Proposal: begin process of moving plugin components in DevWorkspace spec

[amisevsk]

Which area this feature is related to?

/area devworkspace

Which functionality do you think we should add?

Add a new field to DevWorkspaces to store plugin components, separate from the DevWorkspace template:

  kind: DevWorkspace
  apiVersion: workspace.devfile.io/v1alpha2
  metadata:
    name: golang-sample
  spec:
    started: true
+   contributions:
+     - name: che-code
+       uri: https://gist.githubusercontent.com/amisevsk/b342b9ae064b5a79e08945d04d02c208/raw/84cd2df9266b4a608fbc0fd0cc18816bca03e344/theia-contrib.devfile.yaml
    template:
      attributes:
        controller.devfile.io/storage-type: ephemeral
      projects:
        - name: golang-sample
          git:
            remotes:
              origin: "https://github.com/che-samples/golang-example.git"
      components:
        - name: tools
          container:
            image: quay.io/devfile/universal-developer-image:ubi8-0e189d9
            env:
              - name: GOPATH
                value: /projects:/home/user/go
              - name: GOCACHE
                value: /tmp/.cache
            endpoints:
              - name: 8080-tcp
                targetPort: 8080
            memoryLimit: 2Gi
            mountSources: true

This new field would contain a list of items that contain the same information as the current plugin components, but simplified as there is no need to distinguish them from non-plugin components:

contributions:
- name: reference-by-uri
  uri: <URI to devworkspace or devfile yaml/json>

- name: reference-by-k8s
  kubernetes:
    name: <name of DevWorkspaceTemplate>
    namespace: <namespace for DWT; optional -- default is current namespace>

- name: reference-by-id
  id: <ID in a devfile registry>
  registryURL: <URL to registry containing plugin>

Contributions would also support the current plugin overriding functionality, to allow overriding components/commands in the contribution:

contributions:
- name: reference-by-uri
  uri: <URI to devworkspace or devfile yaml/json>
  components:
    - name: theia-ide
      container:
        env:
          - name: THEIA_HOST
            value: 0.0.0.0

Why is this needed? Is your feature request related to a problem?

Since plugin components were removed from the devfile schema (#333), there has been a mismatch between the DevWorkspace custom resource and Devfiles. This leads to the following issues:

• There's not a clear line between a devfile and a devworkspace when plugins are used -- if you want to add plugins to a devfile, the devworkspace.spec.template must be modified, where it should ideally be a copy of the original Devfile
• Converting a DevWorkspace into a Devfile requires filtering the components list for components with type plugin

This change would mean that there is a clear, distinct way to layer on additional components to existing Devfiles when creating a DevWorkspace.

The same DevWorkspace posted above, written with the current DevWorkspace CR, would instead be

  kind: DevWorkspace
  apiVersion: workspace.devfile.io/v1alpha2
  metadata:
    name: golang-sample
  spec:
    started: true
    template:
      attributes:
        controller.devfile.io/storage-type: ephemeral
      projects:
        - name: golang-sample
          git:
            remotes:
              origin: "https://github.com/che-samples/golang-example.git"
      components:
        - name: tools
          attributes:
          container:
            image: quay.io/devfile/universal-developer-image:ubi8-0e189d9
            env:
              - name: GOPATH
                value: /projects:/home/user/go
              - name: GOCACHE
                value: /tmp/.cache
            endpoints:
              - name: 8080-tcp
                targetPort: 8080
            memoryLimit: 2Gi
            mountSources: true
+       - name: che-code
+         plugin:
+           uri: https://gist.githubusercontent.com/amisevsk/b342b9ae064b5a79e08945d04d02c208/raw/84cd2df9266b4a608fbc0fd0cc18816bca03e344/theia-contrib.devfile.yaml

Additional Information

Note that even with this change, the DevWorkspace .spec.template.components still has to support components of type Plugin in v1alpha2, as removing it there would be a backwards-incompatible change. Hopefully this implementation would allow for migration away from plugin components, making it easier to (potentially) drop the plugin component type if/when we reach v1alpha3.

[amisevsk]

cc: @l0rd