An alternative leveled logger package that follows unix convention for output

log.go

// Package log follows linux output convention
// Top level functions like Test() and Verbose() set the package "mode"
package log

import (
	"io/ioutil"
	"log"
	"os"
)

var (
	Debug   *log.Logger
	Info    *log.Logger
	Warning *log.Logger
	Error   *log.Logger
)

var (
	PrefixDebug   = "[DEBUG] "
	PrefixWarning = "[WARNING] "
	PrefixError   = "[ERROR] "
	PrefixInfo    = "[INFO] "
)

const (
	FlagsDefault = log.Lshortfile
	FlagsTest    = log.Lshortfile
	FlagsVerbose = log.Ldate | log.Ltime | log.Lshortfile
	FlagsSilent  = 0
)

func init() {
	Default()
}

// Default sets outputs to sensible defaults (none, stderr, stderr, stdout)
func Default() {
	Debug = log.New(ioutil.Discard, PrefixDebug, FlagsDefault)
	Warning = log.New(os.Stderr, PrefixWarning, FlagsDefault)
	Error = log.New(os.Stderr, PrefixError, FlagsDefault)
	Info = log.New(os.Stdout, PrefixInfo, FlagsDefault)
}

// Test sets outputs to standard out
func Test() {
	Debug = log.New(os.Stdout, PrefixDebug, FlagsTest)
	Warning = log.New(os.Stdout, PrefixWarning, FlagsTest)
	Error = log.New(os.Stdout, PrefixError, FlagsTest)
	Info = log.New(os.Stdout, PrefixInfo, FlagsTest)
}

// Verbose sets outputs to standard out
func Verbose() {
	Debug = log.New(os.Stdout, PrefixDebug, FlagsVerbose)
	Warning = log.New(os.Stdout, PrefixWarning, FlagsVerbose)
	Error = log.New(os.Stdout, PrefixError, FlagsVerbose)
	Info = log.New(os.Stdout, PrefixInfo, FlagsVerbose)
}

// Verbose sets outputs to none
func Silent() {
	Debug = log.New(ioutil.Discard, PrefixDebug, FlagsSilent)
	Warning = log.New(ioutil.Discard, PrefixWarning, FlagsSilent)
	Error = log.New(ioutil.Discard, PrefixError, FlagsSilent)
	Info = log.New(ioutil.Discard, PrefixInfo, FlagsSilent)
}