Read and use request time (#7)

Author: Firehed

README.md

@@ -52,6 +52,7 @@ metadata:
 | Metric Name | Metric Type | Description | Tags |
 | --- | --- | --- | --- |
 | PREFIX.request.count | counter | Request Count | code, method, server_name |
+| PREFIX.request.duration | histogram | Request Duration (total processing time) | code, method, server_name |
 
 **Warning:** These will be counted towards Datadog custom metrics, and the tags could result in many custom metrics even for a single Ingress.
 This could result in increased billing.

src/Rewriter.php

@@ -25,11 +25,20 @@ public function rewrite(string $influxDbMessage)
         list($_, $serverName) = explode('=', $serverNameTagStr, 2);
         $tags = $this->parseTags($tagStr);
 
-        $this->datadog->increment($measurement.'.request.count', 1.0, [
+        $ddTags = [
             'code' => $tags['status'],
             'method' => $tags['method'],
             'server_name' => $serverName,
-        ]);
+        ];
+        // Simple request counter
+        $this->datadog->increment($measurement.'.request.count', 1.0, $ddTags);
+        // Total request duration (value is received in seconds)
+        $this->datadog->microtiming(
+            $measurement.'.request.duration',
+            (float)$tags['request_time'],
+            1.0,
+            $ddTags
+        );
     }
 
     private function parseTags(string $tagStr): array

tests/RewriterTest.php

@@ -22,7 +22,7 @@ class RewriterTest extends \PHPUnit\Framework\TestCase
      * @covers ::rewrite
      * @dataProvider influxDbMessages
      */
-    public function testRewrite(string $message, string $prefix, array $tags)
+    public function testRewrite(string $message, string $prefix, float $time, array $tags)
     {
         $dd = $this->createMock(DogStatsd::class);
         $dd->method('microtiming')
@@ -38,6 +38,7 @@ public function testRewrite(string $message, string $prefix, array $tags)
         $rewriter->rewrite($message);
 
         $this->expectIncrement('request.count');
+        $this->expectTimer('request.duration', $time);
         $this->performAssertions($prefix, $tags);
     }
 
@@ -51,6 +52,7 @@ public function influxDbMessages(): array
                 'content_type="text/plain; charset=utf-8",request_time=0.047',
 
                 'default',
+                0.047,
                 ['code' => '500',
                  'method' => 'GET',
                  'server_name' => 'amp.reefpig.com',
@@ -64,6 +66,11 @@ private function expectIncrement(string $metric)
         $this->expectedIncrements[] = $metric;
     }
 
+    private function expectTimer(string $metric, float $seconds)
+    {
+        $this->expectedTimers[] = [$metric, $seconds];
+    }
+
     private function performAssertions(string $prefix, array $tags)
     {
         $this->assertCount(count($this->expectedIncrements), $this->increments, 'Incorrect increment count');
@@ -78,12 +85,27 @@ private function performAssertions(string $prefix, array $tags)
                     break;
                 }
             }
-            if (!$found) {
-                $this->fail(sprintf('Expected increment metric %s not found', $metric));
-            }
+            $this->assertNotFalse($found, sprintf('Expected increment metric %s not found', $metric));
             ksort($tags);
             ksort($found[2]);
             $this->assertEquals($tags, $found[2], 'Tags do not match');
         }
+
+        foreach ($this->expectedTimers as $et) {
+            list($suffix, $seconds) = $et;
+            $metric = sprintf('%s.%s', $prefix, $suffix);
+            $found = false;
+            foreach ($this->timers as $timer) {
+                if ($timer[0] === $metric) {
+                    $found = $timer;
+                    break;
+                }
+            }
+            $this->assertNotFalse($found, sprintf('Timer metric %s not found', $metric));
+            $this->assertEquals($seconds, $found[1], 'Incorrect timing value');
+            ksort($tags);
+            ksort($found[3]);
+            $this->assertEquals($tags, $found[3], 'Tags do not match');
+        }
     }
 }