Metrics::Any::AdapterBUser:Contributed PMetrics::Any::AdapterBase::Stored(3pm)
NAME
"Metrics::Any::AdapterBase::Stored" - a base class for metrics adapters
which store values
DESCRIPTION
This base class assists in creating Metrics::Any::Adapter classes which
store values of reported metrics directly. These can then be retrieved
later by the containing application, or the subclass code, by using the
"walk" method.
This base class internally stores counter and gauge metrics as single
scalar values directly. In order to provide flexibility for a variety
of use-cases, it requires assistance from the implementing class on how
to store distribution and timer metrics. The implementing class should
provide these methods, returning whatever values it wishes to implement
them with. These values are stored by the base class, and handed back
as part of the "walk" method.
The base class stores a value for each unique set of labels and values
on every metric; the subclass does not need to handle this.
METHODS
walk
$stored->walk( $code )
$code->( $type, $name, $labels, $value )
Given a CODE reference, this method invokes it once per labelset of
every stored metric.
For each labelset, $type will give the metric type (as a string, either
"counter", "distribution", "gauge" or "timer"), $name gives the name it
was registered with, $labels will be a reference to an even-sized array
containing label names and values.
For counter and gauge metrics, $value will be a numerical scalar giving
the current value. For distribution and timer metrics, $value will be
whatever the implementing class's corresponding "store_distribution" or
"store_timer" method returns for them.
clear_values
$stored->clear_values
Clears all of the metric storage. Every labelset of every metric is
deleted. The metric definitions themselves remain.
REQUIRED METHODS
store_distribution
store_timer
$storage = $stored->store_distribution( $storage, $amount )
$storage = $stored->store_timer( $storage, $duration )
The implementing class must provide these two methods to assist in the
management of storage for distribution and timer metrics.
When a new observation for the metric is required, the method will be
invoked, passing in the currently-stored perl value for the given
metric and label values, and the new observation. Whatever the method
returns is stored by the base class, to be passed in next time or used
by the "walk" method.
The base class stores this value directly and does not otherwise
interact with it; letting the implementing class decide what is best.
For example, a simple implementation may just store every observation
individually by pushing them into an array; so the $storage would be an
ARRAY reference:
sub store_distribution
{
my $self = shift;
my ( $storage, $amount ) = @_;
push @$storage, $amount;
return $storage;
}
AUTHOR
Paul Evans <leonerd@leonerd.org.uk>
perl v5.36.0 2022-1Metrics::Any::AdapterBase::Stored(3pm)
Generated by dwww version 1.15 on Sun Jun 23 04:12:16 CEST 2024.