NAME

Net::Prometheus - export monitoring metrics for prometheus

SYNOPSIS

use Net::Prometheus;

my $client = Net::Prometheus->new;

my $counter = $client->new_counter(
   name => "requests",
   help => "Number of received requests",
);

sub handle_request
{
   $counter->inc;
   ...
}

use Plack::Builder;

builder {
   mount "/metrics" => $client->psgi_app;
   ...
}

DESCRIPTION

This module provides the ability for a program to collect monitoring metrics and export them to the prometheus.io monitoring server.

As prometheus will expect to collect the metrics by making an HTTP request, facilities are provided to yield a PSGI application that the containing program can embed in its own structure to provide the results, or the application can generate a plain-text result directly and serve them by its own means.

CONSTRUCTOR

new

$prometheus = Net::Prometheus->new;

Returns a new Net::Prometheus instance.

Takes the following named arguments:

disable_process_collector => BOOL

If present and true, this instance will not load the default process collector from Net::Prometheus::ProcessCollector. If absent or false, such a collector will be loaded by default. This is usually what you want.

METHODS

register

$collector = $prometheus->register( $collector )

Registers a new collector to be collected from by the render method. The collector instance itself is returned, for convenience.

unregister

$prometheus->unregister( $collector )

Removes a previously-registered collector.

new_gauge

$gauge = $prometheus->new_gauge( %args )

Constructs a new Net::Prometheus::Gauge using the arguments given and registers it with the exporter. The newly-constructed gauge is returned.

new_counter

$counter = $prometheus->new_counter( %args )

Constructs a new Net::Prometheus::Counter using the arguments given and registers it with the exporter. The newly-constructed counter is returned.

new_summary

$summary = $prometheus->new_summary( %args )

Constructs a new Net::Prometheus::Summary using the arguments given and registers it with the exporter. The newly-constructed summary is returned.

new_histogram

$histogram = $prometheus->new_histogram( %args )

Constructs a new Net::Prometheus::Histogram using the arguments given and registers it with the exporter. The newly-constructed histogram is returned.

new_metricgroup

$group = $prometheus->new_metricgroup( %args )

Returns a new Metric Group instance as a convenience for registering multiple metrics using the same namespace and subsystem arguments. Takes the following named arguments:

namespace => STR

subsystem => STR

String values to pass by default into new metrics the group will construct.

Once constructed, the group acts as a proxy to the other new_* methods, passing in these values as overrides.

$gauge = $group->new_gauge( ... )
$counter = $group->new_counter( ... )
$summary = $group->new_summary( ... )
$histogram = $group->new_histogram( ... )

render

$str = $prometheus->render

Returns a string in the Prometheus text exposition format containing the current values of all the registered metrics.

psgi_app

$app = $prometheus->psgi_app

Returns a new PSGI application as a CODE reference. This application will render the metrics in the Prometheus text exposition format, suitable for scraping by the Prometheus collector.

This application will respond to any GET request, and reject requests for any other method.

COLLECTORS

The toplevel Net::Prometheus object stores a list of "collector" instances, which are used to generate the values that will be made visible via the "render" method. A collector can be any object instance that has a method called collect, which when invoked is passed no arguments and expected to return a list of "MetricSamples" in Net::Prometheus::Types structures.

@metricsamples = $collector->collect

The Net::Prometheus::Metric class is already a valid collector (and hence, so too are the individual metric type subclasses). This interface allows the creation of new custom collector objects, that more directly collect information to be exported.

TODO

• Perl-specific variable collector - arena stats?

• Split Registry out from toplevel instance.

• Write some actual example programs.

AUTHOR

Paul Evans <leonerd@leonerd.org.uk>

cpanm Net::Prometheus

perl -MCPAN -e shell
install Net::Prometheus