c8d15c9bcc
Six is Python 2 and 3 compatibility. It is no longer needed now that we're purely py3. Change-Id: I28a6f8539b3b3ce35221728ec631380a18c921b3
80 lines
2.2 KiB
Python
80 lines
2.2 KiB
Python
# Copyright (c) 2018 Cisco Systems, Inc.
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# All Rights Reserved.
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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 abc import ABC, abstractmethod
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class HookManager(object):
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"""Extension hooks
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An extension may provide hook-in points where specific events
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within the extension can be tapped into. Initialisation of an
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extension creates a list of hooks in its __init__ call, and
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after all extension have been created all extensions will
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receive an 'initialize' call that will allow each extension
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to hook into the hook points provided by others or by
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the base system.
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The entity hosting the extension may also provide hooks.
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"""
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def __init__(self):
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self.hooks = {}
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def call(self, name, *args, **kwargs):
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for f in self.hooks[name]:
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f(*args, **kwargs)
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def create(self, name):
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"""Called by an extension to advertise a hook"""
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self.hooks[name] = []
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def attach(self, name, call):
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"""Called by an extension to use a hook from another"""
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self.hooks[name].append(call)
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class ExtensionBase(ABC):
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def __init__(self):
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self.hooks = HookManager()
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def deps(self):
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"""List of plugin dependencies by name
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This plugin requires the dependencies, and may hook to
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them.
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"""
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return []
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def initialize(self, manager):
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"""Add cross-references to other extensions if required"""
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pass
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class VPPAgentExtensionBase(ExtensionBase):
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@abstractmethod
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def run(self, host, client_factory, vpp_forwarder):
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"""Begin threads watching etcd."""
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pass
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class MechDriverExtensionBase(ExtensionBase):
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@abstractmethod
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def run(self, communicator):
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pass
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