use multistage build which drastically reduces image size #5

	name: Build Docker toolchain image
	on:
	push:
	paths:
	- runtime/toolchain/**
	- .github/workflows/toolchain.yaml
	workflow_dispatch:


	jobs:
	build-docker:
	runs-on: ubuntu-22.04
	steps:
	# Free up disk space on Github-hosted runner
	- name: Disk usage
	run: df -h
	- uses: jlumbroso/free-disk-space@v1.3.1
	with:
	android: true
	dotnet: true
	haskell: true
	large-packages: true

	- name: Disk usage after freeing up space
	run: df -h
	# Actually build the Docker container
	- uses: actions/checkout@v4

	- uses: docker/setup-buildx-action@v3

	- name: GHCR Log-in
	uses: docker/login-action@v3.1.0
	with:
	registry: ghcr.io
	username: ${{ github.actor }}
	password: ${{ secrets.GITHUB_TOKEN }}

	- name: Build and push
	uses: docker/build-push-action@v5.3.0
	with:
	context: ${{github.workspace}}/runtime/toolchain/
	file: ${{github.workspace}}/runtime/toolchain/Dockerfile
	push: true
	tags: ghcr.io/opencompl/quidditch/toolchain:${{ github.ref_name }}

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