some_histogram_with_default_labels.php

<?php

require __DIR__ . '/../vendor/autoload.php';

use Prometheus\CollectorRegistry;
use Prometheus\Storage\Redis;

error_log('c='. $_GET['c']);

$adapter = $_GET['adapter'];

if ($adapter === 'redis') {
    Redis::setDefaultOptions(array('host' => isset($_SERVER['REDIS_HOST']) ? $_SERVER['REDIS_HOST'] : '127.0.0.1'));
    $adapter = new Prometheus\Storage\Redis();
} elseif ($adapter === 'apc') {
    $adapter = new Prometheus\Storage\APC();
} elseif ($adapter === 'in-memory') {
    $adapter = new Prometheus\Storage\InMemory();
}
$registry = new CollectorRegistry($adapter);

$registry->applyDefaultLabels(['host' => $_SERVER['SERVER_NAME']]);

$histogram = $registry->registerHistogram('test', 'some_histogram', 'it observes', ['type'], [0.005, 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5, 5, 10]);
$histogram->observe($_GET['c'], ['blue']);

echo "OK\n";