Refresh sys.path upon loading a new module

runhouse/resources/module.py

@@ -4,8 +4,10 @@
 import inspect
 import logging
 import os
+import site
 import sys
 from concurrent.futures import ThreadPoolExecutor
+from importlib import reload as importlib_reload
 from pathlib import Path
 from typing import Callable, Dict, List, Optional, Tuple, Type, Union
 
@@ -368,8 +370,15 @@ def _get_obj_from_pointers(module_path, module_name, obj_name, reload=True):
         """Helper method to load a class or function from a module path, module name, and class name."""
         if module_path:
             abs_path = str((Path.home() / module_path).expanduser().resolve())
-            sys.path.insert(0, abs_path)
-            logger.debug(f"Appending {module_path} to sys.path")
+            if not abs_path:
+                logger.debug(f"Could not find module path {module_path}")
+            elif abs_path not in sys.path:
+                sys.path.insert(0, abs_path)
+                logger.debug(f"Appending {module_path} to sys.path")
+
+        # This updates the sys.path with any new paths that have been added since the last time we imported
+        # e.g. if the user ran cluster.run(["pip install my_package"]) since this env was created.
+        importlib_reload(site)
 
         if module_name in obj_store.imported_modules and reload:
             importlib.invalidate_caches()