sapling/eden/test_support/temporary_directory.py

#!/usr/bin/env python3
# Copyright (c) Facebook, Inc. and its affiliates.
#
# This software may be used and distributed according to the terms of the
# GNU General Public License version 2.

# pyre-strict

import abc
import logging
import os
import pathlib
import shutil
import tempfile
import types
import typing
from pathlib import Path
from typing import (
    Any,
    BinaryIO,
    Callable,
    Generic,
    Optional,
    TextIO,
    Tuple,
    Type,
    TypeVar,
    Union,
)


def cleanup_tmp_dir(tmp_dir: Path) -> None:
    """Clean up a temporary directory.

    This is similar to shutil.rmtree() but also handles removing read-only files and
    directories.  This function changes the permissions on files and directories if this
    is necessary to remove them.

    This is necessary for removing Eden checkout directories since "eden clone" makes
    the original mount point directory read-only.
    """
    # If we encounter an EPERM or EACCESS error removing a file try making its parent
    # directory writable and then retry the removal.
    def _remove_readonly(
        func: Callable[[Union[os.PathLike, str]], Any],  # pyre-fixme[2]
        path: Union[os.PathLike, str],
        exc_info: Tuple[Type[BaseException], BaseException, types.TracebackType],
    ) -> None:
        _ex_type, ex, _traceback = exc_info
        if path == tmp_dir:
            logging.warning(
                f"failed to remove temporary test directory {tmp_dir}: {ex}"
            )
            return
        if not isinstance(ex, PermissionError):
            logging.warning(f"error removing file in temporary directory {path}: {ex}")
            return

        try:
            # func() is the function that failed.
            # This is usually os.unlink() or os.rmdir().
            if func not in (os.unlink, os.rmdir):
                raise ex

            # pyre-fixme[6]: Expected `_PathLike[AnyStr]` for 1st param but got
            #  `Union[_PathLike[Any], str]`.
            parent_dir = os.path.dirname(path)
            os.chmod(parent_dir, 0o755)
            func(path)
        except OSError as ex:
            logging.warning(f"error removing file in temporary directory {path}: {ex}")
            return

    shutil.rmtree(tmp_dir, onerror=_remove_readonly)


class TempFileManager:
    """TempFileManager exists for managing a set of temporary files and directories.

    It creates all temporary files and directories in a single top-level directory,
    which can later be cleaned up in one pass.

    This helps make it a little easier to track temporary test artifacts while
    debugging, and helps make it easier to identify when tests have failed to clean up
    their temporary files.

    This is also necessary on Windows because the standard tempfile.NamedTemporaryFile
    class unfortunately does not work well there: the temporary files it creates cannot
    be opened by other processes.
    """

    _temp_dir: Optional[Path] = None
    _prefix: Optional[str]

    def __init__(self, prefix: Optional[str] = "eden_test.") -> None:
        self._prefix = prefix

    def __enter__(self) -> "TempFileManager":
        return self

    def __exit__(
        self,
        exc_type: Optional[Type[BaseException]],
        exc_value: Optional[BaseException],
        tb: Optional[types.TracebackType],
    ) -> None:
        self.cleanup(exc_type is not None)

    def cleanup(self, failure: bool = False) -> None:
        temp_dir = self._temp_dir
        if temp_dir is None:
            return

        cleanup_mode = os.environ.get("EDEN_TEST_CLEANUP", "always").lower()
        if cleanup_mode in ("0", "no", "false") or (
            failure and cleanup_mode == "success-only"
        ):
            print(f"Leaving behind eden test directory {temp_dir}")
        else:
            cleanup_tmp_dir(temp_dir)
        self._temp_dir = None

    def make_temp_dir(self, prefix: Optional[str] = None) -> Path:
        top_level = self.top_level_tmp_dir()
        path_str = tempfile.mkdtemp(prefix=prefix, dir=str(top_level))
        return Path(path_str)

    def make_temp_file(
        self, prefix: Optional[str] = None, mode: str = "r+"
    ) -> "TemporaryTextFile":
        top_level = self.top_level_tmp_dir()
        fd, path_str = tempfile.mkstemp(prefix=prefix, dir=str(top_level))
        file_obj = os.fdopen(fd, mode, encoding="utf-8")
        # pyre-fixme[6]: Expected `TextIO` for 1st param but got `IO[typing.Any]`.
        return TemporaryTextFile(file_obj, Path(path_str))

    def make_temp_binary(
        self, prefix: Optional[str] = None, mode: str = "rb+"
    ) -> "TemporaryBinaryFile":
        top_level = self.top_level_tmp_dir()
        fd, path_str = tempfile.mkstemp(prefix=prefix, dir=str(top_level))
        file_obj = os.fdopen(fd, mode)
        # pyre-fixme[6]: Expected `BinaryIO` for 1st param but got `IO[typing.Any]`.
        return TemporaryBinaryFile(file_obj, Path(path_str))

    def top_level_tmp_dir(self) -> Path:
        top = self._temp_dir
        if top is None:
            top = Path(tempfile.mkdtemp(prefix=self._prefix))
            self._temp_dir = top

        return top

    def set_tmp_prefix(self, prefix: str) -> None:
        if self._temp_dir is not None:
            logging.warning(
                f"cannot update temporary directory prefix to {prefix}: "
                f"temporary directory {self._temp_dir} was already created"
            )
            return
        self._prefix = prefix


IOType = TypeVar("IOType", TextIO, BinaryIO)
T = TypeVar("T")


class TemporaryFileBase(Generic[IOType]):
    """This class is largely equivalent to tempfile.NamedTemporaryFile,
    but it also works on Windows.  (The standard library NamedTemporaryFile class
    creates files that cannot be opened by other processes.)

    We don't have any logic for closing the file here since the entire containing
    directory will eventually be removed by TempFileManager.
    """

    file: IOType
    name: str
    path: Path

    def __init__(self, file: IOType, path: Path) -> None:
        self.file = file
        self.path = path
        self.name = str(path)

    def __getattr__(self, name: str) -> Any:  # pyre-fixme[3]
        if name in ("name", "path"):
            return self.__dict__[name]
        else:
            file = self.__dict__["file"]
            value = getattr(file, name)
            setattr(self, name, value)
            return value

    def __enter__(self: T) -> T:
        return self

    def __exit__(
        self,
        exc_type: Optional[Type[BaseException]],
        exc_value: Optional[BaseException],
        tb: Optional[types.TracebackType],
    ) -> None:
        self.file.close()


class TemporaryTextFile(TemporaryFileBase[TextIO]):
    pass


class TemporaryBinaryFile(TemporaryFileBase[BinaryIO]):
    pass


class TemporaryDirectoryMixin(metaclass=abc.ABCMeta):
    temp_file_manager: TempFileManager = TempFileManager()
    _temp_cleanup_added: bool = False

    def make_temporary_directory(self, prefix: Optional[str] = None) -> str:
        self._ensure_temp_cleanup()
        return str(self.temp_file_manager.make_temp_dir(prefix=prefix))

    def _ensure_temp_cleanup(self) -> None:
        if not self._temp_cleanup_added:
            self.addCleanup(self.temp_file_manager.cleanup)
            self._temp_cleanup_added = True

    def addCleanup(
        self, function: Callable[[], None], *args: Any, **kwargs: Any
    ) -> None:
        raise NotImplementedError()