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Create and use plugin/node abstract classes

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This completes the transitions started in
Ic5a61365ef0132476b11bdbf1dd96885e91c3cb6

The new file plugin.py is the place to start with this change.  The
abstract base classes PluginBase and NodeBase are heavily documented.
NodeBase essentially replaces Digraph.Node

The changes in level?/*.py make no functional changes, but are just
refactoring to implement the plugin and node classes consistently.
Additionally we have added asserts during parsing & generation to
ensure plugins are implemented PluginBase, and get_nodes() is always
returning NodeBase objects for the graph.

Change-Id: Ie648e9224749491260dea65d7e8b8151a6824b9c
This commit is contained in:
Ian Wienand 2017-05-25 11:28:13 +10:00
parent 75817ef205
commit deb832d685
19 changed files with 298 additions and 701 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

16
diskimage_builder/block_device/blockdevice.py
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@ -28,6 +28,8 @@ from diskimage_builder.block_device.config import \
config_tree_to_graph
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 exec_sudo
@ -189,20 +191,24 @@ class BlockDevice(object):
# Instantiate a "plugin" object, passing it the
# configuration entry
# XXX would a "factory" pattern for plugins, where we make
# a method call on an object stevedore has instantiated be
# better here?
if cfg_obj_name not in self.plugin_manager:
raise BlockDeviceSetupException(
("Config element [%s] is not implemented" % cfg_obj_name))
cfg_obj = self.plugin_manager[cfg_obj_name].plugin(
cfg_obj_val, default_config)
plugin = self.plugin_manager[cfg_obj_name].plugin
assert issubclass(plugin, PluginBase)
cfg_obj = plugin(cfg_obj_val, default_config)
# Ask the plugin for the nodes it would like to insert
# into the graph. Some plugins, such as partitioning,
# return multiple nodes from one config entry.
nodes = cfg_obj.get_nodes()
assert isinstance(nodes, list)
for node in nodes:
# would only be missing if a plugin was way out of
# line and didn't put it in...
assert node.name
# plugins should return nodes...
assert isinstance(node, NodeBase)
# ensure node names are unique. networkx by default
# just appends the attribute to the node dict for
# existing nodes, which is not what we want.

17
diskimage_builder/block_device/level0/__init__.py
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@ -1,17 +0,0 @@
# 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.
from diskimage_builder.block_device.level0.localloop import LocalLoop
__all__ = [LocalLoop]

22
diskimage_builder/block_device/level0/localloop.py
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@ -18,14 +18,15 @@ 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
from diskimage_builder.graph.digraph import Digraph
logger = logging.getLogger(__name__)
class LocalLoop(Digraph.Node):
class LocalLoopNode(NodeBase):
"""Level0: Local loop image device handling.
This class handles local loop devices that can be used
@ -34,6 +35,7 @@ class LocalLoop(Digraph.Node):
def __init__(self, config, default_config):
logger.debug("Creating LocalLoop object; config [%s] "
"default_config [%s]" % (config, default_config))
super(LocalLoopNode, self).__init__(config['name'])
if 'size' in config:
self.size = parse_abs_size_spec(config['size'])
logger.debug("Image size [%s]" % self.size)
@ -44,18 +46,12 @@ class LocalLoop(Digraph.Node):
self.image_dir = config['directory']
else:
self.image_dir = default_config['image-dir']
self.name = config['name']
Digraph.Node.__init__(self, self.name)
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 get_nodes(self):
"""Returns nodes for adding to the graph"""
return [self]
@staticmethod
def image_create(filename, size):
logger.info("Create image file [%s]" % filename)
@ -131,3 +127,13 @@ class LocalLoop(Digraph.Node):
def delete(self, state):
self._image_delete(state['blockdev'][self.name]['image'])
class LocalLoop(PluginBase):
def __init__(self, config, defaults):
super(PluginBase, self).__init__()
self.node = LocalLoopNode(config, defaults)
def get_nodes(self):
return [self.node]

18
diskimage_builder/block_device/level1/__init__.py
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@ -1,18 +0,0 @@
# Copyright
# 2016-2017 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.
from diskimage_builder.block_device.level1.partitioning import Partitioning
__all__ = [Partitioning]

27
diskimage_builder/block_device/level1/partition.py
View File

@ -14,26 +14,20 @@ import logging
from diskimage_builder.block_device.exception import \
BlockDeviceSetupException
from diskimage_builder.graph.digraph import Digraph
from diskimage_builder.block_device.plugin import NodeBase
logger = logging.getLogger(__name__)
class Partition(Digraph.Node):
type_string = "partitions"
class PartitionNode(NodeBase):
flag_boot = 1
flag_primary = 2
def __init__(self, config, parent, prev_partition):
if 'name' not in config:
raise BlockDeviceSetupException(
"Missing 'name' in partition config: %s" % config)
self.name = config['name']
Digraph.Node.__init__(self, self.name)
super(PartitionNode, self).__init__(config['name'])
self.base = config['base']
self.partitioning = parent
@ -64,9 +58,6 @@ class Partition(Digraph.Node):
def get_type(self):
return self.ptype
def get_name(self):
return self.name
def get_edges(self):
edge_from = [self.base]
edge_to = []
@ -76,15 +67,3 @@ class Partition(Digraph.Node):
def create(self, result, rollback):
self.partitioning.create(result, rollback)
def umount(self, state):
"""Partition does not need any umount task."""
pass
def cleanup(self, state):
"""Partition does not need any cleanup."""
pass
def delete(self, state):
"""Partition does not need any cleanup."""
pass

30
diskimage_builder/block_device/level1/partitioning.py
View File

@ -20,21 +20,22 @@ from subprocess import CalledProcessError
from diskimage_builder.block_device.exception import \
BlockDeviceSetupException
from diskimage_builder.block_device.level1.mbr import MBR
from diskimage_builder.block_device.level1.partition import \
Partition
from diskimage_builder.block_device.level1.partition import PartitionNode
from diskimage_builder.block_device.plugin import PluginBase
from diskimage_builder.block_device.utils import exec_sudo
from diskimage_builder.block_device.utils import parse_abs_size_spec
from diskimage_builder.block_device.utils import parse_rel_size_spec
from diskimage_builder.graph.digraph import Digraph
logger = logging.getLogger(__name__)
class Partitioning(Digraph.Node):
class Partitioning(PluginBase):
def __init__(self, config, default_config):
logger.debug("Creating Partitioning object; config [%s]" % config)
super(Partitioning, self).__init__()
# Because using multiple partitions of one base is done
# within one object, there is the need to store a flag if the
# creation of the partitions was already done.
@ -75,19 +76,19 @@ class Partitioning(Digraph.Node):
prev_partition = None
for part_cfg in config['partitions']:
np = Partition(part_cfg, self, prev_partition)
np = PartitionNode(part_cfg, self, prev_partition)
self.partitions.append(np)
prev_partition = np
def get_nodes(self):
# return the list of partitions
return self.partitions
def _size_of_block_dev(self, dev):
with open(dev, "r") as fd:
fd.seek(0, 2)
return fd.tell()
def get_nodes(self):
# We just add partitions
return self.partitions
def _all_part_devices_exist(self, expected_part_devices):
for part_device in expected_part_devices:
logger.debug("Checking if partition device [%s] exists" %
@ -127,11 +128,18 @@ class Partitioning(Digraph.Node):
exec_sudo(["kpartx", "-avs", device_path])
def create(self, result, rollback):
# not this is NOT a node and this is not called directly! The
# create() calls in the partition nodes this plugin has
# created are calling back into this.
image_path = result['blockdev'][self.base]['image']
device_path = result['blockdev'][self.base]['device']
logger.info("Creating partition on [%s] [%s]" %
(self.base, image_path))
# This is a bit of a hack. Each of the partitions is actually
# in the graph, so for every partition we get a create() call
# as the walk happens. But we only need to create the
# partition table once...
if self.already_created:
logger.info("Not creating the partitions a second time.")
return
@ -143,9 +151,9 @@ class Partitioning(Digraph.Node):
with MBR(image_path, disk_size, self.align) as part_impl:
for part_cfg in self.partitions:
part_name = part_cfg.get_name()
part_bootflag = Partition.flag_boot \
part_bootflag = PartitionNode.flag_boot \
in part_cfg.get_flags()
part_primary = Partition.flag_primary \
part_primary = PartitionNode.flag_primary \
in part_cfg.get_flags()
part_size = part_cfg.get_size()
part_free = part_impl.free()

17
diskimage_builder/block_device/level2/__init__.py
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@ -1,17 +0,0 @@
# 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.
from diskimage_builder.block_device.level2.mkfs import Mkfs
__all__ = [Mkfs]

39
diskimage_builder/block_device/level2/mkfs.py
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@ -17,8 +17,9 @@ import uuid
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 exec_sudo
from diskimage_builder.graph.digraph import Digraph
logger = logging.getLogger(__name__)
@ -40,12 +41,14 @@ file_system_max_label_length = {
}
class Filesystem(Digraph.Node):
class FilesystemNode(NodeBase):
def __init__(self, config):
logger.debug("Create filesystem object; config [%s]" % config)
super(FilesystemNode, self).__init__(config['name'])
# Parameter check (mandatory)
for pname in ['base', 'name', 'type']:
for pname in ['base', 'type']:
if pname not in config:
raise BlockDeviceSetupException(
"Mkfs config needs [%s]" % pname)
@ -92,8 +95,6 @@ class Filesystem(Digraph.Node):
if self.uuid is None:
self.uuid = str(uuid.uuid4())
Digraph.Node.__init__(self, self.name)
logger.debug("Filesystem created [%s]" % self)
def get_edges(self):
@ -137,36 +138,18 @@ class Filesystem(Digraph.Node):
'fstype': self.type, 'opts': self.opts,
'device': device}
def umount(self, state):
"""Mkfs does not need any umount."""
pass
def cleanup(self, state):
"""Mkfs does not need any cleanup."""
pass
def delete(self, state):
"""Mkfs does not need any delete."""
pass
class Mkfs(object):
"""Module for creating file systems
class Mkfs(PluginBase):
"""Create a file system
This block device module handles creating different file
systems.
"""
type_string = "mkfs"
def __init__(self, config, default_config):
logger.debug("Create Mkfs object; config [%s]" % config)
logger.debug("default_config [%s]" % default_config)
self.config = config
self.default_config = default_config
def __init__(self, config, defaults):
super(Mkfs, self).__init__()
self.filesystems = {}
fs = Filesystem(self.config)
fs = FilesystemNode(config)
self.filesystems[fs.get_name()] = fs
def get_nodes(self):

17
diskimage_builder/block_device/level3/__init__.py
View File

@ -1,17 +0,0 @@
# 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.
from diskimage_builder.block_device.level3.mount import Mount
__all__ = [Mount]

38
diskimage_builder/block_device/level3/mount.py
View File

@ -17,9 +17,10 @@ import os
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 exec_sudo
from diskimage_builder.block_device.utils import sort_mount_points
from diskimage_builder.graph.digraph import Digraph
logger = logging.getLogger(__name__)
@ -32,17 +33,18 @@ mount_points = {}
sorted_mount_points = None
class MountPoint(Digraph.Node):
class MountPointNode(NodeBase):
def __init__(self, mount_base, config):
super(MountPointNode, self).__init__(config['name'])
# Parameter check
self.mount_base = mount_base
for pname in ['base', 'name', 'mount_point']:
for pname in ['base', 'mount_point']:
if pname not in config:
raise BlockDeviceSetupException(
"MountPoint config needs [%s]" % pname)
setattr(self, pname, config[pname])
Digraph.Node.__init__(self, self.name)
logger.debug("MountPoint created [%s]" % self)
def get_node(self):
@ -116,30 +118,22 @@ class MountPoint(Digraph.Node):
logger.info("Called for [%s]" % self.name)
exec_sudo(["umount", state['mount'][self.mount_point]['path']])
def cleanup(self, state):
"""Mount does not need any cleanup."""
pass
def delete(self, state):
self.umount(state)
class Mount(object):
type_string = "mount"
def __init__(self, config, params):
logger.debug("Mounting object; config [%s]" % config)
self.config = config
self.params = params
if 'mount-base' not in self.params:
raise BlockDeviceSetupException(
"Mount default config needs 'mount-base'")
self.mount_base = self.params['mount-base']
class Mount(PluginBase):
def __init__(self, config, defaults):
super(Mount, self).__init__()
self.mount_points = {}
mp = MountPoint(self.mount_base, self.config)
if 'mount-base' not in defaults:
raise BlockDeviceSetupException(
"Mount default config needs 'mount-base'")
self.mount_base = defaults['mount-base']
mp = MountPointNode(self.mount_base, config)
self.mount_points[mp.get_name()] = mp
def get_nodes(self):

17
diskimage_builder/block_device/level4/__init__.py
View File

@ -1,17 +0,0 @@
# 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.
from diskimage_builder.block_device.level4.fstab import Fstab
__all__ = [Fstab]

42
diskimage_builder/block_device/level4/fstab.py
View File

@ -14,30 +14,20 @@
import logging
from diskimage_builder.graph.digraph import Digraph
from diskimage_builder.block_device.plugin import NodeBase
from diskimage_builder.block_device.plugin import PluginBase
logger = logging.getLogger(__name__)
class Fstab(Digraph.Node):
type_string = "fstab"
class FstabNode(NodeBase):
def __init__(self, config, params):
logger.debug("Fstab object; config [%s]" % config)
self.config = config
self.params = params
self.name = self.config['name']
self.base = self.config['base']
Digraph.Node.__init__(self, self.name)
self.options = self.config.get('options', 'defaults')
self.dump_freq = self.config.get('dump-freq', 0)
self.fsck_passno = self.config.get('fsck-passno', 2)
def get_nodes(self):
return [self]
super(FstabNode, self).__init__(config['name'])
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]
@ -59,14 +49,12 @@ class Fstab(Digraph.Node):
'fsck-passno': self.fsck_passno
}
def umount(self, state):
"""Fstab does not need any umount task."""
pass
def cleanup(self, state):
"""Fstab does not need any cleanup."""
pass
class Fstab(PluginBase):
def __init__(self, config, defaults):
super(Fstab, self).__init__()
def delete(self, state):
"""Fstab does not need any cleanup."""
pass
self.node = FstabNode(config, defaults)
def get_nodes(self):
return [self.node]

205
diskimage_builder/block_device/plugin.py Normal file
View File

@ -0,0 +1,205 @@
# 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 abc
import six
#
# Plugins convert configuration entries into graph nodes ready for
# processing. This defines the abstract classes for both.
#
@six.add_metaclass(abc.ABCMeta)
class NodeBase(object):
"""A configuration node entry
This is the main driver class for dib-block-device operation.
The final operations graph is composed of instantiations of this
class. The graph undergoes a topological sort (i.e. is linearised
in dependency order) and each node has :func:`create` called in
order to perform its operations.
Every node has a unique string ``name``. This is its key in the
graph and used for edge relationships. Implementations must
ensure they initalize it; e.g.
.. code-block:: python
class FooNode(NodeBase):
def __init__(name, arg1, ...):
super(FooNode, self).__init__(name)
"""
def __init__(self, name):
self.name = name
def get_name(self):
return self.name
@abc.abstractmethod
def get_edges(self):
"""Return the dependencies/edges for this node
This function will be called after all nodes are created (this
is because some plugins need to know the global state of all
nodes to decide their dependencies).
This function returns a tuple with two lists
* ``edges_from`` : a list of node names that point to us
* ``edges_to`` : a list of node names we point to
In most cases, node creation will have saved a single parent
that was given in the ``base`` parameter of the configuration.
A usual return might look like:
.. code-block:: python
def get_edges(self):
return ( [self.base], [] )
Some nodes (``level0``) don't have a base, however
"""
return
@abc.abstractmethod
def create(self, results, rollback):
"""Main creation driver
This is the main driver function. After the graph is
linearised, each node has it's :func:`create` function called.
Arguments:
:param results: A shared dictionary of prior results. This
dictionary is passed by reference to each call, meaning any
entries inserted will be available to subsequent :func:`create`
calls of following nodes.
:param rollback: A shared list of functions to be called in
the failure case. Nodes should only append to this list.
On failure, the callbacks will be processed in reverse
order.
:raises Exception: A failure should raise an exception. This
will initiate the rollback
:return: None
"""
return
def umount(self, state):
"""Umount actions
Actions to taken when ``dib-block-device umount`` is called
:param state: the current state dictionary. This is the
`results` dictionary from :func:`create` before this call is
made.
:return: None
"""
return
def cleanup(self, state):
"""Cleanup actions
Actions to taken when ``dib-block-device cleanup`` is called.
This is the cleanup path in the *success* case. The nodes are
called in the reverse order to :func:`create`
:param state: the current state dictionary. This is the
`results` dictionary from :func:`create` before this call is
made.
:return: None
"""
return
def delete(self, state):
"""Cleanup actions
Actions to taken when ``dib-block-device delete`` is called.
This is the cleanup path in case of a reported external
*failure*. The nodes are called in the reverse order to
:func:`create`
:param state: the current state dictionary. This is the
`results` dictionary from :func:`create` before this call is
made.
:return: None
"""
return
@six.add_metaclass(abc.ABCMeta)
class PluginBase(object):
"""The base plugin object
This is the base plugin object. Plugins are an instantiation of
this class. There should be an entry-point (see setup.cfg)
defined under ``diskimage_builder.block_device.plugin`` for each
plugin, e.g.
foo = diskimage_builder.block_device.levelX.foo:Foo
A configuration entry in the graph config that matches this entry
point will create an instance of this class, e.g.
.. code-block:: yaml
foo:
name: foo_node
base: parent_node
argument_a: bar
argument_b: baz
The ``__init__`` function will be passed two arguments:
``config``
The full configuration dictionary for the entry.
A unique ``name`` entry can be assumed. In most cases
a ``base`` entry will be present giving the parent node
(see :func:`NodeBase.get_edges`).
``defaults``
The global defaults dictionary (see ``--params``)
``get_nodes()`` should return the node object(s) created by the
config for insertion into the final configuration graph. In the
simplest case, this is probably a single node created during
instantiation. e.g.
.. code-block:: python
class Foo(PluginBase):
def __init__(self, config, defaults):
super(Foo, self).__init__()
self.node = FooNode(config.name, ...)
def get_nodes(self):
return [self.node]
Some plugins require more, however.
"""
def __init__(self):
pass
@abc.abstractmethod
def get_nodes(self):
"""Return nodes created by the plugin
:returns: a list of :class:`.NodeBase` objects for insertion
into the graph
"""
return

4
diskimage_builder/block_device/tests/test_mount_order.py
View File

@ -15,7 +15,7 @@ import mock
import diskimage_builder.block_device.tests.test_config as tc
from diskimage_builder.block_device.level3.mount import MountPoint
from diskimage_builder.block_device.level3.mount import MountPointNode
logger = logging.getLogger(__name__)
@ -42,7 +42,7 @@ class TestMountOrder(tc.TestGraphGeneration):
rollback = []
for node in call_order:
if isinstance(node, MountPoint):
if isinstance(node, MountPointNode):
# XXX: do we even need to create? We could test the
# sudo arguments from the mock in the below asserts
# too

0
diskimage_builder/graph/__init__.py
View File

228
diskimage_builder/graph/digraph.py
View File

@ -1,228 +0,0 @@
# 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 bisect
class Digraph(object):
"""Implements a directed graph.
Each node of the digraph must have a unique name.
"""
class Edge(object):
"""Directed graph edge.
The digraph has weighted edges. This class holds the weight and
a reference to the node.
"""
def __init__(self, node, weight):
self.__node = node
self.__weight = weight
def __eq__(self, other):
return self.__weight == other.get_weight() \
and self.__node == other.get_node()
def __lt__(self, other):
return self.__weight < other.get_weight()
def get_node(self):
"""Return the (pointed to) node"""
return self.__node
def get_weight(self):
"""Return the edge's weight"""
return self.__weight
class Node(object):
"""Directed graph node.
This holds the incoming and outgoing edges as well as the
nodes' name.
"""
def __init__(self, name):
"""Initializes a node.
Incoming and outgoing are lists of nodes. Typically one
direction is provided and the other can be automatically
computed.
"""
self.__name = name
self.__incoming = []
self.__outgoing = []
def __repr__(self):
return "<Node [%s]>" % self.__name
def get_name(self):
"""Returns the name of the node."""
return self.__name
def add_incoming(self, node, weight):
"""Add node to the incoming list."""
bisect.insort(self.__incoming, Digraph.Edge(node, weight))
def add_outgoing(self, node, weight):
"""Add node to the outgoing list."""
bisect.insort(self.__outgoing, Digraph.Edge(node, weight))
def get_iter_outgoing(self):
"""Return an iterator over the outgoing nodes."""
return iter([x.get_node() for x in self.__outgoing])
def has_incoming(self):
"""Returns True if the node has incoming edges"""
return self.__incoming
@staticmethod
def __as_named_list(inlist):
"""Return given list as list of names."""
return [x.get_node().get_name() for x in inlist]
def get_outgoing_as_named_list(self):
"""Return the names of all outgoing nodes as a list."""
return self.__as_named_list(self.__outgoing)
def __init__(self):
"""Create a empty digraph."""
self._named_nodes = {}
def create_from_dict(self, init_dgraph, node_gen_func=Node):
"""Creates a new digraph based on the given information."""
# First run: create all nodes
for node_name in init_dgraph:
# Create the node and put it into the object list of all
# nodes and into the local dictionary of named nodes.
named_node = node_gen_func(node_name)
self.add_node(named_node)
# Second run: run through all nodes and create the edges.
for node_name, outs in init_dgraph.items():
node_from = self.find(node_name)
for onode in outs:
node_to = self.find(onode)
if node_to is None:
raise RuntimeError("Node '%s' is referenced "
"but not specified" % onode)
self.create_edge(node_from, node_to)
def add_node(self, anode):
"""Adds a new node to the graph.
Checks if the node with the same name already exists.
"""
assert issubclass(anode.__class__, Digraph.Node)
for node in self._named_nodes.values():
if node.get_name() == anode.get_name():
raise RuntimeError("Node with name [%s] already "
"exists" % node.get_name())
self._named_nodes[anode.get_name()] = anode
def create_edge(self, anode, bnode, weight=0):
"""Creates an edge from a to b - both must be nodes."""
assert issubclass(anode.__class__, Digraph.Node)
assert issubclass(bnode.__class__, Digraph.Node)
assert anode.get_name() in self._named_nodes.keys()
assert anode == self._named_nodes[anode.get_name()]
assert bnode.get_name() in self._named_nodes.keys()
assert bnode == self._named_nodes[bnode.get_name()]
anode.add_outgoing(bnode, weight)
bnode.add_incoming(anode, weight)
def get_iter_nodes_values(self):
"""Returns the nodes dict to the values.
Note: it is not possible to change things with the help of the
result of this function.
"""
return iter(self._named_nodes.values())
def find(self, name):
"""Get the node with the given name.
Return None if not available.
"""
if name not in self._named_nodes:
return None
return self._named_nodes[name]
def as_dict(self):
"""Outputs this digraph and create a dictionary."""
# Start with an empty dictionary
rval = {}
for node in self._named_nodes.values():
rval[node.get_name()] = node.get_outgoing_as_named_list()
return rval
def topological_sort(self):
"""Digraph topological search.
This algorithm is based upon a depth first search with
'making' some special nodes.
The result is the topological sorted list of nodes.
"""
# List of topological sorted nodes
tsort = []
# List of nodes already visited.
# (This is held here - local to the algorithm - to not modify the
# nodes themselves.)
visited = []
def visit(node):
"""Recursive deep first search function."""
if node not in visited:
visited.append(node)
for onode in node.get_iter_outgoing():
visit(onode)
tsort.insert(0, node)
# The 'main' function of the topological sort
for node in self.get_iter_nodes_values():
if node.has_incoming():
continue
visit(node)
return tsort
# Utility functions
def digraph_create_from_dict(init_dgraph, node_gen_func=Digraph.Node):
"""Creates a new digraph based on the given information."""
digraph = Digraph()
digraph.create_from_dict(init_dgraph, node_gen_func)
return digraph
def node_list_to_node_name_list(node_list):
"""Converts a node list into a list of the corresponding node names."""
node_name_list = []
for node in node_list:
node_name_list.append(node.get_name())
return node_name_list

3
diskimage_builder/tests/functional/test_blockdevice_mbr.py
View File

@ -19,7 +19,8 @@ import subprocess
import tempfile
import testtools
from diskimage_builder.block_device.level0.localloop import LocalLoop
from diskimage_builder.block_device.level0.localloop \
import LocalLoopNode as LocalLoop
from diskimage_builder.block_device.level1.mbr import MBR

143
diskimage_builder/tests/functional/test_graph.py
View File

@ -1,143 +0,0 @@
# 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.
from diskimage_builder.graph.digraph import Digraph
from diskimage_builder.graph.digraph import digraph_create_from_dict
import testtools
class TestDigraph(testtools.TestCase):
def test_constructor_001(self):
"""Test conversion from dictionary to graph and back (two nodes)"""
d = {"A": ["B"], "B": []}
dg = digraph_create_from_dict(d)
e = dg.as_dict()
self.assertEqual(d["A"], list(e["A"]))
def test_constructor_002(self):
"""Test conversion from dictionary to graph and back (zero nodes)"""
d = {}
dg = digraph_create_from_dict(d)
e = dg.as_dict()
self.assertEqual(d, e)
def test_constructor_003(self):
"""Test conversion from dictionary to graph and back (one node)"""
d = {"A": []}
dg = digraph_create_from_dict(d)
e = dg.as_dict()
self.assertEqual(d["A"], list(e["A"]))
def test_constructor_004(self):
"""Test conversion from dictionary to graph and back (one node)"""
d = {"A": ["A"]}
dg = digraph_create_from_dict(d)
e = dg.as_dict()
self.assertEqual(d["A"], list(e["A"]))
def test_constructor_005(self):
"""Test conversion: error: pointed node does not exists"""
d = {"A": ["B"]}
try:
d = digraph_create_from_dict(d)
self.assertTrue(False)
except RuntimeError:
pass
def test_constructor_006(self):
"""Test conversion from dictionary: two node circle"""
d = {"A": ["B"], "B": ["A"]}
dg = digraph_create_from_dict(d)
e = dg.as_dict()
self.assertEqual(d["A"], list(e["A"]))
self.assertEqual(d["B"], list(e["B"]))
def test_constructor_007(self):
"""Test conversion from dictionary: more complex graph"""
d = {"A": ["B"], "B": ["A", "D", "C"], "C": ["A", "D"],
"D": ["D"]}
dg = digraph_create_from_dict(d)
e = dg.as_dict()
self.assertEqual(d['A'], list(e['A']))
self.assertEqual(set(d['B']), set(e['B']))
self.assertEqual(set(d['C']), set(e['C']))
self.assertEqual(d['D'], list(e['D']))
def test_find_01(self):
"""Digraph find with element available"""
d = {"A": ["B"], "B": ["A", "C", "D"], "C": ["A", "D"],
"D": ["D"]}
dg = digraph_create_from_dict(d)
n = dg.find("A")
self.assertEqual("A", n.get_name(),)
def test_find_02(self):
"""Digraph find with element not available"""
d = {"A": ["B"], "B": ["A", "C", "D"], "C": ["A", "D"],
"D": ["D"]}
dg = digraph_create_from_dict(d)
n = dg.find("Z")
self.assertIsNone(n)
def test_get_named_node_01(self):
"""Digraph get named node with map available"""
d = {"A": ["B"], "B": ["A", "C", "D"], "C": ["A", "D"],
"D": ["D"]}
dg = digraph_create_from_dict(d)
n = dg.find("A")
self.assertEqual("A", n.get_name())
def test_add_node_01(self):
"""Digraph add node with two times same name"""
dg = Digraph()
n1 = Digraph.Node("myname")
n2 = Digraph.Node("myname")
dg.add_node(n1)
try:
dg.add_node(n2)
self.assertTrue(False)
except RuntimeError:
pass
def test_iter_outgoing_weight_01(self):
"""Tests iter_outgoing in a graph with weights"""
digraph = Digraph()
node0 = Digraph.Node("R")
digraph.add_node(node0)
node1 = Digraph.Node("A")
digraph.add_node(node1)
node2 = Digraph.Node("B")
digraph.add_node(node2)
node3 = Digraph.Node("C")
digraph.add_node(node3)
digraph.create_edge(node0, node1, 1)
digraph.create_edge(node0, node2, 2)
digraph.create_edge(node0, node3, 3)
self.assertEqual([node1, node2, node3],
list(node0.get_iter_outgoing()))

116
diskimage_builder/tests/functional/test_graph_toposort.py
View File

@ -1,116 +0,0 @@
# 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 testtools
from diskimage_builder.graph.digraph import Digraph
from diskimage_builder.graph.digraph import digraph_create_from_dict
from diskimage_builder.graph.digraph import node_list_to_node_name_list
class TestTopologicalSearch(testtools.TestCase):
def test_tsort_001(self):
"""Simple three node digraph"""
dg = digraph_create_from_dict(
{"A": ["B", "C"], "B": ["C"], "C": []})
tsort = dg.topological_sort()
tnames = node_list_to_node_name_list(tsort)
self.assertEqual(tnames, ['A', 'B', 'C'], "incorrect")
def test_tsort_002(self):
"""Zero node digraph"""
dg = digraph_create_from_dict({})
tsort = dg.topological_sort()
tnames = node_list_to_node_name_list(tsort)
self.assertEqual(tnames, [], "incorrect")
def test_tsort_003(self):
"""One node digraph"""
dg = digraph_create_from_dict({"A": []})
tsort = dg.topological_sort()
tnames = node_list_to_node_name_list(tsort)
self.assertEqual(tnames, ["A"], "incorrect")
def test_tsort_004(self):
"""More complex digraph"""
dg = digraph_create_from_dict(
{"A": ["B", "C"], "B": ["C", "E"], "C": ["D", "E"],
"D": ["E"], "E": []})
tsort = dg.topological_sort()
tnames = node_list_to_node_name_list(tsort)
self.assertEqual(tnames, ['A', 'B', 'C', 'D', 'E'], "incorrect")
def test_tsort_005(self):
"""Digraph with two components"""
dg = digraph_create_from_dict({"A": ["B", "C"], "B": ["C"], "C": [],
"D": ["E"], "E": []})
tsort = dg.topological_sort()
tnames = node_list_to_node_name_list(tsort)
# Because of two components, there exist a couple of different
# possibilities - but these are all the requirements that have
# to be fulfilled to be a correct topological sort:
self.assertTrue(tnames.index('A') < tnames.index('B'))
self.assertTrue(tnames.index('B') < tnames.index('C'))
self.assertTrue(tnames.index('D') < tnames.index('E'))
def test_tsort_006(self):
"""Complex digraph with weights"""
digraph = Digraph()
node0 = Digraph.Node("R")
digraph.add_node(node0)
node1 = Digraph.Node("A")
digraph.add_node(node1)
node2 = Digraph.Node("B")
digraph.add_node(node2)
node3 = Digraph.Node("C")
digraph.add_node(node3)
node4 = Digraph.Node("B1")
digraph.add_node(node4)
node5 = Digraph.Node("B2")
digraph.add_node(node5)
node6 = Digraph.Node("B3")
digraph.add_node(node6)
digraph.create_edge(node0, node1, 1)
digraph.create_edge(node0, node2, 2)
digraph.create_edge(node0, node3, 3)
digraph.create_edge(node2, node4, 7)
digraph.create_edge(node2, node5, 14)
digraph.create_edge(node2, node6, 21)
tsort = digraph.topological_sort()
tnames = node_list_to_node_name_list(tsort)
# Also here: many possible solutions
self.assertTrue(tnames.index('R') < tnames.index('A'))
self.assertTrue(tnames.index('R') < tnames.index('B'))
self.assertTrue(tnames.index('R') < tnames.index('C'))
self.assertTrue(tnames.index('B') < tnames.index('B1'))
self.assertTrue(tnames.index('B') < tnames.index('B2'))
self.assertTrue(tnames.index('B') < tnames.index('B3'))
# In addition in the weighted graph the following
# must also hold:
self.assertTrue(tnames.index('B') < tnames.index('A'))
self.assertTrue(tnames.index('C') < tnames.index('B'))
self.assertTrue(tnames.index('B2') < tnames.index('B1'))
self.assertTrue(tnames.index('B3') < tnames.index('B2'))