ImageUpdateAutomation misinterprets Registry URL when port is defined

[satriashp]

FluxCD's ImageUpdateAutomation is incorrectly parsing the image repository URL when using a local registry (registry.localhost:5000). Instead of properly recognizing the repository and tag, it misinterprets the port number as part of the image name.

To Reproduce

1. Set up a local registry: http://registry.localhost:5000

2. Push an image: registry.localhost:5000/sample-web:0.1.0

3. Define the following ImageRepository:

apiVersion: source.toolkit.fluxcd.io/v1beta2
kind: ImageRepository
metadata:
  name: sample-web
  namespace: flux-system
spec:
  image: registry.localhost:5000/sample-web
  provider: generic
  interval: 1m
  allowInsecure: true

4. Define ImagePolicy:

apiVersion: image.toolkit.fluxcd.io/v1beta2
kind: ImagePolicy
metadata:
  name: sample-web
  namespace: flux-system
spec:
  imageRepositoryRef:
    name: sample-web
  policy:
    semver:
      range: "0.1.x"

5. Apply ImageUpdateAutomation
6. Observe the status of ImageUpdateAutomation:

status:
  observedPolicies:
    sample-web:
      name: registry.localhost
      tag: 5000/sample-web:0.1.1

Expected:
The tag should be 0.1.1, and the repository should remain registry.localhost:5000/sample-web.

Actual:
Flux treats 5000/sample-web as the repository, misplacing the port number.

Expected behavior
FluxCD should correctly interpret the image repository as registry.localhost:5000/sample-web without breaking the tag format.

Environment
FluxCD Version: 2.5.1
Kubernetes Version: v1.32.2
Additional Context:
I'm using k3d to setup kubernetes local cluster
Running Flux with flux-system namespace
Local registry is accessible and works with docker pull registry.localhost:5000/sample-web:0.1.0
Issue persists even with allowInsecure: true
Changing localhost to registry.localhost in /etc/hosts does not fix the issue
Is this a known issue, and is there a workaround?

[matheuscscp]

How about the statuses of ImageRepository and ImagePolicy, did you notice anything strange on them or is it just ImageUpdateAutomation?

[makkes]

I would guess the root cause is this code. The good thing is that only the status file is affected but all other functionality should still work as expected.

[satriashp]

How about the statuses of ImageRepository and ImagePolicy, did you notice anything strange on them or is it just ImageUpdateAutomation?

Here status from 'ImageRepositoty' and 'ImagePolicy', its seem correctly tag image with 0.1.x.

status:
  canonicalImageName: registry.localhost:5000/sample-web
  conditions:
  - lastTransitionTime: "2025-03-15T03:07:37Z"
    message: 'successful scan: found 2 tags'
    observedGeneration: 1
    reason: Succeeded
    status: "True"
    type: Ready
  lastScanResult:
    latestTags:
    - 0.1.1
    - 0.1.0
    scanTime: "2025-03-15T03:07:37Z"
    tagCount: 2
  observedExclusionList:
  - ^.*\.sig$
  observedGeneration: 1

status:
  conditions:
  - lastTransitionTime: "2025-03-15T03:07:37Z"
    message: Latest image tag for 'registry.localhost:5000/sample-web' resolved to
      0.1.1
    observedGeneration: 1
    reason: Succeeded
    status: "True"
    type: Ready
  latestImage: registry.localhost:5000/sample-web:0.1.1
  observedGeneration: 1

I would guess the root cause is this code. The good thing is that only the status file is affected but all other functionality should still work as expected.

I cant tell its related but whenever new image tag being push its not automatically update the deployments.