On flush remove only prometheus specific keys from redis (#31)

Signed-off-by: Matouš Michalík <i@matousmichalik.com>

Author: encero

examples/flush_adapter.php

@@ -2,17 +2,18 @@
 
 require __DIR__ . '/../vendor/autoload.php';
 
-$adapter = $_GET['adapter'];
+$adapterName = $_GET['adapter'];
 
-if ($adapter === 'redis') {
+$adapter = null;
+
+if ($adapterName === 'redis') {
     define('REDIS_HOST', $_SERVER['REDIS_HOST'] ?? '127.0.0.1');
 
-    $redisAdapter = new Prometheus\Storage\Redis(['host' => REDIS_HOST]);
-    $redisAdapter->flushRedis();
-} elseif ($adapter === 'apc') {
-    $apcAdapter = new Prometheus\Storage\APC();
-    $apcAdapter->flushAPC();
-} elseif ($adapter === 'in-memory') {
-    $inMemoryAdapter = new Prometheus\Storage\InMemory();
-    $inMemoryAdapter->flushMemory();
+    $adapter = new Prometheus\Storage\Redis(['host' => REDIS_HOST]);
+} elseif ($adapterName === 'apc') {
+    $adapter = new Prometheus\Storage\APC();
+} elseif ($adapterName === 'in-memory') {
+    $adapter = new Prometheus\Storage\InMemory();
 }
+
+$adapter->wipeStorage();

src/Prometheus/Storage/APC.php

@@ -125,11 +125,21 @@ public function updateCounter(array $data): void
     }
 
     /**
-     * Removes all previously stored data from apcu
+     * @deprecated use replacement method wipeStorage from Adapter interface
      *
      * @return void
      */
     public function flushAPC(): void
+    {
+        $this->wipeStorage();
+    }
+
+    /**
+     * Removes all previously stored data from apcu
+     *
+     * @return void
+     */
+    public function wipeStorage(): void
     {
         //                   /      / | PCRE expresion boundary
         //                    ^       | match from first character only

src/Prometheus/Storage/Adapter.php

@@ -4,6 +4,7 @@
 
 namespace Prometheus\Storage;
 
+use Prometheus\Exception\StorageException;
 use Prometheus\MetricFamilySamples;
 
 interface Adapter
@@ -34,4 +35,12 @@ public function updateGauge(array $data): void;
      * @return void
      */
     public function updateCounter(array $data): void;
+
+    /**
+     * Removes all previously stored metrics from underlying storage
+     *
+     * @throws StorageException
+     * @return void
+     */
+    public function wipeStorage(): void;
 }

src/Prometheus/Storage/InMemory.php

@@ -36,7 +36,18 @@ public function collect(): array
         return $metrics;
     }
 
+    /**
+     * @deprecated use replacement method wipeStorage from Adapter interface
+     */
     public function flushMemory(): void
+    {
+        $this->wipeStorage();
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function wipeStorage(): void
     {
         $this->counters = [];
         $this->gauges = [];

src/Prometheus/Storage/Redis.php

@@ -92,12 +92,47 @@ public static function setPrefix(string $prefix): void
     }
 
     /**
+     * @deprecated use replacement method wipeStorage from Adapter interface
      * @throws StorageException
      */
     public function flushRedis(): void
+    {
+        $this->wipeStorage();
+    }
+
+    /**
+     * @inheritDoc
+     */
+    public function wipeStorage(): void
     {
         $this->ensureOpenConnection();
-        $this->redis->flushAll();
+
+        $searchPattern = "";
+
+        $globalPrefix = $this->redis->getOption(\Redis::OPT_PREFIX);
+        // @phpstan-ignore-next-line false positive, phpstan thinks getOptions returns int
+        if (is_string($globalPrefix)) {
+            $searchPattern .= $globalPrefix;
+        }
+
+        $searchPattern .= self::$prefix;
+        $searchPattern .= '*';
+
+        $this->redis->eval(
+            <<<LUA
+local cursor = "0"
+repeat 
+    local results = redis.call('SCAN', cursor, 'MATCH', ARGV[1])
+    cursor = results[1]
+    for _, key in ipairs(results[2]) do
+        redis.call('DEL', key)
+    end
+until cursor == "0"
+LUA
+            ,
+            [$searchPattern],
+            0
+        );
     }
 
     /**

tests/Test/Prometheus/APC/CollectorRegistryTest.php

@@ -16,6 +16,6 @@ class CollectorRegistryTest extends AbstractCollectorRegistryTest
     public function configureAdapter(): void
     {
         $this->adapter = new APC();
-        $this->adapter->flushAPC();
+        $this->adapter->wipeStorage();
     }
 }

tests/Test/Prometheus/APC/CounterTest.php

@@ -16,6 +16,6 @@ class CounterTest extends AbstractCounterTest
     public function configureAdapter(): void
     {
         $this->adapter = new APC();
-        $this->adapter->flushAPC();
+        $this->adapter->wipeStorage();
     }
 }

tests/Test/Prometheus/APC/GaugeTest.php

@@ -16,6 +16,6 @@ class GaugeTest extends AbstractGaugeTest
     public function configureAdapter(): void
     {
         $this->adapter = new APC();
-        $this->adapter->flushAPC();
+        $this->adapter->wipeStorage();
     }
 }

tests/Test/Prometheus/APC/HistogramTest.php

@@ -16,6 +16,6 @@ class HistogramTest extends AbstractHistogramTest
     public function configureAdapter(): void
     {
         $this->adapter = new APC();
-        $this->adapter->flushAPC();
+        $this->adapter->wipeStorage();
     }
 }

tests/Test/Prometheus/InMemory/CollectorRegistryTest.php

@@ -12,6 +12,6 @@ class CollectorRegistryTest extends AbstractCollectorRegistryTest
     public function configureAdapter(): void
     {
         $this->adapter = new InMemory();
-        $this->adapter->flushMemory();
+        $this->adapter->wipeStorage();
     }
 }