45 lines
1.1 KiB
Go
45 lines
1.1 KiB
Go
// Copyright (C) 2021 Storj Labs, Inc.
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// See LICENSE for copying information.
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package contact
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import (
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"fmt"
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"time"
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"golang.org/x/time/rate"
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"storj.io/common/lrucache"
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)
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// RateLimiter allows to prevent multiple events in fixed period of time.
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type RateLimiter struct {
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limiters *lrucache.ExpiringLRU
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interval time.Duration // interval during which events are not limiting.
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burst int // maximum number of events allowed during duration.
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}
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// NewRateLimiter is a constructor for RateLimiter.
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func NewRateLimiter(interval time.Duration, burst, numLimits int) *RateLimiter {
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return &RateLimiter{
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limiters: lrucache.New(lrucache.Options{Expiration: -1, Capacity: numLimits}),
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interval: interval,
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burst: burst,
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}
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}
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// IsAllowed indicates if event is allowed to happen.
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func (rateLimiter *RateLimiter) IsAllowed(key string) bool {
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limiter, err := rateLimiter.limiters.Get(key, func() (interface{}, error) {
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return rate.NewLimiter(
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rate.Limit(time.Second)/rate.Limit(rateLimiter.interval),
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rateLimiter.burst,
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), nil
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})
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if err != nil {
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panic(fmt.Sprintf("unreachable: %+v", err))
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}
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return limiter.(*rate.Limiter).Allow()
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}
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