Golang Logging Library

The colorful and simple logging library for Golang.

What is this

Opinionated logging library that able to output to io.Reader with file descriptors (os.Stdout, os.Stderr, regular file, etc.) with automatic terminal color support.

The log serverity and behavior can be described as follows:

Severity	Description	Caller Info
Fatal	Unrecoverable error and automatically exit after logging	Yes
Error	Recoverable error but need attention	Yes
Warn	Minor error and does not output the caller info	No
Info	Informational message	No
Debug	Debug message, only shown when debug enabled	Yes
Trace	Trace message, only shown when debug enabled	No

Getting started

Add the go-log package using

go get github.com/withmandala/go-log

And import it to your package by

import (
    "github.com/withmandala/go-log"
)

Use the go-log package with

logger := log.New(os.Stderr)
logger.Info("Hi, this is your logger")

Write to a log file

f, err := os.Create("app.log")
if err != nil {
	fmt.Println(err)
	return
}
logger := log.New(f)

Color support

The library will try to automatically detect the io.Reader file descriptor when calling log.New() for color support. But, if you insist to use or not to use color, you can add .WithColor() or .WithoutColor() respectively.

// With color
logger := log.New(os.Stderr).WithColor()

// Without color
logger := log.New(os.Stderr).WithoutColor()

Debug output

The log library will suppress the .Debug() and .Trace() output by default. To enable or disable the debug output, call (Logger).WithDebug() or (Logger).WithoutDebug() respectively.

// Enable debugging
logger := log.New(os.Stderr).WithDebug()
// Print debug output
logger.Debug("Test debug output")
// Disable debug output
logger.WithoutDebug()
logger.Debug("Test debug output") // This message will not be printed

Be Quiet

If somehow the log is annoying to you, just shush it by calling (Logger).Quiet() and ALL log output will be disappear, although .Fatal() will silently quit the program with error. To re-enable the log output use (Logger).NoQuiet().

Mandala / go-log