FIX: Background App initialization

doc/changelog.d/1026.fixed.md

@@ -0,0 +1 @@
+Process return code

doc/changelog.d/1030.fixed.md

@@ -0,0 +1 @@
+Background App initialization

src/ansys/mechanical/core/embedding/background.py

@@ -28,14 +28,14 @@
 import typing
 
 import ansys.mechanical.core as mech
+from ansys.mechanical.core.embedding import initializer
 from ansys.mechanical.core.embedding.poster import Poster
 import ansys.mechanical.core.embedding.utils as utils
 
 
 def _exit(background_app: "BackgroundApp"):
     """Stop the thread serving the Background App."""
     background_app.stop()
-    atexit.unregister(_exit)
 
 
 class BackgroundApp:
@@ -50,6 +50,7 @@ class BackgroundApp:
     def __init__(self, **kwargs):
         """Construct an instance of BackgroundApp."""
         if BackgroundApp.__app_thread is None:
+            initializer.initialize(kwargs.get("version"))
             BackgroundApp.__app_thread = threading.Thread(
                 target=self._start_app, kwargs=kwargs, daemon=True
             )
@@ -67,8 +68,6 @@ def new():
 
             self.post(new)
 
-        atexit.register(_exit, self)
-
     @property
     def app(self) -> mech.App:
         """Get the App instance of the background thread.
@@ -96,6 +95,7 @@ def stop(self) -> None:
     def _start_app(self, **kwargs) -> None:
         BackgroundApp.__app = mech.App(**kwargs)
         BackgroundApp.__poster = BackgroundApp.__app.poster
+        atexit.register(_exit, self)
         while True:
             if BackgroundApp.__stop_signaled:
                 break

src/ansys/mechanical/core/embedding/initializer.py

@@ -162,24 +162,22 @@
 
 def initialize(version: int = None):
     """Initialize Mechanical embedding."""
-    __check_python_interpreter_architecture()  # blocks 32 bit python
-    __check_for_mechanical_env()  # checks for mechanical-env in linux embedding
-
     global INITIALIZED_VERSION
+    if version is None:
+        version = _get_latest_default_version()
+
+    version = __check_for_supported_version(version=version)
+
     if INITIALIZED_VERSION is not None:
         if INITIALIZED_VERSION != version:
             raise ValueError(
                 f"Initialized version {INITIALIZED_VERSION} "
                 f"does not match the expected version {version}."
             )
-        return
+        return INITIALIZED_VERSION
 
-    if version is None:
-        version = _get_latest_default_version()
-
-    version = __check_for_supported_version(version=version)
-
-    INITIALIZED_VERSION = version
+    __check_python_interpreter_architecture()  # blocks 32 bit python
+    __check_for_mechanical_env()  # checks for mechanical-env in linux embedding
 
     __set_environment(version)
 
@@ -212,4 +210,5 @@
     # attach the resolver
     resolve(version)
 
+    INITIALIZED_VERSION = version
     return version

tests/embedding/test_background.py

@@ -40,7 +40,7 @@ def _run_background_app_test(
 
     subprocess_pass_expected = pass_expected
     if pass_expected and os.name != "nt":
-        if int(version) < 251 or testname == "multiple_instances":
+        if int(version) < 251:
             subprocess_pass_expected = False
 
     process, stdout, stderr = run_subprocess(