Caller returns returns a Valuer that returns a pkg/file:line description of the caller.

NewStdLogger new a logger with writer.

ParseLevel parses a level string into a logger Level value.

Timestamp returns a timestamp Valuer with a custom time format.

Value return the function value.

With with logger fields.

LevelDebug is logger debug level.

LevelError is logger error level.

LevelFatal is logger fatal level.

LevelInfo is logger info level.

LevelKey is logger level key.

LevelWarn is logger warn level.

DefaultCaller is a Valuer that returns the file and line.

DefaultLogger is default logger.

DefaultTimestamp is a Valuer that returns the current wallclock time.

Logger logger 的接口只要是实现了这个接口的.

Level is a logger level.

Valuer is returns a log value.