def atomic_save(obj, dirname, filename, method=None):
"""Save the given object (which must have a .save() method, unless the
method parameter is given) into the given directory with the given
filename, using a temporary file and renaming the temporary file to the
final name."""
prefix, suffix = os.path.splitext(filename)
tempfd, tempfilename = tempfile.mkstemp(prefix=prefix,
suffix=suffix,
dir=dirname)
os.close(tempfd)
logger.debug('saving %s to temporary file %s', str(obj), tempfilename)
if method is not None:
method(obj, tempfilename)
else:
obj.save(tempfilename)
for fn in glob.glob(tempfilename + '*'):
newname = fn.replace(tempfilename, os.path.join(dirname, filename))
logger.debug('renaming temporary file %s to %s', fn, newname)
os.rename(fn, newname)
def debug(self, message):
"""Log a debug message from this backend"""
logger.debug("Backend {}: {}".format(self.backend_id, message))
