Log wrapper for Go stdlib logger

logex.go

package log

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

var (
	// DebugLogger is a Logger dedicated for debug messages
	DebugLogger = stdlog.New(ioutil.Discard, "DEBUG ", stdlog.LstdFlags)

	// InfoLogger is a Logger dedicated for info messages
	InfoLogger = stdlog.New(os.Stderr, "INFO ", stdlog.LstdFlags)
)

func init() {
	if _, ok := os.LookupEnv("VERBOSE"); ok {
		DebugLogger.SetOutput(os.Stderr)
	}
}

// EnableDebug turns on debug logging
func EnableDebug() {
	DebugLogger.SetOutput(os.Stderr)
}

// DisableDebug turns off debug logging
func DisableDebug() {
	DebugLogger.SetOutput(ioutil.Discard)
}

// Debug wrappers

// Debug calls Output to print to the debug logger.
// Arguments are handled in the manner of fmt.Print.
func Debug(v ...interface{}) {
	DebugLogger.Print(v...)
}

// Debugf calls Output to print to the debug logger.
// Arguments are handled in the manner of fmt.Printf.
func Debugf(format string, v ...interface{}) {
	DebugLogger.Printf(format, v...)
}

// Debugln calls Output to print to the debug logger.
// Arguments are handled in the manner of fmt.Println.
func Debugln(v ...interface{}) {
	DebugLogger.Println(v...)
}

// Info wrappers

// Info calls Output to print to the Info logger.
// Arguments are handled in the manner of fmt.Print.
func Info(v ...interface{}) {
	InfoLogger.Print(v...)
}

// Infof calls Output to print to the Info logger.
// Arguments are handled in the manner of fmt.Printf.
func Infof(format string, v ...interface{}) {
	InfoLogger.Printf(format, v...)
}

// Infoln calls Output to print to the Info logger.
// Arguments are handled in the manner of fmt.Println.
func Infoln(v ...interface{}) {
	InfoLogger.Println(v...)
}

// These functions write to the standard logger that is wrapped here.

// SetOutput sets the output destination for the standard logger.
func SetOutput(w io.Writer) {
	stdlog.SetOutput(w)
}

// Print calls Output to print to the standard logger.
// Arguments are handled in the manner of fmt.Print.
func Print(v ...interface{}) {
	stdlog.Print(v...)
}

// Printf calls Output to print to the standard logger.
// Arguments are handled in the manner of fmt.Printf.
func Printf(format string, v ...interface{}) {
	stdlog.Printf(format, v...)
}

// Println calls Output to print to the standard logger.
// Arguments are handled in the manner of fmt.Println.
func Println(v ...interface{}) {
	stdlog.Println(v...)
}

// Fatal is equivalent to Print() followed by a call to os.Exit(1).
func Fatal(v ...interface{}) {
	stdlog.Fatal(v...)
}

// Fatalf is equivalent to Printf() followed by a call to os.Exit(1).
func Fatalf(format string, v ...interface{}) {
	stdlog.Fatalf(format, v...)
}

// Fatalln is equivalent to Println() followed by a call to os.Exit(1).
func Fatalln(v ...interface{}) {
	stdlog.Fatalln(v...)
}

// Panic is equivalent to Print() followed by a call to panic().
func Panic(v ...interface{}) {
	stdlog.Panic(v...)
}

// Panicf is equivalent to Printf() followed by a call to panic().
func Panicf(format string, v ...interface{}) {
	stdlog.Panicf(format, v...)
}

// Panicln is equivalent to Println() followed by a call to panic().
func Panicln(v ...interface{}) {
	Panicln(v...)
}

// Output writes the output for a logging event. The string s contains
// the text to print after the prefix specified by the flags of the
// Logger. A newline is appended if the last character of s is not
// already a newline. Calldepth is the count of the number of
// frames to skip when computing the file name and line number
// if Llongfile or Lshortfile is set; a value of 1 will print the details
// for the caller of Output.
func Output(calldepth int, s string) error {
	return stdlog.Output(calldepth+1, s) // +1 for this frame
}