Extend geofence tranform to accept failover lat/lng sources

[webbpinner]

Currently the geofence transform can only accept one lat/lng source. This feature request is to allow for a fallback lat/lng source should the first source become unavailable.

[davidpablocohn]

Would it make sense to allow boundary_file_name to be a list, with the transform trying them in order (only once, at initialization?). And similarly for boundary_dir_name? The list would only be traversed once, at initialization, though.

[webbpinner]

I don't know. I'd have to ask SIO as they are the team using it the most and who reported the issue with the lat/lng. If I was the tech I would probably prefer having only one file/dir to keep track of. I completely agree with having multiple options for lat/lng as sensor do fail either directly or due to a cabling/networking problem. I'll ping SIO to get more feedback. Good suggestion.