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Author image Paul Evans

NAME

Metrics::Any - abstract collection of monitoring metrics

SYNOPSIS

In a module:

   use Metrics::Any '$metrics',
      strict => 0,
      name_prefix => [ 'my_module_name' ];

   sub do_thing {
      $metrics->inc_counter( 'things_done' );
   }

In a program or top-level program-like module:

   use Metrics::Any::Adapter 'Prometheus';

DESCRIPTION

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 Log::Any, this module splits the overall problem into two sides. Modules wishing to provide metrics for monitoring purposes can use the use Metrics::Any 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 Metrics::Any::Adapter 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).

Future Direction

At present this interface is in an early state of experimentation. The API is fairly specifically-shaped for Net::Prometheus at present, but it is hoped with more adapter implementations (such as for statsd or OpenTelemetry) the API shapes can be expanded and made more generic to support a wider variety of reporting mechanisms.

As a result, any API details for now should be considered experimental and subject to change in later versions.

USE STATEMENT

For a module to use this facility, the use statement importing it should give the name of a variable (as a plain string) to store the collector for that package.

   use Metrics::Any '$metrics';

This variable will be created in the calling package and populated with an instance of Metrics::Any::Collector. The module can then use the collector API to declare new metrics, and eventually report values into them.

Note that the variable is created at the package level; any other packages within the same file will not see it and will have to declare their own.

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>