[QGIS-Developer] Skip loading plugin if errors

[matteo]

Hi devs,

I'm developing a Processing provider plugin that needs some external 
python packages. If these are not installed on the system, when starting 
QGIS and loading the plugin the error message pops up (of course).

Is there a way to have a "more friendly" message without opening the 
Stacktrace? For example creating a messagebox/bar with the message 
"Install the package...... else you cannot use the plugin"

I've added a simple try/except in the plugin classFactory method but I'm 
still stuck in the loop somewhere.

Thanks for any suggestion

Cheers

Matteo