Leaky-bucket rate-limiting with Redis

go-redis/redis_rateopen in new window library implements a leaky bucket scheduling algorithm (AKA generic cell rate algorithm). You can install it with:

go get github.com/go-redis/redis_rate/v10

redis_rate accepts an interface to communicate with Redis and thus supports all flavors of go-redis clients.

rdb := redis.NewClient(&redis.Options{ Addr: "localhost:6379", }) limiter := redis_rate.NewLimiter(rdb) res, err := limiter.Allow(ctx, "project:123", redis_rate.PerSecond(10)) if err != nil { panic(err) } fmt.Println("allowed", res.Allowed, "remaining", res.Remaining)

The following example demonstrates how to use redis_rate in a bunrouteropen in new window middleware for HTTP rate limiting:

func rateLimit(next bunrouter.HandlerFunc) bunrouter.HandlerFunc { return func(w http.ResponseWriter, req bunrouter.Request) error { res, err := limiter.Allow(req.Context(), "project:123", redis_rate.PerMinute(10)) if err != nil { return err } h := w.Header() h.Set("RateLimit-Remaining", strconv.Itoa(res.Remaining)) if res.Allowed == 0 { // We are rate limited. seconds := int(res.RetryAfter / time.Second) h.Set("RateLimit-RetryAfter", strconv.Itoa(seconds)) // Stop processing and return the error. return ErrRateLimited } // Continue processing as normal. return next(w, req) } }