Storing a setting from within phoebus?

[daykin]

What is the preferred way to store a setting in settings.ini from phoebus? When the user opts in or out of my analytics plugin, I want to store the value.

[georgweiss]

Sorry for the delay.
An AppInstance may override save(Memento memento) to store something when application is closed, and pick up saved value in restore(Memento memento).

To save/restore outside the restore/save lifecycle you may need to roll your own, preferably in a directory used by the lifecycle. Locations.user() returns the (hidden) folder containing data created through the lifecycle API. Defaults to ~/.phoebus.

As for settings.ini... I would avoid manipulating it from Phoebus.

[kasemir]

Yes, we don't save preferences other than the "memento".
So you can store the state of a panel in the UI, but once you close that panel, nothing will be saved for that now non-existing panel.

We used to store the preferences like this:

1. Read preferences defaults
2. Check for persisted settings in $HOME/.phoebus/... and read those
3. Read preferences from *.ini files
4. Write end result via FileSystemPreferences to $HOME/.phoebus/...

Whenever you then changed the settings via java.util.prefs, the updated settings would again be written.

That resulted in two issues:
a) If you once ran with -settings /some/settings.ini, the result got persisted.
If you next ran without -settings ..., you would still get the settings from that last used settings.ini, somewhat unexpected.
This could really bite you if ran alarm-server -settings /file/for/alarms.ini and then the GUI: The GUI would now use settings that were meant for the alarm server!!
b) The FileSystemPreferences code which we had basically copied from the Linux preference implementation to get the exact same behavior on Linux, Windows and Mac contained calls to deprecated API.

So in #3041 we simplified. Remove our copy of FileSystemPreferences and simply do this:

1. Read preferences defaults
2. Read preferences from *.ini files
   ..done

You thus get the built-in defaults or what's added via a settings.ini in your product and finally -settings ... command line switches. Nothing else is unexpectedly read from some other files. But there's also nothing persisted any longer.