/ 
Sys-Monitor-Lite-0.07
/ Sys::Monitor::Lite

NAME

Sys::Monitor::Lite - Lightweight system monitoring toolkit with JSON/YAML output

SYNOPSIS

use Sys::Monitor::Lite qw(collect_all to_json);
print Sys::Monitor::Lite::to_json(Sys::Monitor::Lite::collect_all());

DESCRIPTION

A minimal system monitor that outputs structured JSON, YAML, or Prometheus text exposition for easy automation and integration with jq-lite, yq, Prometheus scrape targets, or other tools that consume structured logs.

FUNCTIONS

collect_all

my $data = Sys::Monitor::Lite::collect_all();

Collects all available metrics and returns a hash reference keyed by metric name. This is a convenience wrapper around "collect" with no arguments.

collect

my $subset = Sys::Monitor::Lite::collect(['cpu', 'mem']);

Collects the metrics listed in the array reference (or list). Unknown metrics are ignored. The returned value matches the structure of "collect_all" but contains only the requested keys.

available_metrics

my @names = Sys::Monitor::Lite::available_metrics();

Returns a sorted list of metric names that the module can collect.

metrics_from_thresholds

my @metrics = Sys::Monitor::Lite::metrics_from_thresholds(
    ['mem.used_pct>80'],
    ['load.1min>2'],
);

Parses threshold expressions and returns the top-level metrics (e.g. mem, load) that they reference. This is useful for preloading only the data needed for threshold checks.

evaluate_thresholds

my $result = Sys::Monitor::Lite::evaluate_thresholds(
    $data,
    warn => ['mem.used_pct>80'],
    crit => ['mem.used_pct>90'],
);

Evaluates warning/critical threshold expressions against a collected metrics hashref and returns a structure containing status (0/1/2), human-readable label, and a formatted message suitable for CLI output.

to_json

my $json = Sys::Monitor::Lite::to_json($data, pretty => 1);

Serialises the supplied data structure to a JSON string using JSON::PP. Pass pretty => 1 to enable human-readable output.

to_yaml

my $yaml = Sys::Monitor::Lite::to_yaml($data);

Serialises the supplied data structure to a YAML string using a minimal built-in emitter.

to_prometheus

my $text = Sys::Monitor::Lite::to_prometheus($data, prefix => 'sysmon_');

Serialises the supplied data structure into Prometheus exposition format, converting keys to snake_case gauge metrics. Pass prefix to prepend a metric namespace (e.g. sysmon_), labels to include fixed labels, and timestamp => 1 to append the sample timestamp to each metric line.

EXPORT

This module does not export any symbols by default. Functions can be called with their fully-qualified names, e.g. Sys::Monitor::Lite::collect_all().

AUTHOR

Shingo Kawamura <pannakoota1@gmail.com>

COPYRIGHT AND LICENSE

This software is copyright (c) 2025 by Shingo Kawamura.

This is free software; you can redistribute it and/or modify it under the same terms as the MIT license included with this distribution.