golang 熔斷限流降級實(shí)踐
更新時(shí)間：2025年02月20日 09:11:19 作者：愛編程的 小李
本文主要介紹了golang 熔斷限流降級實(shí)踐,文中通過示例代碼介紹的非常詳細(xì),對大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值,需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧
限流 - 2k 但是我的服務(wù)能力只有1k，所以這個(gè)時(shí)候多出來的流量怎么辦： 1. 拒絕 2. 排隊(duì)等待。用戶體驗(yàn)不太好： 當(dāng)前訪問用戶過多，請稍后重試和你的服務(wù)直接掛了
用戶體驗(yàn)降級了 - 原本是訪問流暢，下單流暢 -> 當(dāng)前訪問用戶過多，請稍后重試
熔斷 - 比如A服務(wù)訪問B服務(wù)，這個(gè)時(shí)候B服務(wù)很慢 - B服務(wù)壓力過大，導(dǎo)致了出現(xiàn)了不少請求錯(cuò)誤，調(diào)用方很容易出現(xiàn)一個(gè)問題： 每次調(diào)用都超時(shí) 2k，結(jié)果這個(gè)時(shí)候數(shù)據(jù)庫出現(xiàn)了問題， 超時(shí)重試 - 網(wǎng)絡(luò) 2k的流量突然變成了3k。這讓原本就滿負(fù)荷的b服務(wù)雪上加霜，如果這個(gè)時(shí)候調(diào)用方有一種機(jī)制：比如說 1. 發(fā)現(xiàn)了大部分請求很慢 - 50%請求都很慢， 2. 發(fā)現(xiàn)我的請求有50%都錯(cuò)誤了 3. 錯(cuò)誤數(shù)量很多，比如1s出現(xiàn)了20個(gè)錯(cuò)誤 。上述三種情況出現(xiàn)，在一段時(shí)間內(nèi)不發(fā)給B服務(wù)，直接拒絕。一段時(shí)間之后再發(fā)送。以此來緩解B服務(wù)的壓力，避免B服務(wù)掛掉的可能。
技術(shù)選型
限流
QPS限流
package main
import (
"fmt"
"log"
"math/rand"
"time"
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/base"
"github.com/alibaba/sentinel-golang/core/flow"
)
const resName = "example-flow-qps-resource"
func main() {
//初始化sentinel
err := sentinel.InitDefault()
if err != nil {
log.Fatal(err)
}
//配置限流規(guī)則
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: resName,
TokenCalculateStrategy: flow.Direct,
ControlBehavior: flow.Reject,
Threshold: 10,
StatIntervalInMs: 1000,
},
})
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
return
}
ch := make(chan struct{})
for i := 0; i < 10; i++ {
go func() {
for {
e, b := sentinel.Entry(resName, sentinel.WithTrafficType(base.Inbound))
if b != nil {
// Blocked. We could get the block reason from the BlockError.
fmt.Println("被限流")
time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
} else {
// Passed, wrap the logic here.
fmt.Println("成功")
time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
// Be sure the entry is exited finally.
e.Exit()
}
}
}()
}
// Simulate a scenario in which flow rules are updated concurrently
go func() {
time.Sleep(time.Second * 10)
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: resName,
TokenCalculateStrategy: flow.Direct,
ControlBehavior: flow.Reject,
Threshold: 80,
StatIntervalInMs: 1000,
},
})
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
return
}
}()
<-ch
}
warmup限流
WarmUp 方式，即預(yù)熱/冷啟動(dòng)方式。當(dāng)系統(tǒng)長期處于低水位的情況下，當(dāng)流量突然增加時(shí)，直接把系統(tǒng)拉升到高水位可能瞬間把系統(tǒng)壓垮。通過"冷啟動(dòng)"，讓通過的流量緩慢增加，在一定時(shí)間內(nèi)逐漸增加到閾值上限，給冷系統(tǒng)一個(gè)預(yù)熱的時(shí)間，避免冷系統(tǒng)被壓垮。這塊設(shè)計(jì)和 Java 類似。通常冷啟動(dòng)的過程系統(tǒng)允許通過的 QPS 曲線如下圖所示：
package main
import (
"fmt"
"log"
"math/rand"
"sync"
"time"
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/base"
"github.com/alibaba/sentinel-golang/core/flow"
)
const resName = "example-flow-qps-resource"
func main() {
//初始化sentinel
err := sentinel.InitDefault()
if err != nil {
log.Fatal(err)
}
//配置限流規(guī)則
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: resName,
TokenCalculateStrategy: flow.WarmUp, //冷啟動(dòng)策略
ControlBehavior: flow.Reject, //直接拒絕
Threshold: 10, //1s10個(gè)并發(fā)
WarmUpPeriodSec: 30, //60s預(yù)熱
},
})
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
return
}
var mutex sync.Mutex
lastSecond := time.Now().Second()
total := 0
totalRestrict := 0
totalPass := 0
ch := make(chan struct{})
for i := 0; i < 10; i++ {
go func() {
for {
e, b := sentinel.Entry(resName, sentinel.WithTrafficType(base.Inbound))
if b != nil {
// Blocked. We could get the block reason from the BlockError.
mutex.Lock()
totalRestrict++
mutex.Unlock()
time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
} else {
// Passed, wrap the logic here.
mutex.Lock()
totalPass++
mutex.Unlock()
time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
// Be sure the entry is exited finally.
e.Exit()
}
mutex.Lock()
total++
mutex.Unlock()
if time.Now().Second() != lastSecond {
mutex.Lock()
lastSecond = time.Now().Second()
fmt.Println("total=", total, ",totalRestrict=", totalRestrict, ",totalPass=", totalPass)
total = 0
totalRestrict = 0
totalPass = 0
mutex.Unlock()
}
}
}()
}
<-ch
}
趨勢逐漸增加，一直到達(dá)每秒10個(gè)左右
Throttling策略
計(jì)算時(shí)間間隔，每過了時(shí)間間隔才允許通過
package main
import (
"fmt"
"log"
"math/rand"
"time"
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/base"
"github.com/alibaba/sentinel-golang/core/flow"
)
const resName = "example-flow-qps-resource"
func main() {
//初始化sentinel
err := sentinel.InitDefault()
if err != nil {
log.Fatal(err)
}
//配置限流規(guī)則
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: resName,
TokenCalculateStrategy: flow.Direct,
ControlBehavior: flow.Throttling,
Threshold: 10,
StatIntervalInMs: 1000,
},
})
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
return
}
ch := make(chan struct{})
for i := 0; i < 10; i++ {
go func() {
for {
e, b := sentinel.Entry(resName, sentinel.WithTrafficType(base.Inbound))
if b != nil {
// Blocked. We could get the block reason from the BlockError.
fmt.Println("被限流")
time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
} else {
// Passed, wrap the logic here.
fmt.Println("成功")
time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
// Be sure the entry is exited finally.
e.Exit()
}
}
}()
}
// Simulate a scenario in which flow rules are updated concurrently
go func() {
time.Sleep(time.Second * 10)
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: resName,
TokenCalculateStrategy: flow.Direct,
ControlBehavior: flow.Reject,
Threshold: 80,
StatIntervalInMs: 1000,
},
})
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
return
}
}()
<-ch
}
package main
import (
"fmt"
"log"
"time"
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/base"
"github.com/alibaba/sentinel-golang/core/flow"
)
const resName = "example-flow-qps-resource"
func main() {
//初始化sentinel
err := sentinel.InitDefault()
if err != nil {
log.Fatal(err)
}
//配置限流規(guī)則
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: resName,
TokenCalculateStrategy: flow.Direct,
ControlBehavior: flow.Throttling,
Threshold: 10,
StatIntervalInMs: 1000,
},
})
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
return
}
for i := 0; i < 10; i++ {
e, b := sentinel.Entry(resName, sentinel.WithTrafficType(base.Inbound))
if b != nil {
// Blocked. We could get the block reason from the BlockError.
fmt.Println("被限流")
} else {
// Passed, wrap the logic here.
fmt.Println("成功")
// Be sure the entry is exited finally.
e.Exit()
}
time.Sleep(100 * time.Millisecond)
}
}
熔斷
Sentinel 熔斷降級基于熔斷器模式 (circuit breaker pattern) 實(shí)現(xiàn)。熔斷器內(nèi)部維護(hù)了一個(gè)熔斷器的狀態(tài)機(jī)，狀態(tài)機(jī)的轉(zhuǎn)換關(guān)系如下圖所示：
熔斷器有三種狀態(tài)：
1.Closed 狀態(tài)：也是初始狀態(tài)，該狀態(tài)下，熔斷器會(huì)保持閉合，對資源的訪問直接通過熔斷器的檢查。
2.Open 狀態(tài)：斷開狀態(tài)，熔斷器處于開啟狀態(tài)，對資源的訪問會(huì)被切斷。
3.Half-Open 狀態(tài)：半開狀態(tài)，該狀態(tài)下除了探測流量，其余對資源的訪問也會(huì)被切斷。探測流量指熔斷器處于半開狀態(tài)時(shí)，會(huì)周期性的允許一定數(shù)目的探測請求通過，如果探測請求能夠正常的返回，代表探測成功，此時(shí)熔斷器會(huì)重置狀態(tài)到 Closed 狀態(tài)，結(jié)束熔斷；如果探測失敗，則回滾到 Open 狀態(tài)。
這三種狀態(tài)之間的轉(zhuǎn)換關(guān)系這里做一個(gè)更加清晰的解釋：
1.初始狀態(tài)下，熔斷器處于 Closed 狀態(tài)。如果基于熔斷器的統(tǒng)計(jì)數(shù)據(jù)表明當(dāng)前資源觸發(fā)了設(shè)定的閾值，那么熔斷器會(huì)切換狀態(tài)到 Open 狀態(tài)；
2.Open 狀態(tài)即代表熔斷狀態(tài)，所有請求都會(huì)直接被拒絕。熔斷器規(guī)則中會(huì)配置一個(gè)熔斷超時(shí)重試的時(shí)間，經(jīng)過熔斷超時(shí)重試時(shí)長后熔斷器會(huì)將狀態(tài)置為 Half-Open 狀態(tài)，從而進(jìn)行探測機(jī)制；
3.處于 Half-Open 狀態(tài)的熔斷器會(huì)周期性去做探測。
Sentinel 提供了監(jiān)聽器去監(jiān)聽熔斷器狀態(tài)機(jī)的三種狀態(tài)的轉(zhuǎn)換，方便用戶去自定義擴(kuò)展：
熔斷策略
Sentinel 熔斷器的三種熔斷策略都支持靜默期 (規(guī)則中通過MinRequestAmount字段表示)。靜默期是指一個(gè)最小的靜默請求數(shù)，在一個(gè)統(tǒng)計(jì)周期內(nèi)，如果對資源的請求數(shù)小于設(shè)置的靜默數(shù)，那么熔斷器將不會(huì)基于其統(tǒng)計(jì)值去更改熔斷器的狀態(tài)。靜默期的設(shè)計(jì)理由也很簡單，舉個(gè)例子，假設(shè)在一個(gè)統(tǒng)計(jì)周期剛剛開始時(shí)候，第 1 個(gè)請求碰巧是個(gè)慢請求，這個(gè)時(shí)候這個(gè)時(shí)候的慢調(diào)用比例就會(huì)是 100%，很明顯是不合理，所以存在一定的巧合性。所以靜默期提高了熔斷器的精準(zhǔn)性以及降低誤判可能性。
Sentinel 支持以下幾種熔斷策略：
慢調(diào)用比例策略 (SlowRequestRatio)
Sentinel 的熔斷器不在靜默期，并且慢調(diào)用的比例大于設(shè)置的閾值，則接下來的熔斷周期內(nèi)對資源的訪問會(huì)自動(dòng)地被熔斷。該策略下需要設(shè)置允許的調(diào)用 RT 臨界值（即最大的響應(yīng)時(shí)間），對該資源訪問的響應(yīng)時(shí)間大于該閾值則統(tǒng)計(jì)為慢調(diào)用。
package main
import (
"errors"
"fmt"
"log"
"math/rand"
"time"
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/circuitbreaker"
"github.com/alibaba/sentinel-golang/core/config"
"github.com/alibaba/sentinel-golang/logging"
"github.com/alibaba/sentinel-golang/util"
)
type stateChangeTestListener struct {
}
func (s *stateChangeTestListener) OnTransformToClosed(prev circuitbreaker.State, rule circuitbreaker.Rule) {
fmt.Printf("rule.steategy: %+v, From %s to Closed, time: %d\n", rule.Strategy, prev.String(), util.CurrentTimeMillis())
}
func (s *stateChangeTestListener) OnTransformToOpen(prev circuitbreaker.State, rule circuitbreaker.Rule, snapshot interface{}) {
fmt.Printf("rule.steategy: %+v, From %s to Open, snapshot: %.2f, time: %d\n", rule.Strategy, prev.String(), snapshot, util.CurrentTimeMillis())
}
func (s *stateChangeTestListener) OnTransformToHalfOpen(prev circuitbreaker.State, rule circuitbreaker.Rule) {
fmt.Printf("rule.steategy: %+v, From %s to Half-Open, time: %d\n", rule.Strategy, prev.String(), util.CurrentTimeMillis())
}
func main() {
conf := config.NewDefaultConfig()
// for testing, logging output to console
conf.Sentinel.Log.Logger = logging.NewConsoleLogger()
err := sentinel.InitWithConfig(conf)
if err != nil {
log.Fatal(err)
}
ch := make(chan struct{})
// Register a state change listener so that we could observer the state change of the internal circuit breaker.
circuitbreaker.RegisterStateChangeListeners(&stateChangeTestListener{})
_, err = circuitbreaker.LoadRules([]*circuitbreaker.Rule{
// Statistic time span=5s, recoveryTimeout=3s, slowRtUpperBound=50ms, maxSlowRequestRatio=50%
{
Resource: "abc",
Strategy: circuitbreaker.SlowRequestRatio,
RetryTimeoutMs: 3000,
MinRequestAmount: 10,
StatIntervalMs: 5000,
StatSlidingWindowBucketCount: 10,
MaxAllowedRtMs: 50, //大于50ms是慢查詢
Threshold: 0.5,
},
})
if err != nil {
log.Fatal(err)
}
logging.Info("[CircuitBreaker SlowRtRatio] Sentinel Go circuit breaking demo is running. You may see the pass/block metric in the metric log.")
go func() {
for {
e, b := sentinel.Entry("abc")
if b != nil {
// g1 blocked
time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
} else {
if rand.Uint64()%20 > 9 {
// Record current invocation as error.
sentinel.TraceError(e, errors.New("biz error"))
}
// g1 passed
time.Sleep(time.Duration(rand.Uint64()%80+10) * time.Millisecond)
e.Exit()
}
}
}()
go func() {
for {
e, b := sentinel.Entry("abc")
if b != nil {
// g2 blocked
time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
} else {
// g2 passed
time.Sleep(time.Duration(rand.Uint64()%80+10) * time.Millisecond)
e.Exit()
}
}
}()
<-ch
}
錯(cuò)誤比例策略 (ErrorRatio)
Sentinel 的熔斷器不在靜默期，并且在統(tǒng)計(jì)周期內(nèi)資源請求訪問異常的比例大于設(shè)定的閾值，則接下來的熔斷周期內(nèi)對資源的訪問會(huì)自動(dòng)地被熔斷。
package main
import (
"errors"
"fmt"
"log"
"math/rand"
"time"
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/circuitbreaker"
"github.com/alibaba/sentinel-golang/core/config"
"github.com/alibaba/sentinel-golang/logging"
"github.com/alibaba/sentinel-golang/util"
)
type stateChangeTestListener struct{}
func (s *stateChangeTestListener) OnTransformToClosed(prev circuitbreaker.State, rule circuitbreaker.Rule) {
fmt.Printf("rule.steategy: %+v, From %s to Closed, time: %d\n", rule.Strategy, prev.String(), util.CurrentTimeMillis())
}
func (s *stateChangeTestListener) OnTransformToOpen(prev circuitbreaker.State, rule circuitbreaker.Rule, snapshot interface{}) {
fmt.Printf("rule.steategy: %+v, From %s to Open, snapshot: %.2f, time: %d\n", rule.Strategy, prev.String(), snapshot, util.CurrentTimeMillis())
}
func (s *stateChangeTestListener) OnTransformToHalfOpen(prev circuitbreaker.State, rule circuitbreaker.Rule) {
fmt.Printf("rule.steategy: %+v, From %s to Half-Open, time: %d\n", rule.Strategy, prev.String(), util.CurrentTimeMillis())
}
func main() {
total := 0
totalPass := 0
totalBlock := 0
totalErr := 0
conf := config.NewDefaultConfig()
// for testing, logging output to console
conf.Sentinel.Log.Logger = logging.NewConsoleLogger()
err := sentinel.InitWithConfig(conf)
if err != nil {
log.Fatal(err)
}
ch := make(chan struct{})
// Register a state change listener so that we could observer the state change of the internal circuit breaker.
circuitbreaker.RegisterStateChangeListeners(&stateChangeTestListener{})
_, err = circuitbreaker.LoadRules([]*circuitbreaker.Rule{
// Statistic time span=5s, recoveryTimeout=3s, maxErrorCount=50
{
Resource: "abc",
Strategy: circuitbreaker.ErrorRatio,
RetryTimeoutMs: 3000,
MinRequestAmount: 10,
StatIntervalMs: 5000,
StatSlidingWindowBucketCount: 10,
Threshold: 0.4,
},
})
if err != nil {
log.Fatal(err)
}
logging.Info("[CircuitBreaker ErrorCount] Sentinel Go circuit breaking demo is running. You may see the pass/block metric in the metric log.")
go func() {
for {
total++
e, b := sentinel.Entry("abc")
if b != nil {
// g1 blocked
totalBlock++
fmt.Println("熔斷")
time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
} else {
if rand.Uint64()%20 > 9 {
totalErr++
// Record current invocation as error.
sentinel.TraceError(e, errors.New("biz error"))
}
totalPass++
// g1 passed
time.Sleep(time.Duration(rand.Uint64()%80+10) * time.Millisecond)
e.Exit()
}
}
}()
go func() {
for {
e, b := sentinel.Entry("abc")
if b != nil {
// g2 blocked
totalBlock++
fmt.Println("寫成熔斷了")
time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
} else {
// g2 passed
totalPass++
time.Sleep(time.Duration(rand.Uint64()%80) * time.Millisecond)
e.Exit()
}
}
}()
go func() {
for {
time.Sleep(time.Second)
fmt.Println(float64(totalErr) / float64(total))
}
}()
<-ch
}
錯(cuò)誤計(jì)數(shù)策略 (ErrorCount)
Sentinel 的熔斷器不在靜默期，并且在統(tǒng)計(jì)周期內(nèi)資源請求訪問異常數(shù)大于設(shè)定的閾值，則接下來的熔斷周期內(nèi)對資源的訪問會(huì)自動(dòng)地被熔斷。
注意：這里的錯(cuò)誤比例熔斷和錯(cuò)誤計(jì)數(shù)熔斷指的業(yè)務(wù)返回錯(cuò)誤的比例或則計(jì)數(shù)。也就是說，如果規(guī)則指定熔斷器策略采用錯(cuò)誤比例或則錯(cuò)誤計(jì)數(shù)，那么為了統(tǒng)計(jì)錯(cuò)誤比例或錯(cuò)誤計(jì)數(shù)，需要調(diào)用API： api.TraceError(entry, err) 埋點(diǎn)每個(gè)請求的業(yè)務(wù)異常。
package main
import (
"errors"
"fmt"
"log"
"math/rand"
"time"
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/circuitbreaker"
"github.com/alibaba/sentinel-golang/core/config"
"github.com/alibaba/sentinel-golang/logging"
"github.com/alibaba/sentinel-golang/util"
)
type stateChangeTestListener struct {
}
func (s *stateChangeTestListener) OnTransformToClosed(prev circuitbreaker.State, rule circuitbreaker.Rule) {
fmt.Printf("rule.steategy: %+v, From %s to Closed, time: %d\n", rule.Strategy, prev.String(), util.CurrentTimeMillis())
}
func (s *stateChangeTestListener) OnTransformToOpen(prev circuitbreaker.State, rule circuitbreaker.Rule, snapshot interface{}) {
fmt.Printf("rule.steategy: %+v, From %s to Open, snapshot: %d, time: %d\n", rule.Strategy, prev.String(), snapshot, util.CurrentTimeMillis())
}
func (s *stateChangeTestListener) OnTransformToHalfOpen(prev circuitbreaker.State, rule circuitbreaker.Rule) {
fmt.Printf("rule.steategy: %+v, From %s to Half-Open, time: %d\n", rule.Strategy, prev.String(), util.CurrentTimeMillis())
}
func main() {
total := 0
totalPass := 0
totalBlock := 0
totalErr := 0
conf := config.NewDefaultConfig()
// for testing, logging output to console
conf.Sentinel.Log.Logger = logging.NewConsoleLogger()
err := sentinel.InitWithConfig(conf)
if err != nil {
log.Fatal(err)
}
ch := make(chan struct{})
// Register a state change listener so that we could observer the state change of the internal circuit breaker.
circuitbreaker.RegisterStateChangeListeners(&stateChangeTestListener{})
_, err = circuitbreaker.LoadRules([]*circuitbreaker.Rule{
// Statistic time span=5s, recoveryTimeout=3s, maxErrorCount=50
{
Resource: "abc",
Strategy: circuitbreaker.ErrorCount,
RetryTimeoutMs: 3000,
MinRequestAmount: 10,
StatIntervalMs: 5000,
StatSlidingWindowBucketCount: 10,
Threshold: 50,
},
})
if err != nil {
log.Fatal(err)
}
logging.Info("[CircuitBreaker ErrorCount] Sentinel Go circuit breaking demo is running. You may see the pass/block metric in the metric log.")
go func() {
for {
total++
e, b := sentinel.Entry("abc")
if b != nil {
// g1 blocked
totalBlock++
fmt.Println("熔斷")
time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
} else {
if rand.Uint64()%20 > 9 {
totalErr++
// Record current invocation as error.
sentinel.TraceError(e, errors.New("biz error"))
}
totalPass++
// g1 passed
time.Sleep(time.Duration(rand.Uint64()%80+10) * time.Millisecond)
e.Exit()
}
}
}()
go func() {
for {
e, b := sentinel.Entry("abc")
if b != nil {
// g2 blocked
totalBlock++
fmt.Println("寫成熔斷了")
time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
} else {
// g2 passed
totalPass++
time.Sleep(time.Duration(rand.Uint64()%80) * time.Millisecond)
e.Exit()
}
}
}()
go func() {
for {
time.Sleep(time.Second)
fmt.Println(totalErr)
}
}()
<-ch
}
gin集成sentinel限流
初始化
package initialize
import (
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/flow"
"go.uber.org/zap"
)
func InitSentinel() {
//初始化sentinel
err := sentinel.InitDefault()
if err != nil {
zap.S().Fatal(err)
}
//配置限流規(guī)則
//這種配置從nacos讀取
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: "test",
TokenCalculateStrategy: flow.Direct,
ControlBehavior: flow.Reject,
Threshold: 10,
StatIntervalInMs: 1000,
},
})
if err != nil {
zap.S().Fatalf("Unexpected error: %+v", err)
return
}
}
調(diào)用
initialize.InitSentinel()
限流
e, b := sentinel.Entry("goods-list", sentinel.WithTrafficType(base.Inbound))
if b != nil {
ctx.JSON(http.StatusTooManyRequests, gin.H{
"msg": "請求過于頻繁，請稍后重試",
})
return
}
r, err := global.GoodsSrvClient.GoodsList(context.WithValue(context.Background(), "ginContext", ctx), request)
if err != nil {
zap.S().Errorw("[List] 查詢 【商品列表】失敗")
return
}
e.Exit()到此這篇關(guān)于golang 熔斷限流降級實(shí)踐的文章就介紹到這了,更多相關(guān)golang 熔斷限流降級內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關(guān)文章希望大家以后多多支持腳本之家！
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