Catch delta table not found error

llmfoundry/command_utils/data_prep/convert_delta_to_json.py

@@ -21,6 +21,7 @@
 from llmfoundry.utils.exceptions import (
     ClusterDoesNotExistError,
     ClusterInvalidAccessMode,
+    DeltaTableNotFoundError,
     FailedToConnectToDatabricksError,
     FailedToCreateSQLConnectionError,
     FaultyDataPrepCluster,
@@ -503,6 +504,29 @@ def fetch(
                 raise InsufficientPermissionsError(str(e)) from e
             elif 'UC_NOT_ENABLED' in str(e):
                 raise UCNotEnabledError() from e
+            elif 'DELTA_TABLE_NOT_FOUND' in str(e):
+                err_str = str(e)
+                # Error string should be in this format:
+                # ---
+                # Error processing `catalog`.`volume_name`.`table_name`:
+                # [DELTA_TABLE_NOT_FOUND] Delta table `volume_name`.`table_name`
+                # doesn't exist.
+                # ---
+                parts = err_str.split('`')
+                if len(parts) < 7:
+                    # Failed to parse error, our codebase is brittle
+                    # with respect to the string representations of
+                    # errors in the spark library.
+                    catalog_name, volume_name, table_name = ['unknown'] * 3
+                else:
+                    catalog_name = parts[1]
+                    volume_name = parts[3]
+                    table_name = parts[5]
+                raise DeltaTableNotFoundError(
+                    catalog_name,
+                    volume_name,
+                    table_name,
+                ) from e
 
         if isinstance(e, InsufficientPermissionsError):
             raise

llmfoundry/utils/exceptions.py

@@ -30,6 +30,8 @@
     'MisconfiguredHfDatasetError',
     'DatasetTooSmallError',
     'RunTimeoutError',
+    'UCNotEnabledError',
+    'DeltaTableNotFoundError',
 ]
 
 ALLOWED_RESPONSE_KEYS = {'response', 'completion'}
@@ -530,5 +532,23 @@ class UCNotEnabledError(UserError):
     """Error thrown when user does not have UC enabled on their cluster."""
 
     def __init__(self) -> None:
-        message = f'Unity Catalog is not enabled on your cluster.'
+        message = 'Unity Catalog is not enabled on your cluster.'
         super().__init__(message)
+
+
+class DeltaTableNotFoundError(UserError):
+    """Error thrown when the delta table passed in training doesn't exist."""
+
+    def __init__(
+        self,
+        catalog_name: str,
+        volume_name: str,
+        table_name: str,
+    ) -> None:
+        message = f'Your data path {catalog_name}.{volume_name}.{table_name} does not exist. Please double check your delta table name'
+        super().__init__(
+            message=message,
+            catalog_name=catalog_name,
+            volume_name=volume_name,
+            table_name=table_name,
+        )

tests/a_scripts/data_prep/test_convert_delta_to_json.py

@@ -8,6 +8,7 @@
 from unittest.mock import MagicMock, mock_open, patch
 
 import grpc
+from pyspark.errors import AnalysisException
 
 from llmfoundry.command_utils.data_prep.convert_delta_to_json import (
     FaultyDataPrepCluster,
@@ -19,6 +20,7 @@
     iterative_combine_jsons,
     run_query,
 )
+from llmfoundry.utils.exceptions import DeltaTableNotFoundError
 
 
 class TestConvertDeltaToJsonl(unittest.TestCase):
@@ -139,25 +141,24 @@ def test_iterative_combine_jsons(self, mock_file: Any, mock_listdir: Any):
 
         mock_listdir.assert_called_once_with(json_directory)
         mock_file.assert_called()
-        """
-        Diagnostic print
-        for call_args in mock_file().write.call_args_list:
-            print(call_args)
-        --------------------
-        call('{')
-        call('"key"')
-        call(': ')
-        call('"value"')
-        call('}')
-        call('\n')
-        call('{')
-        call('"key"')
-        call(': ')
-        call('"value"')
-        call('}')
-        call('\n')
-        --------------------
-        """
+        # Diagnostic print
+        # for call_args in mock_file().write.call_args_list:
+        #     print(call_args)
+        # --------------------
+        # call('{')
+        # call('"key"')
+        # call(': ')
+        # call('"value"')
+        # call('}')
+        # call('\n')
+        # call('{')
+        # call('"key"')
+        # call(': ')
+        # call('"value"')
+        # call('}')
+        # call('\n')
+        # --------------------
+
         self.assertEqual(mock_file().write.call_count, 2)
 
     @patch(
@@ -582,3 +583,40 @@ def test_fetch_DT_grpc_error_handling(
 
         # Verify that fetch was called
         mock_fetch.assert_called_once()
+
+    @patch(
+        'llmfoundry.command_utils.data_prep.convert_delta_to_json.get_total_rows',
+    )
+    def test_fetch_nonexistent_table_error(
+        self,
+        mock_gtr: MagicMock,
+    ):
+        # Create a spark.AnalysisException with specific details
+        analysis_exception = AnalysisException(
+            message='[DELTA_TABLE_NOT_FOUND] yada yada',
+        )
+
+        # Configure the fetch function to raise the AnalysisException
+        mock_gtr.side_effect = analysis_exception
+
+        # Test inputs
+        method = 'dbsql'
+        delta_table_name = 'test_table'
+        json_output_folder = '/tmp/to/jsonl'
+
+        # Act & Assert
+        with self.assertRaises(DeltaTableNotFoundError) as context:
+            fetch(
+                method=method,
+                tablename=delta_table_name,
+                json_output_folder=json_output_folder,
+            )
+
+        # Verify that the DeltaTableNotFoundError contains the expected message
+        self.assertIn(
+            'Please double check your delta table name',
+            str(context.exception),
+        )
+
+        # Verify that get_total_rows was called
+        mock_gtr.assert_called_once()