OCI Image Supported Platforms

Get the OCI Platforms for a given OCI Image or Dockerfile

Inputs

This action supports the following input.

dockerfile

The Dockerfile to get its supported platforms

• Required: No
• Type: string
• Default: Dockerfile
• Example: Dockerfile-alpine-zts

image

Passing anything into the image input will disable checking for the passed dockerfile input value, and will get the platforms for the image(s) you give it. When you pass it two or more, for example ghcr.io/home-assistant/home-assistant:2024.12.2,ghcr.io/wyrihaximusnet/php:8.3-zts-alpine-dev, it will get the platforms for all of them but only return the platforms that are supported by all of them.

• Required: No
• Type: string
• Default: ``
• Example: ghcr.io/wyrihaximusnet/php:8.3-zts-alpine-slim

Output

This action only outputs a list of platforms as JSON through platform, and as CSV platform_csv.

For example when the found platforms are linux/arm64 and linux/amd64 the outputs are the following:

• plarform: ["linux/arm64","linux/amd64"]
• platform_csv: linux/arm64,linux/amd64

Building Example

The following example build a docker image for each upstream platform:

jobs:
  supported-arch-matrix:
    outputs:
      platform: ${{ steps.supported-arch-matrix.outputs.platform }}
    steps:
      # Note: No checkout needed, the action will handle that for you in the most optimized way possible
      # It uses a sparse checkout with only the Dockerfile as the path to check out
      - id: supported-arch-matrix
        name: Generate Arch
        uses: wyrihaximus/github-action-oci-image-supported-platforms@v1
      # You can optionally specify a different Dockerfile path  
      #  with:
      #    dockerfile: Dockerfile-non-default-path
  build-docker-image:
    name: Build ${{ matrix.platform }} image
    strategy:
      fail-fast: false
      matrix:
        platform: ${{ fromJson(needs.supported-arch-matrix.outputs.platform) }}
    needs:
      - supported-arch-matrix
    steps:
      - name: Prepare
        run: |
          platform=${{ matrix.platform }}
          echo "PLATFORM_PAIR=${platform//\//-}" >> $GITHUB_ENV
      - name: Checkout
        uses: actions/checkout@v6
      - run: docker image build --platform=${{ matrix.platform }} -t "ghcr.io/${{ github.repository }}:sha-abc123-${{ env.PLATFORM_PAIR }}" --no-cache .

For more details on how to take it from there, please have a look at this blog post.

Retagging Example

The following example build a docker image for each upstream platform:

jobs:
  oci-retag:
    steps:
      - name: Prepare Dockerfile
        run: |
          echo "ghcr.io/${{ github.repository }}:sha-abc123" | tr '[:upper:]' '[:lower:]'
          printf "FROM %s" $(echo "ghcr.io/${{ github.repository }}:sha-abc123" | tr '[:upper:]' '[:lower:]') >> Dockerfile.tag
          cat Dockerfile.tag
      - name: Detect Platform Flag
        id: platform
        uses: wyrihaximus/github-action-oci-image-supported-platforms@v1
      # Since we want to inspect the already build image, we'll pass its location at the registry, and thus 
      # we don't pass it a dockerfile. THose two options are mutually exclusive.
        with:
          image: ghcr.io/${{ github.repository }}:sha-abc123
      - name: Pull, retag, and push image
        run: |
          docker build --platform=${{ steps.platform.outputs.platform_csv }} --output=type=registry --no-cache -f Dockerfile.tag -t $(echo "ghcr.io/${{ github.repository }}:r123" | tr '[:upper:]' '[:lower:]') .

License

Copyright 2026 Cees-Jan Kiewiet

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.