Atomic token bucket

A basic rate limiting / traffic shaping element. Validated using shuttle.

The basic primitive is TokenBucket which provides ability to limit rate of certain events, while allowing bursts through. More advanced KeyedRateLimiter allows to rate-limit multiple keyed items, such as connections.

Cargo features

• keyed_rate_limiter: enables the keyed rate limiter, adds dep on dashmap
• shuttle-test: needed for shuttle tests

FAQ

• Is this fast enough? Yes.
• Is this safe? Verified with shuttle.
• Is this lock-free?
  • TokenBucket is lock-free.
  • KeyedRateLimiter uses sharded hashmap when new keys are added, and is otherwise lock-free.

Benches

cargo bench

Testing with shuttle

cargo test -F shuttle-test shuttle_test_token_bucket_race

Credits:

• https://github.com/vadorovsky
• https://github.com/alexpyattaev