github.com/realcp1018/tinylog (go): Package log implements a simple logging package. It defines a type, Logger, with methods for formatting output. It also has a predefined 'standard' Logger accessible through helper functions Print[f|ln], Fatal[f|ln], and Panic[f|ln], which are easier to use than creating a Logger manually. That logger writes to standard error and prints the date and time of each logged message. Every log message is output on a separate line: if the message being printed does not end in a newline, the logger will add one. The Fatal functions call os.Exit(1) after writing the log message. The Panic functions call panic after writing the log message.  log.go is a copy of stdlib log from: https://github.com/golang/go/blob/master/src/log/log.go but I made some changes to stdlib log in the formatHeader() function(to pretty the output) this file(tiny.go) add some log levels to stdlib log and hardcoded some configs of lumberjack & logger flags
Keywords: golang|log