b85de3cd9e
A couple of things going on, but I think it makes sense to do them atomically. The NodeBase.create() argument "results" is the global state dictionary that will be saved to "state.json", and re-loaded in later phases and passed to them as the argument "state". So for consistency, call this argument "state" (this fits with the change out to start building the state dictionary earlier in the PluginBase.__init__() calls). Since the "state" is a pretty important part of how everything works, move it into a separate object. This is treated as essentially a singleton. It bundles it nicely together for some added documentation [1]. We move instantiation of this object out of the generic BlockDevice.__init__() call and into the actual cmd_* drivers. This is because there's two distinct instantiation operations -- creating a new state (during cmd_create) and loading an existing state (other cmd_*). This is also safer -- since we know the cmd_* arguments are looking for an existing state.json, we will fail if it somehow goes missing. To more fully unit test this, some testing plugins and new entry-points are added. These add known state values which we check for. These should be a good basis for further tests. [1] as noted, we could probably do some fun things in the future like make this implement a dictionary and have some saftey features like r/o keys. Change-Id: I90eb711b3e9b1ce139eb34bdf3cde641fd06828f
176 lines
7.1 KiB
Python
176 lines
7.1 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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import logging
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import os
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from subprocess import CalledProcessError
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from diskimage_builder.block_device.exception import \
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BlockDeviceSetupException
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from diskimage_builder.block_device.level1.mbr import MBR
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from diskimage_builder.block_device.level1.partition import PartitionNode
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from diskimage_builder.block_device.plugin import PluginBase
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from diskimage_builder.block_device.utils import exec_sudo
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from diskimage_builder.block_device.utils import parse_abs_size_spec
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from diskimage_builder.block_device.utils import parse_rel_size_spec
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logger = logging.getLogger(__name__)
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class Partitioning(PluginBase):
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def __init__(self, config, default_config):
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logger.debug("Creating Partitioning object; config [%s]", config)
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super(Partitioning, self).__init__()
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# Because using multiple partitions of one base is done
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# within one object, there is the need to store a flag if the
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# creation of the partitions was already done.
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self.already_created = False
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# Parameter check
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if 'base' not in config:
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raise BlockDeviceSetupException("Partitioning config needs 'base'")
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self.base = config['base']
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if 'partitions' not in config:
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raise BlockDeviceSetupException(
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"Partitioning config needs 'partitions'")
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if 'label' not in config:
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raise BlockDeviceSetupException(
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"Partitioning config needs 'label'")
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self.label = config['label']
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if self.label not in ("mbr", ):
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raise BlockDeviceSetupException("Label must be 'mbr'")
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# It is VERY important to get the alignment correct. If this
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# is not correct, the disk performance might be very poor.
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# Example: In some tests a 'off by one' leads to a write
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# performance of 30% compared to a correctly aligned
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# partition.
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# The problem for DIB is, that it cannot assume that the host
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# system uses the same IO sizes as the target system,
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# therefore here a fixed approach (as used in all modern
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# systems with large disks) is used. The partitions are
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# aligned to 1MiB (which are about 2048 times 512 bytes
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# blocks)
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self.align = 1024 * 1024 # 1MiB as default
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if 'align' in config:
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self.align = parse_abs_size_spec(config['align'])
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self.partitions = []
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prev_partition = None
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for part_cfg in config['partitions']:
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np = PartitionNode(part_cfg, self, prev_partition)
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self.partitions.append(np)
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prev_partition = np
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def get_nodes(self):
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# return the list of partitions
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return self.partitions
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def _size_of_block_dev(self, dev):
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with open(dev, "r") as fd:
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fd.seek(0, 2)
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return fd.tell()
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def _all_part_devices_exist(self, expected_part_devices):
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for part_device in expected_part_devices:
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logger.debug("Checking if partition device [%s] exists",
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part_device)
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if not os.path.exists(part_device):
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logger.info("Partition device [%s] does not exists",
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part_device)
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return False
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logger.debug("Partition already exists [%s]", part_device)
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return True
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def _notify_os_of_partition_changes(self, device_path, partition_devices):
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"""Notify of of partition table changes
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There is the need to call some programs to inform the operating
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system of partition tables changes.
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These calls are highly distribution and version specific. Here
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a couple of different methods are used to get the best result.
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"""
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try:
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exec_sudo(["partprobe", device_path])
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exec_sudo(["udevadm", "settle"])
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except CalledProcessError as e:
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logger.info("Ignoring settling failure: %s", e)
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pass
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if self._all_part_devices_exist(partition_devices):
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return
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# If running inside Docker, make our nodes manually, because udev
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# will not be working.
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if os.path.exists("/.dockerenv"):
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# kpartx cannot run in sync mode in docker.
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exec_sudo(["kpartx", "-av", device_path])
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exec_sudo(["dmsetup", "--noudevsync", "mknodes"])
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return
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exec_sudo(["kpartx", "-avs", device_path])
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def create(self, state, rollback):
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# not this is NOT a node and this is not called directly! The
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# create() calls in the partition nodes this plugin has
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# created are calling back into this.
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image_path = state['blockdev'][self.base]['image']
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device_path = state['blockdev'][self.base]['device']
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logger.info("Creating partition on [%s] [%s]", self.base, image_path)
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# This is a bit of a hack. Each of the partitions is actually
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# in the graph, so for every partition we get a create() call
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# as the walk happens. But we only need to create the
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# partition table once...
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if self.already_created:
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logger.info("Not creating the partitions a second time.")
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return
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assert self.label == 'mbr'
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partition_devices = set()
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disk_size = self._size_of_block_dev(image_path)
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with MBR(image_path, disk_size, self.align) as part_impl:
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for part_cfg in self.partitions:
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part_name = part_cfg.get_name()
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part_bootflag = PartitionNode.flag_boot \
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in part_cfg.get_flags()
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part_primary = PartitionNode.flag_primary \
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in part_cfg.get_flags()
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part_size = part_cfg.get_size()
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part_free = part_impl.free()
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part_type = part_cfg.get_type()
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logger.debug("Not partitioned space [%d]", part_free)
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part_size = parse_rel_size_spec(part_size,
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part_free)[1]
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part_no \
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= part_impl.add_partition(part_primary, part_bootflag,
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part_size, part_type)
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logger.debug("Create partition [%s] [%d]",
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part_name, part_no)
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partition_device_name = device_path + "p%d" % part_no
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state['blockdev'][part_name] \
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= {'device': partition_device_name}
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partition_devices.add(partition_device_name)
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self.already_created = True
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self._notify_os_of_partition_changes(device_path, partition_devices)
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return
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