Lorri hangs; logs: Too many open files

[nyarly]

Describe the bug

Periodically, Lorri will hang, without returning anything to requests (which e.g. blocks my shell prompt :/).

Logs report INFO Failed accepting a client connection, accept_error: Accept(Os { code: 24, kind: Uncategorized, message: "Too many open files" })

To Reproduce

Run Lorri long enough (? 48 hours)
lorri internal stream-events --kind snapshot
never returns.

Expected behavior

Lorri should have accept_errors

$ lorri info --shell-file shell.nix
lorri version: 1.5
GC roots exist, shell_gc_root: /home/judson/.cache/lorri/gc_roots/c92f309c54f033fb255ee1e6878ad199/gc_root/shell_gc_root

$ uname -a
Linux neumann 5.10.94 #1-NixOS SMP Thu Jan 27 09:54:36 UTC 2022 x86_64 GNU/Linux

[nyarly]

Part of the fix here would be to have stream-events time out after ~100ms (or wrap my call to it in a timeout...),
but I worry that the error may suggest that Lorri isn't building either.

[sersorrel]

glad I'm not the only one running into this! I thought this was caused by me running lorri internal stream-events --kind snapshot on every prompt, rather than strictly a time-based thing, but I don't actually know if that's the case.

[Profpatsch]

I think this was caused by us not closing the unix socket after accepting a request in the daemon.

I added code to manually close the connection after each .accept() to #146

I think you can try to reproduce by running a tight loop around stream-events --kind snapshot and checking the open fds with lsof.