gin框架sentinel流量控制初体验

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流量控制设计理念

流量控制有以下几个角度:

资源和资源之间的关系；
运行指标，例如 QPS、线程池、系统负载等；
控制的效果，例如直接限流、冷启动、匀速+排队等待等。

Sentinel提供了几个组件让用户去实现相关的流控方案：

基于QPS的流量控制：流量控制
基于协程数的隔离流控：并发隔离控制
基于热点参数的流量控制：热点参数限流
基于系统指标的自适应流控：系统自适应流控

Sentinel 的设计理念是让您自由选择控制的角度，并进行灵活组合，从而达到想要的效果。

https://github.com/alibaba/sentinel-golang

demo:

package main

import (
    sentinelPlugin "github.com/alibaba/sentinel-golang/adapter/gin"
    sentinel "github.com/alibaba/sentinel-golang/api"
    "github.com/alibaba/sentinel-golang/core/base"
    "github.com/alibaba/sentinel-golang/core/config"
    "github.com/alibaba/sentinel-golang/core/flow"
    "github.com/alibaba/sentinel-golang/logging"
    "github.com/gin-gonic/gin"
    "log"
    "math/rand"
    "time"
)

func init() {
    //初始化 sentinel
    conf := config.NewDefaultConfig()
    conf.Sentinel.Log.Logger = logging.NewConsoleLogger("cb-integration-normal")
    conf.Sentinel.Log.Dir = "."
    err := sentinel.InitWithConfig(conf)
    if err != nil {
        log.Fatal("err",err)
    }

    //go语言实现暂未发现appLimit即限制客户端每秒请求次数
    if _, err := flow.LoadRules([]*flow.Rule{
        {
            Resource:               "GET:/health",
            MetricType:             flow.QPS,
            Count:                  1,
            TokenCalculateStrategy: flow.Direct,
            ControlBehavior:        flow.Reject,
        },
    });err != nil {
        log.Fatalf("Unexpected error: %+v", err)
        return
    }

}

func main() {
    r := gin.Default()
    // Sentinel 会对每个 API route 进行统计，资源名称类似于 GET:/foo/:id
    // 默认的限流处理逻辑是返回 429 (Too Many Requests) 错误码，支持配置自定义的 fallback 逻辑
    r.Use(sentinelPlugin.SentinelMiddleware())

    _, b := sentinel.Entry("some-test", sentinel.WithTrafficType(base.Inbound))
    if b != nil {
        // Blocked. We could get the block reason from the BlockError.
        time.Sleep(time.Duration(rand.Uint64()%10) * time.Millisecond)
    }else {
        r.GET("/health", func(context *gin.Context) {
            context.JSON(200, map[string]string{"status":"ok"})
        })
    }

    _ = r.Run("0.0.0.0:8080")
}