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#
# Copyright (c) 2018 Red Hat, Inc.
#
# This program is free software; you can redistribute it and/or
# modify it under the terms of the GNU General Public License
# as published by the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program; if not, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
# 02110-1301, USA.
#
"""
ExitStatusMixins - Mixins for exceptions to associate distinguishing exit
status values
These mixins are defined based on the types of error that can occur.
Each mixin is assigned a specific exit status value to disambiguate the
error type via exit status of user-facing utilities.
The values start at 3 to provide distinction from common failure exit
statuses (1 - something went wrong, 2 - argument error) that may be produced
by user-facing utilities.
In accord with mixin best practices these mixins are to be specified
*before* an exception's superclass exception in the exception's definition.
This allows for a subsystem base exception to provide a subsystem-wide
exit status and for subsystem specific exceptions to specialize the
exit status as appropriate.
To avoid subclass proliferation simply to provide specific exit statuses
one can chose to create a subsystem base exception using any of the
ExitStatus hierachy classes (though, generally, one should probably only
use ExitStatus itself) and provide a specific exit status for an exception
at instantiation by passing any of the ExitStatus hierarchy classes as the
'exitStatus' instantiation parameter.
$Id: //eng/vdo-releases/magnesium/src/python/vdo/vdomgmnt/ExitStatusMixins.py#1 $
"""
class ExitStatus(object):
"""Base class for all ExistStatusMixins.
Provides a default exit status value to be interpreted solely as an
error occurred.
"""
_exitStatusMixinValue = 3
######################################################################
# Public methods
######################################################################
@property
def exitStatus(self):
if self._exitStatus is not None:
return self._exitStatus._exitStatusMixinValue
return self._exitStatusMixinValue;
######################################################################
# Overridden methods
######################################################################
def __init__(self, exitStatus = None, *args, **kwargs):
super(ExitStatus, self).__init__(*args, **kwargs)
self._exitStatus = exitStatus
if ((self._exitStatus is not None)
and (not issubclass(self._exitStatus, ExitStatus))):
raise TypeError(
"{0} is not an ExitStatus mixin".format(
type(self._exitStatus).__name__))
########################################################################
class DeveloperExitStatus(ExitStatus):
"""Used to represent an error condition due to a developer oversight.
"""
_exitStatusMixinValue = 4
########################################################################
class StateExitStatus(ExitStatus):
"""Used to represent an error condition due to the state of some entity.
"""
_exitStatusMixinValue = 5
########################################################################
class SystemExitStatus(ExitStatus):
"""Used to represent an error condition due to a failure on the part of
the operating system, hardware, etc.
"""
_exitStatusMixinValue = 6
########################################################################
class UserExitStatus(ExitStatus):
"""Used to represent an error condition due to the user; e.g., bad parameter,
insufficient permissions, etc.
"""
_exitStatusMixinValue = 7
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