Support for Multiple AEDT Instances

[atlanswer]

Hi. #3342 mentioned that some refactorings have been made to support multiple desktop instances in the future. So I'm wondering:

1. Is there a timeline for that to be implemented?

2. Before it arrives, the end users can try to achieve similar functionality by managing references to the desktop objects themselves. At least there's a workaround that is supposed to work for PyAEDT 0.7.

   Users can clear the _desktop_sessions dict after creating one Desktop instance to get to __init__ again. However, if starting_mode == "grpc", the DLL function pyaedt.generic.grpc_plugin.CreateAedtApplication seems to return a singleton, i.e., making every desktop wrapper object created to reference the latest one.

   Fallback to COM by settings.use_grpc_api = False can work. But currently, a lot of instance variables, methods, and properties are referencing the global variables such as the desktop object oDesktop stored in sys.modules["__main__"], which will be overwritten by subsequent initializations of new Desktop objects.

   I think one solution is to get rid of global references like self._main = sys.modules["__main__"]. For instance, setting the odesktop instance variable directly to the AEDT COM object oDesktop, or whatever wrapper the corresponding initialization function may return. Right now, instance variables and methods can be overridden by users but properties without setters couldn't.

   Is this solution the intended one? Are issues and PRs that replace these global references with local ones acceptable? For example:

   pyaedt/pyaedt/desktop.py

   Line 1047 in 09db4b3

   self._main.oDesktop = oApp.GetAppDesktop()

   
   

   pyaedt/pyaedt/desktop.py

   Line 632 in 09db4b3

   self.odesktop = self._main.oDesktop

   - self.odesktop = self._main.oDesktop
   + self.odesktop = oApp.GetAppDesktop()

   pyaedt/pyaedt/desktop.py

   Line 650 in 2a62fa5

   self.aedt_version_id = self._main.oDesktop.GetVersion()[0:6]

   - self.aedt_version_id = self._main.oDesktop.GetVersion()[0:6]
   + self.aedt_version_id = self.odesktop.GetVersion()[0:6]

Thanks. Keep up the good work. 👍

[Samuelopez-ansys]

@atlanswer Let us review your second bullet.

Regarding the first one, it is not a PyAEDT limitation, it is an AEDT issue, there is not timeline for that, but the development team is working on that.

@maxcapodi78

[Samuelopez-ansys]

We found a limitation in Linux to support multiple Desktop instances. But with this Pull request, it will be possible in Widnows:
#4371

[atlanswer]

Cool, thanks for the update.