khenaidoo | b920354 | 2018-09-17 22:56:37 -0400 | [diff] [blame] | 1 | #!/usr/bin/env python |
| 2 | # |
| 3 | # Copyright 2017 the original author or authors. |
| 4 | # |
| 5 | # Licensed under the Apache License, Version 2.0 (the "License"); |
| 6 | # you may not use this file except in compliance with the License. |
| 7 | # You may obtain a copy of the License at |
| 8 | # |
| 9 | # http://www.apache.org/licenses/LICENSE-2.0 |
| 10 | # |
| 11 | # Unless required by applicable law or agreed to in writing, software |
| 12 | # distributed under the License is distributed on an "AS IS" BASIS, |
| 13 | # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 14 | # See the License for the specific language governing permissions and |
| 15 | # limitations under the License. |
| 16 | # |
| 17 | |
| 18 | """ |
| 19 | Simple component registry to provide centralized access to any registered |
| 20 | components. |
| 21 | """ |
| 22 | from collections import OrderedDict |
| 23 | from zope.interface import Interface |
| 24 | |
| 25 | |
| 26 | class IComponent(Interface): |
| 27 | """ |
| 28 | A Voltha Component |
| 29 | """ |
| 30 | |
| 31 | def start(): |
| 32 | """ |
| 33 | Called once the componet is instantiated. Can be used for async |
| 34 | initialization. |
| 35 | :return: (None or Deferred) |
| 36 | """ |
| 37 | |
| 38 | def stop(): |
| 39 | """ |
| 40 | Called once before the component is unloaded. Can be used for async |
| 41 | cleanup operations. |
| 42 | :return: (None or Deferred) |
| 43 | """ |
| 44 | |
| 45 | |
| 46 | class Registry(object): |
| 47 | |
| 48 | def __init__(self): |
| 49 | self.components = OrderedDict() |
| 50 | |
| 51 | def register(self, name, component): |
| 52 | assert IComponent.providedBy(component) |
| 53 | assert name not in self.components |
| 54 | self.components[name] = component |
| 55 | return component |
| 56 | |
| 57 | def unregister(self, name): |
| 58 | if name in self.components: |
| 59 | del self.components[name] |
| 60 | |
| 61 | def __call__(self, name): |
| 62 | return self.components[name] |
| 63 | |
| 64 | def iterate(self): |
| 65 | return self.components.values() |
| 66 | |
| 67 | |
| 68 | # public shared registry |
| 69 | registry = Registry() |