syun64 commented on code in PR #219: URL: https://github.com/apache/iceberg-python/pull/219#discussion_r1450524326
########## pyiceberg/io/pyarrow.py: ########## @@ -698,77 +708,143 @@ def before_field(self, field: pa.Field) -> None: def after_field(self, field: pa.Field) -> None: """Override this method to perform an action immediately after visiting a field.""" + def before_list_element(self, element: pa.Field) -> None: + """Override this method to perform an action immediately before visiting an element within a ListType.""" + + def after_list_element(self, element: pa.Field) -> None: + """Override this method to perform an action immediately after visiting an element within a ListType.""" + + def before_map_key(self, key: pa.Field) -> None: + """Override this method to perform an action immediately before visiting a key within a MapType.""" + + def after_map_key(self, key: pa.Field) -> None: + """Override this method to perform an action immediately after visiting a key within a MapType.""" + + def before_map_value(self, value: pa.Field) -> None: + """Override this method to perform an action immediately before visiting a value within a MapType.""" + + def after_map_value(self, value: pa.Field) -> None: + """Override this method to perform an action immediately after visiting a value within a MapType.""" + @abstractmethod - def schema(self, schema: pa.Schema, field_results: List[Optional[T]]) -> Optional[T]: + def schema(self, schema: pa.Schema, struct_result: T) -> T: """Visit a schema.""" @abstractmethod - def struct(self, struct: pa.StructType, field_results: List[Optional[T]]) -> Optional[T]: + def struct(self, struct: pa.StructType, field_results: List[T]) -> T: """Visit a struct.""" @abstractmethod - def list(self, list_type: pa.ListType, element_result: Optional[T]) -> Optional[T]: + def field(self, field: pa.Field, field_result: T) -> T: + """Visit a field.""" + + @abstractmethod + def list(self, list_type: pa.ListType, element_result: T) -> T: """Visit a list.""" @abstractmethod - def map(self, map_type: pa.MapType, key_result: Optional[T], value_result: Optional[T]) -> Optional[T]: + def map(self, map_type: pa.MapType, key_result: T, value_result: T) -> T: """Visit a map.""" @abstractmethod - def primitive(self, primitive: pa.DataType) -> Optional[T]: + def primitive(self, primitive: pa.DataType) -> T: """Visit a primitive type.""" def _get_field_id(field: pa.Field) -> Optional[int]: - for pyarrow_field_id_key in PYARROW_FIELD_ID_KEYS: - if field_id_str := field.metadata.get(pyarrow_field_id_key): - return int(field_id_str.decode()) + if field.metadata: + for pyarrow_field_id_key in PYARROW_FIELD_ID_KEYS: + if field_id_str := field.metadata.get(pyarrow_field_id_key): + return int(field_id_str.decode()) return None def _get_field_doc(field: pa.Field) -> Optional[str]: - for pyarrow_doc_key in PYARROW_FIELD_DOC_KEYS: - if doc_str := field.metadata.get(pyarrow_doc_key): - return doc_str.decode() + if field.metadata: + for pyarrow_doc_key in PYARROW_FIELD_DOC_KEYS: + if doc_str := field.metadata.get(pyarrow_doc_key): + return doc_str.decode() return None -class _ConvertToIceberg(PyArrowSchemaVisitor[Union[IcebergType, Schema]]): - def _convert_fields(self, arrow_fields: Iterable[pa.Field], field_results: List[Optional[IcebergType]]) -> List[NestedField]: - fields = [] - for i, field in enumerate(arrow_fields): - field_id = _get_field_id(field) - field_doc = _get_field_doc(field) - field_type = field_results[i] - if field_type is not None and field_id is not None: - fields.append(NestedField(field_id, field.name, field_type, required=not field.nullable, doc=field_doc)) - return fields - - def schema(self, schema: pa.Schema, field_results: List[Optional[IcebergType]]) -> Schema: - return Schema(*self._convert_fields(schema, field_results)) - - def struct(self, struct: pa.StructType, field_results: List[Optional[IcebergType]]) -> IcebergType: - return StructType(*self._convert_fields(struct, field_results)) - - def list(self, list_type: pa.ListType, element_result: Optional[IcebergType]) -> Optional[IcebergType]: +class _HasIds(PyArrowSchemaVisitor[bool]): + def schema(self, schema: pa.Schema, struct_result: bool) -> bool: + return struct_result + + def struct(self, struct: pa.StructType, field_results: List[bool]) -> bool: + return all(field_results) + + def field(self, field: pa.Field, field_result: bool) -> bool: + return all([_get_field_id(field) is not None, field_result]) + + def list(self, list_type: pa.ListType, element_result: bool) -> bool: element_field = list_type.value_field element_id = _get_field_id(element_field) - if element_result is not None and element_id is not None: - return ListType(element_id, element_result, element_required=not element_field.nullable) - return None + return element_result and element_id is not None - def map( - self, map_type: pa.MapType, key_result: Optional[IcebergType], value_result: Optional[IcebergType] - ) -> Optional[IcebergType]: + def map(self, map_type: pa.MapType, key_result: bool, value_result: bool) -> bool: key_field = map_type.key_field key_id = _get_field_id(key_field) value_field = map_type.item_field value_id = _get_field_id(value_field) - if key_result is not None and value_result is not None and key_id is not None and value_id is not None: - return MapType(key_id, key_result, value_id, value_result, value_required=not value_field.nullable) - return None + return all([key_id is not None, value_id is not None, key_result, value_result]) + + def primitive(self, primitive: pa.DataType) -> bool: + return True - def primitive(self, primitive: pa.DataType) -> IcebergType: + +class _ConvertToIceberg(PyArrowSchemaVisitor[Union[IcebergType, Schema]]): + """Converts PyArrowSchema to Iceberg Schema. Applies the IDs from name_mapping if provided.""" + + field_names: List[str] + name_mapping: Optional[NameMapping] + + def __init__(self, name_mapping: Optional[NameMapping] = None) -> None: + self.field_names = [] + self.name_mapping = name_mapping + + def _current_path(self) -> str: + return ".".join(self.field_names) + + def _get_field_id(self, field: pa.Field) -> int: Review Comment: @HonahX @Fokko - I wanted to get your thoughts on an idea. In spark, we can currently [create an Iceberg table](https://iceberg.apache.org/docs/latest/spark-writes/#creating-tables) without having to explicitly specify the schema and instead relying on spark-iceberg's conversion of spark dataframe schema to iceberg schema. It looks like we currently have no way of converting a Pyarrow Table schema to an Iceberg Schema that will allow a user to construct a PyIceberg easily. Right now, a user has to manually construct a PyIceberg schema from scratch. Would it make sense to pass an optional argument "**assign_ids**" to _ConvertToIceberg class where the user can ask the class to assign field IDs in order, instead of using the attached metadata field_id or the name_mapping? This optional argument will be used by pyarrow_to_schema, only when a user wants to parse a pyarrow schema to PyIceberg schema for the purpose of creating a new table, and should not be used when reading an Iceberg Table. -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For queries about this service, please contact Infrastructure at: us...@infra.apache.org --------------------------------------------------------------------- To unsubscribe, e-mail: issues-unsubscr...@iceberg.apache.org For additional commands, e-mail: issues-h...@iceberg.apache.org