2 # NEPI, a framework to manage network experiments
3 # Copyright (C) 2013 INRIA
5 # This program is free software: you can redistribute it and/or modify
6 # it under the terms of the GNU General Public License as published by
7 # the Free Software Foundation, either version 3 of the License, or
8 # (at your option) any later version.
10 # This program is distributed in the hope that it will be useful,
11 # but WITHOUT ANY WARRANTY; without even the implied warranty of
12 # MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 # GNU General Public License for more details.
15 # You should have received a copy of the GNU General Public License
16 # along with this program. If not, see <http://www.gnu.org/licenses/>.
18 # Author: Alina Quereilhac <alina.quereilhac@inria.fr>
30 """ Differents flags to characterize an attribute
33 # Attribute value can not be read (it is hidden to the user)
36 # Attribute value can not be modified (it is not editable by the user)
39 # Attribute value can be modified only before deployment
42 # Attribute value will be used at deployment time for initial configuration
43 Construct = 1 << 3 # 8
45 # Attribute provides credentials to access resources
46 Credential = 1 << 4 | Design # 16 + 4
48 # Attribute is a filter used to discover resources
49 Filter = 1 << 5 | Design # 32 + 4
51 # Attribute Flag is reserved for internal RM usage (i.e. should be
52 # transparent to the user)
53 Reserved = 1 << 6 # 64
55 # Attribute global is set to all resources of rtype
59 class Attribute(object):
61 .. class:: Class Args :
63 An Attribute reflects a configuration parameter for
64 a particular resource. Attributes might be read only or
67 :param name: Name of the attribute
70 :param help: Attribute description
73 :param type: The type expected for the attribute value.
74 Should be one of Attribute.Types .
77 :param flags: Defines attribute behavior (i.e. whether it is read-only,
78 read and write, etc). This parameter should take its values from
79 Attribute.Flags. Flags values can be bitwised.
82 :param default: Default value of the attribute
83 :type default: depends on the type of attribute
85 :param allowed: List of values that the attribute can take.
86 This parameter is only meaningful for Enumerate type attributes.
89 :param range: (max, min) tuple with range of possible values for
91 This parameter is only meaningful for Integer or Double type
93 :type range: (int, int) or (float, float)
95 :param set_hook: Function that will be executed whenever a new
96 value is set for the attribute.
97 :type set_hook: function
100 def __init__(self, name, help, type = Types.String,
101 flags = None, default = None, allowed = None,
102 range = None, set_hook = None):
106 self._flags = flags or 0
107 self._allowed = allowed
109 self._default = self._value = default
110 # callback to be invoked upon changing the
112 self.set_hook = set_hook
116 """ Returns the name of the attribute """
121 """ Returns the default value of the attribute """
126 """ Returns the type of the attribute """
131 """ Returns the help of the attribute """
136 """ Returns the flags of the attribute """
141 """ Returns the allowed value for this attribute """
146 """ Returns the range of the attribute """
149 def has_flag(self, flag):
150 """ Returns true if the attribute has the flag 'flag'
152 :param flag: Flag to be checked
155 return (self._flags & flag) == flag
158 """ Returns the value of the attribute """
161 def set_value(self, value):
162 """ Change the value of the attribute after checking the type """
165 if self.type == Types.Enumerate:
166 valid = value in self._allowed
168 if self.type in [Types.Double, Types.Integer] and self.range:
169 (min, max) = self.range
173 valid = (value >= min and value <= max)
175 valid = valid and self.is_valid_value(value)
179 # Hook receives old value, new value
180 value = self.set_hook(self._value, value)
184 raise ValueError("Invalid value %s for attribute %s" %
185 (str(value), self.name))
187 value = property(get_value, set_value)
189 def is_valid_value(self, value):
190 """ Attribute subclasses will override this method to add
191 adequate validation"""
195 def has_changed(self):
196 """ Returns true if the value has changed from the default """
197 return self.value != self.default