Converting Spring Boot Property Variables to Environment Variables with Go

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Since I migrated my personal Spring Boot applications to run on Kubernetes, I've been using Spring Boot's environment variables support to configure the application.

After doing this manually for a while, I've found that it's time to automate it, so I've reached for Go as a means to provide a handy command-line program:

package main

import (

func convert(s string) string {
	s = strings.ReplaceAll(s, ".", "_")
	s = strings.ReplaceAll(s, "-", "")

	listRe := regexp.MustCompile(`\[([0-9]+)\]`)
	s = listRe.ReplaceAllString(s, "_${1}_")

	s = strings.ReplaceAll(s, "__", "_")
	return strings.ToUpper(s)

func main() {
	data, err := io.ReadAll(os.Stdin)
	if err != nil {
	propertyAndValue := strings.Split(strings.TrimSuffix(string(data), "\n"), "=")

	if len(propertyAndValue) == 1 {
	} else {
		fmt.Println(convert(propertyAndValue[0]) + "=" + propertyAndValue[1])

That can be run like so, handling the property's value, as well as list-based configuration:

$ go run main.go <<< spring.main.log-startup-info
$ go run main.go <<<
$ go run main.go <<< my.service[0].other

Written by Jamie Tanna's profile image Jamie Tanna on , and last updated on .

Content for this article is shared under the terms of the Creative Commons Attribution Non Commercial Share Alike 4.0 International, and code is shared under the Apache License 2.0.

#blogumentation #go #command-line #spring-boot.

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