Simple Graphite Server in Golang

simpletgres.go

// go get github.com/tgres/tgres
// go run simpletgres.go

package main

import (
    "fmt"
    "math"
    "net/http"
    "time"

    "github.com/tgres/tgres/dsl"
    h "github.com/tgres/tgres/http"
    "github.com/tgres/tgres/rrd"
)

func sinTime(t time.Time, span time.Duration) float64 {
    x := 2 * math.Pi / span.Seconds() * float64(t.Unix()%(span.Nanoseconds()/1e9))
    return math.Sin(x)
}

func populateSeries(step, span time.Duration) *rrd.DataSource {
    ds := rrd.NewDataSource(rrd.DSSpec{
        Step: 1 * time.Second,
        RRAs: []rrd.RRASpec{
            rrd.RRASpec{Step: step, Span: span},
        },
    })

    start := time.Now().Add(-span)

    for i := 0; i < int(span/step); i++ {
        t := start.Add(time.Duration(i) * step)
        ds.ProcessDataPoint(sinTime(t, span), t)
    }
    return ds
}

func main() {

    step := 10 * time.Second
    span := 100 * step

    ds := populateSeries(step, span)

    rcache := dsl.NewReadCacheFromMap(map[string]rrd.DataSourcer{"foo.bar": ds})

    http.HandleFunc("/metrics/find", h.GraphiteMetricsFindHandler(rcache))
    http.HandleFunc("/render", h.GraphiteRenderHandler(rcache))

    listenSpec := ":8088"
    fmt.Printf("Waiting for requests on %s\n", listenSpec)
    http.ListenAndServe(listenSpec, nil)
}