Merge pull request magento#3933 from magento-thunder/MAGETWO-98151

Fixed issue:
 - MAGETWO-98151: Add support ZooKeeper and flock locks

app/etc/di.xml

@@ -38,7 +38,7 @@
     <preference for="Magento\Framework\Locale\ListsInterface" type="Magento\Framework\Locale\TranslatedLists" />
     <preference for="Magento\Framework\Locale\AvailableLocalesInterface" type="Magento\Framework\Locale\Deployed\Codes" />
     <preference for="Magento\Framework\Locale\OptionInterface" type="Magento\Framework\Locale\Deployed\Options" />
-    <preference for="Magento\Framework\Lock\LockManagerInterface" type="Magento\Framework\Lock\Backend\Database" />
+    <preference for="Magento\Framework\Lock\LockManagerInterface" type="Magento\Framework\Lock\Proxy" />
     <preference for="Magento\Framework\Api\AttributeTypeResolverInterface" type="Magento\Framework\Reflection\AttributeTypeResolver" />
     <preference for="Magento\Framework\Api\Search\SearchResultInterface" type="Magento\Framework\Api\Search\SearchResult" />
     <preference for="Magento\Framework\Api\Search\SearchCriteriaInterface" type="Magento\Framework\Api\Search\SearchCriteria"/>

dev/tests/integration/testsuite/Magento/Framework/Lock/Backend/FileLockTest.php

@@ -0,0 +1,55 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Framework\Lock\Backend;
+
+/**
+ * \Magento\Framework\Lock\Backend\File test case
+ */
+class FileLockTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var \Magento\Framework\Lock\Backend\FileLock
+     */
+    private $model;
+
+    /**
+     * @var \Magento\Framework\ObjectManagerInterface
+     */
+    private $objectManager;
+
+    protected function setUp()
+    {
+        $this->objectManager = \Magento\TestFramework\Helper\Bootstrap::getObjectManager();
+        $this->model = $this->objectManager->create(
+            \Magento\Framework\Lock\Backend\FileLock::class,
+            ['path' => '/tmp']
+        );
+    }
+
+    public function testLockAndUnlock()
+    {
+        $name = 'test_lock';
+
+        $this->assertFalse($this->model->isLocked($name));
+
+        $this->assertTrue($this->model->lock($name));
+        $this->assertTrue($this->model->isLocked($name));
+        $this->assertFalse($this->model->lock($name, 2));
+
+        $this->assertTrue($this->model->unlock($name));
+        $this->assertFalse($this->model->isLocked($name));
+    }
+
+    public function testUnlockWithoutExistingLock()
+    {
+        $name = 'test_lock';
+
+        $this->assertFalse($this->model->isLocked($name));
+        $this->assertFalse($this->model->unlock($name));
+    }
+}

dev/tests/integration/testsuite/Magento/Framework/Lock/Backend/ZookeeperTest.php

@@ -0,0 +1,90 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Framework\Lock\Backend;
+
+use Magento\Framework\Lock\Backend\Zookeeper as ZookeeperLock;
+use Magento\Framework\Lock\LockBackendFactory;
+use Magento\Framework\Config\File\ConfigFilePool;
+use Magento\Framework\App\DeploymentConfig\FileReader;
+use Magento\Framework\Stdlib\ArrayManager;
+
+/**
+ * \Magento\Framework\Lock\Backend\Zookeeper test case
+ */
+class ZookeeperTest extends \PHPUnit\Framework\TestCase
+{
+    /**
+     * @var FileReader
+     */
+    private $configReader;
+
+    /**
+     * @var \Magento\Framework\ObjectManagerInterface
+     */
+    private $objectManager;
+
+    /**
+     * @var LockBackendFactory
+     */
+    private $lockBackendFactory;
+
+    /**
+     * @var ArrayManager
+     */
+    private $arrayManager;
+
+    /**
+     * @var ZookeeperLock
+     */
+    private $model;
+
+    /**
+     * @inheritdoc
+     */
+    protected function setUp()
+    {
+        if (!extension_loaded('zookeeper')) {
+            $this->markTestSkipped('php extension Zookeeper is not installed.');
+        }
+
+        $this->objectManager = \Magento\TestFramework\Helper\Bootstrap::getObjectManager();
+        $this->configReader = $this->objectManager->get(FileReader::class);
+        $this->lockBackendFactory = $this->objectManager->create(LockBackendFactory::class);
+        $this->arrayManager = $this->objectManager->create(ArrayManager::class);
+        $config = $this->configReader->load(ConfigFilePool::APP_ENV);
+
+        if ($this->arrayManager->get('lock/provider', $config) !== 'zookeeper') {
+            $this->markTestSkipped('Zookeeper is not configured during installation.');
+        }
+
+        $this->model = $this->lockBackendFactory->create();
+        $this->assertInstanceOf(ZookeeperLock::class, $this->model);
+    }
+
+    public function testLockAndUnlock()
+    {
+        $name = 'test_lock';
+
+        $this->assertFalse($this->model->isLocked($name));
+
+        $this->assertTrue($this->model->lock($name));
+        $this->assertTrue($this->model->isLocked($name));
+        $this->assertFalse($this->model->lock($name, 2));
+
+        $this->assertTrue($this->model->unlock($name));
+        $this->assertFalse($this->model->isLocked($name));
+    }
+
+    public function testUnlockWithoutExistingLock()
+    {
+        $name = 'test_lock';
+
+        $this->assertFalse($this->model->isLocked($name));
+        $this->assertFalse($this->model->unlock($name));
+    }
+}

lib/internal/Magento/Framework/Lock/Backend/FileLock.php

@@ -0,0 +1,194 @@
+<?php
+/**
+ * Copyright © Magento, Inc. All rights reserved.
+ * See COPYING.txt for license details.
+ */
+declare(strict_types=1);
+
+namespace Magento\Framework\Lock\Backend;
+
+use Magento\Framework\Lock\LockManagerInterface;
+use Magento\Framework\Filesystem\Driver\File as FileDriver;
+use Magento\Framework\Exception\RuntimeException;
+use Magento\Framework\Exception\FileSystemException;
+use Magento\Framework\Phrase;
+
+/**
+ * LockManager using the file system for locks
+ */
+class FileLock implements LockManagerInterface
+{
+    /**
+     * The file driver instance
+     *
+     * @var FileDriver
+     */
+    private $fileDriver;
+
+    /**
+     * The path to the locks storage folder
+     *
+     * @var string
+     */
+    private $path;
+
+    /**
+     * How many microseconds to wait before re-try to acquire a lock
+     *
+     * @var int
+     */
+    private $sleepCycle = 100000;
+
+    /**
+     * The mapping list of the path lock with the file resource
+     *
+     * @var array
+     */
+    private $locks = [];
+
+    /**
+     * @param FileDriver $fileDriver The file driver
+     * @param string $path The path to the locks storage folder
+     * @throws RuntimeException Throws RuntimeException if $path is empty
+     *         or cannot create the directory for locks
+     */
+    public function __construct(FileDriver $fileDriver, string $path)
+    {
+        if (!$path) {
+            throw new RuntimeException(new Phrase('The path needs to be a non-empty string.'));
+        }
+
+        $this->fileDriver = $fileDriver;
+        $this->path = rtrim($path, '/') . '/';
+
+        try {
+            if (!$this->fileDriver->isExists($this->path)) {
+                $this->fileDriver->createDirectory($this->path);
+            }
+        } catch (FileSystemException $exception) {
+            throw new RuntimeException(
+                new Phrase('Cannot create the directory for locks: %1', [$this->path]),
+                $exception
+            );
+        }
+    }
+
+    /**
+     * Acquires a lock by name
+     *
+     * @param string $name The lock name
+     * @param int $timeout Timeout in seconds. A negative timeout value means infinite timeout
+     * @return bool Returns true if the lock is acquired, otherwise returns false
+     * @throws RuntimeException Throws RuntimeException if cannot acquires the lock because FS problems
+     */
+    public function lock(string $name, int $timeout = -1): bool
+    {
+        try {
+            $lockFile = $this->getLockPath($name);
+            $fileResource = $this->fileDriver->fileOpen($lockFile, 'w+');
+            $skipDeadline = $timeout < 0;
+            $deadline = microtime(true) + $timeout;
+
+            while (!$this->tryToLock($fileResource)) {
+                if (!$skipDeadline && $deadline <= microtime(true)) {
+                    $this->fileDriver->fileClose($fileResource);
+                    return false;
+                }
+                usleep($this->sleepCycle);
+            }
+        } catch (FileSystemException $exception) {
+            throw new RuntimeException(new Phrase('Cannot acquire a lock.'), $exception);
+        }
+
+        $this->locks[$lockFile] = $fileResource;
+        return true;
+    }
+
+    /**
+     * Checks if a lock exists by name
+     *
+     * @param string $name The lock name
+     * @return bool Returns true if the lock exists, otherwise returns false
+     * @throws RuntimeException Throws RuntimeException if cannot check that the lock exists
+     */
+    public function isLocked(string $name): bool
+    {
+        $lockFile = $this->getLockPath($name);
+        $result = false;
+
+        try {
+            if ($this->fileDriver->isExists($lockFile)) {
+                $fileResource = $this->fileDriver->fileOpen($lockFile, 'w+');
+                if ($this->tryToLock($fileResource)) {
+                    $result = false;
+                } else {
+                    $result = true;
+                }
+                $this->fileDriver->fileClose($fileResource);
+            }
+        } catch (FileSystemException $exception) {
+            throw new RuntimeException(new Phrase('Cannot verify that the lock exists.'), $exception);
+        }
+
+        return $result;
+    }
+
+    /**
+     * Remove the lock by name
+     *
+     * @param string $name The lock name
+     * @return bool If the lock is removed returns true, otherwise returns false
+     */
+    public function unlock(string $name): bool
+    {
+        $lockFile = $this->getLockPath($name);
+
+        if (isset($this->locks[$lockFile]) && $this->tryToUnlock($this->locks[$lockFile])) {
+            unset($this->locks[$lockFile]);
+            return true;
+        }
+
+        return false;
+    }
+
+    /**
+     * Returns the full path to the lock file by name
+     *
+     * @param string $name The lock name
+     * @return string The path to the lock file
+     */
+    private function getLockPath(string $name): string
+    {
+        return $this->path . $name;
+    }
+
+    /**
+     * Tries to lock a file resource
+     *
+     * @param resource $resource The file resource
+     * @return bool If the lock is acquired returns true, otherwise returns false
+     */
+    private function tryToLock($resource): bool
+    {
+        try {
+            return $this->fileDriver->fileLock($resource, LOCK_EX | LOCK_NB);
+        } catch (FileSystemException $exception) {
+            return false;
+        }
+    }
+
+    /**
+     * Tries to unlock a file resource
+     *
+     * @param resource $resource The file resource
+     * @return bool If the lock is removed returns true, otherwise returns false
+     */
+    private function tryToUnlock($resource): bool
+    {
+        try {
+            return $this->fileDriver->fileLock($resource, LOCK_UN | LOCK_NB);
+        } catch (FileSystemException $exception) {
+            return false;
+        }
+    }
+}