56 lines
1.2 KiB
Go
56 lines
1.2 KiB
Go
// Copyright 2017 Google Inc.
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//
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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//
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package util
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// Limiter is a simple keyed rate limiter.
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type Limiter struct {
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stamp map[string]float64
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}
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// NewLimiter returns a new, initialised limiter.
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func NewLimiter() *Limiter {
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return &Limiter{
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stamp: make(map[string]float64),
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}
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}
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// Ok returns true if at least dt seconds have passed since the last
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// time this function returned true.
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func (l *Limiter) Ok(key string, dt float64) bool {
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now := Now()
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stamp, ok := l.stamp[key]
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if !ok {
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l.stamp[key] = now
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return true
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}
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elapsed := now - stamp
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if elapsed < dt {
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return false
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}
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if elapsed < 2*dt {
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l.stamp[key] = stamp + dt
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} else {
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l.stamp[key] = now
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}
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return true
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}
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