samredai commented on code in PR #4706: URL: https://github.com/apache/iceberg/pull/4706#discussion_r870675392
########## python/src/iceberg/catalog/base.py: ########## @@ -0,0 +1,251 @@ +# Licensed to the Apache Software Foundation (ASF) under one +# or more contributor license agreements. See the NOTICE file +# distributed with this work for additional information +# regarding copyright ownership. The ASF licenses this file +# to you under the Apache License, Version 2.0 (the +# "License"); you may not use this file except in compliance +# with the License. You may obtain a copy of the License at +# +# http://www.apache.org/licenses/LICENSE-2.0 +# +# Unless required by applicable law or agreed to in writing, +# software distributed under the License is distributed on an +# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY +# KIND, either express or implied. See the License for the +# specific language governing permissions and limitations +# under the License. + +from abc import ABC, abstractmethod +from typing import Any, Dict, List, Optional, Tuple + +from iceberg.schema import Schema +from iceberg.table.base import PartitionSpec, Table + + +class Catalog(ABC): + """Base Catalog for table operations like - create, drop, load, list and others. + + Attributes: + name(str): Name of the catalog + properties(Dict[str, str]): Catalog properties + """ + + def __init__(self, name: str, properties: Dict[str, str]): + self._name = name + self._properties = properties + + @property + def name(self) -> str: + return self._name + + @property + def properties(self) -> Dict[str, str]: + return self._properties + + @abstractmethod + def create_table( + self, + *, + namespace: Tuple[str, ...], + name: str, + schema: Schema, + location: Optional[str] = None, + partition_spec: Optional[PartitionSpec] = None, + properties: Optional[Dict[str, str]] = None, + ) -> Table: + """Create a table + + Args: + namespace: A tuple of table's namespace levels. Ex: ('com','org','dept') + name: Table name + schema: Table's schema. + location: Location for the table. Optional Argument. + partition_spec: PartitionSpec for the table. Optional Argument. + properties: Table metadata that can be a string based dictionary. Optional Argument. + + Returns: + Table: the created table instance + + Raises: + AlreadyExistsError: If a table with the name already exists + """ + + @abstractmethod + def table(self, namespace: Tuple[str, ...], name: str) -> Table: + """Loads the table's metadata and returns the table instance. + + You can also use this method to check for table existence using 'try catalog.table() except TableNotFoundError' + Note: This method does not load table's data in any form. + + Args: + namespace: A tuple of table's namespace levels. Ex: ('com','org','dept') + name: Table's name. + + Returns: + Table: the table instance with its metadata + + Raises: + TableNotFoundError: If a table with the name does not exist + """ + + @abstractmethod + def drop_table(self, namespace: Tuple[str, ...], name: str, purge: bool = True) -> None: + """Drop a table; Optionally purge all data and metadata files. + + Args: + namespace: A tuple of table's namespace levels. Ex: ('com','org','dept') + name: table name + purge: Defaults to true, which deletes all data and metadata files in the table; Optional Argument + + Raises: + TableNotFoundError: If a table with the name does not exist + """ + + @abstractmethod + def rename_table(self, from_namespace: Tuple[str, ...], from_name: str, to_namespace: Tuple[str, ...], to_name: str) -> Table: + """Rename a fully classified table name + + Args: + from_namespace: Existing table's namespace. A tuple of table's namespace levels. Ex: ('com','org','dept') + from_name: Existing table's name. + to_namespace: New Table namespace to be assigned. Tuple of namespace levels. Ex: ('com','org','new') + to_name: New Table name to be assigned. + + Returns: + Table: the updated table instance with its metadata + + Raises: + TableNotFoundError: If a table with the name does not exist + """ + + @abstractmethod + def replace_table( + self, + *, + namespace: Tuple[str, ...], + name: str, + schema: Schema, + location: Optional[str] = None, + partition_spec: Optional[PartitionSpec] = None, + properties: Optional[Dict[str, str]] = None, + ) -> Table: + """Starts a transaction and replaces the table with the provided spec. + + Args: + namespace: A tuple of table's namespace levels. Ex: ('com','org','dept') + name: Table name + schema: Table's schema. + location: Location for the table. Optional Argument. + partition_spec: PartitionSpec for the table. Optional Argument. + properties: Table metadata that can be a string based dictionary. Optional Argument. + + Returns: + Table: the replaced table instance with the updated state + + Raises: + TableNotFoundError: If a table with the name does not exist + """ + + @abstractmethod + def create_namespace(self, namespace: Tuple[str, ...], properties: Optional[Dict[str, str]] = None) -> None: + """Create a namespace in the catalog. + + Args: + namespace: The namespace to be created. Tuple of namespace levels. Ex: ('com','org','dept') + properties: A string dictionary of properties for the given namespace + + Raises: + AlreadyExistsError: If a namespace with the name already exists in the namespace + """ + + @abstractmethod + def drop_namespace(self, namespace: Tuple[str, ...]) -> None: + """Drop a namespace. + + Args: + namespace: The namespace to be dropped. Tuple of namespace levels. Ex: ('com','org','dept') + + Raises: + NamespaceNotFoundError: If a namespace with the name does not exist in the namespace + NamespaceNotEmptyError: If the namespace is not empty + """ + + @abstractmethod + def list_tables(self, namespace: Optional[Tuple[str, ...]] = None) -> List[Tuple[Tuple[str, ...], str]]: + """List tables under the given namespace in the catalog. + + If namespace not provided, will list all tables in the catalog. + + Args: + namespace: the namespace to search. Tuple of namespace levels. Ex: ('com','org','dept') + + Returns: + List[Tuple[str, str]]: list of tuple of table namespace and their names. + + Raises: + NamespaceNotFoundError: If a namespace with the name does not exist in the namespace + """ + + @abstractmethod + def list_namespaces(self) -> List[Tuple[str, ...]]: + """List namespaces from the given namespace. If not given, list top-level namespaces from the catalog. + + Returns: + List[Tuple[str, ...]]: a List of namespace, where each element is a Tuple of namespace levels. Ex: ('com','org','dept') + """ + + @abstractmethod + def load_namespace_metadata(self, namespace: Tuple[str, ...]) -> Dict[str, str]: + """Get metadata dictionary for a namespace. + + Args: + namespace: A Tuple of namespace levels. Ex: ('com','org','dept') + + Returns: + Dict[str, str]: a dictionary of properties for the given namespace + + Raises: + NamespaceNotFoundError: If a namespace with the name does not exist in the namespace + """ + + @abstractmethod + def set_namespace_metadata(self, namespace: Tuple[str, ...], metadata: Dict[str, str]) -> None: + """Update or remove metadata for a namespace. + + Note: Existing metadata is overridden, use get, mutate, and then set. + + Args: + namespace: A Tuple of namespace levels. Ex: ('com','org','dept') + metadata: a dictionary of properties for the given namespace + + Raises: + NamespaceNotFoundError: If a namespace with the name does not exist in the namespace + """ + + +class TableNotFoundError(Exception): Review Comment: This is the first time we'll be adding custom exceptions. Since these will probably be used in other parts of the library, I think we should create a file `src/iceberg/exceptions.py` at the root and define these there. Also, (mostly opinion here), I'd rather not override `__init__` just to provide a default message. I've actually found that default messages make debugging harder and I'd rather we simply define the exception types and raise more explicit messages based on the context where they're raise. _exceptions.py_ ```py class TableNotFoundError(Exception): """Raised when a referenced table cannot be found""" pass ``` Then we can require providing a more detailed message whenever it's raised: _catalog/base.py_ ```py raise TableNotFoundError(f"Cannot load table {table}, not found in catalog {catalog}") ``` ```py raise TableNotFoundError(f"Cannot drop table {table}, not found in catalog {catalog}") ``` -- 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: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
