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Diffstat (limited to 'vicn/core/requirement.py')
| -rw-r--r-- | vicn/core/requirement.py | 229 |
1 files changed, 229 insertions, 0 deletions
diff --git a/vicn/core/requirement.py b/vicn/core/requirement.py new file mode 100644 index 00000000..c42cecd9 --- /dev/null +++ b/vicn/core/requirement.py @@ -0,0 +1,229 @@ +#!/usr/bin/env python3 +# -*- coding: utf-8 -*- +# +# Copyright (c) 2017 Cisco and/or its affiliates. +# +# 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 enum + +from netmodel.model.mapper import ObjectSpecification +from vicn.core.exception import VICNException + +#------------------------------------------------------------------------------ +# Enums +#------------------------------------------------------------------------------ + +class RequirementScope(enum.Enum): + INSTANCE = 'Instance' + CLASS = 'Class' + +#------------------------------------------------------------------------------ +# Exceptions +#------------------------------------------------------------------------------ + +class RequirementError(VICNException): + + def __init__(self, instance, attr): + super().__init__() + self._instance = instance + self._attr = attr + + def __str__(self): + return "Requirement on {}.{} could not be satisfied:".format( + self._instance, self._attr) + +class RequiredAttributeError(RequirementError): + + def __str__(self): + return super().__str__() + "could not find attribute {}".format( + self._attr) + +class RequiredPropertyError(RequirementError): + def __init__(self, instance, attr, prop): + super().__init__(instance, attr) + self._prop = prop + + def __str__(self): + return super().__str__()+ "property {} is not verified".format( + self._prop) + +#------------------------------------------------------------------------------ +# Class: Property +#------------------------------------------------------------------------------ + +class Property: + + TYPE_ANY_OF = 0 + #XXX cant think of a good use case for that + #TYPE_ALL_OF = 1 + + def __init__(self, value, property_type=TYPE_ANY_OF): + self._type = property_type + try: + self._value = set(value) + except TypeError: #value is not iterable, it is a single value + self._value = set() + self._value.add(value) + + + @property + def property_type(self): + return self._type + + @property + def value(self): + return self._value + + def check(self, value): + return value in self._value + + def __str__(self): + return str(self._value) + + def merge(self, other): + assert self._type is other.property_type, \ + "Properties must be of same type to be merged" + + #if self._type is TYPE_ANY_OF: + self._value.intersection_update(other.value) + #elif self._type is TYPE_ALL_OF: + # self._value.union_update(other.value) + +#------------------------------------------------------------------------------ +# Class: Requirement +#------------------------------------------------------------------------------ + +class Requirement(ObjectSpecification): + """Resource requirement + + This class allows to specify a requirement on a given resource, or on a + class of resources (all instances of a given class). + """ + + #-------------------------------------------------------------------------- + # Constructor + #-------------------------------------------------------------------------- + + def __init__(self, requirement_type, properties = None, + capabilities = None, scope = RequirementScope.INSTANCE, + fatal = True, must_be_setup = False): + """ + Args: + requirement_type (): the attribute on which the requirement is made + properties (Optional[XXX]): XXX (defaults to None) + scope (Optional[enum RequirementScope]): Is the requirement dealing + with an instance, or a class (all instance of the class) + (defaults to RequirementScope.INSTANCE) + fatal (Optional[bool]): is the failure of the requirement fatal + (raises an error), or not (raises a warning) (defaults to True) + must_be_setup (Optional[bool]): defaults to False + """ + self._type = requirement_type + self._properties = {} + if properties: + for prop in properties: + self._properties[prop] = Property(properties[prop]) + self._capabilities = capabilities if capabilities else set() + self._scope = scope + self._fatal = fatal + self._must_be_up = must_be_setup + + #-------------------------------------------------------------------------- + # Accessors and properties + #-------------------------------------------------------------------------- + + @property + def properties(self): + return self._properties + + @property + def requirement_type(self): + return self._type + + @property + def must_be_up(self): + return self._must_be_up + + #-------------------------------------------------------------------------- + # Display + #-------------------------------------------------------------------------- + + def __str__(self): + prop_str = "{" + ",".join(map(lambda x: "'{}': {}".format(x, + self._properties[x]), self._properties.keys())) +"}" + return "<type={}, properties={}, must_be_up={}>".format(self._type, + prop_str, self._must_be_up) + + #-------------------------------------------------------------------------- + # Requirement operators + #-------------------------------------------------------------------------- + + def check(self, instance): + if not hasattr(instance, self._type): + raise RequiredAttributeError(instance, self._type) + + instance_attr = getattr(instance, self._type) + if not instance_attr: + raise TypeError("instance_attr is none") + + for prop in self.properties: + if not hasattr(instance_attr, prop): + raise RequiredAttributeError(instance, self._type) + if not self._properties[prop].check(getattr(instance_attr, prop)): + raise RequiredPropertyError(instance, self._type, prop) + + return True + + #-------------------------------------------------------------------------- + # Requirement logic + #-------------------------------------------------------------------------- + + def merge(self, other): + assert other.requirement_type == self._type, \ + "Cannot merge Requirements with different types" + + for prop in other.properties: + if prop in self._properties: + self._properties[prop].merge(other.properties[prop]) + else: + self._properties[prop] = other.properties[prop] + + if other._capabilities: + self._capabilities |= other._capabilities + +#------------------------------------------------------------------------------ +# Class: Requirement list +#------------------------------------------------------------------------------ + +class RequirementList(list): + + def __init__(self,x=None): + super().__init__() + if x: + self.extend(x) + + def append(self,x): + assert isinstance(x,Requirement) + # XXX O(n) right now, might be able to do better + for req in self: + if req.requirement_type == x.requirement_type: + req.merge(x) + return + + super().append(x) + + def extend(self, x): + for y in x: + self.append(y) |