Developed by Google, mtail is a very light log processor that is capable of running programs with pattern matching logic, allowing the extraction of metrics from said logs. It supports multiple export formats, such as Prometheus, StatsD, Graphite, and more.
Besides the /metrics endpoint, the / endpoint for the mtail service exposes valuable debug information. This endpoint is available in the static infrastructure test environment at http://192.168.42.11:9197:
Figure 6.7: mtail web interface
The source code and installation files for mtail are available at https://github.com/google/mtail.