Rate Limiting

Simple Implementation

• git/playground/rate-limit
• git/playground/rate-limiting-service

Open Source Projects

There are some open source libraries which could help do the rate limiting.

Doorman

https://github.com/youtube/doorman/tree/master/doc/loadtest

It is used in this scenario: there is a service (RPC, REST, HTTP, .etc) having limited capacity. And you have lots of clients sending requests to the service.

It starts a doorman server. And all the clients ask for limits before sending requests to the target.

Multiple instances of doorman server could be set up to avoid single point of failure, for example, we would run 3 replicas of doorman server in Kubernetes cluster and they would user etcd to elect a leader among themselves.

Traefik

Traefik is a HTTP reverse proxy and load balancer which creates and updates the routers automatically.

You could configure a middleware named rate limiter in Traefik.

https://github.com/containous/traefik/blob/master/pkg/middlewares/ratelimiter/rate_limiter.go

Each request reaches the Traefik and goes through the rate limiter for throttling and then is forwarded to the real target.