diskimage-builder/diskimage_builder/block_device/level0/localloop.py
Ian Wienand 824a9e91c4 Add state to NodeBase class
Making the global state reference a defined part of the node makes
some parts of the block device processing easier and removes the need
for other global values.

The state is passed to PluginNodeBase.__init__() and expected to be
passed into all nodes as they are created.  NodeBase.__init__() is
updated with the new paramater 'state'.

The parameter is removed from the create() call as nodes can simply
reference it at any point as "self.state".

This is similar to 1cdc8b20373c5d582ea928cfd7334469ff36dbce, except it
is based on I68840594a34af28d41d9522addcfd830bd203b97 which loads the
node-list from pickled state for later cmd_* calls.  Thus we only
build the state *once*, at cmd_create() time as we build the node
list.

Change-Id: I468dbf5134947629f125504513703d6f2cdace59
2017-06-08 17:13:26 +10:00

140 lines
4.8 KiB
Python

# Copyright 2016 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
import os
import subprocess
from diskimage_builder.block_device.exception import \
BlockDeviceSetupException
from diskimage_builder.block_device.plugin import NodeBase
from diskimage_builder.block_device.plugin import PluginBase
from diskimage_builder.block_device.utils import parse_abs_size_spec
logger = logging.getLogger(__name__)
def image_create(filename, size):
logger.info("Create image file [%s]", filename)
with open(filename, "w") as fd:
fd.seek(size - 1)
fd.write("\0")
def image_delete(filename):
logger.info("Remove image file [%s]", filename)
os.remove(filename)
def loopdev_attach(filename):
logger.info("loopdev attach")
logger.debug("Calling [sudo losetup --show -f %s]", filename)
subp = subprocess.Popen(["sudo", "losetup", "--show", "-f",
filename], stdout=subprocess.PIPE)
rval = subp.wait()
if rval == 0:
# [:-1]: Cut of the newline
block_device = subp.stdout.read()[:-1].decode("utf-8")
logger.info("New block device [%s]", block_device)
return block_device
else:
logger.error("losetup failed")
raise BlockDeviceSetupException("losetup failed")
def loopdev_detach(loopdev):
logger.info("loopdev detach")
# loopback dev may be tied up a bit by udev events triggered
# by partition events
for try_cnt in range(10, 1, -1):
logger.debug("Calling [sudo losetup -d %s]", loopdev)
subp = subprocess.Popen(["sudo", "losetup", "-d",
loopdev])
rval = subp.wait()
if rval == 0:
logger.info("Successfully detached [%s]", loopdev)
return 0
else:
logger.error("loopdev detach failed")
# Do not raise an error - maybe other cleanup methods
# can at least do some more work.
logger.debug("Gave up trying to detach [%s]", loopdev)
return rval
class LocalLoopNode(NodeBase):
"""Level0: Local loop image device handling.
This class handles local loop devices that can be used
for VM image installation.
"""
def __init__(self, config, default_config, state):
logger.debug("Creating LocalLoop object; config [%s] "
"default_config [%s]", config, default_config)
super(LocalLoopNode, self).__init__(config['name'], state)
if 'size' in config:
self.size = parse_abs_size_spec(config['size'])
logger.debug("Image size [%s]", self.size)
else:
self.size = parse_abs_size_spec(default_config['image-size'])
logger.debug("Using default image size [%s]", self.size)
if 'directory' in config:
self.image_dir = config['directory']
else:
self.image_dir = default_config['image-dir']
self.filename = os.path.join(self.image_dir, self.name + ".raw")
def get_edges(self):
"""Because this is created without base, there are no edges."""
return ([], [])
def create(self, rollback):
logger.debug("[%s] Creating loop on [%s] with size [%d]",
self.name, self.filename, self.size)
rollback.append(lambda: image_delete(self.filename))
image_create(self.filename, self.size)
block_device = loopdev_attach(self.filename)
rollback.append(lambda: loopdev_detach(block_device))
if 'blockdev' not in self.state:
self.state['blockdev'] = {}
self.state['blockdev'][self.name] = {"device": block_device,
"image": self.filename}
logger.debug("Created loop name [%s] device [%s] image [%s]",
self.name, block_device, self.filename)
return
def umount(self, state):
loopdev_detach(state['blockdev'][self.name]['device'])
def cleanup(self, state):
pass
def delete(self, state):
image_delete(state['blockdev'][self.name]['image'])
class LocalLoop(PluginBase):
def __init__(self, config, defaults, state):
super(LocalLoop, self).__init__()
self.node = LocalLoopNode(config, defaults, state)
def get_nodes(self):
return [self.node]