阿里开源的Sentinel流量治理组件之限流熔断降级等简单示例
Go / 管理员 发布于 1年前 490
Sentinel是面向分布式、多语言异构化服务架构的流量治理组件，主要以流量为切入点，
从流量路由、流量控制、流量整形、熔断降级、系统自适应过载保护、热点流量防护等多个维度来帮助开发者保障微服务的稳定性。
Sentinel是阿里开源的项目，提供了流量控制、熔断降级、系统负载保护等多个维度来保障服务之间的稳定性。
官方文档：
https://sentinelguard.io/zh-cn/docs/introduction.html
git官方wiki：
https://github.com/alibaba/Sentinel/wiki
Sentinel-go开源地址：
https://github.com/alibaba/sentinel-golang
官方文档-go语言：
https://sentinelguard.io/zh-cn/docs/golang/quick-start.html
Sentinel-go安装
go get github.com/alibaba/sentinel-golang/api
简单测试限流示例
1.qps限流功能代码示例：
package main
import (
"fmt"
"log"
sentinel "github.com/alibaba/sentinel-golang/api"
"github.com/alibaba/sentinel-golang/core/base"
"github.com/alibaba/sentinel-golang/core/flow"
)
func main() {
//基于sentinel的qps限流
//必须初始化
err := sentinel.InitDefault()
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
}
//配置限流规则：1秒内通过10次
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: "some_test",
TokenCalculateStrategy: flow.Direct,
ControlBehavior: flow.Reject, //超过直接拒绝
Threshold: 10, //请求次数
StatIntervalInMs: 1000, //允许时间内
},
})
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
return
}
for i := 0; i < 12; i++ {
e, b := sentinel.Entry("some_test", sentinel.WithTrafficType(base.Inbound))
if b != nil {
fmt.Println("限流了")
} else {
fmt.Println("检查通过")
e.Exit()
}
}
}打印结果：
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
限流了
限流了2.Thrnotting(限流)功能代码示例
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"
)
func main() {
//基于sentinel的qps限流
//必须初始化
err := sentinel.InitDefault()
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
}
//配置限流规则
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: "some_test",
TokenCalculateStrategy: flow.Direct,
ControlBehavior: flow.Throttling, //匀速通过
Threshold: 10, //请求次数
StatIntervalInMs: 1000, //允许时间内
},
})
if err != nil {
log.Fatalf("Unexpected error: %+v", err)
return
}
for i := 0; i < 12; i++ {
e, b := sentinel.Entry("some_test", sentinel.WithTrafficType(base.Inbound))
if b != nil {
fmt.Println("限流了")
} else {
fmt.Println("检查通过")
e.Exit()
}
time.Sleep(time.Millisecond * 100)
}
}打印结果：
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过
检查通过3.Warrm_up(降级)
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"
)
func main() {
//先初始化sentinel
err := sentinel.InitDefault()
if err != nil {
log.Fatalf("初始化sentinel 异常: %v", err)
}
var globalTotal int
var passTotal int
var blockTotal int
ch := make(chan struct{})
//配置限流规则
_, err = flow.LoadRules([]*flow.Rule{
{
Resource: "some-test",
TokenCalculateStrategy: flow.WarmUp, //冷启动策略
ControlBehavior: flow.Reject, //直接拒绝
Threshold: 1000,
WarmUpPeriodSec: 30,
},
})
if err != nil {
log.Fatalf("加载规则失败: %v", err)
}
//我会在每一秒统计一次，这一秒只能 你通过了多少，总共有多少， block了多少, 每一秒会产生很多的block
for i := 0; i < 100; i++ {
go func() {
for {
globalTotal++
e, b := sentinel.Entry("some-test", sentinel.WithTrafficType(base.Inbound))
if b != nil {
//fmt.Println("限流了")
blockTotal++
time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
} else {
passTotal++
time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
e.Exit()
}
}
}()
}
go func() {
var oldTotal int //过去1s总共有多少个
var oldPass int //过去1s总共pass多少个
var oldBlock int //过去1s总共block多少个
for {
oneSecondTotal := globalTotal - oldTotal
oldTotal = globalTotal
oneSecondPass := passTotal - oldPass
oldPass = passTotal
oneSecondBlock := blockTotal - oldBlock
oldBlock = blockTotal
time.Sleep(time.Second)
fmt.Printf("total:%d, pass:%d, block:%d\n", oneSecondTotal, oneSecondPass, oneSecondBlock)
}
}()
<-ch
}
打印结果：
逐渐到达1k,在1k位置上下波动
total:11, pass:9, block:0
total:21966, pass:488, block:21420
total:21793, pass:339, block:21414
total:21699, pass:390, block:21255
total:21104, pass:393, block:20654
total:21363, pass:453, block:20831
total:21619, pass:491, block:21052
total:21986, pass:533, block:21415
total:21789, pass:594, block:21123
total:21561, pass:685, block:20820
total:21663, pass:873, block:20717
total:20904, pass:988, block:19831
total:21500, pass:996, block:20423
total:21769, pass:1014, block:20682
total:20893, pass:1019, block:19837
total:21561, pass:973, block:20524
total:21601, pass:1014, block:20517
total:21475, pass:993, block:20420
total:21457, pass:983, block:20418
total:21397, pass:1024, block:20320
total:21690, pass:996, block:20641
total:21526, pass:991, block:20457
total:21779, pass:1036, block:20677
分享一个完整的Go熔断实战示例
这里我们介绍一个错误数量的，查看详细熔断机制
https://sentinelguard.io/zh-cn/docs/golang/circuit-breaking.html
error_count 代码示例
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() {
//基于连接数的降级模式
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=10s, recoveryTimeout=3s, maxErrorCount=50
{
Resource: "abc",
Strategy: circuitbreaker.ErrorCount,
RetryTimeoutMs: 3000, //3s只有尝试回复
MinRequestAmount: 10, //静默数
StatIntervalMs: 5000,
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("协程熔断了")
time.Sleep(time.Duration(rand.Uint64()%20) * time.Millisecond)
} else {
totalPass++
if rand.Uint64()%20 > 9 {
totalErr++
// Record current invocation as error.
sentinel.TraceError(e, errors.New("biz error"))
}
// g1 passed
time.Sleep(time.Duration(rand.Uint64()%20+10) * time.Millisecond)
e.Exit()
}
}
}()
go func() {
for {
total++
e, b := sentinel.Entry("abc")
if b != nil {
// g2 blocked
totalBlock++
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
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