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>
52 lines
1.8 KiB
Python
52 lines
1.8 KiB
Python
# Copyright 2017 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 abc
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from diskimage_builder.graph.digraph import Digraph
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import six
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@six.add_metaclass(abc.ABCMeta)
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class PluginBase(object):
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"""Abstract base class for block device plugins"""
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def __init__(self, name):
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"""All plugins must have a name"""
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self.name = name
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@abc.abstractmethod
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def create(self, state, rollback):
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"""Create the block device plugin
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:param state: a dictionary to store results for this plugin.
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These are used in two scenarios: other plugins
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can use this to get information about the
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result of the plugin and it can be used in
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later runs of dib-block-device for cleaning up.
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:type state: dict(str:?)
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:param rollback: a list of python functions that will be
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called in reversed order to cleanup if there
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occurs an error later within the same
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dib-block-device run.
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:type rollback: list(function)
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"""
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class NodePluginBase(PluginBase, Digraph.Node):
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def insert_nodes(self, dg):
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"""Adds self as a node to the given digraph"""
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dg.add_node(self)
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