Uncertainty regarding caching for multiple different docker images in the same pipeline

[LasseGravesen]

Given the following pipeline, I am having trouble getting it to successfully cache the second publish step. If I use the cache_key option, I get the message 'No cache for /drone/docker' no matter how many times I run it. Am I missing something obvious?

pipeline:
  restore-cache-base:
    image: drillster/drone-volume-cache
    restore: true
    environment:
      STEP_TAG: 'BASE'
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH, STEP_TAG ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache
  publish-base:
    image: plugins/docker
    registry: xxxx
    repo: yyyy
    dockerfile: Dockerfile.base
    tags:
      - latest
      - ${DRONE_COMMIT_BRANCH}
      - ${DRONE_COMMIT_BRANCH}-${DRONE_COMMIT_SHA:0:8}
    secrets:
      - docker_username
      - docker_password
    storage_path: /drone/docker
    purge: false
  rebuild-cache-base:
    image: drillster/drone-volume-cache
    rebuild: true
    environment:
      STEP_TAG: 'BASE'
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH, STEP_TAG ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache
      
  restore-cache-zerg:
    image: drillster/drone-volume-cache
    restore: true
    environment:
      STEP_TAG: 'ZERG'
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH, STEP_TAG ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache
  publish-zerg:
    image: plugins/docker
    registry: xxxx
    repo: zzzz
    dockerfile: Dockerfile.zerg
    tags:
      - latest
      - ${DRONE_COMMIT_BRANCH}
      - ${DRONE_COMMIT_BRANCH}-${DRONE_COMMIT_SHA:0:8}
    secrets:
      - docker_username
      - docker_password
    storage_path: /drone/docker
    purge: false
  rebuild-cache-zerg:
    image: drillster/drone-volume-cache
    rebuild: true
    environment:
      STEP_TAG: 'ZERG'
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH, STEP_TAG ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache

[mjwwit]

It doesn't work if you merge the cache steps like so?

pipeline:
  restore-cache:
    image: drillster/drone-volume-cache
    restore: true
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache

  publish-base:
    image: plugins/docker
    registry: xxxx
    repo: yyyy
    dockerfile: Dockerfile.base
    tags:
      - latest
      - ${DRONE_COMMIT_BRANCH}
      - ${DRONE_COMMIT_BRANCH}-${DRONE_COMMIT_SHA:0:8}
    secrets:
      - docker_username
      - docker_password
    storage_path: /drone/docker
    purge: false

  publish-zerg:
    image: plugins/docker
    registry: xxxx
    repo: zzzz
    dockerfile: Dockerfile.zerg
    tags:
      - latest
      - ${DRONE_COMMIT_BRANCH}
      - ${DRONE_COMMIT_BRANCH}-${DRONE_COMMIT_SHA:0:8}
    secrets:
      - docker_username
      - docker_password
    storage_path: /drone/docker
    purge: false

  rebuild-cache:
    image: drillster/drone-volume-cache
    rebuild: true
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache

[LasseGravesen]

This is what it does when they each have separate restore-cache, rebuild-cache steps, after a single build has already been done:

clone               00:02
restore-a-cache     00:03
publish-a           00:06
rebuild-a-cache     00:01
restore-b-cache     00:01
publish-b           00:38 <-- bad step! why isnt it cached?
rebuild-b-cache     00:01

This is what it does when they're merged into a single step after a single build has already been done, as you did above:

clone           00:01
restore-cache   00:03
publish-a       00:04
publish-b       00:36 <-- bad step! why isnt it cached?
rebuild-cache   00:01

Separate cache steps, .drone.yml file:

pipeline:
  restore-a-cache:
    image: drillster/drone-volume-cache
    restore: true
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache
    when:
      status: success
      event: push
      branch: master
      local: false

  publish-a:
    image: plugins/docker
    repo: test-a
    registry: harbor
    dockerfile: docker/Dockerfile.a
    force_tag: true
    tags:
      - latest
      - 2018.10.1-${DRONE_BUILD_NUMBER}-${DRONE_COMMIT_SHA:0:8}
    secrets:
      - docker_username
      - docker_password
    storage_path: /drone/docker
    purge: false
    when:
      status: success
      event: push
      branch: master
      local: false

  rebuild-a-cache:
    image: drillster/drone-volume-cache
    rebuild: true
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH ]
    mount:
    - /drone/docker
    volumes:
    - /tmp/cache:/cache
    when:
      status: success
      event: push
      branch: master
      local: false

  restore-b-cache:
    image: drillster/drone-volume-cache
    restore: true
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH ]
    mount:
    - /drone/docker
    volumes:
    - /tmp/cache:/cache
    when:
      status: success
      event: push
      branch: master
      local: false

  publish-b:
    image: plugins/docker
    repo: test-b
    registry: harbor
    dockerfile: docker/Dockerfile.b
    force_tag: true
    tags:
      - latest
      - 2018.10.1-${DRONE_BUILD_NUMBER}-${DRONE_COMMIT_SHA:0:8}
    when:
      status: success
      event: push
      branch: master
      local: false
    secrets:
      - docker_username
      - docker_password

  rebuild-b-cache:
    image: drillster/drone-volume-cache
    rebuild: true
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH ]
    mount:
    - /drone/docker
    volumes:
    - /tmp/cache:/cache
    when:
      status: success
      event: push
      branch: master
      local: false

Same cache step, .drone.yml file:

pipeline:
  restore-cache:
    image: drillster/drone-volume-cache
    restore: true
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache
    when:
      status: success
      event: push
      branch: master
      local: false

  publish-a:
    image: plugins/docker
    repo: test-b
    registry: harbor
    dockerfile: docker/Dockerfile.a
    force_tag: true
    tags:
      - latest
      - 2018.10.0-${DRONE_BUILD_NUMBER}-${DRONE_COMMIT_SHA:0:8}
    secrets:
      - docker_username
      - docker_password
    storage_path: /drone/docker
    purge: false
    when:
      status: success
      event: push
      branch: master
      local: false

  publish-b:
    image: plugins/docker
    repo: test-b
    registry: harbor
    dockerfile: docker/Dockerfile.b
    force_tag: true
    tags:
      - latest
      - 2018.10.0-${DRONE_BUILD_NUMBER}-${DRONE_COMMIT_SHA:0:8}
    when:
      status: success
      event: push
      branch: master
      local: false
    secrets:
      - docker_username
      - docker_password

  rebuild-cache:
    image: drillster/drone-volume-cache
    rebuild: true
    cache_key: [ DRONE_REPO_OWNER, DRONE_REPO_NAME, DRONE_BRANCH ]
    mount:
      - /drone/docker
    volumes:
      - /tmp/cache:/cache
    when:
      status: success
      event: push
      branch: master
      local: false

[LasseGravesen]

Let me know if you need any more information!

[mjwwit]

Interesting. Logically there is no reason why this shouldn't work... This also leads me to believe this plugin is not at fault here, it may be the Docker plugin or even Docker itself. I know there's also an issue with multi-stage Dockerfiles and caching. I'll have to invest some time to figure out what's going on and why it's not working.