Replace ugly Python code with docker/metadata-action

[jennydaman]

python-chrisapp-template/.github/workflows/ci.yml

Lines 53 to 86 in 1e9e879

	run: |
	import os
	import itertools
	def join_tag(t):
	registry, repo, tag = t
	return f'{registry}/{repo}:{tag}'.lower()
	registries = ['docker.io', 'ghcr.io']
	repos = ['${{ github.repository }}']
	if '${{ github.ref_type }}' == 'branch':
	tags = ['latest']
	elif '${{ github.ref_type }}' == 'tag':
	tag = '${{ github.ref_name }}'
	version = tag[1:] if tag.startswith('v') else tag
	tags = ['latest', version]
	else:
	tags = []
	if '${{ github.ref_type }}' == 'tag':
	local_tag = join_tag(('ghcr.io', '${{ github.repository }}', version))
	else:
	local_tag = join_tag(('localhost', '${{ github.repository }}', 'latest'))
	product = itertools.product(registries, repos, tags)
	tags_csv = ','.join(map(join_tag, product))
	outputs = {
	'tags_csv' : tags_csv,
	'push' : 'true' if tags_csv else 'false',
	'local_tag': local_tag
	}
	with open(os.environ['GITHUB_OUTPUT'], 'a') as out:
	for k, v in outputs.items():
	out.write(f'{k}={v}\n')

This can be replaced with https://github.com/docker/metadata-action