Fix EE Import backoff Logic (#1959)

backend/danswer/utils/variable_functionality.py

@@ -37,9 +37,24 @@ def fetch_versioned_implementation(module: str, attribute: str) -> Any:
     module_full = f"ee.{module}" if is_ee else module
     try:
         return getattr(importlib.import_module(module_full), attribute)
-    except ModuleNotFoundError:
-        # try the non-ee version as a fallback
+    except ModuleNotFoundError as e:
+        logger.warning(
+            "Failed to fetch versioned implementation for %s.%s: %s",
+            module_full,
+            attribute,
+            e,
+        )
+
         if is_ee:
+            if "ee.danswer" not in str(e):
+                # If it's a non Danswer related import failure, this is likely because
+                # a dependent library has not been installed. Should raise this failure
+                # instead of letting the server start up
+                raise e
+
+            # Use the MIT version as a fallback, this allows us to develop MIT
+            # versions independently and later add additional EE functionality
+            # similar to feature flagging
             return getattr(importlib.import_module(module), attribute)
 
         raise