PHP-FPM Pool Monitoring w/ Prometheus

phpfpm-prometheus.php

<?php
declare(strict_types=1);
// Prometheus metrics exporter for PHP-FPM

header("Content-Type: text/plain; version=0.0.4");

$stats = null;
$protocol = ((!empty($_SERVER["HTTPS"]) && $_SERVER["HTTPS"] !== "off") ? "https" : "http");
$result = file_get_contents($protocol ."://" . $_SERVER["SERVER_NAME"] . "/php-fpm-status?json&full");
if ($result !== false) {
    $stats = @json_decode($result, true);
}
if (! is_array($stats)) {
    exit();
}

$metrics = [
    "uptime" => [
        "type" => "counter",
        "help" => "seconds since last restart",
        "value" => ($stats["start since"] ?? null),
    ],
    "accepted_connections_total" => [
        "type" => "counter",
        "help" => "Accepted connections",
        "value" => ($stats["accepted conn"] ?? null),
    ],
    "listen_queue_connections" => [
        "type" => "gauge",
        "help" => "Pending connections queue",
        "value" => ($stats["listen queue"] ?? null),
    ],
    "listen_queue_max_connections" => [
        "type" => "counter",
        "help" => "Max. pending connections queue",
        "value" => ($stats["max listen queue"] ?? null),
    ],
    "listen_queue_length" => [
        "type" => "gauge",
        "help" => "Listen queue length",
        "value" => ($stats["listen queue len"] ?? null),
    ],
    "active_processes" => [
        "type" => "gauge",
        "help" => "Active processes",
        "value" => ($stats["active processes"] ?? null),
    ],
    "idle_processes" => [
        "type" => "gauge",
        "help" => "Idle processes",
        "value" => ($stats["idle processes"] ?? null),
    ],
    "processes" => [
        "type" => "gauge",
        "help" => "Total processes",
        "value" => ($stats["total processes"] ?? null),
    ],
    "active_processes_max" => [
        "type" => "counter",
        "help" => "Max. seen processes",
        "value" => ($stats["max active processes"] ?? null),
    ],
    "max_children_reached_count" => [
        "type" => "counter",
        "help" => "Max. number of processes hit count",
        "value" => ($stats["max children reached"] ?? null),
    ],
    "slow_requests_total" => [
        "type" => "counter",
        "help" => "Slow requests",
        "value" => ($stats["slow requests"] ?? null),
    ],
];

foreach ($metrics as $key => $metric) {
    $key = "phpfpm_" . $key;
    if ($metric["value"] === null) {
        continue;
    }

    print "# HELP {$key} {$metric["help"]}\n";
    print "# TYPE {$key} {$metric["type"]}\n";
    print $key . " " . $metric["value"] . "\n";
}