Add status field to policy resource

[LorcanMcVeigh]

Proposed changes

This PR adds the status field, with the sub-fields 'state', 'reason' and 'message', to the policy resource.
It also prints out the state of the policy when kubectl get policy <policy-name> is ran.

Checklist

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• I have read the CONTRIBUTING doc
• I have added tests that prove my fix is effective or that my feature works
• I have checked that all unit tests pass after adding my changes
• I have updated necessary documentation
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[mikestephen]

Just left a couple of comments, but looking great Lorcan.

[pleshakov]

Hi @LorcanMcVeigh

We need to consider a few more cases related to leader election:

(1) only report the status from the leader. this is needed so that all Ingress Controller pods don't try to report statuses, but only one, to avoid duplicated work/errors related to collisions of updates.

For example, for VS/VSR, before reporting a status, the following check is performed:

if lbc.reportVsVsrStatusEnabled() {

we need to do a similar check for policies.
we can use that function. Better to rename it so it doesn't apply only for VS/VSR. For example, reportCustomResourceStatusEnabled()

(2) when an Ingress Controller pod becomes the leader, it needs to report statuses of the resources it handles. Otherwise, the resources that were processed during the period when there was no elected leader (can happen during upgrades or when the leader pod fails) will not have the status reported.

We already do that for VirtualServer/VirtualServerRoute and Ingresses. See

kubernetes-ingress/internal/k8s/leader.go

Line 51 in 2cdc714

OnStartedLeading: func(ctx context.Context) {

For Policies, we simply need to look go through every policy in the lister and report the status based on the validation.