amocrm/internal/workers/limiter/limiter.go

package limiter

import (
	"context"
	"sync"
	"time"
)

type RateLimiter struct {
	requests    chan struct{}
	done        chan struct{}
	maxRequests int
	Interval    time.Duration
	mutex       sync.Mutex
}

func NewRateLimiter(ctx context.Context, maxRequests int, interval time.Duration) *RateLimiter {
	limiter := &RateLimiter{
		requests:    make(chan struct{}, maxRequests),
		done:        make(chan struct{}),
		maxRequests: maxRequests,
		Interval:    interval,
	}

	go limiter.start(ctx)
	return limiter
}

func (limiter *RateLimiter) start(ctx context.Context) {
	ticker := time.NewTicker(limiter.Interval)
	defer ticker.Stop()

	for {
		select {
		case <-ticker.C:
			limiter.mutex.Lock()
			for i := 0; i < len(limiter.requests); i++ {
				<-limiter.requests
			}
			limiter.mutex.Unlock()
		case <-ctx.Done():
			return
		}
	}
}

func (limiter *RateLimiter) Check() bool {
	select {
	case limiter.requests <- struct{}{}:
		return true
	default:
		return false
	}
}

func (limiter *RateLimiter) Stop(_ context.Context) error {
	return nil
}