freezer/freezer/engine/tar/tar_builders.py

# (c) Copyright 2014,2015 Hewlett-Packard Development Company, L.P.
#
# Licensed 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.


"""
Freezer Tar related functions
"""

from freezer.utils import utils


class TarCommandBuilder(object):
    """
    Building a tar cmd command. To build command invoke method build.
    """

    UNIX_TEMPLATE = (
        "{gnutar_path} --create {algo} --warning=none --no-check-device "
        "--one-file-system --preserve-permissions --same-owner "
        "--seek --ignore-failed-read")

    # local windows template
    WINDOWS_TEMPLATE = (
        "{gnutar_path} -c {algo} --incremental --unlink-first "
        "--ignore-zeros")

    LISTED_TEMPLATE = "{tar_command} --listed-incremental={listed_incremental}"

    DEREFERENCE_MODE = {'soft': '--dereference',
                        'hard': '--hard-dereference',
                        'all': '--hard-dereference --dereference'}

    def __init__(self, filepath, compression_algo, is_windows, tar_path=None):
        self.tar_path = tar_path or utils.tar_path()
        self.dereference = ''
        self.listed_incremental = None
        self.exclude = ''
        self.openssl_path = None
        self.encrypt_pass_file = None
        self.output_file = None
        self.filepath = filepath
        self.compression_algo = get_tar_flag_from_algo(compression_algo)
        self.is_windows = is_windows

    def set_listed_incremental(self, absolute_path):
        self.listed_incremental = absolute_path

    def set_exclude(self, exclude):
        self.exclude = exclude

    def set_dereference(self, mode):
        """
        Dereference hard and soft links according option choices.
            'soft' dereference soft links,
            'hard' dereference hardlinks,
            'all' dereference both.
            Default 'None'.
        """
        self.dereference = self.DEREFERENCE_MODE[mode]

    def set_encryption(self, encrypt_pass_file, openssl_path=None):
        self.openssl_path = openssl_path or utils.openssl_path()
        self.encrypt_pass_file = encrypt_pass_file

    def build(self):
        if self.is_windows:
            tar_command = self.WINDOWS_TEMPLATE.format(
                gnutar_path=self.tar_path, algo=self.compression_algo)
        else:
            tar_command = self.UNIX_TEMPLATE.format(
                gnutar_path=self.tar_path, algo=self.compression_algo)

        if self.dereference:
            tar_command = "{0} {1}".format(tar_command, self.dereference)

        if self.listed_incremental:
            tar_command = self.LISTED_TEMPLATE.format(
                tar_command=tar_command,
                listed_incremental=self.listed_incremental)

        if self.exclude:
            tar_command = '{tar_command} --exclude="{exclude}"'.format(
                tar_command=tar_command, exclude=self.exclude)

        tar_command = '{0} {1}'.format(tar_command, self.filepath)

        if self.encrypt_pass_file:
            openssl_cmd = "{openssl_path} enc -aes-256-cfb -pass file:{file}"\
                .format(openssl_path=self.openssl_path,
                        file=self.encrypt_pass_file)
            tar_command = '{0} | {1} && exit ${{PIPESTATUS[0]}}'\
                .format(tar_command, openssl_cmd)

        return tar_command


class TarCommandRestoreBuilder(object):
    WINDOWS_TEMPLATE = '{0} -x {1} --incremental --unlink-first ' \
        '--ignore-zeros'
    DRY_RUN_TEMPLATE = '{0} {1} --incremental --list ' \
        '--ignore-zeros --warning=none'
    UNIX_TEMPLATE = '{0} {1} --incremental --extract ' \
        '--ignore-zeros --warning=none --overwrite --directory {2}'
    OPENSSL_DEC = "{openssl_path} enc -d -aes-256-cfb -pass file:{file}"

    def __init__(self, restore_path, compression_algo, is_windows,
                 tar_path=None):
        self.dry_run = False
        self.is_windows = False
        self.openssl_path = None
        self.encrypt_pass_file = None
        self.tar_path = tar_path or utils.tar_path()
        self.restore_path = restore_path
        self.compression_algo = get_tar_flag_from_algo(compression_algo)
        self.is_windows = is_windows

    def set_dry_run(self):
        self.dry_run = True

    def set_encryption(self, encrypt_pass_file, openssl_path=None):
        self.openssl_path = openssl_path or utils.openssl_path()
        self.encrypt_pass_file = encrypt_pass_file

    def build(self):
        if self.dry_run:
            tar_command = self.DRY_RUN_TEMPLATE.format(self.tar_path,
                                                       self.compression_algo)
        elif self.is_windows:
            tar_command = self.WINDOWS_TEMPLATE.format(self.tar_path,
                                                       self.compression_algo)
        else:
            tar_command = self.UNIX_TEMPLATE.format(self.tar_path,
                                                    self.compression_algo,
                                                    self.restore_path)

        # Check if encryption file is provided and set the openssl decrypt
        # command accordingly
        if self.encrypt_pass_file:
            openssl_cmd = self.OPENSSL_DEC.format(
                openssl_path=self.openssl_path,
                file=self.encrypt_pass_file)
            tar_command = '{0} | {1} && exit ${{PIPESTATUS[0]}}'\
                .format(openssl_cmd, tar_command)
        return tar_command


def get_tar_flag_from_algo(compression):
    algo = {
        'gzip': '-z',
        'bzip2': '-j',
        'xz': '-J',
    }
    compression_exec = utils.get_executable_path(compression)
    if not compression_exec:
        raise Exception("Critical Error: {0} executable not found ".
                        format(compression))
    return algo.get(compression)