ratelimit

ratelimit is a Go package that provides common rate limiting algorithms. It supports various rate limiting strategies including fixed window, max concurrency, and throttling.

Features

• Fixed Window Rate Limiter: Limits the number of requests in a fixed time window.
• Max Concurrency Rate Limiter: Limits the number of concurrent requests.
• Throttle Rate Limiter: Ensures a minimum time interval between requests.

Installation

To install the package, run:

go get github.com/ericxiao417/ratelimit

Usage

Fixed Window Rate Limiter

The Fixed Window Rate Limiter limits the number of requests in a fixed time window.

package main

import (
	"time"
	"github.com/ericxiao417/ratelimit"
)

func main() {
	r, err := ratelimit.NewFixedWindowRateLimiter(&ratelimit.Config{
		Limit:         5,
		FixedInterval: 15 * time.Second,
	})

	if err != nil {
		panic(err)
	}

	ratelimit.DoWork(r, 10)
}

Max Concurrency Rate Limiter

The Max Concurrency Rate Limiter limits the number of concurrent requests.

package main

import (
	"time"
	"github.com/ericxiao417/ratelimit"
)

func main() {
	r, err := ratelimit.NewMaxConcurrencyRateLimiter(&ratelimit.Config{
		Limit:            4,
		TokenResetsAfter: 10 * time.Second,
	})

	if err != nil {
		panic(err)
	}

	ratelimit.DoWork(r, 10)
}

Throttle Rate Limiter

The Throttle Rate Limiter ensures a minimum time interval between requests.

package main

import (
	"time"
	"github.com/ericxiao417/ratelimit"
)

func main() {
	r, err := ratelimit.NewThrottleRateLimiter(&ratelimit.Config{
		Throttle: 1 * time.Second,
	})

	if err != nil {
		panic(err)
	}

	ratelimit.DoWork(r, 10)
}

Configuration

The Config struct is used to configure the rate limiters:

type Config struct {
	// Limit determines how many rate limit tokens can be active at a time
	Limit int

	// FixedInterval sets the fixed time window for a Fixed Window Rate Limiter
	FixedInterval time.Duration

	// Throttle is the min time between requests for a Throttle Rate Limiter
	Throttle time.Duration

	// TokenResetsAfter is the maximum amount of time a token can live before being
	// forcefully released - if set to zero time then the token may live forever
	TokenResetsAfter time.Duration
}

Error Handling

The package defines several errors that can be used for error handling:

var (
	ErrInvalidLimit           = errors.New("Limit must be greater than zero")
	ErrInvalidInterval        = errors.New("Interval must be greater than zero")
	ErrTokenFactoryNotDefined = errors.New("Token factory must be defined")
)

License

This project is licensed under the MIT License - see the LICENSE file for details.

Contributing

Contributions are welcome! Please open an issue or submit a pull request for any improvements or bug fixes.

Acknowledgements

This package was created by ericxiao417.

References

• GoDoc