[WIP] feat: add limiter

go.mod

@@ -0,0 +1,40 @@
+module github.com/cloudwego-contrib/cwgo-pkg
+
+go 1.21
+
+require (
+	github.com/c9s/goprocinfo v0.0.0-20210130143923-c95fcf8c64a8
+	github.com/cloudwego/hertz v0.9.2
+	github.com/hertz-contrib/limiter v0.0.0-20221008063035-ad27db7cc386
+	github.com/stretchr/testify v1.8.2
+)
+
+require (
+	github.com/bytedance/go-tagexpr/v2 v2.9.2 // indirect
+	github.com/bytedance/gopkg v0.0.0-20240514070511-01b2cbcf35e1 // indirect
+	github.com/bytedance/sonic v1.11.8 // indirect
+	github.com/bytedance/sonic/loader v0.1.1 // indirect
+	github.com/cloudwego/base64x v0.1.4 // indirect
+	github.com/cloudwego/iasm v0.2.0 // indirect
+	github.com/cloudwego/netpoll v0.6.3 // indirect
+	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
+	github.com/fsnotify/fsnotify v1.5.4 // indirect
+	github.com/golang/protobuf v1.5.2 // indirect
+	github.com/google/go-cmp v0.5.7 // indirect
+	github.com/henrylee2cn/ameda v1.4.10 // indirect
+	github.com/henrylee2cn/goutil v0.0.0-20210127050712-89660552f6f8 // indirect
+	github.com/klauspost/cpuid/v2 v2.2.4 // indirect
+	github.com/kr/pretty v0.1.0 // indirect
+	github.com/nyaruka/phonenumbers v1.0.55 // indirect
+	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/tidwall/gjson v1.14.4 // indirect
+	github.com/tidwall/match v1.1.1 // indirect
+	github.com/tidwall/pretty v1.2.0 // indirect
+	github.com/twitchyliquid64/golang-asm v0.15.1 // indirect
+	golang.org/x/arch v0.2.0 // indirect
+	golang.org/x/sys v0.13.0 // indirect
+	golang.org/x/xerrors v0.0.0-20200804184101-5ec99f83aff1 // indirect
+	google.golang.org/protobuf v1.28.1 // indirect
+	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect
+	gopkg.in/yaml.v3 v3.0.1 // indirect
+)

limiter/bbr.go

@@ -0,0 +1,250 @@
+/*
+ * Copyright 2022 CloudWeGo 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 limiter
+
+import (
+	"errors"
+	"github.com/cloudwego-contrib/cwgo-pkg/limiter/internal/utils"
+	"math"
+	"sync/atomic"
+	"time"
+
+	"github.com/c9s/goprocinfo/linux"
+)
+
+var (
+	gCPU     int64
+	gStat    linux.CPUStat
+	ErrLimit = "Hertz Adaptive Limit"
+)
+
+type (
+	cpuGetter func() int64
+)
+
+// getCpuLoad  get CPU state by reading /proc/stat
+func getCpuLoad() linux.CPUStat {
+	stat, err := linux.ReadStat("/proc/stat")
+	if err != nil {
+		panic("stat read fail")
+	}
+	return stat.CPUStatAll
+}
+
+// calcCoreUsage calculate the overall utilization by reading the previous CPU state and the current CPU state
+func calcCoreUsage(curr, prev linux.CPUStat) float64 {
+	PrevIdle := prev.Idle + prev.IOWait
+	Idle := curr.Idle + curr.IOWait
+
+	PrevNonIdle := prev.User + prev.Nice + prev.System + prev.IRQ + prev.SoftIRQ + prev.Steal
+	NonIdle := curr.User + curr.Nice + curr.System + curr.IRQ + curr.SoftIRQ + curr.Steal
+
+	PrevTotal := PrevIdle + PrevNonIdle
+	Total := Idle + NonIdle
+	totald := Total - PrevTotal
+	idled := Idle - PrevIdle
+
+	CPU_Percentage := (float64(totald) - float64(idled)) / float64(totald)
+
+	return CPU_Percentage
+}
+
+func init() {
+	go cpuProc()
+}
+
+// cpuProc  CPU load correction by EMA algorithm
+func cpuProc() {
+	ticker := time.NewTicker(opt.SamplingTime) // same to cpu sample rate
+	defer func() {
+		ticker.Stop()
+		if err := recover(); err != nil {
+			go cpuProc()
+		}
+	}()
+
+	// EMA algorithm: https://blog.csdn.net/m0_38106113/article/details/81542863
+	for range ticker.C {
+		preState := gStat
+		curState := getCpuLoad()
+		usage := calcCoreUsage(preState, curState)
+		prevCPU := atomic.LoadInt64(&gCPU)
+		curCPU := int64(float64(prevCPU)*opt.Decay + float64(usage*10)*(1.0-opt.Decay))
+		atomic.StoreInt64(&gCPU, curCPU)
+	}
+}
+
+// counterCache is used to cache maxPASS and minRt result.
+type counterCache struct {
+	val  int64
+	time time.Time
+}
+
+// BBR implements bbr-like limiter.It is inspired by sentinel.
+// https://github.com/alibaba/Sentinel/wiki/%E7%B3%BB%E7%BB%9F%E8%87%AA%E9%80%82%E5%BA%94%E9%99%90%E6%B5%81
+type BBR struct {
+	cpu             cpuGetter
+	passStat        *utils.RollingWindow // request succeeded
+	rtStat          *utils.RollingWindow // time consume
+	inFlight        int64                // Number of requests being processed
+	bucketPerSecond int64
+	bucketDuration  time.Duration
+
+	// prevDropTime defines previous start drop since initTime
+	prevDropTime atomic.Value
+	maxPASSCache atomic.Value
+	minRtCache   atomic.Value
+
+	opts options
+}
+
+func NewLimiter(opts ...Option) *BBR {
+	opt := NewOption(opts...)
+	bucketDuration := opt.Window / time.Duration(opt.Bucket)
+	// 10s / 100  = 100ms
+	passStat := utils.NewRollingWindow(opt.Bucket, bucketDuration, utils.IgnoreCurrentBucket())
+	rtStat := utils.NewRollingWindow(opt.Bucket, bucketDuration, utils.IgnoreCurrentBucket())
+
+	limiter := &BBR{
+		opts:            opt,
+		passStat:        passStat,
+		rtStat:          rtStat,
+		bucketDuration:  bucketDuration,
+		bucketPerSecond: int64(time.Second / bucketDuration),
+		cpu:             func() int64 { return atomic.LoadInt64(&gCPU) },
+	}
+
+	return limiter
+}
+
+// maxPass maximum number of requests in a single sampling window
+func (l *BBR) maxPass() int64 {
+	passCache := l.maxPASSCache.Load()
+	if passCache != nil {
+		ps := passCache.(*counterCache)
+		if l.timespan(ps.time) < 1 {
+			return ps.val
+		}
+		// Avoid glitches caused by fluctuations
+	}
+	var rawMaxPass float64
+	l.passStat.Reduce(func(b *utils.Bucket) {
+		rawMaxPass = math.Max(float64(b.Sum), rawMaxPass)
+	})
+	if rawMaxPass <= 0 {
+		rawMaxPass = 1
+	}
+	l.maxPASSCache.Store(&counterCache{
+		val:  int64(rawMaxPass),
+		time: time.Now(),
+	})
+	return int64(rawMaxPass)
+}
+
+// timespan returns the passed bucket count
+func (l *BBR) timespan(lastTime time.Time) int {
+	v := int(time.Since(lastTime) / l.bucketDuration)
+	if v > -1 {
+		return v
+	}
+	return l.opts.Bucket
+}
+
+// minRT minimum response time
+func (l *BBR) minRT() int64 {
+	rtCache := l.minRtCache.Load()
+	if rtCache != nil {
+		rc := rtCache.(*counterCache)
+		if l.timespan(rc.time) < 1 {
+			return rc.val
+		}
+	}
+	// Go to the nearest response time within 1s
+	var rawMinRT float64 = 1 << 31
+	l.rtStat.Reduce(func(b *utils.Bucket) {
+		if b.Count <= 0 {
+			return
+		}
+		if rawMinRT > math.Ceil(b.Sum/float64(b.Count)) {
+			rawMinRT = math.Ceil(b.Sum / float64(b.Count))
+		}
+	})
+	if rawMinRT == 1<<31 {
+		rawMinRT = 1
+	}
+	l.minRtCache.Store(&counterCache{
+		val:  int64(rawMinRT),
+		time: time.Now(),
+	})
+	return int64(rawMinRT)
+}
+
+// maxInFlight calculating the load
+func (l *BBR) maxInFlight() int64 {
+	return int64(math.Ceil(float64(l.maxPass()*l.minRT()*l.bucketPerSecond) / 1000.0))
+}
+
+// shouldDrop (CPU load > 80% || (now - prevDrop) < 1s) and (MaxPass * MinRT * windows) / 1000 < InFlight
+func (l *BBR) shouldDrop() bool {
+	now := time.Duration(time.Now().UnixNano())
+	if l.cpu() < l.opts.CPUThreshold {
+		// current cpu payload below the threshold
+		prevDropTime, _ := l.prevDropTime.Load().(time.Duration)
+		if prevDropTime == 0 {
+			// haven't start drop,
+			// accept current request
+			return false
+		}
+		if time.Duration(now-prevDropTime) <= time.Second {
+			// just start drop one second ago,
+			// check current inflight count
+			inFlight := atomic.LoadInt64(&l.inFlight)
+			return inFlight > 1 && inFlight > l.maxInFlight()
+		}
+		l.prevDropTime.Store(time.Duration(0))
+		return false
+	}
+	// current cpu payload exceeds the threshold
+	inFlight := atomic.LoadInt64(&l.inFlight)
+	drop := inFlight > 1 && inFlight > l.maxInFlight()
+	if drop {
+		prevDrop, _ := l.prevDropTime.Load().(time.Duration)
+		if prevDrop != 0 {
+			// already started drop, return directly
+			return drop
+		}
+		// store start drop time
+		l.prevDropTime.Store(now)
+	}
+	return drop
+}
+
+// Allow determines the alarm triggering conditions, record the interface time consumption and QPS
+func (l *BBR) Allow() (func(), error) {
+	if l.shouldDrop() {
+		return nil, errors.New(ErrLimit)
+	}
+	atomic.AddInt64(&l.inFlight, 1)
+	start := time.Now().UnixNano()
+	// DoneFunc record time-consuming
+	return func() {
+		rt := (time.Now().UnixNano() - start) / int64(time.Millisecond)
+		l.rtStat.Add(float64(rt))
+		atomic.AddInt64(&l.inFlight, -1)
+		l.passStat.Add(1)
+	}, nil
+}