mtail is a tool for extracting metrics from application logs to be
exported into a timeseries database or timeseries calculator for
alerting and dashboarding.

It aims to fill a niche between applications that do not export their
own internal state, and existing monitoring systems, without patching
those applications or rewriting the same framework for custom extraction
glue code.

The extraction is controlled by mtail programs which define patterns and
actions. Metrics are exported for scraping by a collector as JSON or
Prometheus format over HTTP, or can be periodically sent to a collectd,
StatsD, or Graphite collector socket.
