Try CI's different conditional on steps #52

	# Experiments:
	# [x] Can I read env.IMAGE_NAME?
	# [x] Can I print git event name?
	# [x] Can I recognize pull requests?
	# [] Can I use if conditions for steps?
	name: Docker CI

	on:
	push:
	branches: try-ci-conditionals
	paths:
	- '*.Dockerfile'
	- '*.Dockerfile.dockerignore'
	- '.github/workflows/*.yaml'

	env:
	REGISTRY: ghcr.io

	jobs:
	docker-build:
	runs-on: ubuntu-latest

	strategy:
	matrix:
	purpose: [builder, emulator]

	env:
	IMAGE_NAME: ghcr.io/${{ github.repository_owner }}/plato-${{ matrix.purpose }}

	permissions:
	packages: write
	contents: read

	steps:
	- name: Checkout repository
	uses: actions/checkout@v4
	with:
	submodules: 'true'

	# Extract metadata (tags, labels) for Docker
	# https://github.com/docker/metadata-action
	- name: Extract Docker metadata
	id: meta
	if: ${{ github.event_name == 'pull_request' }}
	run: echo 'Extract Docker metadata'

	- name: Log into registry ${{ env.REGISTRY }}
	if: ${{ github.event_name == 'pull_request' }}
	run: echo 'Log into registry'

	# Build and push Docker image with Buildx (don't push on PR)
	# https://github.com/docker/build-push-action
	- name: Build and push Docker image
	id: build-and-push
	run: echo 'Build and push Docker image'

	- name: Check image layers
	if: ${{ github.event_name == 'pull_request' }}
	id: check-layers
	run: echo 'Check image layers'

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