InitLogger sets the internal logger instance to the given level and log file.

NewDerivedLoggerWithField returns a logger that inherits all properties of the parent logger, and add the given fields for each log entry.

NewLogger returns the package level logger.

NewLoggerWithField returns a logger that logs with the given fields.

Fields is a collection of field to be passed to the Logger.

Logger is for now, a type alias of Logrus.FieldLogger that defines a broad interface for logging.