cache.md

Cache

• Inline cache
• Registry cache
• GitHub cache
  • Cache backend API
  • Local cache

More info about cache on BuildKit and Buildx repositories.

Inline cache

In most case you want to use the type=inline cache exporter. However, note that the inline cache exporter only supports min cache mode. To enable max cache mode, push the image and the cache separately by using the registry cache exporter as shown in the next example.

name: ci

on:
  push:
    branches:
      - 'master'

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      -
        name: Checkout
        uses: actions/checkout@v2
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
      -
        name: Login to DockerHub
        uses: docker/login-action@v1 
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      -
        name: Build and push
        uses: docker/build-push-action@v2
        with:
          context: .
          push: true
          tags: user/app:latest
          cache-from: type=registry,ref=user/app:latest
          cache-to: type=inline

Registry cache

You can import/export cache from a cache manifest or (special) image configuration on the registry with the type=registry cache exporter.

name: ci

on:
  push:
    branches:
      - 'master'

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      -
        name: Checkout
        uses: actions/checkout@v2
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
      -
        name: Login to DockerHub
        uses: docker/login-action@v1 
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      -
        name: Build and push
        uses: docker/build-push-action@v2
        with:
          context: .
          push: true
          tags: user/app:latest
          cache-from: type=registry,ref=user/app:buildcache
          cache-to: type=registry,ref=user/app:buildcache,mode=max

GitHub cache

Cache backend API

🧪 This cache exporter is considered EXPERIMENTAL until further notice. Please provide feedback on BuildKit repository if you encounter any issues.

Since buildx 0.6.0 and BuildKit 0.9.0, you can use the type=gha cache exporter.

GitHub Actions cache exporter backend uses the GitHub Cache API to fetch and upload cache blobs. That's why this type of cache should be exclusively used in a GitHub Action workflow as the url ($ACTIONS_CACHE_URL) and token ($ACTIONS_RUNTIME_TOKEN) attributes are populated when a workflow is started.

name: ci

on:
  push:
    branches:
      - 'master'

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      -
        name: Checkout
        uses: actions/checkout@v2
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
      -
        name: Login to DockerHub
        uses: docker/login-action@v1 
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      -
        name: Build and push
        uses: docker/build-push-action@v2
        with:
          context: .
          push: true
          tags: user/app:latest
          cache-from: type=gha
          cache-to: type=gha,mode=max

Local cache

⚠️ At the moment caches are copied over the existing cache so it keeps growing. The Move cache step is used as a temporary fix (see moby/buildkit#1896).

You can also leverage GitHub cache using actions/cache and type=local cache exporter with this action:

name: ci

on:
  push:
    branches:
      - 'master'

jobs:
  docker:
    runs-on: ubuntu-latest
    steps:
      -
        name: Checkout
        uses: actions/checkout@v2
      -
        name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v1
      -
        name: Cache Docker layers
        uses: actions/cache@v2
        with:
          path: /tmp/.buildx-cache
          key: ${{ runner.os }}-buildx-${{ github.sha }}
          restore-keys: |
            ${{ runner.os }}-buildx-
      -
        name: Login to DockerHub
        uses: docker/login-action@v1 
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}
      -
        name: Build and push
        uses: docker/build-push-action@v2
        with:
          context: .
          push: true
          tags: user/app:latest
          cache-from: type=local,src=/tmp/.buildx-cache
          cache-to: type=local,dest=/tmp/.buildx-cache-new,mode=max
      -
        # Temp fix
        # https://github.com/docker/build-push-action/issues/252
        # https://github.com/moby/buildkit/issues/1896
        name: Move cache
        run: |
          rm -rf /tmp/.buildx-cache
          mv /tmp/.buildx-cache-new /tmp/.buildx-cache