action.yml

name: Docker Publish Action Tool
description: Build and publish Docker images to Docker Hub
author: Sriman

branding:
  icon: upload-cloud
  color: blue

inputs:
  context_path:
    description: Build context path
    required: false
    default: "."

  docker_username:
    description: Docker Hub username
    required: true

  docker_password:
    description: Docker Hub password or token
    required: true

  dockerfile_path:
    description: Path to the Dockerfile
    required: false
    default: "./Dockerfile"

  image_repo:
    description: Repository for the Docker image (e.g. username/repo)
    required: true

  version:
    description: Application version (e.g. 1.2.3, 1.2.3-beta.2, 1.2.3-34)
    required: true

  dry_run:
    description: Build only, do not push images
    required: false
    default: "false"

  summary:
    description: Generate job summary
    required: false
    default: "true"

runs:
  using: composite
  steps:
    - name: Validate inputs and prepare environment
      shell: bash
      run: |
        set -eu

        echo "::group::Docker authentication"

        if [[ ! "${{ inputs.image_repo }}" =~ .+/.+ ]]; then
          echo "::error::image_repo must be in the format <namespace>/<repository>"
          exit 1
        fi

        if [[ "${{ inputs.dry_run }}" == "true" ]]; then
          echo "::warning::Dry-run mode enabled, images will NOT be pushed"
        fi

        echo "::notice::Using GitHub Actions cache for Docker build layers"
        echo "::notice::Logging in to Docker Hub"

        echo "::endgroup::"

    - name: Log in to Docker Hub
      uses: docker/login-action@af1e73f918a031802d376d3c8bbc3fe56130a9b0 # v4
      with:
        username: ${{ inputs.docker_username }}
        password: ${{ inputs.docker_password }}

    - name: Log QEMU setup
      shell: bash
      run: echo "::notice::Setting up QEMU for multi-architecture builds"

    - name: Set up QEMU
      uses: docker/setup-qemu-action@96fe6ef7f33517b61c61be40b68a1882f3264fb8 # v4

    - name: Log Buildx setup
      shell: bash
      run: echo "::notice::Setting up Docker Buildx builder"

    - name: Set up Buildx
      uses: docker/setup-buildx-action@bb05f3f5519dd87d3ba754cc423b652a5edd6d2c # v4

    - name: Parse version
      id: version
      shell: bash
      run: |
        set -eu
        echo "::group::Version parsing"

        RAW_VERSION="${{ inputs.version }}"
        VERSION="${RAW_VERSION#v}"

        echo "::notice::Raw version: $RAW_VERSION"
        echo "::notice::Normalized version: $VERSION"

        echo "version=$VERSION" >> "$GITHUB_OUTPUT"

        if [[ "$VERSION" == *"-"* ]]; then
          PRERELEASE="${VERSION#*-}"
          echo "prerelease=true" >> "$GITHUB_OUTPUT"

          if [[ "$PRERELEASE" =~ ^[0-9]+$ ]]; then
            echo "kind=numeric" >> "$GITHUB_OUTPUT"
            echo "::notice::Numeric prerelease detected → tag: next"
          else
            LABEL="${PRERELEASE%%.*}"
            echo "kind=labeled" >> "$GITHUB_OUTPUT"
            echo "label=$LABEL" >> "$GITHUB_OUTPUT"
            echo "::notice::Labeled prerelease detected → tag: $LABEL"
          fi
        else
          echo "prerelease=false" >> "$GITHUB_OUTPUT"
          echo "kind=stable" >> "$GITHUB_OUTPUT"
          echo "major=${VERSION%%.*}" >> "$GITHUB_OUTPUT"
          echo "::notice::Stable release detected"
        fi

        echo "::endgroup::"

    - name: Generate Docker tags
      id: docker_tags
      shell: bash
      run: |
        set -eu
        echo "::group::Docker tag generation"

        IMAGE="${{ inputs.image_repo }}"
        VERSION="${{ steps.version.outputs.version }}"
        KIND="${{ steps.version.outputs.kind }}"

        echo "$IMAGE:$VERSION" > tags.txt

        if [[ "$KIND" == "stable" ]]; then
          echo "$IMAGE:latest" >> tags.txt
          echo "$IMAGE:${{ steps.version.outputs.major }}" >> tags.txt

        elif [[ "$KIND" == "numeric" ]]; then
          echo "$IMAGE:next" >> tags.txt

        elif [[ "$KIND" == "labeled" ]]; then
          echo "$IMAGE:${{ steps.version.outputs.label }}" >> tags.txt
        fi

        echo "::notice::Generated Docker tags"
        cat tags.txt

        {
          echo "tags<<EOF"
          cat tags.txt
          echo "EOF"
        } >> "$GITHUB_OUTPUT"

        echo "::endgroup::"

    - name: Validate tag strategy (fail fast)
      shell: bash
      run: |
        set -eu
        echo "::group::Fail-fast validation"

        KIND="${{ steps.version.outputs.kind }}"

        if [[ "$KIND" != "stable" ]] && grep -q ":latest" tags.txt; then
          echo "::error::Invalid tag strategy: prereleases must NOT publish 'latest'"
          exit 1
        fi

        if [[ ! -s tags.txt ]]; then
          echo "::error::No Docker tags were generated"
          exit 1
        fi

        echo "::notice::Tag strategy validated"
        echo "::endgroup::"

    - name: Build and push Docker image
      uses: docker/build-push-action@53b7df96c91f9c12dcc8a07bcb9ccacbed38856a # v7
      with:
        context: ${{ inputs.context_path }}
        file: ${{ inputs.dockerfile_path }}
        push: ${{ inputs.dry_run != 'true' }}
        platforms: linux/amd64,linux/arm64
        tags: ${{ steps.docker_tags.outputs.tags }}
        cache-from: type=gha
        cache-to: type=gha,mode=max

    - name: Job summary
      if: inputs.summary == 'true'
      shell: bash
      run: |
        {
          echo "## Docker Publish Summary"
          echo ""
          echo "**Image:** \`${{ inputs.image_repo }}\`"
          echo "**Version:** \`${{ steps.version.outputs.version }}\`"
          echo "**Strategy:** \`${{ steps.version.outputs.kind }}\`"
          echo "**Mode:** $([[ '${{ inputs.dry_run }}' == 'true' ]] && echo 'dry-run' || echo 'publish')"
          echo ""
          echo "### Tags"
          sed 's/^/- `/' tags.txt | sed 's/$/`/'
          echo ""
          echo "### Platforms"
          echo "- linux/amd64"
          echo "- linux/arm64"
        } >> "$GITHUB_STEP_SUMMARY"