summaryrefslogtreecommitdiffstats
path: root/vicn/core/state.py
blob: d5069b24564aad99cb4639f075c517c2ecc79cdd (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
#!/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 asyncio
import random
import string

class NEVER_SET:
    pass

# Separator for components of the UUID
UUID_SEP = '-'

# Length of the random component of the UUID
UUID_LEN = 5

class ResourceState:
    UNINITIALIZED       = 'UNINITIALIZED'
    PENDING_DEPS        = 'PENDING_DEPS'
    DEPS_OK             = 'DEPS_OK'
    PENDING_INIT        = 'PENDING_INIT'
    INITIALIZED         = 'INITIALIZED'
    PENDING_GET         = 'PENDING_GET'
    GET_DONE            = 'GET_DONE'
    PENDING_KEYS        = 'PENDING_KEYS'
    KEYS_OK             = 'KEYS_OK'
    PENDING_CREATE      = 'PENDING_CREATE'
    CREATED             = 'CREATED'
    DIRTY               = 'DIRTY'
    CLEAN               = 'CLEAN'
    PENDING_UPDATE      = 'PENDING_UPDATE'
    PENDING_DELETE      = 'PENDING_DELETE'
    DELETED             = 'DELETED'

class AttributeState:
    UNINITIALIZED       = 'UNINITIALIZED'
    INITIALIZED         = 'INITIALIZED'
    DIRTY               = 'DIRTY'
    PENDING_INIT        = 'PENDING_INIT'
    PENDING_UPDATE      = 'PENDING_UPDATE'
    CLEAN               = 'CLEAN'

class Operations:
    SET = 'set'
    LIST_ADD = 'add'
    LIST_REMOVE = 'remove'
    LIST_CLEAR = 'clear'

class UUID:
    def __init__(self, name, cls):
        self._uuid = self._make_uuid(name, cls)

    def _make_uuid(self, name, cls):
        """Generate a unique resource identifier

        The UUID consists in the type of the resource, to which is added a
        random identifier of length UUID_LEN. Components of the UUID are
        separated by UUID_SEP.
        """
        uuid = ''.join(random.choice(string.ascii_uppercase + string.digits) 
                for _ in range(UUID_LEN))
        if name:
            uuid = name # + UUID_SEP + uuid
        return UUID_SEP.join([cls.__name__, uuid])

    def __repr__(self):
        return '<UUID {}>'.format(self._uuid)

    def __lt__(self, other):
        return self._uuid < other._uuid

    __str__ = __repr__

class PendingValue:
    def __init__(self, value = None):
        self.clear(value)

    def clear(self, value=NEVER_SET):
        self.value = NEVER_SET
        self.operations = list()

    def trigger(self, action, value, cur_value = None):

        if self.value is NEVER_SET:
            if cur_value is not None:
                self.value = cur_value

        if action == Operations.SET:
            self.value = value
            self.operations = [(Operations.SET, value)] 
        elif action == Operations.LIST_CLEAR:
            self.value = list()
            self.operations = [(Operations.LIST_CLEAR, None)]
        else:
            if action == Operations.LIST_ADD:
                self.value.append(value)
            elif action == Operations.LIST_REMOVE:
                self.value.remove(value)
            else:
                raise RuntimeError
            self.operations.append((action, value))

class InstanceState:
    def __init__(self, manager, instance, name = None):

        # Unique identifier for the instance. This is useful for relation
        # between resources
        self.uuid = UUID(name, instance.__class__)
        self.instance       = instance

        # Instance manager
        self.manager        = manager

        # Events
        self.events         = dict()

        # Stores the requested value : attribute_name -> requested operations =
        # LIST set add remove clear
        self.dirty          = dict()


        # Initialize resource state
        self.lock = asyncio.Lock() 
        self.write_lock = asyncio.Lock()
        self.state          = ResourceState.UNINITIALIZED
        self.clean = asyncio.Event()
        self.clean.clear()
        self.init  = asyncio.Event()
        self.init.clear()
        self.change_event = asyncio.Event()
        self.change_event.clear()
        self.change_success = None
        self.change_value = None
        self.log = list()

        self.attr_lock = dict()
        self.attr_init = dict()
        self.attr_clean = dict()
        self.attr_state = dict()
        self.attr_change_event = dict()
        self.attr_change_success = dict()
        self.attr_change_value= dict()
        self.attr_log = dict()
        # Initialize attribute state
        for attribute in instance.iter_attributes():
            self.attr_lock[attribute.name] = asyncio.Lock() 
            self.attr_init[attribute.name] = asyncio.Event()
            self.attr_clean[attribute.name] = asyncio.Event()
            self.attr_state[attribute.name] = AttributeState.UNINITIALIZED
            self.attr_change_event[attribute.name] = asyncio.Event()
            self.attr_change_event[attribute.name].clear()
            self.attr_change_success[attribute.name] = None
            self.attr_change_value[attribute.name] = None
            self.dirty[attribute.name] = PendingValue(NEVER_SET)
            self.attr_log[attribute.name] = list()

    def set_dirty(self, attr_name):
        self.attr_dirty.add(attr_name)
        self.manager.set_dirty(self.uuid)

    def trigger(self, attribute_name, action, value):
        self.dirty[attribute_name].trigger(action, value)