From 6a6c280c3bb895fb30345961268a5748c084439b Mon Sep 17 00:00:00 2001
From: dmitry krokhin <nekufa@gmail.com>
Date: Tue, 17 Aug 2021 20:55:37 +0300
Subject: [PATCH] prometheus metrics order fix

---
 src/Metrics/Exporter/PrometheusExporter.php | 12 +++++-----
 tests/Metrics/ExporterTest.php              | 26 +++++++++++++++++++++
 2 files changed, 32 insertions(+), 6 deletions(-)

diff --git a/src/Metrics/Exporter/PrometheusExporter.php b/src/Metrics/Exporter/PrometheusExporter.php
index df4c1fa..af6e092 100644
--- a/src/Metrics/Exporter/PrometheusExporter.php
+++ b/src/Metrics/Exporter/PrometheusExporter.php
@@ -17,16 +17,14 @@ public function toFile(string $path, string $prefix = '', array $labels = []): v
 
     public function toString(string $prefix = '', array $labels = []): string
     {
-        $info = [];
         $result = [];
 
         foreach ($this->toArray($labels) as $row) {
             $key = $prefix . $row['key'];
 
-            if (!array_key_exists($key, $info)) {
-                $result[] = sprintf('# HELP %s %s', $key, $row['help']);
-                $result[] = sprintf('# TYPE %s %s', $key, $row['type']);
-                $info[$key] = true;
+            if (!array_key_exists($key . '!h', $result)) {
+                $result[$key . '!h'] = sprintf('# HELP %s %s', $key, $row['help']);
+                $result[$key . '!t'] = sprintf('# TYPE %s %s', $key, $row['type']);
             }
 
             $rowLabels = [];
@@ -37,9 +35,11 @@ public function toString(string $prefix = '', array $labels = []): string
                 $key .= '{' . implode(',', $rowLabels) . '}';
             }
 
-            $result[] = sprintf('%s %s', $key, $row['value']);
+            $result[$key] = sprintf('%s %s', $key, $row['value']);
         }
 
+        ksort($result);
+
         return implode(PHP_EOL, $result);
     }
 }
diff --git a/tests/Metrics/ExporterTest.php b/tests/Metrics/ExporterTest.php
index 5f48ed2..6cead30 100644
--- a/tests/Metrics/ExporterTest.php
+++ b/tests/Metrics/ExporterTest.php
@@ -80,6 +80,32 @@ public function testExporter(): void
 
         $this->assertCount(2, explode('HELP svc_request_counter', $result));
     }
+
+    public function testMetricsOrder()
+    {
+        $registry = new Registry();
+        $registry->set('todo', 1, ['queue' => 'web.bundle']);
+        $registry->set('complete', 2, ['queue' => 'flow.promote']);
+        $registry->set('todo', 3, ['queue' => 'space.housekeeping']);
+
+        $info = new Info();
+        $info->set('todo', 'waiting');
+        $info->set('complete', 'complete');
+
+        $string = (new PrometheusExporter($registry, $info))->toString();
+
+        $shouldbe = implode(PHP_EOL, [
+            '# HELP complete complete',
+            '# TYPE complete gauge',
+            'complete{queue="flow.promote"} 2',
+            '# HELP todo waiting',
+            '# TYPE todo gauge',
+            'todo{queue="space.housekeeping"} 3',
+            'todo{queue="web.bundle"} 1',
+        ]);
+        $this->assertSame($string, $shouldbe);
+    }
+
     public function testExtraLabels()
     {
         $registry = new Registry();