[Enhancement] Patch OmniStage.try_collect() with _proc alive checks (#1560)

Signed-off-by: Daniel Huang <daniel1.huang@intel.com>

tests/entrypoints/test_omni_diffusion.py

@@ -345,7 +345,7 @@ def _setup_multiprocessing_mocks(monkeypatch: pytest.MonkeyPatch, mocker: Mocker
     fake_process_instance = mocker.MagicMock()
     fake_process_instance.start = mocker.MagicMock()
     fake_process_instance.join = mocker.MagicMock()
-    fake_process_instance.is_alive = mocker.MagicMock(return_value=False)
+    fake_process_instance.is_alive = mocker.MagicMock(return_value=True)
     fake_process_instance.terminate = mocker.MagicMock()
     fake_process_class.return_value = fake_process_instance
 

vllm_omni/entrypoints/omni_stage.py

@@ -693,8 +693,14 @@ class OmniStage:
         assert self._out_q is not None
         try:
             return self._out_q.get_nowait()
-        except Exception:
-            return None
+        except queue.Empty:
+            pass
+        except Exception as e:
+            logger.error("Unexpected error when collecting OmniStage output queue:", exc_info=e)
+            self.stop_stage_worker()
+            raise
+        if self._proc is not None and not self._proc.is_alive():
+            raise RuntimeError(f"OmniStage Worker process died unexpectedly with exit code {self._proc.exitcode}")
 
     def process_engine_inputs(
         self,