002 Gauge

Gauge

Gauge 比较适合的场景就用来记录一下当前值是多少，比如当前 MySQL 的连接数，当前 go 程序的协程数 ...

package main

import (
    "fmt"
    "log"
    "runtime"
    "time"

    "github.com/kataras/iris/v12"
    "github.com/rcrowley/go-metrics"
)

func main() {
    app := iris.New()

    g := metrics.NewGauge()
    metrics.GetOrRegister("goroutines.now", g)
    go metrics.Log(metrics.DefaultRegistry, time.Second*5, log.Default())

    app.Get("/", func(ctx iris.Context) {
        ctx.Text("goroutines.now " + fmt.Sprintf("%d", g.Value()))
    })

    go func() {
        t := time.NewTicker(time.Second) //定时器
        for range t.C {
            c := runtime.NumGoroutine()
            g.Update(int64(c))
        }
    }()

    app.Listen("127.0.0.1:8080")
}

运行效果

./webs
Iris Version: 12.2.10

Now listening on: http://127.0.0.1:8080
Application started. Press CTRL+C to shut down.
2024/04/03 20:28:23 gauge goroutines.now
2024/04/03 20:28:23   value:               8
2024/04/03 20:28:28 gauge goroutines.now
2024/04/03 20:28:28   value:               8

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