tekton-buildpacks.yml

---
apiVersion: tekton.dev/v1beta1
kind: Task
metadata:
  name: buildpacks-phases
  labels:
    app.kubernetes.io/version: "0.1"
  annotations:
    tekton.dev/pipelines.minVersion: "0.12.1"
    tekton.dev/tags: image-build
    tekton.dev/displayName: "buildpacks-phases"
spec:
  description: >-
    The Buildpacks-Phases task builds source into a container image and pushes it to
    a registry, using Cloud Native Buildpacks. This command separately calls the aspects of the
    Cloud Native Buildpacks lifecycle, to provide more granular control over the construction of
    the image.

    Cloud Native Buildpacks are pluggable, modular tools that transform application source code
    into OCI images. They replace Dockerfiles in the app development lifecycle, and allow for swift
    rebasing of images, and give modular control over images through the use of builders, among other
    benefits. This command uses a builder to construct the image, and pushes it to the registry provided.

  params:
    - name: BUILDER_IMAGE
      description: The image on which builds will run (must include lifecycle and compatible buildpacks).
    - name: CACHE
      description: The name of the persistent app cache volume.
      default: empty-dir
    - name: PLATFORM_DIR
      description: The name of the platform directory.
      default: empty-dir
    - name: USER_ID
      description: The user ID of the builder image user.
      default: "1000"
    - name: GROUP_ID
      description: The group ID of the builder image user.
      default: "1000"
    - name: PROCESS_TYPE
      description: The default process type to set on the image.
      default: "web"
    - name: SOURCE_SUBPATH
      description: A subpath within the `source` input where the source to build is located.
      default: ""

  resources:
    outputs:
      - name: image
        type: image

  workspaces:
    - name: source

  stepTemplate:
    env:
      - name: CNB_PLATFORM_API
        value: "0.3"

  steps:
    # Ensure the builder's user has read/write permissions for needed directories.
    - name: prepare
      image: alpine
      imagePullPolicy: Always
      command: ["/bin/sh"]
      args:
        - "-c"
        - >
          chown -R "$(params.USER_ID):$(params.GROUP_ID)" "/tekton/home" &&
          chown -R "$(params.USER_ID):$(params.GROUP_ID)" "/layers" &&
          chown -R "$(params.USER_ID):$(params.GROUP_ID)" "/cache" &&
          chown -R "$(params.USER_ID):$(params.GROUP_ID)" "$(workspaces.source.path)"
      volumeMounts:
        - name: layers-dir
          mountPath: /layers
        - name: $(params.CACHE)
          mountPath: /cache
      securityContext:
        privileged: true

    # Copy stack.toml so that it will be accessible to the exporter, since the lifecycle image will not contain it.
    - name: copy-stack-toml
      image: $(params.BUILDER_IMAGE)
      imagePullPolicy: Always
      command: ["/bin/sh"]
      args:
        - "-c"
        - >
          cp /cnb/stack.toml /layers/
      volumeMounts:
        - name: layers-dir
          mountPath: /layers

    - name: detect
      image: $(params.BUILDER_IMAGE)
      imagePullPolicy: Always
      command: ["/cnb/lifecycle/detector"]
      args:
        - "-app=$(workspaces.source.path)/$(params.SOURCE_SUBPATH)"
        - "-group=/layers/group.toml"
        - "-plan=/layers/plan.toml"
      volumeMounts:
        - name: layers-dir
          mountPath: /layers
        - name: $(params.PLATFORM_DIR)
          mountPath: /platform
        - name: empty-dir
          mountPath: /tekton/home

    - name: analyze
      image: buildpacksio/lifecycle:0.8.1
      imagePullPolicy: Always
      command: ["/cnb/lifecycle/analyzer"]
      args:
        - "-layers=/layers"
        - "-group=/layers/group.toml"
        - "-cache-dir=/cache"
        - "-uid=$(params.USER_ID)"
        - "-gid=$(params.GROUP_ID)"
        - "$(resources.outputs.image.url)"
      volumeMounts:
        - name: $(params.CACHE)
          mountPath: /cache
        - name: layers-dir
          mountPath: /layers

    - name: restore
      image: buildpacksio/lifecycle:0.8.1
      imagePullPolicy: Always
      command: ["/cnb/lifecycle/restorer"]
      args:
        - "-group=/layers/group.toml"
        - "-layers=/layers"
        - "-cache-dir=/cache"
        - "-uid=$(params.USER_ID)"
        - "-gid=$(params.GROUP_ID)"
      volumeMounts:
        - name: $(params.CACHE)
          mountPath: /cache
        - name: layers-dir
          mountPath: /layers

    - name: build
      image: $(params.BUILDER_IMAGE)
      imagePullPolicy: Always
      command: ["/cnb/lifecycle/builder"]
      args:
        - "-app=$(workspaces.source.path)/$(params.SOURCE_SUBPATH)"
        - "-layers=/layers"
        - "-group=/layers/group.toml"
        - "-stack-group=/layers/stack-group.toml"
        - "-plan=/layers/plan.toml"
      volumeMounts:
        - name: layers-dir
          mountPath: /layers
        - name: $(params.PLATFORM_DIR)
          mountPath: /platform
        - name: empty-dir
          mountPath: /tekton/home
          
    - name: extend
      image: $(params.RUN_IMAGE)
      imagePullPolicy: Always
      command: ["/cnb/lifecycle/extender"]
      args:
        - "-layers=/layers"
        - "-stack-group=/layers/group.toml"
        - "-plan=/layers/plan.toml"
      volumeMounts:
        - name: lifecycle-dir
          mountPath: /cnb/lifecycle
        - name: layers-dir
          mountPath: /layers
        - name: $(params.PLATFORM_DIR)
          mountPath: /platform
        - name: empty-dir
          mountPath: /tekton/home

    - name: export
      image: buildpacksio/lifecycle:0.8.1
      imagePullPolicy: Always
      command: ["/cnb/lifecycle/exporter"]
      args:
        - "-app=$(workspaces.source.path)/$(params.SOURCE_SUBPATH)"
        - "-layers=/layers"
        - "-group=/layers/group.toml"
        - "-cache-dir=/cache"
        - "-process-type=$(params.PROCESS_TYPE)"
        - "-uid=$(params.USER_ID)"
        - "-gid=$(params.GROUP_ID)"
        - "-stack=/layers/stack.toml"
        - "$(resources.outputs.image.url)"
      volumeMounts:
        - name: layers-dir
          mountPath: /layers
        - name: $(params.CACHE)
          mountPath: /cache

  volumes:
    - name: empty-dir
      emptyDir: {}
    - name: layers-dir
      emptyDir: {}

Notes

• The prepare phase could populate the lifecycle-dir so that the extend phase can mount it into the run-image
• is there anyway to set the RUN_IMAGE dynamically from the builder (so that you don't need it as an input to this config)?