Fix #73 Redis::ensureOpenConnection should only connect once (#76)

Signed-off-by: Dirk Adler <dirx@klitsche.de>

Co-authored-by: Lukas Kämmerling <lukas.kaemmerling@hetzner-cloud.de>

Author: dirx

src/Prometheus/Storage/Redis.php

@@ -204,6 +204,8 @@ private function ensureOpenConnection(): void
         }
 
         $this->redis->setOption(\Redis::OPT_READ_TIMEOUT, $this->options['read_timeout']);
+
+        $this->connectionInitialized = true;
     }
 
     /**

tests/Test/Prometheus/Storage/RedisTest.php

@@ -78,4 +78,72 @@ public function itShouldNotClearWholeRedisOnFlush(): void
             ])
         );
     }
+
+    /**
+     * @test
+     */
+    public function itShouldOnlyConnectOnceOnSubsequentCalls(): void
+    {
+        $clientId = $this->redisConnection->rawCommand('client', 'id');
+        $expectedClientId = 'id=' . ($clientId + 1) . ' ';
+        $notExpectedClientId = 'id=' . ($clientId + 2) . ' ';
+
+        $redis = new Redis(['host' => REDIS_HOST]);
+
+        $redis->collect();
+
+        $this->assertStringContainsString(
+            $expectedClientId,
+            $this->redisConnection->rawCommand('client', 'list')
+        );
+        $this->assertStringNotContainsString(
+            $notExpectedClientId,
+            $this->redisConnection->rawCommand('client', 'list')
+        );
+
+        $redis->collect();
+
+        $this->assertStringContainsString(
+            $expectedClientId,
+            $this->redisConnection->rawCommand('client', 'list')
+        );
+        $this->assertStringNotContainsString(
+            $notExpectedClientId,
+            $this->redisConnection->rawCommand('client', 'list')
+        );
+    }
+
+    /**
+     * @test
+     */
+    public function itShouldOnlyConnectOnceForInjectedRedisConnectionOnSubsequentCalls(): void
+    {
+        $clientId = $this->redisConnection->rawCommand('client', 'id');
+        $expectedClientId = 'id=' . $clientId . ' ';
+        $notExpectedClientId = 'id=' . ($clientId + 1) . ' ';
+
+        $redis = Redis::fromExistingConnection($this->redisConnection);
+
+        $redis->collect();
+
+        $this->assertStringContainsString(
+            $expectedClientId,
+            $this->redisConnection->rawCommand('client', 'list')
+        );
+        $this->assertStringNotContainsString(
+            $notExpectedClientId,
+            $this->redisConnection->rawCommand('client', 'list')
+        );
+
+        $redis->collect();
+
+        $this->assertStringContainsString(
+            $expectedClientId,
+            $this->redisConnection->rawCommand('client', 'list')
+        );
+        $this->assertStringNotContainsString(
+            $notExpectedClientId,
+            $this->redisConnection->rawCommand('client', 'list')
+        );
+    }
 }