P5-metrics-any

Abstract collection of monitoring metrics

MetricsAny provides a central location for modules to report monitoring metrics, such as counters of the number of times interesting events have happened, and programs to collect up and send those metrics to monitoring services.

Inspired by LogAny, this module splits the overall problem into two sides. Modules wishing to provide metrics for monitoring purposes can use the use MetricsAny statement to obtain a collector into which they can report metric events. By default this collector doesn’t actually do anything, so modules can easily use it without adding extra specific dependencies for specific reporting.

A program using one or more such modules can apply a different policy and request a particular adapter implementation in order to actually report these metrics to some external system, by using the use MetricsAnyAdapter statement.

This separation of concerns allows module authors to write code which will report metrics without needing to care about the exact mechanism of that reporting as well as to write code which does not itself depend on the code required to perform that reporting.