const (
// Bits or'ed together to control what's printed. There is no control over the
// order they appear (the order listed here) or the format they present (as
// described in the comments). A colon appears after these items:
// 2009/01/23 01:23:23.123123 /a/b/c/d.go:23: message
Ldate = 1 << iota // the date: 2009/01/23
Ltime // the time: 01:23:23
Lmicroseconds // microsecond resolution: 01:23:23.123123. assumes Ltime.
Llongfile // full file name and line number: /a/b/c/d.go:23
Lshortfile // final file name element and line number: d.go:23. overrides Llongfile
LstdFlags = Ldate | Ltime // initial values for the standard logger
)
These flags define which text to prefix to each log entry generated by the Logger.
func Fatal(v ...interface{})
Fatal is equivalent to Print() followed by a call to os.Exit(1).
func Fatalf(format string, v ...interface{})
Fatalf is equivalent to Printf() followed by a call to os.Exit(1).
func Fatalln(v ...interface{})
Fatalln is equivalent to Println() followed by a call to os.Exit(1).
func Flags() int
Flags returns the output flags for the standard logger.
func Panic(v ...interface{})
Panic is equivalent to Print() followed by a call to panic().
func Panicf(format string, v ...interface{})
Panicf is equivalent to Printf() followed by a call to panic().
func Panicln(v ...interface{})
Panicln is equivalent to Println() followed by a call to panic().
func Prefix() string
Prefix returns the output prefix for the standard logger.
func Print(v ...interface{})
Print calls Output to print to the standard logger. Arguments are handled in the manner of fmt.Print.
func Printf(format string, v ...interface{})
Printf calls Output to print to the standard logger. Arguments are handled in the manner of fmt.Printf.
func Println(v ...interface{})
Println calls Output to print to the standard logger. Arguments are handled in the manner of fmt.Println.
func SetFlags(flag int)
SetFlags sets the output flags for the standard logger.
func SetOutput(w io.Writer)
SetOutput sets the output destination for the standard logger.
func SetPrefix(prefix string)
SetPrefix sets the output prefix for the standard logger.
type Logger struct {
// contains filtered or unexported fields
}
A Logger represents an active logging object that generates lines of output to an io.Writer. Each logging operation makes a single call to the Writer's Write method. A Logger can be used simultaneously from multiple goroutines; it guarantees to serialize access to the Writer.
▹ Example
func New(out io.Writer, prefix string, flag int) *Logger
New creates a new Logger. The out variable sets the destination to which log data will be written. The prefix appears at the beginning of each generated log line. The flag argument defines the logging properties.
func (l *Logger) Fatal(v ...interface{})
Fatal is equivalent to l.Print() followed by a call to os.Exit(1).
func (l *Logger) Fatalf(format string, v ...interface{})
Fatalf is equivalent to l.Printf() followed by a call to os.Exit(1).
func (l *Logger) Fatalln(v ...interface{})
Fatalln is equivalent to l.Println() followed by a call to os.Exit(1).
func (l *Logger) Flags() int
Flags returns the output flags for the logger.
func (l *Logger) Output(calldepth int, s string) error
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 used to recover the PC and is provided for generality, although at the moment on all pre-defined paths it will be 2.
func (l *Logger) Panic(v ...interface{})
Panic is equivalent to l.Print() followed by a call to panic().
func (l *Logger) Panicf(format string, v ...interface{})
Panicf is equivalent to l.Printf() followed by a call to panic().
func (l *Logger) Panicln(v ...interface{})
Panicln is equivalent to l.Println() followed by a call to panic().
func (l *Logger) Prefix() string
Prefix returns the output prefix for the logger.
func (l *Logger) Print(v ...interface{})
Print calls l.Output to print to the logger. Arguments are handled in the manner of fmt.Print.
func (l *Logger) Printf(format string, v ...interface{})
Printf calls l.Output to print to the logger. Arguments are handled in the manner of fmt.Printf.
func (l *Logger) Println(v ...interface{})
Println calls l.Output to print to the logger. Arguments are handled in the manner of fmt.Println.
func (l *Logger) SetFlags(flag int)
SetFlags sets the output flags for the logger.
func (l *Logger) SetPrefix(prefix string)
SetPrefix sets the output prefix for the logger.