utils/limiter.go

package utils

import (
	"sync"

	"golang.org/x/time/rate"
)

type RateLimiter struct {
	ips map[interface{}]*rate.Limiter
	mu  *sync.RWMutex
	r   rate.Limit
	b   int
}

func NewRateLimiter(r rate.Limit, b int) *RateLimiter {
	i := &RateLimiter{
		ips: make(map[interface{}]*rate.Limiter),
		mu:  &sync.RWMutex{},
		r:   r,
		b:   b,
	}

	return i
}

func (i *RateLimiter) AddIP(ip interface{}) *rate.Limiter {
	i.mu.Lock()
	defer i.mu.Unlock()

	limiter := rate.NewLimiter(i.r, i.b)

	i.ips[ip] = limiter

	return limiter
}

func (i *RateLimiter) GetLimiter(ip interface{}) *rate.Limiter {
	i.mu.Lock()
	limiter, exists := i.ips[ip]

	if !exists {
		i.mu.Unlock()
		return i.AddIP(ip)
	}

	i.mu.Unlock()

	return limiter
}