samredai commented on a change in pull request #4081: URL: https://github.com/apache/iceberg/pull/4081#discussion_r810664660
########## File path: python/src/iceberg/io/pyarrow.py ########## @@ -0,0 +1,154 @@ +# 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. +"""FileIO implementation for reading and writing table files that uses pyarrow.fs + +This file contains a FileIO implementation that relies on the filesystem interface provided +by PyArrow. It relies on PyArrow's `from_uri` method that infers the correct filesystem +type to use. Theoretically, this allows the supported storage types to grow naturally +with the pyarrow library. +""" + +import os +from typing import Union +from urllib.parse import urlparse + +from pyarrow.fs import FileSystem, FileType + +from iceberg.io.base import FileIO, InputFile, InputStream, OutputFile, OutputStream + + +class PyArrowFile(InputFile, OutputFile): + """A combined InputFile and OutputFile implementation that uses a pyarrow filesystem to generate pyarrow.lib.NativeFile instances + + Args: + location(str): A URI or a path to a local file + + Attributes: + location(str): The URI or path to a local file for a PyArrowFile instance + exists(bool): Whether the file exists or not + filesystem(pyarrow.fs.FileSystem): An implementation of the FileSystem base class inferred from the location + + Examples: + >>> from iceberg.io.pyarrow import PyArrowFile + >>> input_file = PyArrowFile("s3://foo/bar.txt") + >>> file_content = input_file.open().read() # Read the contents of the PyArrowFile instance + >>> output_file = PyArrowFile("s3://baz/qux.txt") + >>> output_file.create().write(b'foobytes') # Write bytes to the PyArrowFile instance + """ + + def __init__(self, location: str): + parsed_location = urlparse(location) # Create a ParseResult from the uri + if not parsed_location.scheme: # If no scheme, assume the path is to a local file + self._filesystem, self._path = FileSystem.from_uri(os.path.abspath(location)) + else: + self._filesystem, self._path = FileSystem.from_uri(location) # Infer the proper filesystem + super().__init__(location=location) + + def __len__(self) -> int: + """Returns the total length of the file, in bytes""" + file = self._filesystem.open_input_file(self._path) + return file.size() + + @property + def exists(self) -> bool: + """Checks whether the file exists""" + file_info = self._filesystem.get_file_info(self._path) + return False if file_info.type == FileType.NotFound else True + + def open(self) -> InputStream: + """Opens the location using a PyArrow FileSystem inferred from the location + + Returns: + pyarrow.lib.NativeFile: A NativeFile instance for the file located at `self.location` + """ + input_file = self._filesystem.open_input_file(self._path) + if not isinstance(input_file, InputStream): + raise TypeError( + f"Object of type {type(input_file)} returned from PyArrowFile.open does not match the InputStream protocol." + ) + return input_file + + def create(self, overwrite: bool = False) -> OutputStream: + """Creates a writable pyarrow.lib.NativeFile for this PyArrowFile's location + + Args: + overwrite(bool): Whether to overwrite the file if it already exists + + Returns: + pyarrow.lib.NativeFile: A NativeFile instance for the file located at self.location + + Raises: + FileExistsError: If the file already exists at `self.location` and `overwrite` is False + """ + if not overwrite and self.exists: + raise FileExistsError( + f"A file already exists at this location. If you would like to overwrite it, set `overwrite=True`: {self.location}" + ) + output_file = self._filesystem.open_output_stream(self._path) + if not isinstance(output_file, OutputStream): + raise TypeError( + f"Object of type {type(output_file)} returned from PyArrowFile.create(...) does not match the OutputStream protocol." + ) + return output_file + + def to_input_file(self) -> "PyArrowFile": + """Returns a new PyArrowFile for the location of an existing PyArrowFile instance + + This method is included to abide by the OutputFile abstract base class. Since this implementation uses a single + PyArrowFile class (as opposed to separate InputFile and OutputFile implementations), this method effectively returns + a copy of the same instance. + """ + return PyArrowFile(self.location) Review comment: It definitely can, [updated](https://github.com/apache/iceberg/pull/4081/commits/f960ec9ee28bb50c5cf3fe68d20315f8682c3a33)! -- This is an automated message from the Apache Git Service. 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