docker.build.yaml

name: reusable docker build workflow

on:
  # make this workflow reusable (and only so)
  workflow_call:
    inputs:
      CONTEXT:
        type: string
        description: context sub folder in .github/docker
        required: true
      IMAGE:
        type: string
        description: image tag
        required: false
      ROS_DISTRO:
        type: string
        description: ROS distribution
        required: false
        default: one
      DEB_DISTRO:
        type: string
        description: The Debian/Ubuntu distribution codename to compile for.
        required: false
        default: jammy


# Define environment variables from input, from configuration variables, or defaults - in this order!
# All inputs (declared above) are deliberately optional and don't provide an explicit default.
# Thus, if an input is not explicitly provided, we can fall back to the configuration variable here (var.* context).
# This variable context originates from the _calling_ workflow. Finally, a hard-coded default is given.
# https://docs.github.com/en/actions/learn-github-actions/variables#defining-configuration-variables-for-multiple-workflows
env:
  IMAGE: ${{ inputs.IMAGE || format('ubiagni/ros:{0}-{1}', inputs.DEB_DISTRO, inputs.CONTEXT) }}

jobs:
  build:
    runs-on: ubuntu-22.04

    steps:
      - uses: rhaschke/docker-run-action@main
        name: Check for apt updates
        continue-on-error: true
        id: apt
        with:
          image: ${{ env.IMAGE }}
          run: |
            apt-get update
            have_updates=$(apt-get --simulate upgrade | grep -q "^0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.$" && echo false || echo true)
            echo "no_cache=$have_updates" >> "$GITHUB_OUTPUT"
            test "$have_updates" = "true" && echo "Updates available. Disabling docker cache." || echo "No updates available. Using docker cache."

      - name: Set up Docker Buildx
        uses: docker/setup-buildx-action@v3

      - name: Login to DockerHub
        uses: docker/login-action@v3
        with:
          username: ${{ secrets.DOCKERHUB_USERNAME }}
          password: ${{ secrets.DOCKERHUB_TOKEN }}

      - name: Checkout
        uses: actions/checkout@v4

      - name: Build and Push
        uses: docker/build-push-action@v5
        with:
          context: .github/docker/${{ inputs.CONTEXT }}
          build-args: ROS_DISTRO=${{ inputs.ROS_DISTRO }} DEB_DISTRO=${{ inputs.DEB_DISTRO }}
          push: true
          no-cache: ${{ steps.apt.outputs.no_cache || github.event_name == 'workflow_dispatch' }}
          cache-from: type=registry,ref=${{ env.IMAGE }}
          cache-to: type=inline
          tags: ${{ env.IMAGE }}