DefaultLogger returns default logger.

Error logs to the ERROR logs.

Errorf logs to the ERROR logs.

Errorln logs to the ERROR logs.

Fatal logs to the FATAL logs, then calls os.Exit(1).

Fatalf logs to the FATAL logs, then calls os.Exit(1).

Fatalln logs to the FATAL logs, then calls os.Exit(1).

Info logs to the INFO log.

Infof logs to the INFO log.

Infoln logs to the INFO log.

NewStdLogger creates a stdandard logger for logging to stderr.

SetDefaultLogger sets default logger.

V reports whether verbosity at the call site is at least the requested level.

Warning logs to the WARNING logs.

Warningf logs to the WARNING logs.

Warningln logs to the WARNING logs.

LevelDebug is for debug info.

SeverityError is for error.

SeverityFatal is for panic error.

SeverityInfo is for usual log.

SeverityWarning is for warning.

SilentLogger logs nothing.

Logger provides a set of methods to output log.

Verboser is an interface type that implements Info(f|ln) .

Level is log level of verboser.

Severity has four classes to correspond with log situation.