rename remote_thumbnail to remote_thumbnails

[HarHarLinks]

Description

Configuring backups, I want to exclude media that can be regenerated since it originates on other servers. I almost did this incorrectly, since /media_store/remote_thumbnail does not end in s while the other 2 thumbnail folders for local and url previews do.

Steps to reproduce

look at the /media_store

Version information

• Homeserver:

If not matrix.org: my own

• Version: 1.43.0

• Install method:

pip

• Platform:

Debian 9 stretch

[squahtx]

The inconsistency surprised me too!

Unfortunately it's not trivial to rename the directory since we have to keep existing Synapse deployments in mind. While we could do the rename on startup, files in storage providers would still retain the old spelling, so we'd end up maintaining extra logic to check both spellings.

Also there's this script that would need updating too:
https://github.com/matrix-org/synapse-s3-storage-provider/blob/04d5fb7fe983672320d45a37186f396c543e891a/scripts/s3_media_upload#L131-L138

[clokep]

See also #10556.

[clokep]

I'm going to close this -- it is annoying, but documented. I think the effort to fix it is not worthwhile.