Prometheus, developed by the team behind SoundCloud, is an Open Source monitoring and alerting toolkit.
The application’s main functions consist of the Prometheus server for collecting and archiving records, various client libraries for running applications, and an alert manager. It also provides “exporters”, applications that forward records to third-party provider tools, such as HAProxy, StatsD, Graphite, etc.
Prometheus itself, as well as most of the applications and plugins, are written in GO.