Add image labels to .ko.yaml config

[ericsmalling]

I would like to be able to configure image labels/annotations from the the .ko.yaml file so that oranizations with standardized label requirements can specify them there instead of only via the CLI --image-label flag.

Additionally, the values for these labels should be able to be interpolated/expanded at run time via environment variables.

Example config:

...
image-labels:
  - org: mycorp-devrel
  - ci-build: {{ Env.GITHUB_SERVER_URL }}/{{ Env.GITHUB_REPOSITORY }}/actions/runs/{{ Env.GITHUB_RUN_ID }}

[ericsmalling]

I'm going to start hacking on a solution for this but am a novice Go coder so be kind in code reviews, plz! :)

[ericsmalling]

updated description to use go template for Env var expansion since I see we already have that for other configs

[halvards]

If you'd like to use Skaffold to build your ko images, env var support in image labels is already available: https://skaffold.dev/docs/pipeline-stages/builders/ko/#image-labels

[developer-guy]

Are you still interested in working on this @ericsmalling? Maybe I can take care of this one if you don't have enough time to look at it.

[ericsmalling]

I am, but my schedule this week is slammed. If you have time for it, go right ahead, otherwise I'll pick it up when I can.

[dio]

@ericsmalling I think https://github.com/ko-build/ko/compare/main...dio:ko:labels?expand=1 will work.

I have a question: Do you think we need to allow to set labels for each build in builds?

[dio]

I have a use case for setting image-related information and putting that somehow as a map to a binary (package) build.

For example, I have the following structure:

.
├── proj1
│   ├── .ko.yaml
│   ├── Labels.mk
│   ├── Makefile
│   └── cmd
│       └── a
└── proj2
    ├── .ko.yaml
    ├── Labels.mk
    ├── Makefile
    └── cmd
        ├── a
        └── b

So for example, between proj2/cmd/a proj2/cmd/b we need different labels (for name, summary, description, etc as required by https://github.com/redhat-openshift-ecosystem/openshift-preflight). Currently, we manage that separately (inside a .mk that can be included in the corresponding Makefile), not in the .ko.yaml. Do you think we can extend .ko.yaml to accommodate this, by doing one of the following?

1. Add an images field, each of its entries that map with each entry in builds.
2. Extends build to allow image-related information.

For 1,

builds:
  id: a

images:
  id: a
  labels:
    - name: ok
    - release: v{{ .Env.Tag }}

or for 2,

builds:
  id: a
  image:
    labels:
      - name: ok
      - release: v{{ .Env.Tag }}

@ericsmalling @imjasonh do you think this makes sense?

[github-actions]

This issue is stale because it has been open for 90 days with no
activity. It will automatically close after 30 more days of
inactivity. Keep fresh with the 'lifecycle/frozen' label.

[jtcarnes]

any movement/idea on the issue?