How does Magento 2 process «events.xml» configuration files?

dmitrii_fediuk · November 13, 2015, 9:05am

Step 1

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/Event/Manager.php#L57


 * Calls all observer callbacks registered for this event
 * and multiple observers matching event name pattern
 *
 * @param string $eventName
 * @param array $data
 * @return void
 */
public function dispatch($eventName, array $data = [])
{
    \Magento\Framework\Profiler::start('EVENT:' . $eventName, ['group' => 'EVENT', 'name' => $eventName]);
    foreach ($this->_eventConfig->getObservers($eventName) as $observerConfig) {
        $event = new \Magento\Framework\Event($data);
        $event->setName($eventName);


        $wrapper = new Observer();
        $wrapper->setData(array_merge(['event' => $event], $data));


        \Magento\Framework\Profiler::start('OBSERVER:' . $observerConfig['name']);
        $this->_invoker->dispatch($observerConfig, $wrapper);
        \Magento\Framework\Profiler::stop('OBSERVER:' . $observerConfig['name']);
    }

Step 2

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/Event/Config.php#L37


}


/**
 * Get observers by event name
 *
 * @param string $eventName
 * @return null|array|mixed
 */
public function getObservers($eventName)
{
    return $this->_dataContainer->get($eventName, []);
}
}

Step 3

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/Config/Data/Scoped.php#L81




/**
 * Get config value by key
 *
 * @param string $path
 * @param mixed $default
 * @return array|mixed|null
 */
public function get($path = null, $default = null)
{
    $this->_loadScopedData();
    return parent::get($path, $default);
}


/**
 * Load data for current scope
 *
 * @return void
 */
protected function _loadScopedData()
{

Step 4

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/Config/Data/Scoped.php#L103


if (false == isset($this->_loadedScopes[$scope])) {
    if (false == in_array($scope, $this->_scopePriorityScheme)) {
        $this->_scopePriorityScheme[] = $scope;
    }
    foreach ($this->_scopePriorityScheme as $scopeCode) {
        if (false == isset($this->_loadedScopes[$scopeCode])) {
            if ($scopeCode !== 'primary' && ($data = $this->_cache->load($scopeCode . '::' . $this->_cacheId))
            ) {
                $data = unserialize($data);
            } else {
                $data = $this->_reader->read($scopeCode);
                if ($scopeCode !== 'primary') {
                    $this->_cache->save(serialize($data), $scopeCode . '::' . $this->_cacheId);
                }
            }
            $this->merge($data);
            $this->_loadedScopes[$scopeCode] = true;
        }
        if ($scopeCode == $scope) {
            break;
        }

Step 5

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/Config/Reader/Filesystem.php#L113




/**
 * Load configuration scope
 *
 * @param string|null $scope
 * @return array
 */
public function read($scope = null)
{
    $scope = $scope ?: $this->_defaultScope;
    $fileList = $this->_fileResolver->get($this->_fileName, $scope);
    if (!count($fileList)) {
        return [];
    }
    $output = $this->_readFiles($fileList);


    return $output;
}


/**
 * Read configuration files

Step 6

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/App/Config/FileResolver.php#L65


    switch ($scope) {
        case 'primary':
            $directory = $this->filesystem->getDirectoryRead(DirectoryList::CONFIG);
            $absolutePaths = [];
            foreach ($directory->search('{' . $filename . ',*/' . $filename . '}') as $path) {
                $absolutePaths[] = $directory->getAbsolutePath($path);
            }
            $iterator = $this->iteratorFactory->create($absolutePaths);
            break;
        case 'global':
            $iterator = $this->_moduleReader->getConfigurationFiles($filename);
            break;
        default:
            $iterator = $this->_moduleReader->getConfigurationFiles($scope . '/' . $filename);
            break;
    }
    return $iterator;
}
}

или

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/App/Config/FileResolver.php#L68


            $absolutePaths = [];
            foreach ($directory->search('{' . $filename . ',*/' . $filename . '}') as $path) {
                $absolutePaths[] = $directory->getAbsolutePath($path);
            }
            $iterator = $this->iteratorFactory->create($absolutePaths);
            break;
        case 'global':
            $iterator = $this->_moduleReader->getConfigurationFiles($filename);
            break;
        default:
            $iterator = $this->_moduleReader->getConfigurationFiles($scope . '/' . $filename);
            break;
    }
    return $iterator;
}
}

Step 7

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/Module/Dir/Reader.php#L75


}


/**
 * Go through all modules and find configuration files of active modules
 *
 * @param string $filename
 * @return FileIterator
 */
public function getConfigurationFiles($filename)
{
    return $this->fileIteratorFactory->create($this->getFiles($filename, Dir::MODULE_ETC_DIR));
}


/**
 * Go through all modules and find composer.json files of active modules
 *
 * @return FileIterator
 */
public function getComposerJsonFiles()
{
    return $this->fileIteratorFactory->create($this->getFiles('composer.json'));

Step 8

github.com

magento/magento2/blob/2335247d4ae2dc1e0728ee73022b0a244ccd7f4c/lib/internal/Magento/Framework/Module/Dir/Reader.php#L95-L108


private function getFiles($filename, $subDir = '')
{
    $result = [];
    foreach ($this->modulesList->getNames() as $moduleName) {
        $moduleEtcDir = $this->getModuleDir($subDir, $moduleName);
        $file = $moduleEtcDir . '/' . $filename;
        $directoryRead = $this->readFactory->create($moduleEtcDir);
        $path = $directoryRead->getRelativePath($file);
        if ($directoryRead->isExist($path)) {
            $result[] = $file;
        }
    }
    return $result;
}