Resources for Tasks with many images in the same registry are repetitive

[bobcatfish]

Expected Behavior

If I'm creating a Task that needs to build a lot of images, that means I need to provide many image resources. If these all need to get pushed to the same image registry, it would be great if I only needed to provide this information once.

Actual Behavior

While working on #528 I started to create a Task that can publish all the images required for this project. There are a lot of them tho and so what I've currently got is something like this:

---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: entrypoint-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/entrypoint # Replace this with your own image registry
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: kubeconfigwriter-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/kubeconfigwriter # Replace this with your own image registry
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: creds-init-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/creds-init # Replace this with your own image registry
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: git-init-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/git-init # Replace this with your own image registry
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: nop-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/nop # Replace this with your own image registry
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: bash-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/bash # Replace this with your own image registry
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: gsutil-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/gsutil # Replace this with your own image registry
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: controller-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/controller # Replace this with your own image registry
---
apiVersion: tekton.dev/v1alpha1
kind: PipelineResource
metadata:
  name: webhook-image
spec:
  type: image
  params:
   - name: url
     value: gcr.io/christiewilson-catfactory/webhook # Replace this with your own image registry

If someone wants to use the Task that consumes these with their own registry, they're going to have to change each of those url values.

Additional Info

Note that these images are built using ko, which doesn't take as input information about individual images, it just takes the KO_DOCKER_REPO

[abayer]

Would need to be overridable per-image, I'd assume?

[bobcatfish]

I think the future of the image resource is going to look very different from what we have today (#1673) - and with Tasks able to emit results (e.g. in this example https://github.com/tektoncd/pipeline/blob/master/docs/migrating-v1alpha1-to-v1beta1.md#replacing-pipelineresources-with-tasks) it seems like image resources really arent that useful. So I'm going to close this for now!