bug #21908 [Cache] Fix Redis pipelining/multi-ops (nicolas-grekas)

This PR was merged into the 3.2 branch.

Discussion
----------

[Cache] Fix Redis pipelining/multi-ops

| Q             | A
| ------------- | ---
| Branch?       | 3.2
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #21858
| License       | MIT
| Doc PR        | -

`MSET` doesn't work on clustered connections. Let's use pipelining instead.

Commits
-------

f1648e2 [Cache] Fix Redis pipelining/multi-ops

src/Symfony/Component/Cache/Adapter/RedisAdapter.php

@@ -14,6 +14,7 @@
 use Predis\Connection\Factory;
 use Predis\Connection\Aggregate\PredisCluster;
 use Predis\Connection\Aggregate\RedisCluster;
+use Predis\Response\Status;
 use Symfony\Component\Cache\Exception\InvalidArgumentException;
 
 /**
@@ -136,11 +137,14 @@ public static function createConnection($dsn, array $options = array())
     protected function doFetch(array $ids)
     {
         if ($ids) {
-            $values = $this->redis->mGet($ids);
-            $index = 0;
-            foreach ($ids as $id) {
-                if ($value = $values[$index++]) {
-                    yield $id => parent::unserialize($value);
+            $values = $this->pipeline(function () use ($ids) {
+                foreach ($ids as $id) {
+                    yield 'get' => array($id);
+                }
+            });
+            foreach ($values as $id => $v) {
+                if ($v) {
+                    yield $id => parent::unserialize($v);
                 }
             }
         }
@@ -251,61 +255,63 @@ protected function doSave(array $values, $lifetime)
             return $failed;
         }
 
-        if (0 >= $lifetime) {
-            $this->redis->mSet($serialized);
-
-            return $failed;
-        }
-
-        $this->pipeline(function ($pipe) use (&$serialized, $lifetime) {
+        $results = $this->pipeline(function () use ($serialized, $lifetime) {
             foreach ($serialized as $id => $value) {
-                $pipe('setEx', $id, array($lifetime, $value));
+                if (0 >= $lifetime) {
+                    yield 'set' => array($id, $value);
+                } else {
+                    yield 'setEx' => array($id, $lifetime, $value);
+                }
             }
         });
+        foreach ($results as $id => $result) {
+            if (true !== $result && (!$result instanceof Status || $result !== Status::get('OK'))) {
+                $failed[] = $id;
+            }
+        }
 
         return $failed;
     }
 
-    private function execute($command, $id, array $args, $redis = null)
+    private function pipeline(\Closure $generator)
     {
-        array_unshift($args, $id);
-        call_user_func_array(array($redis ?: $this->redis, $command), $args);
-    }
+        $ids = array();
 
-    private function pipeline(\Closure $callback)
-    {
-        $redis = $this->redis;
-
-        try {
-            if ($redis instanceof \Predis\Client) {
-                $redis->pipeline(function ($pipe) use ($callback) {
-                    $this->redis = $pipe;
-                    $callback(array($this, 'execute'));
-                });
-            } elseif ($redis instanceof \RedisArray) {
-                $connections = array();
-                $callback(function ($command, $id, $args) use (&$connections) {
-                    if (!isset($connections[$h = $this->redis->_target($id)])) {
-                        $connections[$h] = $this->redis->_instance($h);
-                        $connections[$h]->multi(\Redis::PIPELINE);
-                    }
-                    $this->execute($command, $id, $args, $connections[$h]);
-                });
-                foreach ($connections as $c) {
-                    $c->exec();
+        if ($this->redis instanceof \Predis\Client) {
+            $results = $this->redis->pipeline(function ($redis) use ($generator, &$ids) {
+                foreach ($generator() as $command => $args) {
+                    call_user_func_array(array($redis, $command), $args);
+                    $ids[] = $args[0];
                 }
-            } else {
-                $pipe = $redis->multi(\Redis::PIPELINE);
-                try {
-                    $callback(array($this, 'execute'));
-                } finally {
-                    if ($pipe) {
-                        $redis->exec();
-                    }
+            });
+        } elseif ($this->redis instanceof \RedisArray) {
+            $connections = $results = $ids = array();
+            foreach ($generator() as $command => $args) {
+                if (!isset($connections[$h = $this->redis->_target($args[0])])) {
+                    $connections[$h] = array($this->redis->_instance($h), -1);
+                    $connections[$h][0]->multi(\Redis::PIPELINE);
                 }
+                call_user_func_array(array($connections[$h][0], $command), $args);
+                $results[] = array($h, ++$connections[$h][1]);
+                $ids[] = $args[0];
+            }
+            foreach ($connections as $h => $c) {
+                $connections[$h] = $c[0]->exec();
+            }
+            foreach ($results as $k => list($h, $c)) {
+                $results[$k] = $connections[$h][$c];
             }
-        } finally {
-            $this->redis = $redis;
+        } else {
+            $this->redis->multi(\Redis::PIPELINE);
+            foreach ($generator() as $command => $args) {
+                call_user_func_array(array($this->redis, $command), $args);
+                $ids[] = $args[0];
+            }
+            $results = $this->redis->exec();
+        }
+
+        foreach ($ids as $k => $id) {
+            yield $id => $results[$k];
         }
     }
 }

src/Symfony/Component/Cache/Tests/Adapter/PredisClusterAdapterTest.php

@@ -0,0 +1,27 @@
+<?php
+
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
+namespace Symfony\Component\Cache\Tests\Adapter;
+
+class PredisClusterAdapterTest extends AbstractRedisAdapterTest
+{
+    public static function setupBeforeClass()
+    {
+        parent::setupBeforeClass();
+        self::$redis = new \Predis\Client(array(getenv('REDIS_HOST')));
+    }
+
+    public static function tearDownAfterClass()
+    {
+        self::$redis->getConnection()->getConnectionByKey('foo')->executeCommand(self::$redis->createCommand('FLUSHDB'));
+        self::$redis = null;
+    }
+}