57c9e0bb41
This patch introduces stevedore plugin mechanism for use with the block device layer. This makes it possible that other projects pass in their own block device plugins. Change-Id: Id3ea56aaf75f5a20a4e1b6ac2a68adb12c56b574 Signed-off-by: Andreas Florath <andreas@florath.net>
127 lines
4.7 KiB
Python
127 lines
4.7 KiB
Python
# Copyright 2016 Andreas Florath (andreas@florath.net)
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#
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# Licensed under the Apache License, Version 2.0 (the "License"); you may
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# not use this file except in compliance with the License. You may obtain
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# a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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# License for the specific language governing permissions and limitations
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# under the License.
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from diskimage_builder.block_device.blockdevicesetupexception \
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import BlockDeviceSetupException
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from diskimage_builder.block_device.plugin_base import NodePluginBase
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from diskimage_builder.block_device.utils import parse_abs_size_spec
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from diskimage_builder.graph.digraph import Digraph
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import logging
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import os
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import subprocess
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logger = logging.getLogger(__name__)
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class LocalLoop(NodePluginBase):
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"""Level0: Local loop image device handling.
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This class handles local loop devices that can be used
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for VM image installation.
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"""
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def __init__(self, config, default_config):
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logger.debug("Creating LocalLoop object; config [%s] "
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"default_config [%s]" % (config, default_config))
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if 'size' in config:
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self.size = parse_abs_size_spec(config['size'])
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logger.debug("Image size [%s]" % self.size)
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else:
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self.size = parse_abs_size_spec(default_config['image_size'])
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logger.debug("Using default image size [%s]" % self.size)
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if 'directory' in config:
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self.image_dir = config['directory']
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else:
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self.image_dir = default_config['image_dir']
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self.name = config['name']
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Digraph.Node.__init__(self, self.name)
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self.filename = os.path.join(self.image_dir, self.name + ".raw")
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def insert_edges(self, dg):
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"""Because this is created without base, there are no edges."""
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pass
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@staticmethod
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def image_create(filename, size):
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logger.info("Create image file [%s]" % filename)
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with open(filename, "w") as fd:
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fd.seek(size - 1)
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fd.write("\0")
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@staticmethod
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def _image_delete(filename):
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logger.info("Remove image file [%s]" % filename)
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os.remove(filename)
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@staticmethod
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def _loopdev_attach(filename):
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logger.info("loopdev attach")
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logger.debug("Calling [sudo losetup --show -f %s]", filename)
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subp = subprocess.Popen(["sudo", "losetup", "--show", "-f",
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filename], stdout=subprocess.PIPE)
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rval = subp.wait()
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if rval == 0:
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# [:-1]: Cut of the newline
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block_device = subp.stdout.read()[:-1].decode("utf-8")
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logger.info("New block device [%s]" % block_device)
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return block_device
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else:
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logger.error("losetup failed")
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raise BlockDeviceSetupException("losetup failed")
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@staticmethod
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def _loopdev_detach(loopdev):
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logger.info("loopdev detach")
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# loopback dev may be tied up a bit by udev events triggered
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# by partition events
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for try_cnt in range(10, 1, -1):
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logger.debug("Calling [sudo losetup -d %s]", loopdev)
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subp = subprocess.Popen(["sudo", "losetup", "-d",
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loopdev])
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rval = subp.wait()
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if rval == 0:
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logger.info("Successfully detached [%s]" % loopdev)
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return 0
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else:
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logger.error("loopdev detach failed")
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# Do not raise an error - maybe other cleanup methods
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# can at least do some more work.
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logger.debug("Gave up trying to detach [%s]" % loopdev)
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return rval
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def create(self, result, rollback):
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logger.debug("[%s] Creating loop on [%s] with size [%d]" %
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(self.name, self.filename, self.size))
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rollback.append(lambda: self._image_delete(self.filename))
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self.image_create(self.filename, self.size)
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block_device = self._loopdev_attach(self.filename)
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rollback.append(lambda: self._loopdev_detach(block_device))
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result[self.name] = {"device": block_device,
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"image": self.filename}
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logger.debug("Created loop name [%s] device [%s] image [%s]"
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% (self.name, block_device, self.filename))
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return
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def umount(self, state):
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self._loopdev_detach(state[self.name]['device'])
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def cleanup(self, state):
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pass
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def delete(self, state):
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self._image_delete(state[self.name]['image'])
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