Working with a docker image of a spring boot application I encoutered some issues: it is very difficult to set properties via docker secrets. Docker secrets are stored in the container as files. To simplify the configuration process some images(like postgres) let you define properties via environment variables in the PROPERTY_NAME=value style (like spring boot) but also in the PROPERTY_NAME_FILE=/path/to/file/with/value.
I changed the code that read system properties to, after attempting to read the system property and the environment variable, search a environment variable with the _FILE appended and read the content of the file in the path thus defined.
P.S.
This is my first time looking at this code, I have not understood things like the directory arrangement or the general working. I suppose that I have modified the correct file but I'm not sure(I've found it using the github code search feature querying for System.getenv and System.getProperty).
Plus, my code comments and function names are not very good, they should probably be modified.
Comment From: wilkinsona
Thanks for the proposal. This looks to overlap with Spring Boot's existing support for "config trees". If you were not already aware of that support, please read through the documentation to see if it meets your needs. If it does not, please open a new issue describing exactly what you want to do and why config trees do not meet your needs. I'm afraid we won't be able to merge this proposal as-is. Instead, we would want to consider expanding the existing config tree support.