Add new Zookeeper Data Store. Add functional test for Zookeeper Data Store. Modify Store Factory to support initialization of Zookeeper Data Store.

.travis.yml

@@ -13,6 +13,8 @@ addons:
         - ldap-utils
         - slapd
         - librabbitmq-dev
+        - zookeeperd
+        - libzookeeper-mt-dev
 
 env:
     global:
@@ -161,6 +163,7 @@ before_install:
           tfold ext.mongodb tpecl mongodb-1.5.0 mongodb.so $INI
           tfold ext.amqp tpecl amqp-1.9.3 amqp.so $INI
           tfold ext.igbinary tpecl igbinary-2.0.6 igbinary.so $INI
+          tfold ext.zookeeper tpecl zookeeper-0.5.0 zookeeper.so $INI
       done
 
     - |

phpunit.xml.dist

@@ -19,6 +19,7 @@
         <env name="LDAP_PORT" value="3389" />
         <env name="REDIS_HOST" value="localhost" />
         <env name="MEMCACHED_HOST" value="localhost" />
+        <env name="ZOOKEEPER_HOST" value="localhost" />
     </php>
 
     <testsuites>

src/Symfony/Component/Lock/CHANGELOG.md

@@ -5,6 +5,7 @@ CHANGELOG
 -----
 
  * added the PDO Store
+ * Add a new Zookeeper Data Store for Lock Component.
 
 3.4.0
 -----

src/Symfony/Component/Lock/Store/StoreFactory.php

@@ -22,9 +22,9 @@ use Symfony\Component\Lock\Exception\InvalidArgumentException;
 class StoreFactory
 {
     /**
-     * @param \Redis|\RedisArray|\RedisCluster|\Predis\Client|\Memcached $connection
+     * @param \Redis|\RedisArray|\RedisCluster|\Predis\Client|\Memcached|\Zookeeper $connection
      *
-     * @return RedisStore|MemcachedStore
+     * @return RedisStore|MemcachedStore|ZookeeperStore
      */
     public static function createStore($connection)
     {
@@ -34,6 +34,9 @@ class StoreFactory
         if ($connection instanceof \Memcached) {
             return new MemcachedStore($connection);
         }
+        if ($connection instanceof \Zookeeper) {
+            return new ZookeeperStore($connection);
+        }
 
         throw new InvalidArgumentException(sprintf('Unsupported Connection: %s.', \get_class($connection)));
     }

src/Symfony/Component/Lock/Store/ZookeeperStore.php

@@ -0,0 +1,150 @@
+<?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\Lock\Store;
+
+use Symfony\Component\Lock\Exception\LockAcquiringException;
+use Symfony\Component\Lock\Exception\LockConflictedException;
+use Symfony\Component\Lock\Exception\LockReleasingException;
+use Symfony\Component\Lock\Exception\NotSupportedException;
+use Symfony\Component\Lock\Key;
+use Symfony\Component\Lock\StoreInterface;
+
+/**
+ * ZookeeperStore is a StoreInterface implementation using Zookeeper as store engine.
+ *
+ * @author Ganesh Chandrasekaran <gchandrasekaran@wayfair.com>
+ */
+class ZookeeperStore implements StoreInterface
+{
+    private $zookeeper;
+
+    public function __construct(\Zookeeper $zookeeper)
+    {
+        $this->zookeeper = $zookeeper;
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function save(Key $key)
+    {
+        if ($this->exists($key)) {
+            return;
+        }
+
+        $resource = $this->getKeyResource($key);
+        $token = $this->getUniqueToken($key);
+
+        $this->createNewLock($resource, $token);
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function delete(Key $key)
+    {
+        if (!$this->exists($key)) {
+            return;
+        }
+        $resource = $this->getKeyResource($key);
+        try {
+            $this->zookeeper->delete($resource);
+        } catch (\ZookeeperException $exception) {
+            // For Zookeeper Ephemeral Nodes, the node will be deleted upon session death. But, if we want to unlock
+            // the lock before proceeding further in the session, the client should be aware of this
+            throw new LockReleasingException($exception);
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function exists(Key $key): bool
+    {
+        $resource = $this->getKeyResource($key);
+        try {
+            return $this->zookeeper->get($resource) === $this->getUniqueToken($key);
+        } catch (\ZookeeperException $ex) {
+            return false;
+        }
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function waitAndSave(Key $key)
+    {
+        throw new NotSupportedException();
+    }
+
+    /**
+     * {@inheritdoc}
+     */
+    public function putOffExpiration(Key $key, $ttl)
+    {
+        throw new NotSupportedException();
+    }
+
+    /**
+     * Creates a zookeeper node.
+     *
+     * @param string $node  The node which needs to be created
+     * @param string $value The value to be assigned to a zookeeper node
+     *
+     * @throws LockConflictedException
+     * @throws LockAcquiringException
+     */
+    private function createNewLock(string $node, string $value)
+    {
+        // Default Node Permissions
+        $acl = array(array('perms' => \Zookeeper::PERM_ALL, 'scheme' => 'world', 'id' => 'anyone'));
+        // This ensures that the nodes are deleted when the client session to zookeeper server ends.
+        $type = \Zookeeper::EPHEMERAL;
+
+        try {
+            $this->zookeeper->create($node, $value, $acl, $type);
+        } catch (\ZookeeperException $ex) {
+            if (\Zookeeper::NODEEXISTS === $ex->getCode()) {
+                throw new LockConflictedException($ex);
+            }
+
+            throw new LockAcquiringException($ex);
+        }
+    }
+
+    private function getKeyResource(Key $key): string
+    {
+        // Since we do not support storing locks as multi-level nodes, we convert them to be stored at root level.
+        // For example: foo/bar will become /foo-bar and /foo/bar will become /-foo-bar
+        $resource = (string) $key;
+
+        if (false !== \strpos($resource, '/')) {
+            $resource = \strtr($resource, array('/' => '-')).'-'.sha1($resource);
+        }
+
+        if ('' === $resource) {
+            $resource = sha1($resource);
+        }
+
+        return '/'.$resource;
+    }
+
+    private function getUniqueToken(Key $key): string
+    {
+        if (!$key->hasState(self::class)) {
+            $token = base64_encode(random_bytes(32));
+            $key->setState(self::class, $token);
+        }
+
+        return $key->getState(self::class);
+    }
+}

src/Symfony/Component/Lock/StoreInterface.php

@@ -11,7 +11,9 @@
 
 namespace Symfony\Component\Lock;
 
+use Symfony\Component\Lock\Exception\LockAcquiringException;
 use Symfony\Component\Lock\Exception\LockConflictedException;
+use Symfony\Component\Lock\Exception\LockReleasingException;
 use Symfony\Component\Lock\Exception\NotSupportedException;
 
 /**
@@ -24,6 +26,7 @@ interface StoreInterface
     /**
      * Stores the resource if it's not locked by someone else.
      *
+     * @throws LockAcquiringException
      * @throws LockConflictedException
      */
     public function save(Key $key);
@@ -52,6 +55,8 @@ interface StoreInterface
 
     /**
      * Removes a resource from the storage.
+     *
+     * @throws LockReleasingException
      */
     public function delete(Key $key);
 

src/Symfony/Component/Lock/Tests/Store/ZookeeperStoreTest.php

@@ -0,0 +1,108 @@
+<?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\Lock\Tests\Store;
+
+use Symfony\Component\Lock\Key;
+use Symfony\Component\Lock\Store\StoreFactory;
+use Symfony\Component\Lock\Store\ZookeeperStore;
+
+/**
+ * @author Ganesh Chandrasekaran <gchandrasekaran@wayfair.com>
+ *
+ * @requires extension zookeeper
+ */
+class ZookeeperStoreTest extends AbstractStoreTest
+{
+    public function getStore(): ZookeeperStore
+    {
+        $zookeeper_server = getenv('ZOOKEEPER_HOST').':2181';
+
+        $zookeeper = new \Zookeeper(implode(',', array($zookeeper_server)));
+
+        return StoreFactory::createStore($zookeeper);
+    }
+
+    public function testSaveSucceedsWhenPathContainsMoreThanOneNode()
+    {
+        $store = $this->getStore();
+        $resource = '/baseNode/lockNode';
+        $key = new Key($resource);
+
+        $store->save($key);
+        $this->assertTrue($store->exists($key));
+
+        $store->delete($key);
+        $this->assertFalse($store->exists($key));
+    }
+
+    public function testSaveSucceedsWhenPathContainsOneNode()
+    {
+        $store = $this->getStore();
+        $resource = '/baseNode';
+        $key = new Key($resource);
+
+        $store->save($key);
+        $this->assertTrue($store->exists($key));
+
+        $store->delete($key);
+        $this->assertFalse($store->exists($key));
+    }
+
+    public function testSaveSucceedsWhenPathsContainSameFirstNode()
+    {
+        $store = $this->getStore();
+        $resource = 'foo/bar';
+        $key = new Key($resource);
+
+        $store->save($key);
+        $this->assertTrue($store->exists($key));
+
+        $resource2 = 'foo';
+        $key2 = new Key($resource2);
+
+        $this->assertFalse($store->exists($key2));
+        $store->save($key2);
+        $this->assertTrue($store->exists($key2));
+
+        $store->delete($key2);
+        $this->assertFalse($store->exists($key2));
+
+        $store->delete($key);
+        $this->assertFalse($store->exists($key));
+    }
+
+    public function testRootPathIsLockable()
+    {
+        $store = $this->getStore();
+        $resource = '/';
+        $key = new Key($resource);
+
+        $store->save($key);
+        $this->assertTrue($store->exists($key));
+
+        $store->delete($key);
+        $this->assertFalse($store->exists($key));
+    }
+
+    public function testEmptyStringIsLockable()
+    {
+        $store = $this->getStore();
+        $resource = '';
+        $key = new Key($resource);
+
+        $store->save($key);
+        $this->assertTrue($store->exists($key));
+
+        $store->delete($key);
+        $this->assertFalse($store->exists($key));
+    }
+}

src/Symfony/Component/Lock/phpunit.xml.dist

@@ -12,6 +12,7 @@
         <ini name="error_reporting" value="-1" />
         <env name="REDIS_HOST" value="localhost" />
         <env name="MEMCACHED_HOST" value="localhost" />
+        <env name="ZOOKEEPER_HOST" value="localhost" />
     </php>
 
     <testsuites>