[janbar]

In fact, the addon already handle the job once it succeeded the first handshake with the backend.
On a backend sleep or shutdown the addon receive an event from cppmyth (eventHandler) and then it go in a loop to sleep for times and retry to connect (every 5 sec). Once a connection succeeded because the backend becomes available, it go out of the loop and relaunch its great activity for our pleasure.

Since krypton Kodi seems to launch one time only the function ADDON_create() and never recall it. So at this point we have to do things to handshake with the backend or launch a thread to loop for future negociation. I choosen to handshake or cancel the negociation depending of what user wants: If the backend is up and the addon succeeded to connect, it launches these workers and returns OK.
If it fails to connect or handshake , it will send a magic packet (trying to wakeup the backend) and then will ask to user what to do by a GUI box. While user ask to retry, it will retry. Else it will leave and will be never restarted until the next startup of kodi.

With version 4.11.6 , I just added the loop to allow user to retry any time that necessary to handshake (in fact the time required by the backend to wakeup). Or maybe the time the user need to investigate why the backend is down.

Before the change, the loop wasn't required because kodi launched the ADDON_create in its loop until a permanent failure.