refactor: extract exception handling to Function base class

rustyconover · claude · rustyconover · commit b99ee015cb9c · 2026-01-04T21:49:29.000-05:00
Move _should_terminate and add _create_error_output helper to the Function base class, eliminating duplication across ScalarFunctionGenerator, TableFunctionGenerator, and TableInOutGeneratorFunction. - Add _should_terminate() to Function (was duplicated 3x) - Add _create_error_output() helper to Function - Update _process_with_exception_handling in all 3 classes to use helper - Net reduction of 9 lines of code 🤖 Generated with [Claude Code](https://claude.com/claude-code) Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>
diff --git a/.beads/issues.jsonl b/.beads/issues.jsonl
@@ -8,15 +8,15 @@
 {"id":"vgi-python-79e","title":"Unify ProtocolInput classes with shared base","description":"ProtocolInput classes in scalar_function.py:151-166 and table_in_out_function.py:109-142 have similar structure with batch and metadata fields. The table_in_out version adds is_finalize logic. Create shared base ProtocolInput in protocol_types.py with table_in_out extending it.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.31917-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:16.240397-05:00"}
 {"id":"vgi-python-a99","title":"Add settings accessor to function base classes","description":"Add a property to access DuckDB settings values in function implementations.\n\nChanges needed:\n- Add 'settings: dict[str, str]' property to Function base class\n- Property should return self.invocation.duckdb_settings or empty dict\n- Add convenience method like 'get_setting(name, default=None)'\n- Update ScalarFunction, TableFunctionGenerator, TableInOutFunction\n\nExample usage in function:\ndef compute(self, batch):\n    tz = self.get_setting('timezone', 'UTC')\n    # or\n    tz = self.settings.get('timezone', 'UTC')","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:48.221602-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.171991-05:00","closed_at":"2026-01-04T13:20:41.171991-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-a99","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.738212-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-aad","title":"Design: DuckDB settings/pragmas access for VGI functions","description":"Design how VGI functions can declare required DuckDB settings/pragmas in their Meta class, and how these settings values should be passed during the bind phase.\n\nKey design decisions:\n1. How to declare required settings in function Meta (e.g., required_settings = ['timezone', 'threads'])\n2. How to add settings to Invocation dataclass\n3. How settings values should be accessed in function code\n4. Serialization format for settings in Arrow IPC\n\nRecommendation: Add 'duckdb_settings: dict[str, str] | None' to Invocation and 'required_settings: list[str]' to Meta class.","status":"closed","priority":1,"issue_type":"task","created_at":"2026-01-04T13:05:47.619105-05:00","created_by":"rusty","updated_at":"2026-01-04T13:11:13.197139-05:00","closed_at":"2026-01-04T13:11:13.197139-05:00","close_reason":"Design document created at docs/design-duckdb-settings.md"}
-{"id":"vgi-python-bi8","title":"Extract common _process_with_exception_handling into mixin","description":"The _process_with_exception_handling and _process_and_validate methods are duplicated across scalar_function.py:296-346, table_function.py:386-438, and table_in_out_function.py:586-642. All follow same pattern: try _process_and_validate, catch exceptions, return OutputComplete with error message. Extract to ProcessingMixin that all function types inherit from.","status":"open","priority":2,"issue_type":"task","created_at":"2026-01-04T20:06:41.02111-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:15.947758-05:00","dependencies":[{"issue_id":"vgi-python-bi8","depends_on_id":"vgi-python-6o0","type":"blocks","created_at":"2026-01-04T20:07:49.181408-05:00","created_by":"rusty"}]}
+{"id":"vgi-python-bi8","title":"Extract common _process_with_exception_handling into mixin","description":"The _process_with_exception_handling and _process_and_validate methods are duplicated across scalar_function.py:296-346, table_function.py:386-438, and table_in_out_function.py:586-642. All follow same pattern: try _process_and_validate, catch exceptions, return OutputComplete with error message. Extract to ProcessingMixin that all function types inherit from.","status":"in_progress","priority":2,"issue_type":"task","created_at":"2026-01-04T20:06:41.02111-05:00","created_by":"rusty","updated_at":"2026-01-04T21:44:11.818421-05:00","dependencies":[{"issue_id":"vgi-python-bi8","depends_on_id":"vgi-python-6o0","type":"blocks","created_at":"2026-01-04T20:07:49.181408-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-bku","title":"Change cardinality() method to property for consistency with output_schema","description":"Inconsistent access patterns: output_schema is a property but cardinality() is a method. Both return immutable data. Change cardinality() to a property for API consistency. Located in table_function.py:304-314.","status":"closed","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:53.211782-05:00","created_by":"rusty","updated_at":"2026-01-04T21:33:10.617152-05:00","closed_at":"2026-01-04T21:33:10.617152-05:00","close_reason":"PR #6 created: https://github.com/Query-farm/vgi-python/pull/6"}
 {"id":"vgi-python-bqb","title":"Update worker to handle DuckDB settings during bind","description":"Update vgi/worker.py to process DuckDB settings from Invocation during the bind phase.\n\nChanges needed:\n- Read settings from invocation.duckdb_settings\n- Validate that all required_settings (from Meta) are present in invocation\n- Pass settings to function instance for access\n- Log settings usage for debugging\n\nThe worker should validate settings early in bind to fail fast if required settings are missing.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:48.04037-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.17079-05:00","closed_at":"2026-01-04T13:20:41.17079-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-bqb","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.714281-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-c2b","title":"Add duckdb_settings field to Invocation class","description":"Update vgi/invocation.py to add a duckdb_settings field to the Invocation dataclass.\n\nChanges needed:\n- Add 'duckdb_settings: dict[str, str] | None = None' field to Invocation\n- Update serialize() to include settings in Arrow IPC batch\n- Update deserialize() to read settings from Arrow IPC batch\n- Handle None case (no settings requested)\n\nSerialization: Use a struct field with string key-value pairs or a map type.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:47.765077-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.167817-05:00","closed_at":"2026-01-04T13:20:41.167817-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-c2b","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.664038-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-e37","title":"move Invocation from function.py out to own file","description":"The Invocation clas is kind of seperate from functions, so it should be in its own file.  Move it and all of its other associated classes like InvocationType to its own file","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T09:18:46.605941-05:00","created_by":"rusty","updated_at":"2026-01-04T09:24:37.922675-05:00","closed_at":"2026-01-04T09:24:37.922675-05:00","close_reason":"Closed"}
 {"id":"vgi-python-e9q","title":"Unify ProtocolOutput classes with shared base","description":"ProtocolOutput classes in table_function.py:177-224 and table_in_out_function.py:144-207 share similar metadata() method and from_process_result() classmethod. The table_in_out version adds status field. Create shared base with table_in_out extending it for status support.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.45014-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:16.371419-05:00"}
 {"id":"vgi-python-ivf","title":"Add required_settings to function Meta class","description":"Update function metadata to support declaring required DuckDB settings.\n\nChanges needed:\n- Add 'required_settings: list[str]' to FunctionMeta in vgi/metadata.py\n- Update Meta class resolution in vgi/function.py\n- Add validation that required_settings is a list of strings\n- Make it available via get_metadata() for introspection\n\nExample usage:\nclass MyFunction(TableInOutFunction):\n    class Meta:\n        required_settings = ['timezone', 'threads']","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:47.903747-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.169516-05:00","closed_at":"2026-01-04T13:20:41.169516-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-ivf","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.690253-05:00","created_by":"rusty"}]}
 {"id":"vgi-python-j4t","title":"Update client to pass DuckDB settings in Invocation","description":"Update vgi/client/client.py to support passing DuckDB settings.\n\nChanges needed:\n- Add 'duckdb_settings: dict[str, str] | None = None' parameter to relevant methods\n- Include settings in Invocation creation\n- Add helper to query function's required_settings from metadata\n\nThe client needs to know what settings to pass. Options:\n1. Client queries worker for function metadata first\n2. Settings passed explicitly by caller\n3. Client introspects function class if available locally","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T13:05:48.358656-05:00","created_by":"rusty","updated_at":"2026-01-04T13:20:41.173178-05:00","closed_at":"2026-01-04T13:20:41.173178-05:00","close_reason":"Implementation complete, all tests pass","dependencies":[{"issue_id":"vgi-python-j4t","depends_on_id":"vgi-python-aad","type":"blocks","created_at":"2026-01-04T13:06:13.761572-05:00","created_by":"rusty"}]}
-{"id":"vgi-python-kz4","title":"Rename TableInOutGeneratorFunction to TableInOutGenerator for consistency","description":"Naming inconsistency: TableFunctionGenerator uses *Generator suffix, but TableInOutGeneratorFunction uses *GeneratorFunction suffix. Rename TableInOutGeneratorFunction to TableInOutGenerator for consistency. Also consider renaming ScalarFunctionGenerator if needed.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.581028-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:16.506499-05:00"}
+{"id":"vgi-python-kz4","title":"Rename TableInOutGeneratorFunction to TableInOutGenerator for consistency","description":"Naming inconsistency: TableFunctionGenerator uses *Generator suffix, but TableInOutGeneratorFunction uses *GeneratorFunction suffix. Rename TableInOutGeneratorFunction to TableInOutGenerator for consistency. Also consider renaming ScalarFunctionGenerator if needed.","status":"closed","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:41.581028-05:00","created_by":"rusty","updated_at":"2026-01-04T21:43:58.141038-05:00","closed_at":"2026-01-04T21:43:58.141038-05:00","close_reason":"PR #7 created: https://github.com/Query-farm/vgi-python/pull/7"}
 {"id":"vgi-python-odi","title":"Change max_processes from method to property in Function hierarchy","description":"Refactor max_processes from a method to a property across the Function class hierarchy (Function, ScalarFunction, TableFunctionGenerator, TableInOutFunction, etc.). This makes the API more consistent since max_processes is effectively a constant per function class and properties are more idiomatic for such values.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T11:25:29.750648-05:00","created_by":"rusty","updated_at":"2026-01-04T11:50:57.566545-05:00","closed_at":"2026-01-04T11:50:57.566545-05:00","close_reason":"Closed"}
 {"id":"vgi-python-p91","title":"Move exception classes from function.py to own file","description":"Move InitIdentifierError and SchemaValidationError from vgi/function.py to a new vgi/exceptions.py file. Update imports in function.py and any other files that reference these exceptions.","status":"closed","priority":2,"issue_type":"task","created_at":"2026-01-04T09:12:28.058227-05:00","created_by":"rusty","updated_at":"2026-01-04T09:17:52.477661-05:00","closed_at":"2026-01-04T09:17:52.477661-05:00","close_reason":"Closed"}
 {"id":"vgi-python-r3t","title":"Consolidate test client infrastructure in testing.py","description":"testing.py has three test client classes (FunctionTestClient, TableFunctionTestClient, ScalarFunctionTestClient) with shared infrastructure patterns. Extend _BaseTestClient pattern to reduce code duplication. Consider using a single unified client with method dispatch based on function type.","status":"open","priority":3,"issue_type":"task","created_at":"2026-01-04T20:06:53.913912-05:00","created_by":"rusty","updated_at":"2026-01-04T20:07:38.132591-05:00"}
diff --git a/vgi/function.py b/vgi/function.py
@@ -42,10 +42,12 @@
 import structlog
 
 import vgi.ipc_utils
+import vgi.log
 from vgi.exceptions import ExecutionIdentifierError, SchemaValidationError
 from vgi.function_storage import FunctionStorage, FunctionStorageSqlite
 from vgi.invocation import InitResult, Invocation
 from vgi.metadata import MetadataMixin, ResolvedMetadata
+from vgi.output_complete import OutputComplete
 
 __all__ = [
     "Function",
@@ -584,6 +586,22 @@ def _validate_output_schema(self, batch: pa.RecordBatch) -> None:
                 context=f"output from {type(self).__name__}",
             )
 
+    @final
+    def _should_terminate(self, result: OutputComplete) -> bool:
+        """Check if processing should terminate due to an exception."""
+        return (
+            result.log_message is not None
+            and result.log_message.level == vgi.log.Level.EXCEPTION
+        )
+
+    @final
+    def _create_error_output(self, exception: Exception) -> OutputComplete:
+        """Create an OutputComplete with error message from exception."""
+        return OutputComplete(
+            batch=self.empty_output_batch,
+            log_message=vgi.log.Message.from_exception(exception),
+        )
+
     @property
     def input_schema(self) -> pa.Schema:
         """Return the input schema from the invocation.
diff --git a/vgi/scalar_function.py b/vgi/scalar_function.py
@@ -309,18 +309,9 @@ def _process_with_exception_handling(
         try:
             return self._process_and_validate(generator, input_batch)
         except Exception as e:
-            return OutputComplete(
-                batch=self.empty_output_batch,
-                log_message=vgi.log.Message.from_exception(e),
-            )
+            return self._create_error_output(e)
 
-    @final
-    def _should_terminate(self, result: OutputComplete) -> bool:
-        """Check if processing should terminate due to an exception."""
-        return (
-            result.log_message is not None
-            and result.log_message.level == vgi.log.Level.EXCEPTION
-        )
+    # _should_terminate inherited from Function
 
     @abstractmethod
     def process(self, batch: pa.RecordBatch) -> ScalarOutputGenerator:
diff --git a/vgi/table_function.py b/vgi/table_function.py
@@ -385,18 +385,9 @@ def _process_with_exception_handling(
         except StopIteration:
             raise
         except Exception as e:
-            return OutputComplete(
-                batch=self.empty_output_batch,
-                log_message=vgi.log.Message.from_exception(e),
-            )
+            return self._create_error_output(e)
 
-    @final
-    def _should_terminate(self, result: OutputComplete) -> bool:
-        """Check if processing should terminate due to an exception."""
-        return (
-            result.log_message is not None
-            and result.log_message.level == vgi.log.Level.EXCEPTION
-        )
+    # _should_terminate inherited from Function
 
     def process(self) -> OutputGenerator:
         """Process batches during the DATA phase.
diff --git a/vgi/table_in_out_function.py b/vgi/table_in_out_function.py
@@ -583,18 +583,9 @@ def _process_with_exception_handling(
         try:
             return self._process_and_validate(generator, batch)
         except Exception as e:
-            return OutputComplete(
-                batch=self.empty_output_batch,
-                log_message=vgi.log.Message.from_exception(e),
-            )
+            return self._create_error_output(e)
 
-    @final
-    def _should_terminate(self, result: OutputComplete) -> bool:
-        """Check if processing should terminate due to an exception."""
-        return (
-            result.log_message is not None
-            and result.log_message.level == vgi.log.Level.EXCEPTION
-        )
+    # _should_terminate inherited from Function
 
     def process(self, batch: pa.RecordBatch) -> OutputGenerator:
         """Process input batches during the DATA phase.
