Prometheus_unixSourceReport metrics for Prometheus. See: https://prometheus.io/
Notes:
Prometheus_app with support for cmdliner option parsing, a server pre-configured for Unix, and a start-time metric that uses Unix.gettimeofday.serve config starts a Cohttp server according to config. It returns a singleton list containing the thread to monitor, or an empty list if no server is configured.
opts is the extra command-line options to offer Prometheus monitoring.