Caddyfile

# Redirect caddyfile for processing systemd-sysupdate requests.
#
# This Caddyfile will redirect incoming requests to GitHub releases, making it appear to clients like systemd-sysupdate
#  as if all sysexts #  released on the Bakery are in the same directory.
# For clients, the directory layout looks like e.g.:
#
# SHA256SUMS
# kubernetes-v1.28.2-amd64.raw
# kubernetes-v1.28.2-arm64.raw
# kubernetes-v1.28.4-amd64.raw
# kubernetes-v1.28.4-arm64.raw
# kubernetes-v1.29.1-amd64.raw
# kubernetes-v1.29.1-arm64.raw
# ...
#
# while in fact requests are being redirected to GitHub releases depending on which pattern matches the request.

# For testing locally, uncomment the below and comment 'extensions.flatcar.org {',
#  then run
# docker run --rm -ti -v ${PWD}/Caddyfile:/etc/caddy/Caddyfile -p 8080:80 caddy
#:80 {
extensions.flatcar.org {
	vars base_dest_url "https://github.com/flatcar/sysext-bakery/releases/download"

	# Extension image.
	#     <extension>-<version>-<arch>.raw
	#       ==>  https://[...]/releases/download/<extension>-<version>/<extension>-<version>-<arch>.raw
	# Match groups: 1 - extension, 2 - version, 3 - arch
	@raw path_regexp raw ^.*/extensions/([^/]+)-([^/]+)-(x86-64|arm64).raw$
	redir @raw {vars.base_dest_url}/{re.raw.1}-{re.raw.2}/{re.raw.1}-{re.raw.2}-{re.raw.3}.raw

	# Sysupdate conf. This is only used by Ignition.
	#     <extension>-<version>.conf
	#       ==>  https://[...]/releases/download/<extension>-<version>/<extension>-<version>.conf
	# Match groups: 1 - extension, 2 - version
	@conf path_regexp conf ^.*/extensions/([^/]+).conf$
	redir @conf {vars.base_dest_url}/{re.conf.1}/{re.conf.1}.conf

	# Sysupdate or extension image with explicit release sub-path.
	#     /<release>/<extension-conf-or-raw>
	#       ==>  https://[...]/releases/download/<release>/<extension-conf-or-raw>
	# Match groups: 1 - release, 2 - filename, 3 - suffix
	@expl path_regexp expl ^.*/extensions/([^/]+)/([^/]+).(conf|raw)$
	redir @expl {vars.base_dest_url}/{re.expl.1}/{re.expl.2}.{re.expl.3}

	# Extension specific SHA file with extension name in path (group 1)
	#     <extension>/SHA256SUMS
	#       ==>  https://[...]/releases/download/<extension>/SHA256SUMS
	@esha path_regexp esha ^/extensions/([^/]+)/SHA256SUMS$
	redir @esha {vars.base_dest_url}/{re.esha.1}/SHA256SUMS

	# Global SHA file with all extensions in it.
	#     /SHA256SUMS
	#       ==>  https://[...]/releases/download/SHA256SUMS/SHA256SUMS
	@sha path_regexp sha ^/extensions/SHA256SUMS$
	redir @sha {vars.base_dest_url}/SHA256SUMS/SHA256SUMS

	# None of the above matched, redirect to the website.
	redir https://flatcar.github.io/sysext-bakery{uri}
}