name: Install apt packages
description: >
  Installs apt packages with bounded download retries and Ubuntu mirror fallback. Caches downloaded packages as an optimization; apt resolves dependencies on every run.

inputs:
  packages:
    description: Space separated list of package names to install
    required: true
  attempts:
    description: Maximum number of download attempts
    default: "3"
  attempt-timeout:
    description: Seconds before a single download attempt is killed
    default: "180"
runs:
  using: composite
  steps:
    - name: Identify apt cache
      id: cache-key
      shell: bash
      env:
        PACKAGES: ${{ inputs.packages }}
      run: |
        . /etc/os-release
        packages_hash=$(printf '%s' "$PACKAGES" | sha256sum | cut -d ' ' -f 1)
        # Cached downloads are optional: apt fetches any missing/newer packages.
        # Refresh weekly, including inside job containers without ImageVersion.
        echo "key=apt-v2-${ID}-${VERSION_ID}-$(dpkg --print-architecture)-$(date -u +%G-%V)-${packages_hash}" >> "$GITHUB_OUTPUT"
    - name: Restore apt packages
      id: cache
      uses: actions/cache/restore@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
      with:
        path: |
          ${{ runner.temp }}/apt-packages/*.deb
          ${{ runner.temp }}/apt-packages/.keep
        key: ${{ steps.cache-key.outputs.key }}
    - name: Install ${{ inputs.packages }}
      shell: bash
      env:
        PACKAGES: ${{ inputs.packages }}
        ATTEMPTS: ${{ inputs.attempts }}
        ATTEMPT_TIMEOUT: ${{ inputs.attempt-timeout }}
        CACHE_DIR: ${{ runner.temp }}/apt-packages
      run: bash "$GITHUB_ACTION_PATH/install.sh"
    # Save immediately: a later test failure must not discard downloaded packages.
    - name: Save apt packages
      if: steps.cache.outputs.cache-hit != 'true'
      uses: actions/cache/save@55cc8345863c7cc4c66a329aec7e433d2d1c52a9 # v6.1.0
      with:
        path: |
          ${{ runner.temp }}/apt-packages/*.deb
          ${{ runner.temp }}/apt-packages/.keep
        key: ${{ steps.cache-key.outputs.key }}