name: Build Image
description: Build a container image locally with buildx and optionally run a smoke test. Does not push to registry.
inputs:
  image:
    description: Full image name without tag (e.g. code.fritzlab.net/fritzlab/chrony)
    required: true
  context:
    description: Docker build context path
    required: false
    default: .
  build-args:
    description: Multiline KEY=VALUE pairs passed to docker build
    required: false
  smoke-test:
    description: |
      Shell command run after build. The image is exposed as $IMAGE
      (e.g. "docker run --rm --entrypoint /usr/sbin/chronyd $IMAGE -v").
      Empty = no test.
    required: false
    default: ''
outputs:
  tag:
    description: Numeric tag assigned to the built image (= github.run_number)
    value: ${{ github.run_number }}
runs:
  using: composite
  steps:
    - name: Build (load to local docker)
      uses: docker/build-push-action@v6
      with:
        context: ${{ inputs.context }}
        push: false
        load: true
        provenance: false
        network: host
        build-args: ${{ inputs.build-args }}
        tags: ${{ inputs.image }}:${{ github.run_number }}

    - name: Smoke test
      if: ${{ inputs.smoke-test != '' }}
      shell: bash
      env:
        IMAGE: ${{ inputs.image }}:${{ github.run_number }}
      run: |
        set -euo pipefail
        echo "+ ${{ inputs.smoke-test }}"
        ${{ inputs.smoke-test }}