actions/docker-publish/action.yml

# yaml-language-server: $schema=https://json.schemastore.org/github-action.json
# permissions:
#   - packages: write  # Required for publishing to Docker registries
#   - contents: read   # Required for checking out repository
#
# Security Considerations:
#
# Trust Model: This action should only be used in trusted workflows controlled by repository owners.
# Do not pass untrusted user input (e.g., PR labels, comments, external webhooks) to the `context`
# or `dockerfile` parameters.
#
# Input Validation: The action validates `context` and `dockerfile` inputs to prevent code injection attacks:
#
# - `context`: Must be a relative path (e.g., `.`, `./app`, `subdir/`). Absolute paths are rejected.
#   Remote URLs trigger a warning and should only be used from trusted sources.
# - `dockerfile`: Must be a relative path (e.g., `Dockerfile`, `./docker/Dockerfile`). Absolute paths
#   and URLs are rejected.
#
# These validations help prevent malicious actors from:
# - Building Docker images from arbitrary file system locations
# - Fetching malicious Dockerfiles from untrusted remote sources
# - Executing code injection attacks through build context manipulation
#
# Best Practices:
# 1. Only use hard-coded values or trusted workflow variables for `context` and `dockerfile`
# 2. Never accept these values from PR comments, labels, or external webhooks
# 3. Review workflow permissions before granting write access to this action
# 4. Use SHA-pinned action references: `ivuorinen/actions/docker-publish@<commit-sha>`
---
name: Docker Publish
description: Simple wrapper to publish Docker images to GitHub Packages and/or Docker Hub
author: Ismo Vuorinen

branding:
  icon: upload-cloud
  color: blue

inputs:
  registry:
    description: 'Registry to publish to (dockerhub, github, or both)'
    required: false
    default: 'both'
  image-name:
    description: 'Docker image name (defaults to repository name)'
    required: false
  tags:
    description: 'Comma-separated list of tags (e.g., latest,v1.0.0)'
    required: false
    default: 'latest'
  platforms:
    description: 'Platforms to build for (comma-separated)'
    required: false
    default: 'linux/amd64,linux/arm64'
  context:
    description: 'Build context path'
    required: false
    default: '.'
  dockerfile:
    description: 'Path to Dockerfile'
    required: false
    default: 'Dockerfile'
  build-args:
    description: 'Build arguments (newline-separated KEY=VALUE pairs)'
    required: false
  push:
    description: 'Whether to push the image'
    required: false
    default: 'true'
  token:
    description: 'GitHub token for authentication (for GitHub registry)'
    required: false
    default: ''
  dockerhub-username:
    description: 'Docker Hub username (required if publishing to Docker Hub)'
    required: false
  dockerhub-token:
    description: 'Docker Hub token (required if publishing to Docker Hub)'
    required: false

outputs:
  image-name:
    description: 'Full image name with registry'
    value: ${{ steps.meta.outputs.image-name }}
  tags:
    description: 'Tags that were published'
    value: ${{ steps.meta.outputs.tags }}
  digest:
    description: 'Image digest'
    value: ${{ steps.build.outputs.digest }}
  metadata:
    description: 'Build metadata'
    value: ${{ steps.build.outputs.metadata }}

runs:
  using: composite
  steps:
    - name: Validate Inputs
      id: validate
      shell: sh
      env:
        INPUT_REGISTRY: ${{ inputs.registry }}
        INPUT_DOCKERHUB_USERNAME: ${{ inputs.dockerhub-username }}
        INPUT_DOCKERHUB_TOKEN: ${{ inputs.dockerhub-token }}
        INPUT_TOKEN: ${{ inputs.token }}
        INPUT_CONTEXT: ${{ inputs.context }}
        INPUT_DOCKERFILE: ${{ inputs.dockerfile }}
      run: |
        set -eu

        # Validate registry input
        case "$INPUT_REGISTRY" in
          dockerhub|github|both)
            ;;
          *)
            echo "::error::Invalid registry value. Must be 'dockerhub', 'github', or 'both'"
            exit 1
            ;;
        esac

        # Validate Docker Hub credentials if needed
        if [ "$INPUT_REGISTRY" = "dockerhub" ] || [ "$INPUT_REGISTRY" = "both" ]; then
          if [ -z "$INPUT_DOCKERHUB_USERNAME" ] || [ -z "$INPUT_DOCKERHUB_TOKEN" ]; then
            echo "::error::Docker Hub username and token are required when publishing to Docker Hub"
            exit 1
          fi
        fi

        # Validate GitHub token if needed
        if [ "$INPUT_REGISTRY" = "github" ] || [ "$INPUT_REGISTRY" = "both" ]; then
          token="${INPUT_TOKEN:-${GITHUB_TOKEN:-}}"
          if [ -z "$token" ]; then
            echo "::error::GitHub token is required when publishing to GitHub Packages"
            exit 1
          fi
        fi

        # Validate context input for security
        INPUT_CONTEXT="${INPUT_CONTEXT:-.}"
        case "$INPUT_CONTEXT" in
          .|./*|*/*)
            # Relative paths are allowed
            ;;
          /*)
            echo "::error::Context cannot be an absolute path: '$INPUT_CONTEXT'"
            echo "::error::Use relative paths (e.g., '.', './app') to prevent code injection"
            exit 1
            ;;
          *://*)
            echo "::warning::Context is a remote URL: '$INPUT_CONTEXT'"
            echo "::warning::Ensure this URL is from a trusted source to prevent code injection"
            ;;
        esac

        # Validate dockerfile input for security
        INPUT_DOCKERFILE="${INPUT_DOCKERFILE:-Dockerfile}"
        case "$INPUT_DOCKERFILE" in
          Dockerfile|*/Dockerfile|*.dockerfile|*/*.dockerfile)
            # Common dockerfile patterns are allowed
            ;;
          /*)
            echo "::error::Dockerfile path cannot be absolute: '$INPUT_DOCKERFILE'"
            echo "::error::Use relative paths (e.g., 'Dockerfile', './docker/Dockerfile')"
            exit 1
            ;;
          *://*)
            echo "::error::Dockerfile path cannot be a URL: '$INPUT_DOCKERFILE'"
            exit 1
            ;;
        esac

        echo "Input validation completed successfully"

    - name: Set up Docker Buildx
      uses: docker/setup-buildx-action@c47758b77c9736f4b2ef4073d4d51994fabfe349 # v3.7.1

    - name: Determine Image Names and Tags
      id: meta
      shell: sh
      env:
        INPUT_REGISTRY: ${{ inputs.registry }}
        INPUT_IMAGE_NAME: ${{ inputs.image-name }}
        INPUT_TAGS: ${{ inputs.tags }}
        GITHUB_REPOSITORY: ${{ github.repository }}
      run: |
        set -eu

        # Determine base image name
        if [ -n "$INPUT_IMAGE_NAME" ]; then
          base_name="$INPUT_IMAGE_NAME"
        else
          # Use repository name (lowercase)
          base_name=$(echo "$GITHUB_REPOSITORY" | tr '[:upper:]' '[:lower:]')
        fi

        # Build full image names based on registry
        image_names=""
        case "$INPUT_REGISTRY" in
          dockerhub)
            image_names="docker.io/${base_name}"
            ;;
          github)
            image_names="ghcr.io/${base_name}"
            ;;
          both)
            image_names="docker.io/${base_name},ghcr.io/${base_name}"
            ;;
        esac

        # Build full tags (image:tag format)
        tags=""
        IFS=','
        for image in $image_names; do
          for tag in $INPUT_TAGS; do
            tag=$(echo "$tag" | sed 's/^[[:space:]]*//;s/[[:space:]]*$//')
            if [ -n "$tags" ]; then
              tags="$(printf '%s\n%s' "$tags" "${image}:${tag}")"
            else
              tags="${image}:${tag}"
            fi
          done
        done

        # Output results
        printf 'image-name=%s\n' "$base_name" >> "$GITHUB_OUTPUT"
        {
          echo 'tags<<EOF'
          echo "$tags"
          echo 'EOF'
        } >> "$GITHUB_OUTPUT"

        echo "Image name: $base_name"
        echo "Tags:"
        echo "$tags"

    - name: Login to Docker Hub
      if: inputs.registry == 'dockerhub' || inputs.registry == 'both'
      uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567 # v3.3.0
      with:
        username: ${{ inputs.dockerhub-username }}
        password: ${{ inputs.dockerhub-token }}

    - name: Login to GitHub Container Registry
      if: inputs.registry == 'github' || inputs.registry == 'both'
      uses: docker/login-action@9780b0c442fbb1117ed29e0efdff1e18412f7567 # v3.3.0
      with:
        registry: ghcr.io
        username: ${{ github.actor }}
        password: ${{ inputs.token || github.token }}

    - name: Build and Push Docker Image
      id: build
      uses: docker/build-push-action@4f58ea79222b3b9dc2c8bbdd6debcef730109a75 # v6.9.0
      with:
        context: ${{ inputs.context }}
        file: ${{ inputs.dockerfile }}
        platforms: ${{ inputs.platforms }}
        push: ${{ inputs.push }}
        tags: ${{ steps.meta.outputs.tags }}
        build-args: ${{ inputs.build-args }}
        cache-from: type=gha
        cache-to: type=gha,mode=max