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License: MIT Go Report Card Coverage Status reference Mentioned in Awesome Go

debug logging tool inspired by

Why is it named kemba?

debug is more generally considered to be runtime/debug within Go. Since this takes heavy inspiration from my experiences using the npm module debug I wanted to find a word that was somewhat connected to the inspiration. According to Google translate "debug" in English translated to Icelandic results in "kemba".


The kemba logger reads the DEBUG and KEMBA environment variables to determine if a log line should be output. The logger outputs to STDERR.

When it is not set, the logger will immediately return, taking no action.

When the value is set (ex. DEBUG=example:*,tool:details and/or KEMBA=plugin:fxn:start), the logger will determine if it should be enabled when instantiated.

The value of these flags can be a simple regex alternative where a wildcard (*) are replaced with .* and all terms are prepended with ^ and appended with $. If a term does not include a wildcard, then an exact match it required.

Example of a wildcard in the middle of a tag string: DEBUG=example:*:fxn will match tags like [example:tag1:fxn, example:tag2:fxn, example:anything:fxn, ...]

To disabled colors, set the NOCOLOR environment variable to any value.


package main

import (


type myType struct {
	a, b int

// When the DEBUG or KEMBA environment variable is set to DEBUG=example:* the kemba logger will output to STDERR
func main () {
    k := kemba.New("example:tag")
    var x = []myType{
    	{1, 2},
    	{3, 4},
    k.Printf("%#v", x)
    // Output to os.Stderr
    // example:tag []main.myType{main.myType{a:1, b:2}, main.myType{a:3, b:4}} +0s

    // Artificial delay to demonstrate the time tagging
    time.Sleep(250 * time.Millisecond)
    k.Printf("%# v", x)

    // Artificial delay to demonstrate the time tagging
    time.Sleep(100 * time.Millisecond)
    // All result in the same output to os.Stderr
    // example:tag []main.myType{ +XXms
    // example:tag     {a:1, b:2},
    // example:tag     {a:3, b:4},
    // example:tag }

    // Create a new logger with an extended tag
    k1 := k.Extend("1")
    k1.Println("a string", 12, true)
    // Output to os.Stderr
    // example:tag:1 a string +0s
    // example:tag:1 int(12)
    // example:tag:1 bool(true)


  1. Fork the clok/kemba repo
  2. Use go >= 1.16
  3. Branch & Code
  4. Run linters 🧹 golangci-lint run
  5. Commit with a Conventional Commit
  6. Open a PR