We should introduce webhook for Tobiko (and other test-operator CRs). If possible we should try to make the webhook as generic as possible (minimize the duplicate code).

DoD:

• There is a webhook code for each test-operator supported CR.
• If a CR uses workflows then the merging between the workflow and non workflow section is done in the webhook [1].
• The webhook ensures that an error is printed out when user tries to update an already existing CR [2].

[1] https://github.com/openstack-k8s-operators/test-operator/blob/9b7b3a98244e3e8243573809b46d5b1024b00312/controllers/tobiko_controller.go#L302
[2] https://github.com/openstack-k8s-operators/test-operator/pull/113

Reviews:

• https://github.com/openstack-k8s-operators/test-operator/pull/160
• https://github.com/openstack-k8s-operators/test-operator/pull/168