Description
I want to use docker-swarm secrets in my Dockerized Spring-Boot application. These secrets are mounted as special files into the docker container: the secret text is accessible by reading the file at /run/secrets/<secret_name>. This is deemed best-practice in secret handling regarding containers (as opposed to injecting the secret text as environment variable, which isn't even supported by docker-swarm).
It would be great if Spring-Boot offered a way to set a property's value from the content of a file so I can write something like this:
spring.data.mongodb.password=${fileContent./var/run/secrets/mongo_db_password}
This would be similar to how RandomValuePropertySource works. Looking at its source it should be straight forward to provide a PropertySource implementation for reading file content. However, I wasn't able to properly inject my custom PropertySource into the Spring-Boot application start up process.
I also wonder if there might be already some spring magic that would allow to set a property's value from file?
If this is a valid feature request, I'd be happy to help out with a pull request and a PropertySource implementation thats handled similar to the RandomValuePropertySource. Otherwise it would be great to provide some information on how I could properly inject my PropertySource into the start up process.