[#13] Redis INCR/EXPIRE race can permanently block an IP

[utksh1]

rate_limiter.py: INCR then EXPIRE are not atomic; if EXPIRE is lost (Redis reconnect) the counter key persists forever with no TTL, permanently blocking the IP (DoS).

Fix: use INCR with EXPIRE only when TTL is -1, or a single SET ... NX EX command.

[utksh1]

Hey @ANU-2524, this issue matches your skills. Would you like to take it on? Comment below and I'll assign it to you once you accept the collaborator invite.

[tanishka-kuwar]

Hi @utksh1!

I'd like to work on fixing the atomic Redis INCR/EXPIRE race condition in rate_limiter.py. Could you please assign issue #1759 to me?

Thanks!