diskimage-builder/diskimage_builder/block_device/level4/fstab.py
Ian Wienand 1d1e4ccb3e Move rollback into NodeBase object
Currently we pass a reference to a global "rollback" list to create()
to keep rollback functions.  Other nodes don't need to know about
global rollback state, and by passing by reference we're giving them
the chance to mess it up for everyone else.

Add a "add_rollback()" function in NodeBase for create() calls to
register rollback calls within themselves.  As they hit rollback
points they can add a new entry.  lambda v arguments is much of a
muchness -- but this is similar to the standard atexit() call so with
go with that pattern.  A new "rollback()" call is added that the
driver will invoke on each node as it works its way backwards in case
of failure.

On error, nodes will have rollback() called in reverse order (which
then calls registered rollbacks in reverse order).

A unit test is added to test rollback behaviour

Change-Id: I65214e72c7ef607dd08f750a6d32a0b10fe97ac3
2017-06-08 17:14:20 +10:00

60 lines
1.8 KiB
Python

# Copyright 2017 Andreas Florath (andreas@florath.net)
#
# 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.
import logging
from diskimage_builder.block_device.plugin import NodeBase
from diskimage_builder.block_device.plugin import PluginBase
logger = logging.getLogger(__name__)
class FstabNode(NodeBase):
def __init__(self, config, state):
super(FstabNode, self).__init__(config['name'], state)
self.base = config['base']
self.options = config.get('options', 'defaults')
self.dump_freq = config.get('dump-freq', 0)
self.fsck_passno = config.get('fsck-passno', 2)
def get_edges(self):
edge_from = [self.base]
edge_to = []
return (edge_from, edge_to)
def create(self):
logger.debug("fstab create called [%s]", self.name)
if 'fstab' not in self.state:
self.state['fstab'] = {}
self.state['fstab'][self.base] = {
'name': self.name,
'base': self.base,
'options': self.options,
'dump-freq': self.dump_freq,
'fsck-passno': self.fsck_passno
}
class Fstab(PluginBase):
def __init__(self, config, defaults, state):
super(Fstab, self).__init__()
self.node = FstabNode(config, state)
def get_nodes(self):
return [self.node]