README.md

Go rate limiter

This package provides a Golang implementation of the leaky-bucket rate limit algorithm. This implementation refills the bucket based on the time elapsed between requests instead of requiring an interval clock to fill the bucket discretely.

Create a rate limiter with a maximum number of operations to perform per second. Call Take() before each operation. Take will sleep until you can continue.

import (
	"fmt"
	"time"

	"go.uber.org/ratelimit"
)

func main() {
    rl := ratelimit.New(100) // per second

    prev := time.Now()
    for i := 0; i < 10; i++ {
        now := rl.Take()
        fmt.Println(i, now.Sub(prev))
        prev = now
    }

    // Output:
    // 0 0
    // 1 10ms
    // 2 10ms
    // 3 10ms
    // 4 10ms
    // 5 10ms
    // 6 10ms
    // 7 10ms
    // 8 10ms
    // 9 10ms
}

FAQ:

• What's the major diff v.s. https://pkg.go.dev/golang.org/x/time/rate? (based on #77)

  This ratelimiter was meant to have a (1) simple API and (2) minimal overhead. For more complex use-cases x/time/rate is a great choice. See here for historical context, and here for benchmarks (from 2016).

• Why does example_test.go fail when I run it locally on Windows? (based on #80)

  Windows has some known issues with timers precision. See golang/go#44343. We don't expect to work around it.