecessary error log message:

    I1008 18:58:53.808993       1 controller.go:1467] delete "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716": started
    I1008 18:58:54.125842       1 controller.go:1482] delete "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716": volume deleted
    I1008 18:58:54.159675       1 controller.go:1532] delete "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716": persistentvolume deleted
    I1008 18:58:54.159706       1 controller.go:1537] delete "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716": succeeded
    E1008 18:58:54.159752       1 controller.go:1056] volume "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716" in work queue no longer exists

[pohly]

Potentially related to this PR (I'm currently running an external-provisioner with this patch):

I1008 18:58:53.808993       1 controller.go:1467] delete "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716": started
I1008 18:58:54.125842       1 controller.go:1482] delete "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716": volume deleted
I1008 18:58:54.159675       1 controller.go:1532] delete "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716": persistentvolume deleted
I1008 18:58:54.159706       1 controller.go:1537] delete "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716": succeeded
E1008 18:58:54.159752       1 controller.go:1056] volume "pvc-0e8331f7-de7a-4c0c-a678-724e05c3b716" in work queue no longer exists

Line numbers are a bit different because of other changes, but I think that's from

sig-storage-lib-external-provisioner/controller/controller.go

Lines 1043 to 1055 in bb73692

	// syncVolumeHandler gets the volume from informer's cache then calls syncVolume
	func (ctrl *ProvisionController) syncVolumeHandler(ctx context.Context, key string) error {
	volumeObj, exists, err := ctrl.volumes.GetByKey(key)
	if err != nil {
	return err
	}
	if !exists {
	utilruntime.HandleError(fmt.Errorf("volume %q in work queue no longer exists", key))
	return nil
	}
	return ctrl.syncVolume(ctx, volumeObj)
	}

Should that really be logged as error? I think it is (now?) normal that some work items in the queue get removed.

Same with

sig-storage-lib-external-provisioner/controller/controller.go

Lines 1023 to 1041 in bb73692

	// syncClaimHandler gets the claim from informer's cache then calls syncClaim. A non-nil error triggers requeuing of the claim.
	func (ctrl *ProvisionController) syncClaimHandler(ctx context.Context, key string) error {
	objs, err := ctrl.claimsIndexer.ByIndex(uidIndex, key)
	if err != nil {
	return err
	}
	var claimObj interface{}
	if len(objs) > 0 {
	claimObj = objs[0]
	} else {
	obj, found := ctrl.claimsInProgress.Load(key)
	if !found {
	utilruntime.HandleError(fmt.Errorf("claim %q in work queue no longer exists", key))
	return nil
	}
	claimObj = obj
	}
	return ctrl.syncClaim(ctx, claimObj)
	}

[wongma7]

Just merged #89 which is making the same fix.

I agree with you that an object missing from cache should not be logged as an error, it will be logged unnecessarily every single time a volume is deleted+removed from cache since the deletion itself will trigger the informer to call syncVolume again

[pohly]

I agree with you that an object missing from cache should not be logged as an error, it will be logged unnecessarily every single time a volume is deleted+removed from cache since the deletion itself will trigger the informer to call syncVolume again

Let's use this PR to get rid of that log message. Commit added and description updated.

[pohly]

/assign @wongma7

[wongma7]

/lgtm
/retest
flake issue: #95

[pohly]

/retest

[wongma7]

whoops

/approve

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