import logging
import time

from app import app, storage, chunk_cleanup_queue
from workers.queueworker import QueueWorker, JobException
from util.log import logfile_path

logger = logging.getLogger(__name__)


POLL_PERIOD_SECONDS = 10


class ChunkCleanupWorker(QueueWorker):
  """ Worker which cleans up chunks enqueued by the storage engine(s). This is typically used to
      cleanup empty chunks which are no longer needed.
  """
  def process_queue_item(self, job_details):
    logger.debug('Got chunk cleanup queue item: %s', job_details)
    storage_location = job_details['location']
    storage_path = job_details['path']

    if not storage.exists([storage_location], storage_path):
      logger.debug('Chunk already deleted')
      return

    try:
      storage.remove([storage_location], storage_path)
    except IOError:
      raise JobException()


if __name__ == "__main__":
  logging.config.fileConfig(logfile_path(debug=False), disable_existing_loggers=False)

  engines = set([config[0] for config in app.config.get('DISTRIBUTED_STORAGE_CONFIG', {}).values()])
  if 'SwiftStorage' not in engines:
    logger.debug('Swift storage not detected; sleeping')
    while True:
      time.sleep(10000)

  logger.debug('Starting chunk cleanup worker')
  worker = ChunkCleanupWorker(chunk_cleanup_queue, poll_period_seconds=POLL_PERIOD_SECONDS)
  worker.start()