Remote media purge leaves a lot of directories

[namazso]

Description

I recently noticed my remote media folder grew to 5 GB again, so I ran a media purge for all files (timestamp in future). However, after finishing the remote media folder still weighed 500 MB. It turns out that was the combined size of the empty folders left behind.

Steps to reproduce

• run homeserver for a while
• run media purge
• observe leftover empty folders

Homeserver

namazso.eu

Synapse Version

1.91.0

Installation Method

Docker (matrixdotorg/synapse)

Database

PostgreSQL 15

Workers

Single process

Platform

Linux 6.5.0

Configuration

No response

Relevant log output

-

Anything else that would be useful to know?

No response

[DMRobertson]

Relevant source:

synapse/synapse/media/media_repository.py

Lines 934 to 970 in 3de82bb

	async def delete_old_remote_media(self, before_ts: int) -> Dict[str, int]:
	old_media = await self.store.get_remote_media_ids(
	before_ts, include_quarantined_media=False
	)
	deleted = 0
	for media in old_media:
	origin = media["media_origin"]
	media_id = media["media_id"]
	file_id = media["filesystem_id"]
	key = (origin, media_id)
	logger.info("Deleting: %r", key)
	# TODO: Should we delete from the backup store
	async with self.remote_media_linearizer.queue(key):
	full_path = self.filepaths.remote_media_filepath(origin, file_id)
	try:
	os.remove(full_path)
	except OSError as e:
	logger.warning("Failed to remove file: %r", full_path)
	if e.errno == errno.ENOENT:
	pass
	else:
	continue
	thumbnail_dir = self.filepaths.remote_media_thumbnail_dir(
	origin, file_id
	)
	shutil.rmtree(thumbnail_dir, ignore_errors=True)
	await self.store.delete_remote_media(origin, media_id)
	deleted += 1
	return {"deleted": deleted}

I suppose when deleting a file on disk we could try to os.rmdir() its parent directories, catching and ignoring OSError due to the directory not being empty?

Would probably also want to do something similar in delete_old_local_media.

As a one-time cleanup job I guess one could find -empty -type d -delete?

[clokep]

Duplicate of #7690.