Python try-else

example.py

@contextlib.contextmanager
def temp_file_path(path):
	"""
	Context manager which returns slight variation of the specified path, which can be used to write a file to without clobbering an already existing file until the write is successful. The file at the returned path will either be moved onto the passed path (if the context is left normally) or deleted (if the context is left by throwing an exception).
	"""
	
	temp_path = path + '~'
	dir_path = os.path.dirname(path)
	
	if not os.path.exists(dir_path):
		os.makedirs(dir_path)
	
	try:
		yield temp_path
	except:
		# Remove temporary file.
		os.unlink(temp_path)
		
		# Re-raise exception.
		raise
	else:
		# Overwrite old file with newly written one.
		os.replace(temp_path, path)