[GitHub] [iceberg] rdblue commented on a diff in pull request #5332: [Python] S3fsFileIO, a FileIO that wraps s3fs

[GitBox <gi...@apache.org>]

rdblue commented on code in PR #5332:
URL: https://github.com/apache/iceberg/pull/5332#discussion_r933896122


##########
python/pyiceberg/io/s3fs.py:
##########
@@ -0,0 +1,235 @@
+# 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 s3fs"""
+
+from typing import Optional, Union
+
+from s3fs import S3FileSystem
+
+from pyiceberg.io.base import (
+    FileIO,
+    InputFile,
+    InputStream,
+    OutputFile,
+    OutputStream,
+)
+
+
+class S3fsInputStream(InputStream):
+    """A seekable wrapper for reading an S3 Object that abides by the InputStream protocol
+
+    Args:
+        s3_object(s3fs.core.S3File): An s3 object
+    """
+
+    def __init__(self, s3_object):
+        self._s3_object = s3_object
+
+    def read(self, size: int = -1) -> bytes:
+        """Read the byte content of the s3 object
+
+        Args:
+            size (int, optional): The number of bytes to read. Defaults to -1 which reads the entire file.
+
+        Returns:
+            bytes: The byte content of the file
+        """
+        return self._s3_object.read(length=size)
+
+    def seek(self, offset: int, whence: int = 0) -> int:
+        return self._s3_object.seek(loc=offset, whence=whence)
+
+    def tell(self) -> int:
+        return self._s3_object.tell()
+
+    def closed(self) -> bool:
+        return self._s3_object.closed
+
+    def close(self) -> None:
+        self._s3_object.close()
+
+
+class S3fsOutputStream(OutputStream):
+    """A wrapper for writing an S3 Object that abides by the OutputStream protocol
+
+    Args:
+        s3_object(s3fs.core.S3FileSystem): An s3 object
+    """
+
+    def __init__(self, s3_object):
+        self._s3_object = s3_object
+
+    def write(self, b: bytes) -> int:
+        """Write to the S3 Object
+
+        Args:
+            b(bytes): The bytes to write to the S3 Object
+
+        Returns:
+            int: The number of bytes written
+
+        Raises:
+            ValueError: When the file is closed
+        """
+        return self._s3_object.write(b)
+
+    def closed(self) -> bool:
+        """Returns whether the stream is closed or not"""
+        return self._s3_object.closed
+
+    def close(self) -> None:
+        """Closes the stream and uploads the bytes to S3"""
+        self._s3_object.close()
+
+
+class S3fsInputFile(InputFile):
+    """An input file implementation for the S3fsFileIO
+
+    Args:
+        location(str): An S3 URI
+
+    Attributes:
+        location(str): An S3 URI
+    """
+
+    def __init__(self, location: str, s3):
+        self._s3 = s3
+        super().__init__(location=location)
+
+    def __len__(self) -> int:
+        """Returns the total length of the file, in bytes"""
+        object_info = self._s3.info(self.location)
+        if object_info.get("Size"):  # s3fs versions seem inconsistent on the case used for size
+            return object_info["Size"]
+        elif object_info.get("size"):
+            return object_info["size"]
+        raise RuntimeError(f"Cannot retrieve object info: {self.location}")
+
+    def exists(self) -> bool:
+        """Checks whether the location exists"""
+        return self._s3.lexists(self.location)
+
+    def open(self) -> S3fsInputStream:
+        """Create an S3fsInputStream for reading the contents of the file
+
+        Returns:
+            S3fsInputStream: An S3fsInputStream instance for the file located at `self.location`
+        """
+        return S3fsInputStream(s3_object=self._s3.open(self.location, "rb"))
+
+
+class S3fsOutputFile(OutputFile):
+    """An output file implementation for the S3fsFileIO
+
+    Args:
+        location(str): An S3 URI
+
+    Attributes:
+        location(str): An S3 URI
+    """
+
+    def __init__(self, location: str, s3):
+        self._s3 = s3
+        super().__init__(location=location)
+
+    def __len__(self) -> int:
+        """Returns the total length of the file, in bytes"""
+        object_info = self._s3.info(self.location)
+        if object_info.get("Size"):  # s3fs versions seem inconsistent on the case used for size
+            return object_info["Size"]
+        elif object_info.get("size"):
+            return object_info["size"]
+        raise RuntimeError(f"Cannot retrieve object info: {self.location}")
+
+    def exists(self) -> bool:
+        """Checks whether the location exists"""
+        return self._s3.lexists(self.location)
+
+    def create(self, overwrite: bool = False) -> S3fsOutputStream:
+        """Create an S3fsOutputStream for reading the contents of the file
+
+        Args:
+            overwrite(bool): Whether to overwrite the file if it already exists
+
+        Returns:
+            S3fsOutputStream: A wrapper for writing to an s3 object located at self.location
+
+        Raises:
+            FileExistsError: If the file already exists at `self.location` and `overwrite` is False
+
+        Note:
+            If overwrite is set to False, a check is first performed to verify that the file does not exist.
+            This is not thread-safe and a possibility does exist that the file can be created by a concurrent
+            process after the existence check yet before the output stream is created. In such a case, the default
+            behavior will truncate the contents of the existing file when opening the output stream.
+        """
+        if not overwrite and self.exists():
+            raise FileExistsError(f"Cannot create file, file already exists: {self.location}")
+        self._s3.touch(self.location)
+        return S3fsOutputStream(s3_object=self._s3.open(self.location, "wb"))
+
+    def to_input_file(self) -> S3fsInputFile:
+        """Returns a new S3fsInputFile for the location at `self.location`"""
+        return S3fsInputFile(location=self.location, s3=self._s3)
+
+
+class S3fsFileIO(FileIO):
+    """A FileIO implementation that uses s3fs"""
+
+    def __init__(self, client_kwargs: Optional[dict] = None, **s3fs_filesystem_kwargs):
+        if client_kwargs:
+            self._s3_filesystem = S3FileSystem(client_kwargs=client_kwargs, **s3fs_filesystem_kwargs)
+        else:
+            self._s3_filesystem = S3FileSystem(**s3fs_filesystem_kwargs)

Review Comment:
   The default value of `client_kwargs` is `None`, so you shouldn't need the `if` / `else`. You can always call the one above.



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