add histogram metric for prometheus

src/Adapters/Redis/AbstractRedisStorage.php

@@ -84,6 +84,15 @@ final public function setMetricValue(string $name, float $value, array $tags = [
         $this->redisConnection->setMetrics([new MetricDto($name, $value, $tags)]);
     }
 
+    /**
+     * @param HistogramMetricDto $metricDto
+     * @return void
+     */
+    final public function adjustHistogramMetric(HistogramMetricDto $metricDto): void
+    {
+        $this->redisConnection->adjustHistogramMetric($metricDto);
+    }
+
     /** {@inheritdoc} */
     final public function adjustMetricValue(string $name, float $value, array $tags = []): float
     {

src/Adapters/Redis/HistogramMetricDto.php

@@ -0,0 +1,49 @@
+<?php
+
+namespace Lamoda\Metric\Adapters\Redis;
+
+class HistogramMetricDto
+{
+    /** @var string */
+    public $name;
+    /** @var float */
+    public $value;
+    /** @var array<string, string> */
+    public $tags;
+    /** @var float[] */
+    public $buckets;
+    /** @var string */
+    public $le;
+
+    /**
+     * @param array<string, string> $tags
+     * @param float[]|int[] $buckets
+     */
+    public function __construct(string $name, float $value, array $buckets, array $tags)
+    {
+        $this->name = $name;
+        $this->value = $value;
+        $this->tags = $tags;
+        sort($buckets);
+        $this->buckets = $buckets;
+        $this->le = $this->calculateLe($buckets, $value);
+    }
+
+    /**
+     * @param float[] $buckets
+     * @param float $value
+     * @return string
+     */
+    private function calculateLe(array $buckets, float $value): string
+    {
+        $bucketToIncrease = '+Inf';
+        foreach ($buckets as $bucket) {
+            if ($value <= $bucket) {
+                $bucketToIncrease = $bucket;
+                break;
+            }
+        }
+
+        return (string) $bucketToIncrease;
+    }
+}

src/Adapters/Redis/MutatorRedisConnectionInterface.php

@@ -12,4 +12,10 @@ public function adjustMetric(string $key, float $delta, array $tags): float;
      * @param MetricDto[] $metricsData
      */
     public function setMetrics(array $metricsData): void;
+
+    /**
+     * @param HistogramMetricDto $metricDto
+     * @return float
+     */
+    public function adjustHistogramMetric(HistogramMetricDto $metricDto): float;
 }

src/Adapters/Redis/RedisConnection.php

@@ -58,6 +58,17 @@ public function setMetrics(array $metricsData): void
         $this->client->hmset($this->metricsKey, $fields);
     }
 
+    /** {@inheritdoc} */
+    public function adjustHistogramMetric(HistogramMetricDto $metricDto): float
+    {
+        $this->client->multi();
+        $this->client->hincrbyfloat($this->metricsKey, $this->buildHistogramFieldForSum($metricDto), $metricDto->value);
+        $this->client->hincrby($this->metricsKey, $this->buildHistogramFieldForValue($metricDto), 1);
+        $result = $this->client->exec();
+
+        return (float) ($result[0] ?? null);
+    }
+
     /** {@inheritdoc} */
     public function getMetricValue(string $key, array $tags): ?float
     {
@@ -77,6 +88,48 @@ private function buildField(string $name, array $tags)
         ]);
     }
 
+    /**
+     * @param HistogramMetricDto $histogramMetricDto
+     * @return string
+     */
+    private function buildHistogramFieldForValue(HistogramMetricDto $histogramMetricDto): string
+    {
+        return json_encode([
+            'name' => $histogramMetricDto->name,
+            'tags' => $this->convertTagsForStorage(array_merge(
+                $histogramMetricDto->tags, 
+                [
+                    'le' => $histogramMetricDto->le,
+                    '_meta' => [
+                        'type' => 'histogram',
+                        'buckets' => $histogramMetricDto->buckets
+                    ]
+                ]
+            ))
+        ]);
+    }
+
+    /**
+     * @param HistogramMetricDto $histogramMetricDto
+     * @return string
+     */
+    private function buildHistogramFieldForSum(HistogramMetricDto $histogramMetricDto): string
+    {
+        return json_encode([
+            'name' => $histogramMetricDto->name,
+            'tags' => $this->convertTagsForStorage(array_merge(
+                $histogramMetricDto->tags,
+                [
+                    '_meta' => [
+                        'type' => 'histogram',
+                        'buckets' => $histogramMetricDto->buckets,
+                        'is_sum' => true
+                    ]
+                ]
+            ))
+        ]);
+    }
+
     private function convertTagsForStorage(array $tags): string
     {
         return json_encode($this->normalizeTags($tags));

src/Responder/ResponseFactory/PrometheusResponseFactory.php

@@ -3,6 +3,7 @@
 namespace Lamoda\Metric\Responder\ResponseFactory;
 
 use GuzzleHttp\Psr7\Response;
+use Lamoda\Metric\Common\MetricInterface;
 use Lamoda\Metric\Common\MetricSourceInterface;
 use Lamoda\Metric\Responder\ResponseFactoryInterface;
 use Psr\Http\Message\ResponseInterface;
@@ -29,21 +30,128 @@ final class PrometheusResponseFactory implements ResponseFactoryInterface
     public function create(MetricSourceInterface $source, array $options = []): ResponseInterface
     {
         $data = [];
+        $histogramMetricsData = [];
+        $prefix = $options['prefix'] ?? '';
         foreach ($source->getMetrics() as $metric) {
+            $tags = $metric->getTags();
+
+            if (isset($tags['_meta']) && ($tags['_meta']['type'] ?? '') === 'histogram') {
+                $histogramMetricsData = $this->prepareHistogramMetric($metric, $histogramMetricsData);
+                continue;
+            }
+
             $data[] = [
-                'name' => ($options['prefix'] ?? '') . $metric->getName(),
+                'name' => $prefix . $metric->getName(),
                 'value' => $metric->resolve(),
-                'tags' => $metric->getTags(),
+                'tags' => $tags,
             ];
         }
+
+        $histogramData = $this->calculateHistogramMetric($histogramMetricsData, $prefix);
 
         return new Response(
             200,
             ['Content-Type' => self::CONTENT_TYPE],
-            $this->getContent($data)
+            $this->getContent(array_merge($data, $histogramData))
         );
     }
 
+    private function buildHistogramMetricHash(MetricInterface $metric): string
+    {
+        return md5($metric->getName() . implode('', $this->clearTags($metric->getTags())));
+    }
+
+    /**
+     * @param array<string, string> $tags
+     * @return array<string, string>
+     */
+    private function clearTags(array $tags): array
+    {
+        if (isset($tags['_meta'])) {
+            unset($tags['_meta']);
+        }
+
+        if (isset($tags['le'])) {
+            unset($tags['le']);
+        }
+
+        return $tags;
+    }
+
+    /**
+     * @param array<string, array<string, mixed>> $preparedHistogramMetricsData
+     * @return array<string, array<string, mixed>>
+     */
+    private function prepareHistogramMetric(MetricInterface $metric, array $preparedHistogramMetricsData): array
+    {
+        $tags = $metric->getTags();
+        $metaTags = $tags['_meta'];
+        $le = $tags['le'] ?? null;
+        $tags = $this->clearTags($tags);
+        $keyMetric = $this->buildHistogramMetricHash($metric);
+
+        if (!isset($preparedHistogramMetricsData[$keyMetric])) {
+            $preparedHistogramMetricsData[$keyMetric] = [
+                'name' => $metric->getName(),
+                'buckets' => $metaTags['buckets'],
+                'tags' => $tags,
+                'data' => [],
+                'sum' => 0,
+            ];
+        }
+
+        if (isset($metaTags['is_sum'])) {
+            $preparedHistogramMetricsData[$keyMetric]['sum'] = $metric->resolve();
+        }
+
+        if ($le !== null) {
+            $preparedHistogramMetricsData[$keyMetric]['data'][(string) $le] = $metric->resolve();
+        }
+
+        return $preparedHistogramMetricsData;
+    }
+
+    /**
+     * @return array<string, array<int, mixed>> $histogramMetricsData
+     * @return array<int, array<string, string>>
+     */
+    private function calculateHistogramMetric(array $histogramMetricsData, string $prefix = ''): array
+    {
+        $data = [];
+        foreach ($histogramMetricsData as $histogramMetricData) {
+            $total = 0;
+            $buckets = $histogramMetricData['buckets'];
+            if (!in_array('+Inf', $buckets)) {
+                $buckets[] = '+Inf';
+            }
+
+            foreach ($buckets as $bucket) {
+                $value = $histogramMetricData['data'][(string)$bucket] ?? 0;
+                $total += $value;
+
+                $data[] = [
+                    'name' => $prefix . $histogramMetricData['name'] . '_bucket',
+                    'value' => $total,
+                    'tags' => array_merge($histogramMetricData['tags'], ['le' => (string) $bucket])
+                ];
+            }
+
+            $data[] = [
+                'name' => $prefix . $histogramMetricData['name'] . '_sum',
+                'value' => $histogramMetricData['sum'],
+                'tags' => $histogramMetricData['tags'],
+            ];
+
+            $data[] = [
+                'name' => $prefix . $histogramMetricData['name'] . '_count',
+                'value' => $total,
+                'tags' => $histogramMetricData['tags'],
+            ];
+        }
+
+        return $data;
+    }
+
     /**
      * Get response content.
      *

tests/Adapters/Redis/RedisConnectionTest.php

@@ -4,6 +4,7 @@
 
 namespace Adapters\Redis;
 
+use Lamoda\Metric\Adapters\Redis\HistogramMetricDto;
 use Lamoda\Metric\Adapters\Redis\MetricDto;
 use Lamoda\Metric\Adapters\Redis\RedisConnection;
 use PHPUnit\Framework\MockObject\MockObject;
@@ -57,6 +58,36 @@ public function testAdjustMetric(): void
         self::assertEquals(17, $actual);
     }
 
+    public function testAdjustHistogramMetric(): void
+    {
+        $value = 1.5;
+        $this->redis
+            ->expects($this->once())
+            ->method('hincrbyfloat')
+            ->with(
+                self::METRICS_KEY,
+                '{"name":"test","tags":"{\"_meta\":{\"type\":\"histogram\",\"buckets\":[1,2,3],\"is_sum\":true},\"severity\":\"high\"}"}',
+                $value
+            );
+
+        $this->redis
+            ->expects($this->once())
+            ->method('hincrby')
+            ->with(
+                self::METRICS_KEY,
+                '{"name":"test","tags":"{\"_meta\":{\"type\":\"histogram\",\"buckets\":[1,2,3]},\"le\":\"2\",\"severity\":\"high\"}"}',
+                1
+            );
+
+        $this->redis
+            ->expects($this->once())
+            ->method('exec')
+            ->willReturn([$value, 1]);
+
+        $actual = $this->redisConnection->adjustHistogramMetric(new HistogramMetricDto('test', $value, [1, 2, 3], ['severity' => 'high']));
+        self::assertEquals($value, $actual);
+    }
+
     public function testSetMetrics(): void
     {
         $fields = [

tests/Responder/ResponseFactory/PrometheusResponseFactoryTest.php

@@ -19,6 +19,8 @@ public function testResponseFormat(): void
                 new Metric('metrics_orders', 200.0, ['country' => 'ru']),
                 new Metric('metrics_errors', 0.0, ['country' => 'ru']),
                 new Metric('untagged_metric', 5.0),
+                new Metric('histogram_metric', 1.0, ['_meta' => ['type' => 'histogram', 'buckets' => [0.1,0.5,0.9]], 'country' => 'ru', 'le' =>'0.5']),
+                new Metric('histogram_metric', 0.5, ['_meta' => ['type' => 'histogram', 'buckets' => [0.1,0.5,0.9], 'is_sum' => true], 'country' => 'ru'])
             ]
         );
 
@@ -30,6 +32,12 @@ public function testResponseFormat(): void
 metrics_orders{country="ru"} 200
 metrics_errors{country="ru"} 0
 untagged_metric 5
+histogram_metric_bucket{country="ru",le="0.1"} 0
+histogram_metric_bucket{country="ru",le="0.5"} 1
+histogram_metric_bucket{country="ru",le="0.9"} 1
+histogram_metric_bucket{country="ru",le="+Inf"} 1
+histogram_metric_sum{country="ru"} 0.5
+histogram_metric_count{country="ru"} 1
 
 PROMETHEUS
             ,