python/pyspark/files.py

#
# 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.
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#

import os


__all__ = ["SparkFiles"]

from typing import cast, ClassVar, Optional, TYPE_CHECKING

if TYPE_CHECKING:
    from pyspark import SparkContext


class SparkFiles:

    """
    Resolves paths to files added through :meth:`SparkContext.addFile`.

    SparkFiles contains only classmethods; users should not create SparkFiles
    instances.
    """

    _root_directory: ClassVar[Optional[str]] = None
    _is_running_on_worker: ClassVar[bool] = False
    _sc: ClassVar[Optional["SparkContext"]] = None

    def __init__(self) -> None:
        raise NotImplementedError("Do not construct SparkFiles objects")

    @classmethod
    def get(cls, filename: str) -> str:
        """
        Get the absolute path of a file added through :meth:`SparkContext.addFile`.
        """
        path = os.path.join(SparkFiles.getRootDirectory(), filename)
        return os.path.abspath(path)

    @classmethod
    def getRootDirectory(cls) -> str:
        """
        Get the root directory that contains files added through
        :meth:`SparkContext.addFile`.
        """
        if cls._is_running_on_worker:
            return cast(str, cls._root_directory)
        else:
            # This will have to change if we support multiple SparkContexts:
            assert cls._sc is not None
            assert cls._sc._jvm is not None
            return cls._sc._jvm.org.apache.spark.SparkFiles.getRootDirectory()