Python filecache

filecache.py

class FileCache(object):
  use_cache = True

  def __init__(self, expire=CACHE_EXPIRATION):
    self._expire = expire

  def __call__(self, func):
    """Simple cache decorator. Cache the values in a file in `/var/tmp`"""
    @wraps(func)
    def wrapped_function(*args):
      assert not LG.debug("%r", func.__name__)
      filename = self.mk_cache_filename(func.__name__)
      if not self.use_cache:
        assert not LG.debug("Cache disabled")
        # invalidating the cache
        try:
          os.unlink(filename)
        except OSError:
          pass
        return func(*args)

      try:
        if os.path.exists(filename):
          fstat = os.stat(filename)
          if fstat.st_mtime + self._expire < time.time():
            os.unlink(filename)
      except IOError as err:
        LG.warning('NO CACHING: File cache error: %s', err)
        return func(*args)

      try:
        with open(filename) as fdcache:
          result = cPickle.load(fdcache)
      except KeyError as err:
        LG.warning('Cache file error: %s', err)
      except IOError as err:
        LG.warning('Cache file %s error. re-creating it', filename)
      else:
        LG.info('%s information read from cache', func.__name__)
        return result

      result = func(*args)
      assert not LG.info("Caching %r - %s", func.__name__, result)
      with open(filename, 'w') as fdcache:
        cPickle.dump(result, fdcache)
      return result
    return wrapped_function

  @staticmethod
  def mk_cache_filename(name):
    return '/tmp/.hcache-' + md5(str(name)).hexdigest()

  @staticmethod
  def disable():
    FileCache.use_cache = False

  @staticmethod
  def enable():
    FileCache.use_cache = True