Add distribution metrics to datadog client (#36)

* Updated client to support sending Distribution metrics

* Added unit test for Distribution metrics

* Fixed test method name

Author: rares-mollie

src/Client.php

@@ -470,6 +470,27 @@ public function histogram($metric, $value, $sampleRate = 1.0, array $tags = [])
         return $this;
     }
 
+    /**
+     * Distribution
+     *
+     * @param string   $metric     Metric to send
+     * @param float    $value      Value to send
+     * @param float    $sampleRate Sample rate of metric
+     * @param string[] $tags       List of tags for this metric
+     *
+     * @return Client This instance
+     */
+    public function distribution($metric, $value, $sampleRate = 1.0, array $tags = [])
+    {
+        if ($this->isSampled($sampleRate, $postfix)) {
+            return $this->send(
+                [$metric => $value . '|d' . $postfix],
+                $tags
+            );
+        }
+        return $this;
+    }
+
     /**
      * Sets - count the number of unique elements for a group
      *

tests/unit/DistributionTest.php

@@ -0,0 +1,57 @@
+<?php
+/**
+ * This file is part of graze/dog-statsd
+ *
+ * Copyright (c) 2016 Nature Delivered Ltd. <https://www.graze.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ *
+ * @license https://github.com/graze/dog-statsd/blob/master/LICENSE.md
+ * @link    https://github.com/graze/dog-statsd
+ */
+
+namespace Graze\DogStatsD\Test\Unit;
+
+use Graze\DogStatsD\Test\TestCase;
+
+class DistributionTest extends TestCase
+{
+    public function testDistribution()
+    {
+        $this->client->distribution('test_metric', 10);
+        $this->assertEquals('test_metric:10|d', $this->client->getLastMessage());
+
+        $this->client->distribution('test_metric', 1.2);
+        $this->assertEquals('test_metric:1.2|d', $this->client->getLastMessage());
+    }
+
+    public function testDistributionSample()
+    {
+        while ($this->client->getLastMessage() === '') {
+            $this->client->distribution('test_metric', 5, 0.75);
+        }
+        $this->assertEquals('test_metric:5|d|@0.75', $this->client->getLastMessage());
+    }
+
+    public function testDistributionSampleFailure()
+    {
+        $this->client->distribution('test_metric', 5, 0);
+        $this->assertEquals('', $this->client->getLastMessage());
+    }
+
+    public function testDistributionTags()
+    {
+        $this->client->distribution('test_metric', 10, 1.0, []);
+        $this->assertEquals('test_metric:10|d', $this->client->getLastMessage());
+
+        $this->client->distribution('test_metric', 10, 1.0, ['tag1']);
+        $this->assertEquals('test_metric:10|d|#tag1', $this->client->getLastMessage());
+
+        $this->client->distribution('test_metric', 10, 1.0, ['tag1', 'tag2']);
+        $this->assertEquals('test_metric:10|d|#tag1,tag2', $this->client->getLastMessage());
+
+        $this->client->distribution('test_metric', 10, 1.0, ['tag1', 'tag1']);
+        $this->assertEquals('test_metric:10|d|#tag1,tag1', $this->client->getLastMessage());
+    }
+}