=head1 NAME

	BuddyCheck - Report the systemd health of a host

=head1 SYNPOSIS

	buddycheck
	BUDDYCHECK_HOST=localhost buddycheck
	BUDDYCHECK_HOST=example.com BUDDYCHECK_PORT=9000 buddycheck

=head1 DESCRIPTION

	This application queries the "node_systemd_system_running" metric of a Prometheus Node Exporter with enabled systemd collector
	and reflects the metric result with both a human understandable message printed to stderr and a computer parseable exit code.

	If the remote system is healthy, the application will report "Buddy is healthy" and exit with 0.
	With any other responses, the remote system should be assumed as faulty.

=head1 CAVEATS

	The application does not assess whether the remote HTTP server is indeed a Prometheus Node Exporter.
	An abitrary HTTP server could easily serve the string "node_systemd_system_running" with a value of its choice.

=head1 EXIT CODES

	0	HTTP server responded with metric, and result is 0
	111	HTTP server did not respond
	125	HTTP server responded with metric, result is not 1
	255	HTTP response was not 200 or required variable was not set

=head1 AUTHOR

	Georg Pfuetzenreuter

=head1 LICENSE

	Licensed under the European Union Public Licence.