NAME
Mojolicious::Plugin::Prometheus - Mojolicious Plugin
SYNOPSIS
# Mojolicious, no extra options
$self->plugin('Prometheus');
# Mojolicious::Lite, no extra options
plugin 'Prometheus';
# Mojolicious::Lite, with custom response buckets and metrics pr endpoint
plugin 'Prometheus' => {
http_requests_total => {
buckets => [qw/4 5 6/],
labels => [qw/worker method endpoint code/],
cb => sub {
my $c = shift;
my $endpoint = $c->match->endpoint ? $c->match->endpoint->to_string : undef;
return ($$, $c->req->method, $endpoint || $c->req->url, $c->res->code);
},
},
};
# You can add your own route to do access control
my $under = app->routes->under('/secret' =>sub {
my $c = shift;
return 1 if $c->req->url->to_abs->userinfo eq 'Bender:rocks';
$c->res->headers->www_authenticate('Basic');
$c->render(text => 'Authentication required!', status => 401);
return undef;
});
plugin Prometheus => {route => $under};DESCRIPTION
Mojolicious::Plugin::Prometheus is a Mojolicious plugin that exports Prometheus metrics from Mojolicious.
Hooks are also installed to measure requests response time and count requests based on method and HTTP return code.
HELPERS
prometheus.instance
Create further instrumentation into your application by using this helper which gives access to the Net::Prometheus object. Please note that this represents a change from versions up to and including 1.4.x where prometheus was the method that returned the Prometheus instance.
See Net::Prometheus for further usage information.
prometheus.register($collector, $scope)
Register new / custom collectors. This method lets you differentiate those collectors that collect worker-specific metrics and those that collect more generic / global metrics. The difference between these two categories of collectors is that the results of calling collect on worker-specific collectors is cached to shared memory using IPC::ShareLite so that one worker can return collected results for all workers. Results of calling collect on generic / global collectors are not cached. This separation ensures that collectors that are global is not duplicated in the output, ie. does not appear once for each worker.
METHODS
Mojolicious::Plugin::Prometheus inherits all methods from Mojolicious::Plugin and implements the following new ones.
register
$plugin->register($app, \%config);Register plugin in Mojolicious application. You may pass a hashref containing configuration overrides to register this will be merged with the default configuration values.
%config can have:
route
Mojolicious::Routes::Route object to attach the metrics to, defaults to generating a new one for '/'.
Default: /
path
The path to mount the exporter.
Default: /metrics
prometheus
Override the Net::Prometheus object. The default is a new singleton instance of Net::Prometheus.
namespace, subsystem
These will be prefixed to the metrics exported.
shm_key
Key used for shared memory access between workers, see $key in IPC::ShareLite for details. Default is the process id read from
$$.http_request_duration_seconds
Structure that overrides the configuration for the
http_request_duration_secondsmetric. See below.http_request_size_bytes
Structure that overrides the configuration for the
http_request_size_bytesmetric. See below.http_response_size_bytes
Structure that overrides the configuration for the
http_response_size_bytesmetric. See below.http_requests_total
Structure that overrides the configuration for the
http_requests_totalmetric. See below.perl_collector
Structure that tells the plugin to enable or disable a Perl collector. Previously the Perl collector from Net::Prometheus was used, but that is no longer in use due to it not being possible to add dynamic label values. Now Mojolicious::Plugin::Prometheus::Collector::Perl is used. The configuration here need as follows:
- enabled
-
Boolean-ish value indicating if this collector should be used.
- labels_cb
-
A subref that the collector can call to dynamically resolve which labels and corresponding label values should be added to each metric. Default is:
{ enabled => 1, labels_cb => sub { { worker => $$ } }, }
process_collector
Structure that tells the plugin to enable or disable a process collector. The process collector from Net::Prometheus is used for this. The configuration here need as follows:
- enabled
-
Boolean-ish value indicating if this collector should be used.
- labels_cb
-
A subref that the collector can call to dynamically resolve which labels and corresponding label values should be added to each metric. Default is:
{ enabled => 1, labels_cb => sub { { worker => $$ } }, }
METRICS
In addition to exposing the default process metrics that Net::Prometheus already expose this plugin will also expose
http_requests_total, request counter partitioned over HTTP method and HTTP response codehttp_request_duration_seconds, request duration histogram partitioned over HTTP methodhttp_request_size_bytes, request size histogram partitioned over HTTP methodhttp_response_size_bytes, response size histogram partitioned over HTTP method
Custom configuration of the built in metrics is possible. An example structure can be seen in the synopsis. The four built in metrics from this plugin all have more or less the same structure. Metrics provided by the Perl- and Process-collectors from Net::Prometheus can be used and changed by providing a custom prometheus object instead of using the defaults as detailed previously.
Default configuration for the built in metrics are as follows:
http_request_duration_seconds => {
buckets => [.005, .01, .025, .05, .075, .1, .25, .5, .75, 1.0, 2.5, 5.0, 7.5, 10],
labels => [qw/worker method/],
cb => sub($c) { $$, $c->req->method, tv_interval($c->stash('prometheus.start_time')) },
}
http_request_size_bytes => {
buckets => [1, 50, 100, 1_000, 10_000, 50_000, 100_000, 500_000, 1_000_000],
labels => [qw/worker method/],
cb => sub($c) { $$, $c->req->method, $c->req->content->body_size },
}
http_response_size_bytes => {
buckets => [5, 50, 100, 1_000, 10_000, 50_000, 100_000, 500_000, 1_000_000],
labels => [qw/worker method code/],
cb => sub($c) { $$, $c->req->method, $c->res->code, $c->res->content->body_size },
}
http_requests_total => {
labels => [qw/worker method code/],
cb => sub($c) { $$, $c->req->method, $c->res->code },
}AUTHOR
(the IPC::ShareLite parts of this code is shamelessly stolen from Mojolicious::Plugin::Status written by Sebastian Riedel and mangled into something that works for me)
COPYRIGHT AND LICENSE
Copyright (C) 2018, Vidar Tyldum
This program is free software, you can redistribute it and/or modify it under the terms of the Artistic License version 2.0.