@KineticCafe/docker-image-update-checker

This action checks using the DockerHub API if your image, which is based on a documented base-image, needs to be rebuilt to use the most recent version of your base-image.

Example Usage

This example shows a check for user/app:latest against an updated nginx base image for the linux/amd64 architecture.

name: Check docker image for update

on:
  schedule:
    - cron: '0 4 * * *'

jobs:
  docker-update-check:
    runs-on: ubuntu-latest
    steps:
      - uses: KineticCafe/docker-image-update-checker@v1
        id: check
        with:
          base-image: nginx:1.21.0
          image: user/app:latest

      - uses: actions/checkout@v4
        if: steps.check.outputs.needs-update == 'true'

      - uses: docker/build-push-action@5.1.0
        with:
          context: .
          push: true
          tags: user/app:latest
        if: steps.check.outputs.needs-update == 'true'

Multiple Platform Support

This example shows a check for user/app:latest against an updated nginx base image for both linux/amd64 and linux/arm64. The needs-update flag is set if any one of the platform abase images requires update.

name: Check docker image for update (multiple platforms)

on:
  schedule:
    - cron: '0 4 * * *'

jobs:
  check:
    runs-on: ubuntu-latest
    steps:
      - uses: KineticCafe/docker-image-update-checker@v1
        id: check
        with:
          base-image: nginx:1.21.0
          image: user/app:latest
          platform: linux/amd64,linux/arm64

  build:
    runs-on: ubuntu-latest
    needs: check
    if: needs.check.outputs.needs-updating == 'true'

    steps:
      - uses: actions/checkout@v4

      - uses: docker/setup-qemu-action@v3.0.0
      - uses: docker/setup-buildx-action@v3.1.0

      - uses: docker/build-push-action@5.1.0
        with:
          context: .
          push: true
          tags: user/app:latest
          platforms: |
            linux/amd64
            linux/arm64

Inputs

• image: The target docker image for comparison.
• base-image: The base docker image to compare against.
• platforms: Image platforms to check. Defaults to linux/amd64. If any of the platforms are not present in either image or base-image, this action will exit with an error.

Outputs

• needs-output: Returns true if the image needs to be updated because the base-imge has received an update.

Debugging

To debug this action, set the DEBUG environment variable in the workflow file. For convenience, DEBUG can be set from ${{ secrets.ACTIONS_STEP_DEBUG }}, which works even when re-running the action with the Re-run job button and Enable debug logging. To read more about debugging actions, see Debugging actions.

Contributing

@KineticCafe/docker-image-update-checker welcomes contributions. This project, like all Kinetic Commerce open source projects, is under the Kinetic Commerce Open Source Code of Conduct.

This project is licensed under the MIT license and requires certification via a Developer Certificate of Origin. See Licence.md for more details.

Releasing

Releases are prepared with @vercel/ncc to produce a single file which must be committed to dist/. Run pnpm package or pnpm all to produce this file.