Support for Spring Boot DevTools YAML Configuration

[ddcruver]

DevTools should support DevTools overrides formatted with yaml.

So in addition to reading in .spring-boot-devtools.properties it should also read in
.spring-boot-devtools.yaml. It could also read .spring-boot-devtools.yml but when both are provided then an order would need to be determined.

See DevToolsHomePropertiesPostProcessor

Side note why doesn't .spring-boot-devtools place folder at the root instead of making a hidden folder for future proofing of additional files.

Value Adds:

• YAML subjectively can provide better organization of properties
• You can define mulitple profiles in a YAML File

[philwebb]

Side note why doesn't .spring-boot-devtools place folder at the root instead of making a hidden folder for future proofing of additional files.

Good idea. If we add additional file support we could consider .config/spring-boot/ to align with https://specifications.freedesktop.org/basedir-spec/basedir-spec-latest.html

[ddcruver]

I don't recall if I have seen others follow the .config standard; most pollute the home directory or slightly better make a hidden folder of their choosing. If you do that I believe then on Windows you should use that platforms recommendations. I believe that is to store it in AppData (%LOCALAPPDATA%).

References:
Windows Shell Developer's Guide - Default Known Folders in Windows
Microsoft UWP Documentation

[ddcruver]

Here is a Python project https://github.com/ActiveState/appdirs that tries to address cross platform storage of configuration files per-user which on Linux appears to uses XDG spec and Windows uses Microsoft recommendations.

Maybe this can be used as a model of what to do.

See user_config_dir in https://github.com/ActiveState/appdirs/blob/master/appdirs.py.

[philwebb]

Closing in favor of PR #17915