1
|
|
|
"""Module Graph of kytos/pathfinder Kytos Network Application.""" |
2
|
|
|
|
3
|
1 |
|
from itertools import combinations |
4
|
|
|
|
5
|
1 |
|
from kytos.core import log |
6
|
1 |
|
|
7
|
1 |
|
try: |
8
|
|
|
import networkx as nx |
9
|
|
|
from networkx.exception import NodeNotFound, NetworkXNoPath |
10
|
|
|
except ImportError: |
11
|
|
|
PACKAGE = 'networkx>=2.2' |
12
|
|
|
log.error(f"Package {PACKAGE} not found. Please 'pip install {PACKAGE}'") |
13
|
1 |
|
|
14
|
|
|
|
15
|
|
|
class Filter: |
16
|
1 |
|
"""Class responsible for removing items with disqualifying values.""" |
17
|
1 |
|
|
18
|
|
|
def __init__(self, filter_type, filter_function): |
19
|
1 |
|
self._filter_type = filter_type |
20
|
|
|
self._filter_fun = filter_function |
21
|
1 |
|
|
22
|
|
|
def run(self, value, items): |
23
|
1 |
|
"""Filter out items. Filter chosen is picked at runtime.""" |
24
|
|
|
if isinstance(value, self._filter_type): |
25
|
1 |
|
return filter(self._filter_fun(value), items) |
26
|
1 |
|
|
27
|
1 |
|
raise TypeError(f"Expected type: {self._filter_type}") |
28
|
|
|
|
29
|
1 |
|
|
30
|
|
|
class KytosGraph: |
31
|
1 |
|
"""Class responsible for the graph generation.""" |
32
|
1 |
|
|
33
|
1 |
|
def __init__(self): |
34
|
|
|
self.graph = nx.Graph() |
35
|
1 |
|
self._filter_fun_dict = {} |
36
|
1 |
|
|
37
|
1 |
|
def filter_leq(metric): # Lower values are better |
38
|
|
|
return lambda x: (lambda y: y[2].get(metric, x) <= x) |
|
|
|
|
39
|
|
|
|
40
|
|
|
def filter_geq(metric): # Higher values are better |
41
|
|
|
return lambda x: (lambda y: y[2].get(metric, x) >= x) |
|
|
|
|
42
|
1 |
|
|
43
|
|
|
def filter_eeq(metric): # Equivalence |
44
|
1 |
|
return lambda x: (lambda y: y[2].get(metric, x) == x) |
|
|
|
|
45
|
1 |
|
|
46
|
1 |
|
self._filter_fun_dict["ownership"] = Filter( |
47
|
1 |
|
str, filter_eeq("ownership")) |
48
|
1 |
|
self._filter_fun_dict["bandwidth"] = Filter( |
49
|
1 |
|
(int, float), filter_geq("bandwidth")) |
50
|
1 |
|
self._filter_fun_dict["priority"] = Filter( |
51
|
1 |
|
(int, float), filter_geq("priority")) |
52
|
1 |
|
self._filter_fun_dict["reliability"] = Filter( |
53
|
|
|
(int, float), filter_geq("reliability")) |
54
|
1 |
|
self._filter_fun_dict["utilization"] = Filter( |
55
|
|
|
(int, float), filter_leq("utilization")) |
56
|
1 |
|
self._filter_fun_dict["delay"] = Filter( |
57
|
|
|
(int, float), filter_leq("delay")) |
58
|
|
|
self._path_fun = nx.all_shortest_paths |
59
|
|
|
|
60
|
|
|
def set_path_fun(self, path_fun): |
61
|
|
|
"""Set the shortest path function.""" |
62
|
1 |
|
self._path_fun = path_fun |
63
|
1 |
|
|
64
|
1 |
|
def clear(self): |
65
|
1 |
|
"""Remove all nodes and links registered.""" |
66
|
|
|
self.graph.clear() |
67
|
1 |
|
|
68
|
|
|
def update_topology(self, topology): |
69
|
|
|
"""Update all nodes and links inside the graph.""" |
70
|
1 |
|
self.graph.clear() |
71
|
1 |
|
self.update_nodes(topology.switches) |
72
|
1 |
|
self.update_links(topology.links) |
73
|
|
|
|
74
|
1 |
|
def update_nodes(self, nodes): |
75
|
|
|
"""Update all nodes inside the graph.""" |
76
|
1 |
|
for node in nodes.values(): |
77
|
1 |
|
try: |
78
|
|
|
self.graph.add_node(node.id) |
79
|
|
|
|
80
|
|
|
for interface in node.interfaces.values(): |
81
|
|
|
self.graph.add_node(interface.id) |
82
|
1 |
|
self.graph.add_edge(node.id, interface.id) |
83
|
|
|
|
84
|
|
|
except AttributeError: |
85
|
|
|
pass |
86
|
|
|
|
87
|
|
|
def update_links(self, links): |
88
|
|
|
"""Update all links inside the graph.""" |
89
|
|
|
keys = [] |
90
|
|
|
for link in links.values(): |
91
|
|
|
if link.is_active(): |
92
|
|
|
self.graph.add_edge(link.endpoint_a.id, link.endpoint_b.id) |
93
|
|
|
for key, value in link.metadata.items(): |
94
|
|
|
keys.append(key) |
95
|
|
|
endpoint_a = link.endpoint_a.id |
96
|
|
|
endpoint_b = link.endpoint_b.id |
97
|
|
|
self.graph[endpoint_a][endpoint_b][key] = value |
98
|
|
|
|
99
|
|
|
def get_metadata_from_link(self, endpoint_a, endpoint_b): |
100
|
|
|
"""Return the metadata of a link.""" |
101
|
|
|
return self.graph.edges[endpoint_a, endpoint_b] |
102
|
|
|
|
103
|
|
|
@staticmethod |
104
|
|
|
def _remove_switch_hops(circuit): |
105
|
|
|
"""Remove switch hops from a circuit hops list.""" |
106
|
|
|
for hop in circuit['hops']: |
107
|
|
|
if len(hop.split(':')) == 8: |
108
|
|
|
circuit['hops'].remove(hop) |
109
|
|
|
|
110
|
|
|
def shortest_paths(self, source, destination, parameter=None): |
111
|
|
|
"""Calculate the shortest paths and return them.""" |
112
|
|
|
try: |
113
|
|
|
paths = list(self._path_fun(self.graph, |
114
|
|
|
source, destination, parameter)) |
115
|
|
|
except (NodeNotFound, NetworkXNoPath): |
116
|
|
|
return [] |
117
|
|
|
return paths |
118
|
|
|
|
119
|
|
|
def constrained_flexible_paths(self, source, destination, complete_metrics, |
120
|
|
|
flexible=None): |
121
|
|
|
"""Calculate the constrained shortest paths with flexibility.""" |
122
|
|
|
metrics, flexible_metrics = KytosGraph.unpack_metrics(complete_metrics) |
123
|
|
|
# Grab all edges with meta data and remove the |
124
|
|
|
# ones that do not meet metric requirements. |
125
|
|
|
default_edge_list = list(self._filter_edges( |
126
|
|
|
self.graph.edges(data=True), **metrics)) |
127
|
|
|
# Determine the size of the power subset of flexible metrics. |
128
|
|
|
length = len(flexible_metrics) |
129
|
|
|
if flexible is None: |
130
|
|
|
flexible = length |
131
|
|
|
flexible = min(length, max(0, flexible)) |
132
|
|
|
results = [] |
133
|
|
|
result = [] |
134
|
|
|
i = 0 |
135
|
|
|
# Traverse through each combination in the power subset |
136
|
|
|
# and use the combination to find edges that partially |
137
|
|
|
# meet flexible metric requirements. |
138
|
|
|
while (result == [] and i in range(0, flexible+1)): |
139
|
|
|
for combo in combinations(flexible_metrics.items(), length-i): |
140
|
|
|
temp_dict = dict(combo) |
141
|
|
|
result = self._constrained_shortest_paths( |
142
|
|
|
source, destination, ((u, v) for u, v, d in |
|
|
|
|
143
|
|
|
self._filter_edges(default_edge_list, |
144
|
|
|
**temp_dict))) |
145
|
|
|
if result != []: |
146
|
|
|
results.append( |
147
|
|
|
{"paths": result, "metrics": {**metrics, **temp_dict}}) |
148
|
|
|
i = i + 1 |
149
|
|
|
return results |
150
|
|
|
|
151
|
|
|
@staticmethod |
152
|
|
|
def pack_metrics(inflexible=None, flexible=None): |
153
|
|
|
"""Store flexible and inflexible metrics in a dictionary.""" |
154
|
|
|
if inflexible is None: |
155
|
|
|
inflexible = {} |
156
|
|
|
if flexible is None: |
157
|
|
|
flexible = {} |
158
|
|
|
return dict(metrics=inflexible, flexible_metrics=flexible) |
159
|
|
|
|
160
|
|
|
@staticmethod |
161
|
|
|
def unpack_metrics(complete_metrics): |
162
|
|
|
"""Return inflexible and flexible metrics.""" |
163
|
|
|
return (complete_metrics["metrics"], |
164
|
|
|
complete_metrics["flexible_metrics"]) |
165
|
|
|
|
166
|
|
|
def _constrained_shortest_paths(self, source, destination, edges): |
167
|
|
|
paths = [] |
168
|
|
|
try: |
169
|
|
|
paths = list(self._path_fun(self.graph.edge_subgraph(edges), |
170
|
|
|
source, destination)) |
171
|
|
|
except NetworkXNoPath: |
172
|
|
|
pass |
173
|
|
|
except NodeNotFound: |
174
|
|
|
if source == destination: |
175
|
|
|
if source in self.graph.nodes: |
176
|
|
|
paths = [[source]] |
177
|
|
|
return paths |
178
|
|
|
|
179
|
|
|
def _filter_edges(self, edges, **metrics): |
180
|
|
|
for metric, value in metrics.items(): |
181
|
|
|
fil = self._filter_fun_dict.get(metric, None) |
182
|
|
|
if fil is not None: |
183
|
|
|
try: |
184
|
|
|
edges = fil.run(value, edges) |
185
|
|
|
except TypeError as err: |
186
|
|
|
raise TypeError(f"Error in {metric} filter: {err}") |
187
|
|
|
return edges |
188
|
|
|
|