Builder not using cache

Behaviour

Hi, I can’t seem to get the build-push-action to use the restored cache when building. I’ve tried following the steps in the market place instructions and recommendation here: https://github.com/docker/build-push-action/issues/132#issuecomment-699502544, but to no avail.

The logs indicate that the cache is restored, but when the build runs it seems to build everything from scratch.

Steps to reproduce

I have this in a test repo here: https://github.com/ltamrazov/testingactions

Expected behaviour

Cache is used to rebuild images on rerunning a workflow and on any new workflow run.

Actual behaviour

Images are rebuild from scratch.

Configuration

• Repository URL (if public): https://github.com/ltamrazov/testingactions
• Build URL (if public): https://github.com/ltamrazov/testingactions/runs/1203552549

name: ci

on:
    push:
        branches: [ master ]
    pull_request:
        branches: [ master ]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
    - name: Builder
      uses: docker/setup-buildx-action@v1
      id: buildx

    - name: Cache main image layers
      uses: actions/cache@v2
      with:
        path: /tmp/.buildx-cache
        key: ${{ runner.os }}-buildx-${{ github.sha }}
        restore-keys: |
          ${{ runner.os }}-buildx-

    - name: Checkout Code
      uses: actions/checkout@v2
    
    - name: Determine Image Tag
      id: generate_tag
      run: |
          _tag=latest
          if [ "${{ github.event_name }}" == "pull_request" ]
          then
              _tag=pr-${{ github.event.number }}
          fi
          _full=test/dev:${_tag}
          echo ::set-output name=tag::${_full}

    - name: Build code
      uses: docker/build-push-action@v2
      with:
        builder: ${{ steps.buildx.outputs.name }}
        push: false
        target: test
        load: true
        cache-from: type=local,src=/tmp/.buildx-cache
        cache-to: type=local,mode=max,dest=/tmp/.buildx-cache
        tags: ${{ steps.generate_tag.outputs.tag }}
    
    - name: Build DB
      uses: docker/build-push-action@v2
      with:
        builder: ${{ steps.buildx.outputs.name }}
        file: Dockerfile.postgres
        load: true
        cache-from: type=local,src=/tmp/.buildx-cache
        cache-to: type=local,mode=max,dest=/tmp/.buildx-cache
        tags: db-${{ steps.generate_tag.outputs.tag }}
    
    - name: Run Tests
      run: |
        API_IMAGE_TAG=${{ steps.generate_tag.outputs.tag }} DB_IMAGE_TAG=db-${{ steps.generate_tag.outputs.tag }} docker-compose -f docker-compose.yml --env-file .env.ci run test-api

Logs

logs_20.zip

Thank you!

[crazy-max]

Hi @ltamrazov

That’s because your cache is mixed with 2 images. You have to create another cache:

name: ci

on:
    push:
        branches: [ master ]
    pull_request:
        branches: [ master ]

jobs:
  test:
    runs-on: ubuntu-latest
    steps:
    - name: Builder
      id: buildx
      uses: docker/setup-buildx-action@v1
      with:
        buildkitd-flags: --debug

    - name: Cache main image layers
      uses: actions/cache@v2
      with:
        path: /tmp/.buildx-main-cache
        key: ${{ runner.os }}-buildx-main-${{ github.sha }}
        restore-keys: |
          ${{ runner.os }}-buildx-main-

    - name: Cache postgres image layers
      uses: actions/cache@v2
      with:
        path: /tmp/.buildx-postgres-cache
        key: ${{ runner.os }}-buildx-postgres-${{ github.sha }}
        restore-keys: |
          ${{ runner.os }}-buildx-postgres-

    - name: Checkout Code
      uses: actions/checkout@v2
    
    - name: Determine Image Tag
      id: generate_tag
      run: |
          _tag=latest
          if [ "${{ github.event_name }}" == "pull_request" ]
          then
              _tag=pr-${{ github.event.number }}
          fi
          _full=test/dev:${_tag}
          echo ::set-output name=tag::${_full}
    - name: Build code
      uses: docker/build-push-action@v2
      with:
        builder: ${{ steps.buildx.outputs.name }}
        push: false
        target: test
        load: true
        cache-from: type=local,src=/tmp/.buildx-main-cache
        cache-to: type=local,mode=max,dest=/tmp/.buildx-main-cache
        tags: ${{ steps.generate_tag.outputs.tag }}
    
    - name: Build DB
      uses: docker/build-push-action@v2
      with:
        builder: ${{ steps.buildx.outputs.name }}
        file: Dockerfile.postgres
        load: true
        cache-from: type=local,src=/tmp/.buildx-postgres-cache
        cache-to: type=local,mode=max,dest=/tmp/.buildx-postgres-cache
        tags: db-${{ steps.generate_tag.outputs.tag }}
    
    - name: Run Tests
      run: |
        API_IMAGE_TAG=${{ steps.generate_tag.outputs.tag }} DB_IMAGE_TAG=db-${{ steps.generate_tag.outputs.tag }} docker-compose -f docker-compose.yml --env-file .env.ci run test-api

Tested: https://github.com/crazy-max/testingactions/runs/1204121486?check_suite_focus=true

[ltamrazov]

aaah, ya that did the trick. After pruning it started to rebuild from scratch, so it was never using the specified cache. Thank you for the quick response and your time!