91 lines
2.2 KiB
Go
91 lines
2.2 KiB
Go
/*
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* owobot - Your server's guardian and entertainer
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* Copyright (C) 2023 owobot Contributors
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*
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* This program is free software: you can redistribute it and/or modify
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* it under the terms of the GNU Affero General Public License as published by
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* the Free Software Foundation, either version 3 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU Affero General Public License for more details.
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*
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* You should have received a copy of the GNU Affero General Public License
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* along with this program. If not, see <https://www.gnu.org/licenses/>.
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*/
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package limiter
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import (
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"sync"
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"time"
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)
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// Limiter is a token bucket rate limiter
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type Limiter struct {
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TotalAmt int
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WarnAmt int
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Duration time.Duration
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mu sync.Mutex
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tokens map[string]int
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}
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// New returns a new limiter with the given parameters
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func New(warnAmt, totalAmt int, duration time.Duration) *Limiter {
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limiter := &Limiter{
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TotalAmt: totalAmt,
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WarnAmt: warnAmt,
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Duration: duration,
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tokens: map[string]int{},
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}
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go limiter.resetTokens()
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return limiter
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}
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// Decrement removes one token from the bucket with the given key
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func (l *Limiter) Decrement(key string) {
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l.mu.Lock()
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defer l.mu.Unlock()
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tokenAmt, ok := l.tokens[key]
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if ok {
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l.tokens[key] = tokenAmt - 1
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} else {
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l.tokens[key] = l.TotalAmt - 1
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}
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}
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// IsWarning returns true if the token amount equals the warn amount of l.
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func (l *Limiter) IsWarning(key string) bool {
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l.mu.Lock()
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defer l.mu.Unlock()
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tokenAmt, ok := l.tokens[key]
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if !ok {
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return false
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}
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return tokenAmt > 0 && tokenAmt <= (l.TotalAmt-l.WarnAmt)
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}
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// IsWarning returns true if the token amount for the given key is depleted.
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func (l *Limiter) IsDepleted(key string) bool {
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l.mu.Lock()
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defer l.mu.Unlock()
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tokenAmt, ok := l.tokens[key]
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if !ok {
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return false
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}
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return tokenAmt <= 0
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}
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// resetTokens resets all the token buckets at a regular interval
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func (l *Limiter) resetTokens() {
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for {
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l.mu.Lock()
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l.tokens = map[string]int{}
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l.mu.Unlock()
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time.Sleep(l.Duration)
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}
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}
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