[BE] [Bug]: Local instance is processing remote updates even if not subcribed anymore #3568

github.com [Bug]: Local instance is processing remote updates even if not subcribed anymore · Issue #3568 · LemmyNet/lemmy

Requirements Is this a bug report? For questions or discussions use https://lemmy.ml/c/lemmy_support Did you check to see if this issue already exists? Is this only a single bug? Do not put multipl...

Requirements

[X] Is this a bug report? For questions or discussions use https://lemmy.ml/c/lemmy_support

[X] Did you check to see if this issue already exists?

[X] Is this only a single bug? Do not put multiple bugs in one issue.

[X] Is this a backend issue? Use the lemmy-ui repo for UI / frontend issues.

Summary

If you simply prune your database, so not unsubscribing to every previously subscribed communities, your local instance is still processing every update pushed by the remotes instances, populating your database and your media folder with unwanted stuff.

Steps to Reproduce

Stash your database

Restart your federated instance

Every POST /inbox is processed with code 200, tables are updated, images stored, etc

Remove federation and every POST /inbox is going to error 400

Technical Details

I understand you SHOULD unsubscribe for the remote instances to be aware you don't want updates anymore. But if for whatever reason this information is lost or not processed correctly, the local instance is bombarded with remote junk. Moreover, with this system, a rogue instance can push everything to everyone. The best would be the local instance to refuse any unwanted updates, and tell the remote to stop pushing these unsolicited uodates. It would be safer, more robust and less detrimental for both server's resources.

Version

0.18.1

Lemmy Instance URL

michelsup.org

Originally posted by michelsup in #3568

2 comments

I like the idea. It would be useful for an instance admin to be able to tell a remote instance to wipe all subscribers and stop sending updates to it. I thought that the allow/block lists in federation settings would do that but from reading logs they only locally reject the updates

Originally posted by MagsMagnoli in #3568
Confirming that removed communities without any subscribers still receive posts and comments. The remove options only seems to hide the community from non-mods/admin.

Is there a way to tell remote instances to stop pushing updates no longer needed until that is fixed?

I even tried a fresh lemmy install, but the "stuck" communities begin populating immediately.

Originally posted by Jasdemi in #3568