equalizer
A rate limiters package for Go.
Pick one of the rate limiters to throttle requests and control quota.
Equalizer
Equalizer is a rate limiter that manages quota based on previous requests' statuses and slows down or accelerates accordingly.
Usage
offset := equalizer.NewRandomOffset(96)
// an Equalizer with the bitmap size of 96 with 16 reserved
// positive bits and the random offset manager
eq := equalizer.NewEqualizer(96, 16, offset)
// non-blocking quota request
haveQuota := eq.Ask()
// update with ten previous successful requests
eq.Notify(true, 10)
Benchmarks
BenchmarkEqualizerShortAskStep-16 30607452 37.5 ns/op 0 B/op 0 allocs/op
BenchmarkEqualizerShortAskRandom-16 31896340 34.5 ns/op 0 B/op 0 allocs/op
BenchmarkEqualizerShortNotify-16 12715494 81.9 ns/op 0 B/op 0 allocs/op
BenchmarkEqualizerLongAskStep-16 34627239 35.4 ns/op 0 B/op 0 allocs/op
BenchmarkEqualizerLongAskRandom-16 32399748 34.0 ns/op 0 B/op 0 allocs/op
BenchmarkEqualizerLongNotify-16 59935 20343 ns/op 0 B/op 0 allocs/op
Slider
Slider rate limiter is based on a sliding window with a specified quota capacity. Implements the Limiter interface.
Usage
// a Slider with one second window size, 100 millis sliding interval
// and the capacity of 32
slider := equalizer.NewSlider(time.Second, time.Millisecond*100, 32)
// non-blocking quota request
haveQuota := slider.Ask()
// blocking call
slider.Take()
Benchmarks
BenchmarkSliderShortWindow-16 123488035 9.67 ns/op 0 B/op 0 allocs/op
BenchmarkSliderLongerWindow-16 128023276 9.76 ns/op 0 B/op 0 allocs/op
TokenBucket
TokenBucket rate limiter is based on the token bucket algorithm with a refill interval. Implements the Limiter interface.
Usage
// a TokenBucket with the capacity of 32 and 100 millis refill interval
tokenBucket := equalizer.NewTokenBucket(32, time.Millisecond*100)
// non-blocking quota request
haveQuota := tokenBucket.Ask()
// blocking call
tokenBucket.Take()
Benchmarks
BenchmarkTokenBucketDenseRefill-16 212631714 5.64 ns/op 0 B/op 0 allocs/op
BenchmarkTokenBucketSparseRefill-16 211491368 5.63 ns/op 0 B/op 0 allocs/op
License
Licensed under the MIT License.
