Spring properties order-by-configurations

This library reorders *.properties files priorities depending on which @Configuration classes they're defined on and how those classes are linked via @Import. This enables you to define a stable ordering, making property resolution predictable.

Installation

Just install the latest version of org.framefork:spring-properties-order-by-configurations dependency, and everything should start working - the configuration autoloads in a Spring Boot project.

Currently, the oldest supported Spring Boot is 3.2+

Motivation

The author of this library typically structures their Spring Boot applications with the following illustrative modules:

• app (depends on core-business-logic)
• core-business-logic (depends on common and core-separate-module)
• core-separate-module (depends on common)
• commons

Where

• The app adds "entrypoints" (controllers, cli commands, etc.) and may also add some .properties file(s)
• The core-* have separate tests, and somewhat separate configurations with some .properties file(s)
• The .properties are loaded with @PropertySource(...) on a @Configuration class
• The core-* may want to define some "defaults" like spring.main.web-application-type=none, but the app would like it to be spring.main.web-application-type=servlet

With this, you might end up with working core-* but broken app because Spring may give the .properties in core-* a higher priority which causes the spring.main.web-application-type=servlet to be ignored.

This happens because Spring sorts the classes based on some arbitrary rule (or even better - randomly), and the only ordering you can rely on is when you put both @PropertySource's on the same @Configuration class. But that kinda defeats the purpose of splitting the application into modules.

I think that it's reasonable to assume, that if app depends on core-* it might want to be able to override some default values provided by the core-*, and this library solves that. It sorts the .properties based on the @Import()'s on your @Configuration classes, so that in app you can add @Import on some core-* @Configuration to say "I depend on this, allow me to override its properties".

For working example, look into the testing/ directory.