server1.go

package main

import (
    "encoding/json"
    "github.com/thehivecorporation/log"
    "net/http"
    "time"
)

type res struct {
    Success bool
}

func main() {
    http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
        potentiallySlowOperation(5)

        byt, err := json.Marshal(res{Success: true})
        if err != nil {
            w.WriteHeader(500)
            return
        }

        w.Write(byt)
    })

    http.ListenAndServe(":8080", nil)
}

func potentiallySlowOperation(s time.Duration) {
    log.Infof("'Processing' for %d seconds", s)

    now := time.Now()
    defer func(now time.Time) {
        log.WithField("elapsed", time.Since(now)).Info("Returning")
    }(now)

    time.Sleep(time.Second * s)

    log.Info("Processing done")
}