mirror of
https://github.com/k3s-io/kubernetes.git
synced 2025-10-31 13:50:01 +00:00
6b3a6e6b98
Instead of saying "Google Inc." (which is not always correct) say "The Kubernetes Authors", which is generic.
126 lines
2.9 KiB
Go
126 lines
2.9 KiB
Go
/*
|
|
Copyright 2014 The Kubernetes Authors All rights reserved.
|
|
|
|
Licensed under the Apache License, Version 2.0 (the "License");
|
|
you may not use this file except in compliance with the License.
|
|
You may obtain a copy of the License at
|
|
|
|
http://www.apache.org/licenses/LICENSE-2.0
|
|
|
|
Unless required by applicable law or agreed to in writing, software
|
|
distributed under the License is distributed on an "AS IS" BASIS,
|
|
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
See the License for the specific language governing permissions and
|
|
limitations under the License.
|
|
*/
|
|
|
|
package util
|
|
|
|
import (
|
|
"sync"
|
|
"time"
|
|
)
|
|
|
|
type RateLimiter interface {
|
|
// CanAccept returns true if the rate is below the limit, false otherwise
|
|
CanAccept() bool
|
|
// Accept returns once a token becomes available.
|
|
Accept()
|
|
// Stop stops the rate limiter, subsequent calls to CanAccept will return false
|
|
Stop()
|
|
}
|
|
|
|
type tickRateLimiter struct {
|
|
lock sync.Mutex
|
|
tokens chan bool
|
|
ticker <-chan time.Time
|
|
stop chan bool
|
|
}
|
|
|
|
// NewTokenBucketRateLimiter creates a rate limiter which implements a token bucket approach.
|
|
// The rate limiter allows bursts of up to 'burst' to exceed the QPS, while still maintaining a
|
|
// smoothed qps rate of 'qps'.
|
|
// The bucket is initially filled with 'burst' tokens, the rate limiter spawns a go routine
|
|
// which refills the bucket with one token at a rate of 'qps'. The maximum number of tokens in
|
|
// the bucket is capped at 'burst'.
|
|
// When done with the limiter, Stop() must be called to halt the associated goroutine.
|
|
func NewTokenBucketRateLimiter(qps float32, burst int) RateLimiter {
|
|
ticker := time.Tick(time.Duration(float32(time.Second) / qps))
|
|
rate := newTokenBucketRateLimiterFromTicker(ticker, burst)
|
|
go rate.run()
|
|
return rate
|
|
}
|
|
|
|
type fakeRateLimiter struct{}
|
|
|
|
func NewFakeRateLimiter() RateLimiter {
|
|
return &fakeRateLimiter{}
|
|
}
|
|
|
|
func newTokenBucketRateLimiterFromTicker(ticker <-chan time.Time, burst int) *tickRateLimiter {
|
|
if burst < 1 {
|
|
panic("burst must be a positive integer")
|
|
}
|
|
rate := &tickRateLimiter{
|
|
tokens: make(chan bool, burst),
|
|
ticker: ticker,
|
|
stop: make(chan bool),
|
|
}
|
|
for i := 0; i < burst; i++ {
|
|
rate.tokens <- true
|
|
}
|
|
return rate
|
|
}
|
|
|
|
func (t *tickRateLimiter) CanAccept() bool {
|
|
select {
|
|
case <-t.tokens:
|
|
return true
|
|
default:
|
|
return false
|
|
}
|
|
}
|
|
|
|
// Accept will block until a token becomes available
|
|
func (t *tickRateLimiter) Accept() {
|
|
<-t.tokens
|
|
}
|
|
|
|
func (t *tickRateLimiter) Stop() {
|
|
close(t.stop)
|
|
}
|
|
|
|
func (r *tickRateLimiter) run() {
|
|
for {
|
|
if !r.step() {
|
|
break
|
|
}
|
|
}
|
|
}
|
|
|
|
func (r *tickRateLimiter) step() bool {
|
|
select {
|
|
case <-r.ticker:
|
|
r.increment()
|
|
return true
|
|
case <-r.stop:
|
|
return false
|
|
}
|
|
}
|
|
|
|
func (t *tickRateLimiter) increment() {
|
|
// non-blocking send
|
|
select {
|
|
case t.tokens <- true:
|
|
default:
|
|
}
|
|
}
|
|
|
|
func (t *fakeRateLimiter) CanAccept() bool {
|
|
return true
|
|
}
|
|
|
|
func (t *fakeRateLimiter) Stop() {}
|
|
|
|
func (t *fakeRateLimiter) Accept() {}
|