Added support of Predis library as storage adapter (#127)

Signed-off-by: Łukasz Adamczewski <tworzenieweb@gmail.com>

composer.json

@@ -25,11 +25,13 @@
         "phpstan/phpstan-phpunit": "^1.1.0",
         "phpstan/phpstan-strict-rules": "^1.1.0",
         "phpunit/phpunit": "^9.4",
+        "predis/predis": "^2.0",
         "squizlabs/php_codesniffer": "^3.6",
         "symfony/polyfill-apcu": "^1.6"
     },
     "suggest": {
         "ext-redis": "Required if using Redis.",
+        "predis/predis": "Required if using Predis.",
         "ext-apc": "Required if using APCu.",
         "promphp/prometheus_push_gateway_php": "An easy client for using Prometheus PushGateway.",
         "symfony/polyfill-apcu": "Required if you use APCu on PHP8.0+"

examples/metrics.php

@@ -11,6 +11,8 @@
 if ($adapter === 'redis') {
     Redis::setDefaultOptions(['host' => $_SERVER['REDIS_HOST'] ?? '127.0.0.1']);
     $adapter = new Prometheus\Storage\Redis();
+} elseif ($adapter === 'predis') {
+    $adapter = new Prometheus\Storage\Predis(['host' => $_SERVER['REDIS_HOST'] ?? '127.0.0.1']);
 } elseif ($adapter === 'apc') {
     $adapter = new Prometheus\Storage\APC();
 } elseif ($adapter === 'apcng') {

src/Prometheus/Storage/Predis.php

@@ -0,0 +1,111 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Prometheus\Storage;
+
+use Predis\Configuration\Option\Prefix;
+use Prometheus\Exception\StorageException;
+use Predis\Client;
+
+/**
+ * @property Client $redis
+ */
+final class Predis extends Redis
+{
+    /**
+     * @var mixed[]
+     */
+    private static array $defaultOptions = [
+        'host' => '127.0.0.1',
+        'port' => 6379,
+        'scheme' => 'tcp',
+        'timeout' => 0.1,
+        'read_timeout' => '10',
+        'persistent' => 0,
+        'password' => null,
+    ];
+
+    public function __construct(array $options = [])
+    {
+        $this->options = array_merge(self::$defaultOptions, $options);
+
+        parent::__construct($options);
+
+        $this->redis = new Client($this->options);
+    }
+
+    public static function fromClient(Client $redis): self
+    {
+        if ($redis->isConnected() === false) {
+            throw new StorageException('Connection to Redis server not established');
+        }
+
+        $self = new self();
+        $self->redis = $redis;
+
+        return $self;
+    }
+
+    protected function ensureOpenConnection(): void
+    {
+        if ($this->redis->isConnected() === false) {
+            $this->redis->connect();
+        }
+    }
+
+    public static function fromExistingConnection(\Redis $redis): Redis
+    {
+        throw new \RuntimeException('This method is not supported by predis adapter');
+    }
+
+    protected function getGlobalPrefix(): ?string
+    {
+        if ($this->redis->getOptions()->prefix === null) {
+            return null;
+        }
+
+        if ($this->redis->getOptions()->prefix instanceof Prefix) {
+            return $this->redis->getOptions()->prefix->getPrefix();
+        }
+
+        return null;
+    }
+
+    /**
+     * @param mixed[] $args
+     * @param int $keysCount
+     * @return mixed[]
+     */
+    protected function evalParams(array $args, int $keysCount): array
+    {
+        return  [$keysCount, ...$args];
+    }
+
+
+    protected function prefix(string $key): string
+    {
+        // the predis is doing key prefixing on its own
+        return '';
+    }
+
+    protected function setParams(array $input): array
+    {
+        $values = array_values($input);
+        $params = [];
+
+        if (isset($input['EX'])) {
+            $params[] = 'EX';
+            $params[] = $input['EX'];
+        }
+
+        if (isset($input['PX'])) {
+            $params[] = 'PX';
+            $params[] = $input['PX'];
+        }
+
+        $params[] = $values[0];
+
+        return $params;
+    }
+}

src/Prometheus/Storage/Redis.php

@@ -5,6 +5,7 @@
 namespace Prometheus\Storage;
 
 use InvalidArgumentException;
+use Predis\Client;
 use Prometheus\Counter;
 use Prometheus\Exception\StorageException;
 use Prometheus\Gauge;
@@ -38,12 +39,12 @@ class Redis implements Adapter
     /**
      * @var mixed[]
      */
-    private $options = [];
+    protected $options = [];
 
     /**
-     * @var \Redis
+     * @var \Redis|Client
      */
-    private $redis;
+    protected $redis;
 
     /**
      * @var boolean
@@ -112,8 +113,7 @@ public function wipeStorage(): void
 
         $searchPattern = "";
 
-        $globalPrefix = $this->redis->getOption(\Redis::OPT_PREFIX);
-        // @phpstan-ignore-next-line false positive, phpstan thinks getOptions returns int
+        $globalPrefix = $this->getGlobalPrefix();
         if (is_string($globalPrefix)) {
             $searchPattern .= $globalPrefix;
         }
@@ -133,8 +133,10 @@ public function wipeStorage(): void
 until cursor == "0"
 LUA
             ,
-            [$searchPattern],
-            0
+            ...$this->evalParams(
+                [$searchPattern],
+                0
+            )
         );
     }
 
@@ -187,7 +189,7 @@ function (array $metric): MetricFamilySamples {
     /**
      * @throws StorageException
      */
-    private function ensureOpenConnection(): void
+    protected function ensureOpenConnection(): void
     {
         if ($this->connectionInitialized === true) {
             return;
@@ -260,15 +262,17 @@ public function updateHistogram(array $data): void
 return result
 LUA
             ,
-            [
-                $this->toMetricKey($data),
-                self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
-                json_encode(['b' => 'sum', 'labelValues' => $data['labelValues']]),
-                json_encode(['b' => $bucketToIncrease, 'labelValues' => $data['labelValues']]),
-                $data['value'],
-                json_encode($metaData),
-            ],
-            2
+            ...$this->evalParams(
+                [
+                    $this->toMetricKey($data),
+                    self::$prefix . Histogram::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
+                    json_encode(['b' => 'sum', 'labelValues' => $data['labelValues']]),
+                    json_encode(['b' => $bucketToIncrease, 'labelValues' => $data['labelValues']]),
+                    $data['value'],
+                    json_encode($metaData),
+                ],
+                2
+            )
         );
     }
 
@@ -301,7 +305,7 @@ public function updateSummary(array $data): void
         $done = false;
         while (!$done) {
             $sampleKey = $valueKey . ':' . uniqid('', true);
-            $done = $this->redis->set($sampleKey, $data['value'], ['NX', 'EX' => $data['maxAgeSeconds']]);
+            $done = $this->redis->set($sampleKey, $data['value'], ...$this->setParams(['NX', 'EX' => $data['maxAgeSeconds']]));
         }
     }
 
@@ -331,15 +335,17 @@ public function updateGauge(array $data): void
 end
 LUA
             ,
-            [
-                $this->toMetricKey($data),
-                self::$prefix . Gauge::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
-                $this->getRedisCommand($data['command']),
-                json_encode($data['labelValues']),
-                $data['value'],
-                json_encode($metaData),
-            ],
-            2
+            ...$this->evalParams(
+                [
+                    $this->toMetricKey($data),
+                    self::$prefix . Gauge::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
+                    $this->getRedisCommand($data['command']),
+                    json_encode($data['labelValues']),
+                    $data['value'],
+                    json_encode($metaData),
+                ],
+                2
+            )
         );
     }
 
@@ -362,15 +368,17 @@ public function updateCounter(array $data): void
 return result
 LUA
             ,
-            [
-                $this->toMetricKey($data),
-                self::$prefix . Counter::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
-                $this->getRedisCommand($data['command']),
-                $data['value'],
-                json_encode($data['labelValues']),
-                json_encode($metaData),
-            ],
-            2
+            ...$this->evalParams(
+                [
+                    $this->toMetricKey($data),
+                    self::$prefix . Counter::TYPE . self::PROMETHEUS_METRIC_KEYS_SUFFIX,
+                    $this->getRedisCommand($data['command']),
+                    $data['value'],
+                    json_encode($data['labelValues']),
+                    json_encode($metaData),
+                ],
+                2
+            )
         );
     }
 
@@ -395,7 +403,7 @@ private function collectHistograms(): array
         sort($keys);
         $histograms = [];
         foreach ($keys as $key) {
-            $raw = $this->redis->hGetAll(str_replace($this->redis->_prefix(''), '', $key));
+            $raw = $this->redis->hGetAll(str_replace($this->prefix(''), '', $key));
             if (!isset($raw['__meta'])) {
                 continue;
             }
@@ -473,12 +481,11 @@ private function collectHistograms(): array
      */
     private function removePrefixFromKey(string $key): string
     {
-        // @phpstan-ignore-next-line false positive, phpstan thinks getOptions returns int
-        if ($this->redis->getOption(\Redis::OPT_PREFIX) === null) {
+        if ($this->getGlobalPrefix() === null) {
             return $key;
         }
-        // @phpstan-ignore-next-line false positive, phpstan thinks getOptions returns int
-        return substr($key, strlen($this->redis->getOption(\Redis::OPT_PREFIX)));
+
+        return substr($key, strlen($this->getGlobalPrefix()));
     }
 
     /**
@@ -578,7 +585,7 @@ private function collectGauges(bool $sortMetrics = true): array
         sort($keys);
         $gauges = [];
         foreach ($keys as $key) {
-            $raw = $this->redis->hGetAll(str_replace($this->redis->_prefix(''), '', $key));
+            $raw = $this->redis->hGetAll(str_replace($this->prefix(''), '', $key));
             if (!isset($raw['__meta'])) {
                 continue;
             }
@@ -614,7 +621,7 @@ private function collectCounters(bool $sortMetrics = true): array
         sort($keys);
         $counters = [];
         foreach ($keys as $key) {
-            $raw = $this->redis->hGetAll(str_replace($this->redis->_prefix(''), '', $key));
+            $raw = $this->redis->hGetAll(str_replace($this->prefix(''), '', $key));
             if (!isset($raw['__meta'])) {
                 continue;
             }
@@ -699,4 +706,30 @@ private function decodeLabelValues(string $values): array
         }
         return $decodedValues;
     }
+
+    protected function getGlobalPrefix(): ?string
+    {
+        // @phpstan-ignore-next-line false positive, phpstan thinks getOptions returns int
+        return $this->redis->getOption(\Redis::OPT_PREFIX);
+    }
+
+    /**
+     * @param mixed[] $args
+     * @param int $keysCount
+     * @return mixed[]
+     */
+    protected function evalParams(array $args, int $keysCount): array
+    {
+        return  [$args, $keysCount];
+    }
+
+    protected function prefix(string $key): string
+    {
+        return $this->redis->_prefix($key);
+    }
+
+    protected function setParams(array $params): array
+    {
+        return [$params];
+    }
 }

tests/Test/Prometheus/Predis/CollectorRegistryTest.php

@@ -0,0 +1,21 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Test\Prometheus\Predis;
+
+use Predis\Client;
+use Prometheus\Storage\Predis;
+use Test\Prometheus\AbstractCollectorRegistryTest;
+
+/**
+ * @requires predis
+ */
+class CollectorRegistryTest extends AbstractCollectorRegistryTest
+{
+    public function configureAdapter(): void
+    {
+        $this->adapter = new Predis(['host' => REDIS_HOST]);
+        $this->adapter->wipeStorage();
+    }
+}

tests/Test/Prometheus/Predis/CounterTest.php

@@ -0,0 +1,22 @@
+<?php
+
+declare(strict_types=1);
+
+namespace Test\Prometheus\Predis;
+
+use Predis\Client;
+use Prometheus\Storage\Predis;
+use Test\Prometheus\AbstractCounterTest;
+
+/**
+ * See https://prometheus.io/docs/instrumenting/exposition_formats/
+ * @requires extension redis
+ */
+class CounterTest extends AbstractCounterTest
+{
+    public function configureAdapter(): void
+    {
+        $this->adapter = new Predis(['host' => REDIS_HOST]);
+        $this->adapter->wipeStorage();
+    }
+}