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"""Module Graph of kytos/pathfinder Kytos Network Application.""" |
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from kytos.core import log |
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try: |
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import networkx as nx |
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from networkx.exception import NodeNotFound, NetworkXNoPath |
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except ImportError: |
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PACKAGE = 'networkx>=2.2' |
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log.error(f"Package {PACKAGE} not found. Please 'pip install {PACKAGE}'") |
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class KytosGraph: |
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"""Class responsible for the graph generation.""" |
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def __init__(self): |
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self.graph = nx.Graph() |
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def clear(self): |
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"""Remove all nodes and links registered.""" |
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self.graph.clear() |
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def update_topology(self, topology): |
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"""Update all nodes and links inside the graph.""" |
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self.graph.clear() |
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self.update_nodes(topology.switches) |
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self.update_links(topology.links) |
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def update_nodes(self, nodes): |
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"""Update all nodes inside the graph.""" |
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for node in nodes.values(): |
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self.graph.add_node(node.id) |
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for interface in node.interfaces.values(): |
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self.graph.add_node(interface.id) |
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self.graph.add_edge(node.id, interface.id) |
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except AttributeError: |
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pass |
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def update_links(self, links): |
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"""Update all links inside the graph.""" |
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keys = [] |
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for link in links.values(): |
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if link.is_active(): |
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self.graph.add_edge(link.endpoint_a.id, link.endpoint_b.id) |
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for key, value in link.metadata.items(): |
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keys.append(key) |
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endpoint_a = link.endpoint_a.id |
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endpoint_b = link.endpoint_b.id |
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self.graph[endpoint_a][endpoint_b][key] = value |
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self._set_default_metadata(keys) |
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def _set_default_metadata(self, keys): |
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"""Set metadata to all links. |
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Set the value to zero for inexistent metadata in a link to make those |
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irrelevant in pathfinding. |
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""" |
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for key in keys: |
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for endpoint_a, endpoint_b in self.graph.edges: |
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if key not in self.graph[endpoint_a][endpoint_b]: |
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self.graph[endpoint_a][endpoint_b][key] = 0 |
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@staticmethod |
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def _remove_switch_hops(circuit): |
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"""Remove switch hops from a circuit hops list.""" |
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for hop in circuit['hops']: |
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if len(hop.split(':')) == 8: |
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circuit['hops'].remove(hop) |
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def shortest_paths(self, source, destination, parameter=None): |
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"""Calculate the shortest paths and return them.""" |
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try: |
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paths = list(nx.shortest_simple_paths(self.graph, |
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source, |
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destination, parameter)) |
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except (NodeNotFound, NetworkXNoPath): |
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return [] |
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return paths |
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kytos /
pathfinder
