Add permissions check for delta table reading (#1522)

llmfoundry/command_utils/data_prep/convert_delta_to_json.py

@@ -22,6 +22,7 @@
     ClusterDoesNotExistError,
     FailedToConnectToDatabricksError,
     FailedToCreateSQLConnectionError,
+    InsufficientPermissionsError,
 )
 
 if TYPE_CHECKING:
@@ -454,6 +455,12 @@ def fetch(
             sparkSession,
         )
     except Exception as e:
+        from pyspark.errors import AnalysisException
+        if isinstance(e, AnalysisException):
+            if 'INSUFFICIENT_PERMISSIONS' in e.message:  # pyright: ignore
+                raise InsufficientPermissionsError(
+                    action=f'reading from {tablename}',
+                ) from e
         raise RuntimeError(
             f'Error in get rows from {tablename}. Restart sparkSession and try again',
         ) from e

llmfoundry/utils/exceptions.py

@@ -427,3 +427,11 @@ def __init__(
             window_size=window_size,
             loss_window=loss_window,
         )
+
+
+class InsufficientPermissionsError(UserError):
+    """Error thrown when the user does not have sufficient permissions."""
+
+    def __init__(self, action: str) -> None:
+        message = f'Insufficient permissions when {action}. Please check your permissions.'
+        super().__init__(message, action=action)