fix(storage): Fix RedisStorage doesn't clear histograms

Author: zlodes

composer.json

@@ -14,7 +14,7 @@
     "ext-redis": "*",
     "laravel/framework": "^9.0 || ^10.0",
     "webmozart/assert": "^1.11",
-    "zlodes/prometheus-client": "^1.1"
+    "zlodes/prometheus-client": "^1.1.2"
   },
   "require-dev": {
     "ergebnis/composer-normalize": "dev-main",

src/Storage/RedisStorage.php

@@ -43,9 +43,13 @@ public function clear(): void
             $this->connection->command('DEL', [self::SIMPLE_HASH_NAME]);
             $this->connection->command('DEL', [self::HISTOGRAM_SUM_HASH_NAME]);
             $this->connection->command('DEL', [self::HISTOGRAM_COUNT_HASH_NAME]);
+
+            // Using leading asterisk to ignore Laravel Redis connection prefix (like laravel_database_)
+            $histogramKeyPattern = ['*' . self::HISTOGRAM_HASH_NAME_PREFIX . '*'];
+
             $this->connection->command('EVAL', [
-                "return redis.call('del', unpack(redis.call('keys', KEYS[1])))",
-                [self::HISTOGRAM_HASH_NAME_PREFIX],
+                "return redis.call('del', unpack(redis.call('keys', ARGV[1])))",
+                $histogramKeyPattern,
                 0,
             ]);
         } catch (Exception $e) {

tests/Storage/RedisStorageTest.php

@@ -35,6 +35,35 @@ public function setUp(): void
         $redis->command('FLUSHALL');
     }
 
+    public function testClear(): void
+    {
+        /** @var Connection $redis */
+        $redis = $this->app->make(Connection::class);
+
+        $storage = $this->app->make(RedisStorage::class, [
+            'connection' => $redis,
+        ]);
+
+        $storage->setValue(new MetricValue(
+            new MetricNameWithLabels('foo', []),
+            42,
+        ));
+
+        $storage->persistHistogram(
+            new MetricValue(
+                new MetricNameWithLabels('bar'),
+                0.5,
+            ),
+            [0.1, 0.2, 0.3]
+        );
+
+        $storage->clear();
+
+        $keys = $redis->command('KEYS', ['*']);
+
+        self::assertEquals([], $keys);
+    }
+
     public function testRedisExceptionWhileFetch(): void
     {
         $storage = new RedisStorage(