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# -*- coding: utf-8 -*-
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#
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# Copyright 2012 GRNET S.A. All rights reserved.
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#
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# Redistribution and use in source and binary forms, with or
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# without modification, are permitted provided that the following
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# conditions are met:
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#
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#   1. Redistributions of source code must retain the above
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#      copyright notice, this list of conditions and the following
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#      disclaimer.
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#
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#   2. Redistributions in binary form must reproduce the above
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#      copyright notice, this list of conditions and the following
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#      disclaimer in the documentation and/or other materials
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#      provided with the distribution.
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#
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# THIS SOFTWARE IS PROVIDED BY GRNET S.A. ``AS IS'' AND ANY EXPRESS
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# OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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# WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
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# PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL GRNET S.A OR
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# CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
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# SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
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# LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
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# USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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# AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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# LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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# ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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# POSSIBILITY OF SUCH DAMAGE.
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#
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# The views and conclusions contained in the software and
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# documentation are those of the authors and should not be
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# interpreted as representing official policies, either expressed
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# or implied, of GRNET S.A.
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"""This package provides various classes for preparing different Operating
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Systems for image creation.
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"""
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from image_creator.util import FatalError
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import textwrap
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import re
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from collections import namedtuple
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from functools import wraps
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def os_cls(distro, osfamily):
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    """Given the distro name and the osfamily, return the appropriate class"""
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    module = None
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    classname = None
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    try:
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        module = __import__("image_creator.os_type.%s" % distro,
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                            fromlist=['image_creator.os_type'])
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        classname = distro.capitalize()
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    except ImportError:
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        module = __import__("image_creator.os_type.%s" % osfamily,
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                            fromlist=['image_creator.os_type'])
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        classname = osfamily.capitalize()
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    return getattr(module, classname)
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def add_prefix(target):
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    """Decorator that adds a prefix to the result of a function"""
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    def wrapper(self, *args):
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        prefix = args[0]
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        return [prefix + path for path in target(self, *args)]
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    return wrapper
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def sysprep(message, enabled=True, **kwargs):
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    """Decorator for system preparation tasks"""
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    def wrapper(method):
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        method.sysprep = True
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        method.enabled = enabled
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        method.executed = False
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        for key, val in kwargs.items():
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            setattr(method, key, val)
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        @wraps(method)
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        def inner(self, print_message=True):
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            if print_message:
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                self.out.output(message)
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            return method(self)
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        return inner
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    return wrapper
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def add_sysprep_param(name, type, default, descr, validate=lambda x: True):
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    """Decorator for __init__ that adds the definition for a system preparation
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    parameter in an instance of a os_type class
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    """
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    def wrapper(init):
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        @wraps(init)
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        def inner(self, *args, **kwargs):
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            init(self, *args, **kwargs)
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            self.needed_sysprep_params[name] = \
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                self.SysprepParam(type, default, descr, validate)
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            if default is not None:
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                self.sysprep_params[name] = default
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        return inner
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    return wrapper
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def del_sysprep_param(name):
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    """Decorator for __init__ that deletes a previously added sysprep parameter
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    definition from an instance of a os_type class.
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    """
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    def wrapper(func):
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        @wraps(func)
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        def inner(self, *args, **kwargs):
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            del self.needed_sysprep_params[name]
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            func(self, *args, **kwargs)
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        return inner
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    return wrapper
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class OSBase(object):
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    """Basic operating system class"""
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    SysprepParam = namedtuple('SysprepParam',
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                              ['type', 'default', 'description', 'validate'])
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    def __init__(self, image, **kargs):
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        self.image = image
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        self.root = image.root
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        self.out = image.out
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        self.needed_sysprep_params = {}
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        self.sysprep_params = \
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            kargs['sysprep_params'] if 'sysprep_params' in kargs else {}
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        self.meta = {}
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        self.mounted = False
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        # Many guestfs compilations don't support scrub
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        self._scrub_support = True
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        try:
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            self.image.g.available(['scrub'])
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        except RuntimeError:
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            self._scrub_support = False
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    def collect_metadata(self):
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        """Collect metadata about the OS"""
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        try:
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            if not self.mount(readonly=True):
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                raise FatalError("Unable to mount the media read-only")
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            self.out.output('Collecting image metadata ...', False)
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            self._do_collect_metadata()
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            self.out.success('done')
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        finally:
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            self.umount()
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        self.out.output()
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    def list_syspreps(self):
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        """Returns a list of sysprep objects"""
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        objs = [getattr(self, name) for name in dir(self)
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                if not name.startswith('_')]
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        return [x for x in objs if self._is_sysprep(x) and x.executed is False]
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    def sysprep_info(self, obj):
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        """Returns information about a sysprep object"""
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        assert self._is_sysprep(obj), "Object is not a sysprep"
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        SysprepInfo = namedtuple("SysprepInfo", "name description")
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        return SysprepInfo(obj.__name__.replace('_', '-'),
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                           textwrap.dedent(obj.__doc__))
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    def get_sysprep_by_name(self, name):
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        """Returns the sysprep object with the given name"""
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        error_msg = "Syprep operation %s does not exist for %s" % \
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                    (name, self.__class__.__name__)
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        method_name = name.replace('-', '_')
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        method = None
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        try:
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            method = getattr(self, method_name)
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        except AttributeError:
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            raise FatalError(error_msg)
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        if not self._is_sysprep(method):
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            raise FatalError(error_msg)
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        return method
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    def enable_sysprep(self, obj):
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        """Enable a system preparation operation"""
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        setattr(obj.im_func, 'enabled', True)
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    def disable_sysprep(self, obj):
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        """Disable a system preparation operation"""
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        setattr(obj.im_func, 'enabled', False)
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    def print_syspreps(self):
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        """Print enabled and disabled system preparation operations."""
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        syspreps = self.list_syspreps()
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        enabled = [sysprep for sysprep in syspreps if sysprep.enabled]
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        disabled = [sysprep for sysprep in syspreps if not sysprep.enabled]
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        wrapper = textwrap.TextWrapper()
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        wrapper.subsequent_indent = '\t'
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        wrapper.initial_indent = '\t'
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        wrapper.width = 72
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        self.out.output("Enabled system preparation operations:")
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        if len(enabled) == 0:
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            self.out.output("(none)")
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        else:
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            for sysprep in enabled:
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                name = sysprep.__name__.replace('_', '-')
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                descr = wrapper.fill(textwrap.dedent(sysprep.__doc__))
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                self.out.output('    %s:\n%s\n' % (name, descr))
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        self.out.output("Disabled system preparation operations:")
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        if len(disabled) == 0:
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            self.out.output("(none)")
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        else:
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            for sysprep in disabled:
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                name = sysprep.__name__.replace('_', '-')
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                descr = wrapper.fill(textwrap.dedent(sysprep.__doc__))
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                self.out.output('    %s:\n%s\n' % (name, descr))
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    def print_sysprep_params(self):
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        """Print the system preparation parameter the user may use"""
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        self.out.output("Needed system preparation parameters:")
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        if len(self.needed_sysprep_params) == 0:
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            self.out.output("(none)")
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            return
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        for name, param in self.needed_sysprep_params.items():
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            self.out.output("\t%s (%s): %s" %
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                            (param.description, name,
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                             self.sysprep_params[name] if name in
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                             self.sysprep_params else "(none)"))
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    def do_sysprep(self):
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        """Prepare system for image creation."""
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        self.out.output('Preparing system for image creation:')
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        if hasattr(self.image, "unsupported"):
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            self.out.warn(
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                "System preparation is disabled for unsupported media")
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            return
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        try:
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            if not self.mount(readonly=False):
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                raise FatalError("Unable to mount the media read-write")
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            enabled = [task for task in self.list_syspreps() if task.enabled]
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            size = len(enabled)
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            cnt = 0
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            for task in enabled:
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                cnt += 1
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                self.out.output(('(%d/%d)' % (cnt, size)).ljust(7), False)
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                task()
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                setattr(task.im_func, 'executed', True)
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        finally:
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            self.umount()
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        self.out.output()
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    def mount(self, readonly=False):
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        """Mount image."""
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        if getattr(self, "mounted", False):
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            return True
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        mount_type = 'read-only' if readonly else 'read-write'
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        self.out.output("Mounting the media %s ..." % mount_type, False)
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        if not self._do_mount(readonly):
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            return False
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        self.mounted = True
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        self.out.success('done')
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        return True
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    def umount(self):
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        """Umount all mounted filesystems."""
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        self.out.output("Umounting the media ...", False)
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        self.image.g.umount_all()
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        self.mounted = False
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        self.out.success('done')
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    def _is_sysprep(self, obj):
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        """Checks if an object is a sysprep"""
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        return getattr(obj, 'sysprep', False) and callable(obj)
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    @add_prefix
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    def _ls(self, directory):
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        """List the name of all files under a directory"""
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        return self.image.g.ls(directory)
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    @add_prefix
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    def _find(self, directory):
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        """List the name of all files recursively under a directory"""
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        return self.image.g.find(directory)
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    def _foreach_file(self, directory, action, **kargs):
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        """Perform an action recursively on all files under a directory.
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        The following options are allowed:
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        * maxdepth: If defined the action will not be performed on
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          files that are below this level of directories under the
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          directory parameter.
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        * ftype: The action will only be performed on files of this
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          type. For a list of all allowed filetypes, see here:
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          http://libguestfs.org/guestfs.3.html#guestfs_readdir
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        * exclude: Exclude all files that follow this pattern.
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        """
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        if not self.image.g.is_dir(directory):
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            self.out.warn("Directory: `%s' does not exist!" % directory)
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            return
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        maxdepth = None if 'maxdepth' not in kargs else kargs['maxdepth']
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        if maxdepth == 0:
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            return
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        # maxdepth -= 1
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        maxdepth = None if maxdepth is None else maxdepth - 1
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        kargs['maxdepth'] = maxdepth
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        exclude = None if 'exclude' not in kargs else kargs['exclude']
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        ftype = None if 'ftype' not in kargs else kargs['ftype']
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        has_ftype = lambda x, y: y is None and True or x['ftyp'] == y
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        for f in self.image.g.readdir(directory):
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            if f['name'] in ('.', '..'):
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                continue
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            full_path = "%s/%s" % (directory, f['name'])
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            if exclude and re.match(exclude, full_path):
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                continue
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            if has_ftype(f, 'd'):
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                self._foreach_file(full_path, action, **kargs)
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            if has_ftype(f, ftype):
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                action(full_path)
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    def _do_collect_metadata(self):
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        """helper method for collect_metadata"""
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        self.meta['ROOT_PARTITION'] = \
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            "%d" % self.image.g.part_to_partnum(self.root)
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        self.meta['OSFAMILY'] = self.image.g.inspect_get_type(self.root)
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        self.meta['OS'] = self.image.g.inspect_get_distro(self.root)
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        if self.meta['OS'] == "unknown":
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            self.meta['OS'] = self.meta['OSFAMILY']
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        self.meta['DESCRIPTION'] = \
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            self.image.g.inspect_get_product_name(self.root)
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    def _do_mount(self, readonly):
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        """helper method for mount"""
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        try:
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            self.image.g.mount_options(
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                'ro' if readonly else 'rw', self.root, '/')
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        except RuntimeError as msg:
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            self.out.warn("unable to mount the root partition: %s" % msg)
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            return False
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        return True
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