mtail
Extract internal monitoring data from application logs
...It fills a monitoring niche by being the glue between applications that do not export their own internal state (other than via logs) and existing monitoring systems, such that system operators do not need to patch those applications to instrument them or writing custom extraction code for every such application. 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. Precompiled binaries for released versions are available in the Releases page on Github. ...