Merge pull request #43 from lsst/tickets/DM-42606 #355

	name: build_sync_container

	on:
	push:
	branches: [ main ]
	tags: [ "*" ]
	pull_request:
	branches: [ main ]

	jobs:
	build_image:
	runs-on: ubuntu-latest

	# Only do Docker builds of tagged releases and pull requests from ticket
	# branches. This will still trigger on pull requests from untrusted
	# repositories whose branch names match our tickets/* branch convention,
	# but in this case the build will fail with an error since the secret
	# won't be set.
	if: >
	startsWith(github.ref, 'refs/tags/')
	\|\| startsWith(github.head_ref, 'tickets/')

	steps:
	- uses: actions/checkout@v2

	- name: Define the Docker tag
	id: vars
	run: echo ::set-output name=tag::$(script/docker-tag.sh "$GITHUB_REF")

	- name: Print the tag
	id: print
	run: echo ${{ steps.vars.outputs.tag }}

	- name: Set up Docker Buildx
	uses: docker/setup-buildx-action@v1

	- name: Cache Docker layers
	uses: actions/cache@v2
	with:
	path: /tmp/.buildx-cache
	key: ${{ runner.os }}-buildx-${{ github.sha }}
	restore-keys:
	${{ runner.os }}-buildx-

	- name: Log in to Docker Hub
	uses: docker/login-action@v1
	with:
	username: ${{ secrets.DOCKER_HUB_USERNAME }}
	password: ${{ secrets.DOCKER_HUB_ACCESS_TOKEN }}

	- name: Build and push
	uses: docker/build-push-action@v2
	with:
	context: .
	push: true
	tags: lsstdm/lsst_alert_packet:${{ steps.vars.outputs.tag }}
	cache-from: type=local,src=/tmp/.buildx-cache
	cache-to: type=local,dest=/tmp/.buildx-cache-new

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