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https://github.com/reugn/equalizer

A set of performant rate limiters for Go
https://github.com/reugn/equalizer

api quota quotas rate rate-limit rate-limiter rate-limiting ratelimit ratelimiter sliding-window throttle throttler throttling tokenbucket

Last synced: 24 days ago
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A set of performant rate limiters for Go

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equalizer




  

  

  

  



A rate limiters package for Go.



Pick one of the rate limiters to throttle requests and control quota.

* [Equalizer](#equalizer)

* [Slider](#slider)

* [TokenBucket](#tokenbucket)



## Equalizer

`Equalizer` is a rate limiter that manages quota based on previous requests' statuses and slows down or accelerates accordingly.



### Usage

```go

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

```sh

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

```go

// 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

```sh

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

```go

// 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

```sh

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.