mirror of
https://github.com/ceph/ceph-csi.git
synced 2024-12-21 04:20:23 +00:00
144 lines
3.4 KiB
Go
144 lines
3.4 KiB
Go
/*
|
|
Copyright 2014 The Kubernetes Authors.
|
|
|
|
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 flowcontrol
|
|
|
|
import (
|
|
"sync"
|
|
"time"
|
|
|
|
"golang.org/x/time/rate"
|
|
)
|
|
|
|
type RateLimiter interface {
|
|
// TryAccept returns true if a token is taken immediately. Otherwise,
|
|
// it returns false.
|
|
TryAccept() bool
|
|
// Accept returns once a token becomes available.
|
|
Accept()
|
|
// Stop stops the rate limiter, subsequent calls to CanAccept will return false
|
|
Stop()
|
|
// QPS returns QPS of this rate limiter
|
|
QPS() float32
|
|
}
|
|
|
|
type tokenBucketRateLimiter struct {
|
|
limiter *rate.Limiter
|
|
clock Clock
|
|
qps float32
|
|
}
|
|
|
|
// 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, and refills at a rate of 'qps'.
|
|
// The maximum number of tokens in the bucket is capped at 'burst'.
|
|
func NewTokenBucketRateLimiter(qps float32, burst int) RateLimiter {
|
|
limiter := rate.NewLimiter(rate.Limit(qps), burst)
|
|
return newTokenBucketRateLimiter(limiter, realClock{}, qps)
|
|
}
|
|
|
|
// An injectable, mockable clock interface.
|
|
type Clock interface {
|
|
Now() time.Time
|
|
Sleep(time.Duration)
|
|
}
|
|
|
|
type realClock struct{}
|
|
|
|
func (realClock) Now() time.Time {
|
|
return time.Now()
|
|
}
|
|
func (realClock) Sleep(d time.Duration) {
|
|
time.Sleep(d)
|
|
}
|
|
|
|
// NewTokenBucketRateLimiterWithClock is identical to NewTokenBucketRateLimiter
|
|
// but allows an injectable clock, for testing.
|
|
func NewTokenBucketRateLimiterWithClock(qps float32, burst int, c Clock) RateLimiter {
|
|
limiter := rate.NewLimiter(rate.Limit(qps), burst)
|
|
return newTokenBucketRateLimiter(limiter, c, qps)
|
|
}
|
|
|
|
func newTokenBucketRateLimiter(limiter *rate.Limiter, c Clock, qps float32) RateLimiter {
|
|
return &tokenBucketRateLimiter{
|
|
limiter: limiter,
|
|
clock: c,
|
|
qps: qps,
|
|
}
|
|
}
|
|
|
|
func (t *tokenBucketRateLimiter) TryAccept() bool {
|
|
return t.limiter.AllowN(t.clock.Now(), 1)
|
|
}
|
|
|
|
// Accept will block until a token becomes available
|
|
func (t *tokenBucketRateLimiter) Accept() {
|
|
now := t.clock.Now()
|
|
t.clock.Sleep(t.limiter.ReserveN(now, 1).DelayFrom(now))
|
|
}
|
|
|
|
func (t *tokenBucketRateLimiter) Stop() {
|
|
}
|
|
|
|
func (t *tokenBucketRateLimiter) QPS() float32 {
|
|
return t.qps
|
|
}
|
|
|
|
type fakeAlwaysRateLimiter struct{}
|
|
|
|
func NewFakeAlwaysRateLimiter() RateLimiter {
|
|
return &fakeAlwaysRateLimiter{}
|
|
}
|
|
|
|
func (t *fakeAlwaysRateLimiter) TryAccept() bool {
|
|
return true
|
|
}
|
|
|
|
func (t *fakeAlwaysRateLimiter) Stop() {}
|
|
|
|
func (t *fakeAlwaysRateLimiter) Accept() {}
|
|
|
|
func (t *fakeAlwaysRateLimiter) QPS() float32 {
|
|
return 1
|
|
}
|
|
|
|
type fakeNeverRateLimiter struct {
|
|
wg sync.WaitGroup
|
|
}
|
|
|
|
func NewFakeNeverRateLimiter() RateLimiter {
|
|
rl := fakeNeverRateLimiter{}
|
|
rl.wg.Add(1)
|
|
return &rl
|
|
}
|
|
|
|
func (t *fakeNeverRateLimiter) TryAccept() bool {
|
|
return false
|
|
}
|
|
|
|
func (t *fakeNeverRateLimiter) Stop() {
|
|
t.wg.Done()
|
|
}
|
|
|
|
func (t *fakeNeverRateLimiter) Accept() {
|
|
t.wg.Wait()
|
|
}
|
|
|
|
func (t *fakeNeverRateLimiter) QPS() float32 {
|
|
return 1
|
|
}
|