Feature Request: Add system:properties and system:env as sources

[kevin-canadian]

I would like to be able to specify system properties and/or environment variables as one potential source for properties in addition to files, especially when using the MERGE load type. Mainly I want to be able to conveniently override default values with system parameters.

Currently it is easy to add ALL system properties or environment variables to a config object. But I'd like to be able to specify the system as one potential source, rather than bloating my config object with everything.

Currently this can be done with a utility class, which checks if a property is in the config object before including new properties from the system. But it would be great if this was supported natively.

Specifically, I would like to be able to do something like the following.

@LoadPolicy(LoadType.MERGE)
@Sources({
  "system:properties",
  "system:env",
  "file:~/myconfig.properties",
  "file:/etc/myconfig.properties",
  "classpath:/myconfig.properties" })
public interface MyConfig extends Config {
  ...
}

In this case I would like the properties to be taken first from system properties, other from environment variables, otherwise from ~/myconfig.properties, etc.

[lviggiano]

👍 Good idea.

[StFS]

Hmm... that commit doesn't seem to do very much?

[lviggiano]

I merged this pull request #122:

a2b914d Revert LoadStrategyTest
083a539 Put FIRST and MERGE strategies into new test class
c6acd56 Add test system properties hot reload
5d5e855 make all tests pass
3f48e86 remove header template
85436e7 resolve #110

[StFS]

ahh ok... the close activity just looked weird because it only referenced the last commit. Sorry about that.

[lviggiano]

No problem; myself would have been confused as well.

[lviggiano]

@StFS please double check the code and the feature to ensure your use case is covered. If you (or @gintau) have time, some documentation on owner-site module, would be useful.