Simple script to export metrics to Prometheus

Author: vrza

lrpm-prometheus-metrics.php

@@ -0,0 +1,58 @@
+<?php
+# php -S 127.0.0.1:8080 lrpm-prometheus-metrics.php
+
+$program = __DIR__ . '/bin/lrpmctl';
+$request = 'jsonstatus';
+$json = shell_exec("$program $request");
+$status = json_decode($json, true);
+$output = lrpm_status_to_prometheus_metrics($status);
+echo($output);
+
+function lrpm_status_to_prometheus_metrics(array $status): string
+{
+    $taskCount = count($status);
+    $activeTaskCount = get_number_of_active_tasks($status);
+    $inactiveTaskCount = $taskCount - $activeTaskCount;
+    $output = "lrpm_task_count $taskCount" . PHP_EOL;
+    $output .= "lrpm_inactive_task_count $inactiveTaskCount" . PHP_EOL;
+
+    foreach ($status as $jobId => $jobStatus) {
+        $config = $jobStatus['config'];
+        $state = $jobStatus['state'];
+        $name = $config['name'];
+        $workerClass = $config['workerClass'];
+        $mtime = $config['mtime'];
+        if (isset($state['restartAt']) && $state['restartAt'] > $state['startedAt']) {
+            $backoffDuration = $state['restartAt'] - $state['startedAt'];
+            $metric = serialize_prometheus_metric('lrpm_task_backoff', ['id' => $jobId, 'name' => $name], $backoffDuration);
+            $output .= $metric . PHP_EOL;
+        }
+    }
+
+    return $output;
+}
+
+function get_number_of_active_tasks(array $status)
+{
+    $active_tasks = array_filter($status, function ($task) {
+        return isset($task['state']['pid']) && is_int($task['state']['pid']);
+    });
+    return count($active_tasks);
+}
+
+function serialize_prometheus_metric(string $name, array $labels, $value, $timestamp = null): string
+{
+    $output = $name;
+    if (!empty($labels)) {
+        $output .= '{';
+        $sep = '';
+        foreach ($labels as $labelName => $labelValue) {
+            $output .= $sep . $labelName . '=' . $labelValue;
+            $sep = ',';
+        }
+        $output .= '}';
+    }
+    $output .= ' ' . $value;
+    if (isset($timestamp)) $output .= ' ' . $timestamp;
+    return $output;
+}