public static function BrightcoveUtil::runWithSemaphore in Brightcove Video Connect 8

Same name and namespace in other branches

1. 8.2 src/BrightcoveUtil.php \Drupal\brightcove\BrightcoveUtil::runWithSemaphore()
2. 3.x src/BrightcoveUtil.php \Drupal\brightcove\BrightcoveUtil::runWithSemaphore()

Run a piece of code with semaphore check.

Parameters

callable $function: Function that needs to be run in sync.

Return value

bool|mixed FALSE if the execution was failed, otherwise it will return what the callable function returned.

2 calls to BrightcoveUtil::runWithSemaphore()

BrightcoveSubscriptionController::notificationCallback in src/Controller/BrightcoveSubscriptionController.php

Menu callback to handle the Brightcove notification callback.

BrightcoveVideoController::ingestionCallback in src/Controller/BrightcoveVideoController.php

Ingestion callback for Brightcove.

File

src/BrightcoveUtil.php, line 490

Class

BrightcoveUtil

Utility class for Brightcove.

Namespace

Drupal\brightcove

Code

public static function runWithSemaphore(callable $function) {

  /* @var \Drupal\Core\KeyValueStore\KeyValueStoreInterface $state */
  $state = \Drupal::getContainer()
    ->get('state');
  try {

    // Basic semaphore to prevent race conditions, this is needed
    // because Brightcove may call callbacks again before the previous one
    // would finish.
    //
    // To make sure that the waiting doesn't run indefinitely limit the
    // maximum iterations to 600 cycles, which in worst case scenario would
    // mean 5 minutes maximum wait time.
    $limit = 600;
    for ($i = 0; $i < $limit; $i++) {

      // Try to acquire semaphore.
      for (; $i < $limit && $state
        ->get('brightcove_semaphore', FALSE) == TRUE; $i++) {

        // Wait random time between 100 and 500 milliseconds on each
        // try.
        usleep(mt_rand(100000, 500000));
      }

      // Make sure that other processes have not acquired the semaphore
      // while we waited.
      if ($state
        ->get('brightcove_semaphore', FALSE) == FALSE) {

        // Acquire semaphore as soon as we can.
        $state
          ->set('brightcove_semaphore', TRUE);
        break;
      }
    }

    // If we couldn't acquire the semaphore in the given time, release the
    // semaphore (finally block will do this), and return with FALSE.
    if (600 <= $i) {
      return FALSE;
    }

    // Run function.
    return $function();
  } catch (\Exception $e) {

    // Log error, and return with FALSE.
    watchdog_exception('brightcove', $e, $e
      ->getMessage());
    return FALSE;
  } finally {

    // Release semaphore.
    // This will always run regardless what happened.
    $state
      ->set('brightcove_semaphore', FALSE);
  }
}