PegasusWang/ratelimit

Distributed rate limit library based on Redis

Distributed rate-limit library based on Redis

---

Overview

The goal of this library is to be able to implement distributed rate limit functions simply and rudely. Similar to the usage of the ID generator, the client takes back the data from Redis - batch data (just a value here), as long as it Is not consumed.it doesn't exceed rate-limit.

• 中文 README

Advantage

• Less dependencies, only rely on Redis, no special services required
• use Redis own clock, The clients no need to have the same clock
• Thread (coroutine) security
• Low system overhead and little pressure on redis

How to get

go get github.com/vearne/ratelimit

Usage

1. create redis.Client

with "github.com/go-redis/redis"
Supports both redis master-slave mode and cluster mode

	client := redis.NewClient(&redis.Options{
		Addr:     "localhost:6379",
		Password: "xxx", // no password set
		DB:       0,  // use default DB
	})

	client := redis.NewClusterClient(&redis.ClusterOptions{
		Addrs:    []string{"127.0.0.1:6379"},
		Password: "xxxx",
	})

2. create RateLimiter

limiter, err := ratelimit.NewTokenBucketRateLimiter(client,                
        "push", time.Second, 200, 20, 5)

Indicates that 200 operations per second are allowed

limiter, err := ratelimit.NewTokenBucketRateLimiter(client,                
        "push", time.Minute, 200, 20, 5)

Support multiple algorithms

2.1 Counter algorithm

func NewCounterRateLimiter(client redis.Cmdable, key string, duration time.Duration,
	throughput int,
	batchSize int) (Limiter, error)

parameter	Description
key	Key in Redis
duration	Indicates that the operation throughput is allowed in the duration time interval
throughput	Indicates that the operation throughput is allowed in the duration time interval
batchSize	The number of available operations each time retrieved from redis

2.2 Token bucket algorithm

func NewTokenBucketRateLimiter(client redis.Cmdable, key string, duration time.Duration,
	throughput int, maxCapacity int,
	batchSize int) (Limiter, error)

parameter	Description
key	Key in Redis
duration	Indicates that the operation throughput is allowed in the duration time interval
throughput	Indicates that the operation throughput is allowed in the duration time interval
maxCapacity	The maximum number of tokens that can be stored in the token bucket
batchSize	The number of available operations each time retrieved from redis

2.3 Leaky bucket algorithm

func NewLeakyBucketLimiter(client redis.Cmdable, key string, duration time.Duration,
	throughput int) (Limiter, error)

parameter	Description
key	Key in Redis
duration	Indicates that the operation throughput is allowed in the duration time interval
throughput	Indicates that the operation throughput is allowed in the duration time interval

Complete example

package main

import (
	"fmt"
	"github.com/go-redis/redis"
	"github.com/vearne/ratelimit"
	"math/rand"
	"sync"
	"time"
)

func consume(r *ratelimit.RedisRateLimiter, group *sync.WaitGroup) {
	for {
		if r.Take() {
			group.Done()
		} else {
			time.Sleep(time.Duration(rand.Intn(10)+1) * time.Millisecond)
		}
	}
}

func main() {
	client := redis.NewClient(&redis.Options{
		Addr: "localhost:6379",
		Password: "xxxxx", // password set
		DB: 0, // use default DB
	})

	limiter, _ := ratelimit.NewRedisRateLimiter(client,
		"push",
		1*time.Second,
		500,
		10,
		//ratelimit.CounterAlg,
		ratelimit.TokenBucketAlg,
	)

	var wg sync.WaitGroup
	total := 5000
	wg.Add(total)
	start := time.Now()
	for i := 0; i < 100; i++ {
		go consume(limiter, &wg)
	}
	wg.Wait()
	cost := time.Since(start)
	fmt.Println("cost", time.Since(start), "rate", float64(total)/cost.Seconds())
}

Dependency

go-redis/redis

Thanks

The development of the module was inspired by the Reference 1.

Reference

1. Performance million/s: Tencent lightweight global flow control program

Thanks