NAME

    Metrics::Any - abstract collection of monitoring metrics

SYNOPSIS

    In a module:

       use Metrics::Any '$metrics';
    
       $metrics->make_counter( thing =>
          name => "things_done",
       );
    
       sub do_thing {
          $metrics->inc_counter( 'thing' );
       }

    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>

