Image update policy doesn't support kustomization

[rverma-dev]

Describe the bug

ImageUpdation doesn't work on flux's Kustomization. Image policy reflect the right image though.

To Reproduce

Steps to reproduce the behaviour:
If we have image ovveride in the Kustomization like

apiVersion: kustomize.toolkit.fluxcd.io/v1beta1
kind: Kustomization
metadata:
  name: demo
  namespace: apps
spec:
  images:
    - name: ghcr.io/nslhb/rollouts-demo
      newTag: green # {"$imagepolicy": "apps:rollouts-demo:tag"}

and define Imageupdation as

apiVersion: image.toolkit.fluxcd.io/v1alpha2
kind: ImageUpdateAutomation
metadata:
  name: flux-system
  namespace: flux-system
spec:
  git:
    checkout:
      ref:
        branch: main
    commit:
      author:
        email: [email protected]
        name: fluxcdbot
      messageTemplate: '{{range .Updated.Images}}{{println .}}{{end}}'
    push:
      branch: main
  interval: 1m0s
  sourceRef:
    kind: GitRepository
    name: flux-system
  update:
    path: ./tenants/services/ap-south-1
    strategy: Setters

Expected behavior

Flux should commit the newly discoverd image as reflected by imagepolicy.

Additional context

• Kubernetes version: 1.19
• Git provider: github
• Container registry provider: github

Below please provide the output of the following commands:

flux --version : 0.13.2
flux check : all checks passed 

Image automation controller log

{"level":"info","ts":"2021-05-02T16:50:03.095Z","logger":"controller-runtime.manager.controller.imageupdateautomation","msg":"Starting workers","reconciler group":"image.toolkit.fluxcd.io","reconciler kind":"ImageUpdateAutomation","worker count":1}
{"level":"error","ts":"2021-05-03T12:19:57.450Z","logger":"controller-runtime.manager.controller.imageupdateautomation","msg":"Reconciler error","reconciler group":"image.toolkit.fluxcd.io","reconciler kind":"ImageUpdateAutomation","name":"flux-system","namespace":"flux-system","error":"object not found"}
{"level":"error","ts":"2021-05-03T12:50:43.095Z","logger":"controller-runtime.manager.controller.imageupdateautomation","msg":"Reconciler error","reconciler group":"image.toolkit.fluxcd.io","reconciler kind":"ImageUpdateAutomation","name":"flux-system","namespace":"flux-system","error":"object not found"}

another thing is that the ImageUpdateAutomation have namespace as flux-system
while ImageRepository/ImagePolicy belong to namespace apps

---
apiVersion: image.toolkit.fluxcd.io/v1alpha2
kind: ImageRepository
metadata:
  name: rollouts-demo
  namespace: apps
spec:
  image: ghcr.io/nslhb/rollouts-demo
  interval: 1m0s

---
apiVersion: image.toolkit.fluxcd.io/v1alpha2
kind: ImagePolicy
metadata:
  name: rollouts-demo
  namespace: apps
spec:
  imageRepositoryRef:
    name: rollouts-demo
  filterTags:
    pattern: '^${color}-(?P<timestamp>.*)-(?P<sha>.*)$'
    extract: '$timestamp'
  policy:
    numerical:
      order: asc

[stefanprodan]

another thing is that the ImageUpdateAutomation have namespace as flux-system while ImageRepository/ImagePolicy belong to namespace apps

This is not currently supported, please comment on this RFC fluxcd/image-automation-controller#157