変数：varステートメント、代入

sample.go

package main

import (
  "fmt"
  "time"
)

var start, finish time.Time
var appName, severity, sleep = "SAMPLE", "INFO", 1000 * time.Millisecond

func main() {
  logStart()
  time.Sleep( sleep )
  logMessage( "SLEEPED" )
  time.Sleep( sleep )
  logFinish()
}

func logStart() {
  start = time.Now()
  logMessage( "STARTED" )
}

func logFinish() {
  logMessage( "FINISHED" )
  finish = time.Now()
  elapsed := finish.Sub( start )
  // elapsed := finish.Sub( time.Now() )
  // elapsed = "hoge"
  fmt.Println( elapsed )
}

func logMessage( message string ) {
  fmt.Println( buildMessage( message ) )
}

func getTime() string {
  return time.Now().String()
}

func getSeverity() string {
  return severity
}

func buildMessage( message string ) ( tm, svr, msg string ) {
  tm  = getTime()
  svr = getSeverity()
  msg = appName + ": " + message
  return
}