POST /api/v1/prom/write

package main

import (
    "fmt"
    "time"

    "github.com/prometheus/client_golang/prometheus"
    "github.com/prometheus/client_golang/prometheus/push"
    "github.com/prometheus/common/expfmt"
)

var completionTime = prometheus.NewGauge(prometheus.GaugeOpts{
    Name: "db_backup_last_completion_timestamp_seconds",
    Help: "The timestamp of the last successful completion of a DB backup.",
})

func do() {
    completionTime.SetToCurrentTime()
}

func ExamplePusher_Push() {
    if err := push.New("http://$IP:$PORT", "db_backup").
        BasicAuth("$APPID", "$TOKEN").
        Collector(completionTime).
        Grouping("instance", "$INSTANCE").
        Grouping("db", "customers").
        Format(expfmt.FmtText).
        Push(); err != nil {
        fmt.Println("Could not push completion time to Pushgateway:", err)
    }
}

func main() {
    do()
    ticker := time.NewTicker(2 * time.Second)
    done := make(chan bool)
    for {
        select {
        case <-done:
            return
        case <-ticker.C:
            ExamplePusher_Push()
        }
    }
}