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"""Main module of kytos/pathfinder Kytos Network Application.""" |
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from threading import Lock |
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from flask import jsonify, request |
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from kytos.core import KytosNApp, log, rest |
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from kytos.core.helpers import listen_to |
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from napps.kytos.pathfinder.graph import KytosGraph |
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# pylint: disable=import-error |
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from werkzeug.exceptions import BadRequest |
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class Main(KytosNApp): |
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""" |
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Main class of kytos/pathfinder NApp. |
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This class is the entry point for this napp. |
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""" |
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def setup(self): |
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"""Create a graph to handle the nodes and edges.""" |
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self.graph = KytosGraph() |
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self._topology = None |
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self._lock = Lock() |
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def execute(self): |
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"""Do nothing.""" |
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def shutdown(self): |
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"""Shutdown the napp.""" |
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def _filter_paths_le_cost(self, paths, max_cost): |
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"""Filter by paths where the cost is le <= max_cost.""" |
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if not max_cost: |
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return paths |
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return [path for path in paths if path["cost"] <= max_cost] |
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def _map_endpoints_from_link_ids(self, link_ids: list[str]) -> dict: |
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"""Map endpoints from link ids.""" |
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endpoints = {} |
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for link_id in link_ids: |
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try: |
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link = self._topology.links[link_id] |
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endpoint_a, endpoint_b = link.endpoint_a, link.endpoint_b |
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endpoints[(endpoint_a.id, endpoint_b.id)] = link |
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endpoints[(endpoint_b.id, endpoint_a.id)] = link |
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except KeyError: |
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pass |
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return endpoints |
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def _find_any_link_ids( |
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self, paths: list[dict], link_ids: list[str] |
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) -> set[int]: |
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"""Find indexes of the paths that contain any of the link ids.""" |
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endpoints_links = self._map_endpoints_from_link_ids(link_ids) |
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indexes: set[int] = set() |
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for idx, path in enumerate(paths): |
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head, tail = path["hops"][:-1], path["hops"][1:] |
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if idx in indexes: |
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continue |
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for endpoints in zip(head, tail): |
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if endpoints in endpoints_links: |
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indexes.add(idx) |
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break |
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return indexes |
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def _filter_paths_undesired_links( |
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self, paths: list[dict], undesired: list[str] |
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) -> list[dict]: |
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"""Filter by undesired_links, it performs a logical OR.""" |
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if not undesired: |
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return paths |
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excluded_indexes = self._find_any_link_ids(paths, undesired) |
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return [path for idx, path in enumerate(paths) if idx not in excluded_indexes] |
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def _filter_paths_desired_links( |
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self, paths: list[dict], desired: list[str] |
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) -> list[dict]: |
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"""Filter by desired_links, it performs a logical OR.""" |
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if not desired: |
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return paths |
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included_indexes = self._find_any_link_ids(paths, desired) |
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return [path for idx, path in enumerate(paths) if idx in included_indexes] |
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def _validate_payload(self, data): |
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"""Validate shortest_path v2/ POST endpoint.""" |
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if data.get("desired_links"): |
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if not isinstance(data["desired_links"], list): |
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raise BadRequest( |
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f"TypeError: desired_links is supposed to be a list." |
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f" type: {type(data['desired_links'])}" |
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) |
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if data.get("undesired_links"): |
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if not isinstance(data["undesired_links"], list): |
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raise BadRequest( |
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f"TypeError: undesired_links is supposed to be a list." |
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f" type: {type(data['undesired_links'])}" |
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) |
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parameter = data.get("parameter") |
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spf_attr = data.get("spf_attribute") |
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if not spf_attr: |
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spf_attr = parameter or "hop" |
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data["spf_attribute"] = spf_attr |
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if spf_attr not in self.graph.spf_edge_data_cbs: |
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raise BadRequest( |
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"Invalid 'spf_attribute'. Valid values: " |
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f"{', '.join(self.graph.spf_edge_data_cbs.keys())}" |
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) |
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try: |
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data["spf_max_paths"] = max(int(data.get("spf_max_paths", 2)), 1) |
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except (TypeError, ValueError): |
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raise BadRequest( |
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f"spf_max_paths {data.get('spf_max_pahts')} must be an int" |
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) |
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spf_max_path_cost = data.get("spf_max_path_cost") |
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if spf_max_path_cost: |
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try: |
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spf_max_path_cost = max(int(spf_max_path_cost), 1) |
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data["spf_max_path_cost"] = spf_max_path_cost |
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except (TypeError, ValueError): |
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raise BadRequest( |
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f"spf_max_path_cost {data.get('spf_max_path_cost')} must" |
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" be an int" |
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) |
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data["mandatory_metrics"] = data.get("mandatory_metrics", {}) |
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data["flexible_metrics"] = data.get("flexible_metrics", {}) |
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try: |
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minimum_hits = data.get("minimum_flexible_hits") |
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if minimum_hits: |
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minimum_hits = min( |
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len(data["flexible_metrics"]), max(0, int(minimum_hits)) |
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) |
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data["minimum_flexible_hits"] = minimum_hits |
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except (TypeError, ValueError): |
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raise BadRequest( |
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f"minimum_hits {data.get('minimum_flexible_hits')} must be an int" |
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) |
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return data |
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@rest("v2/", methods=["POST"]) |
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def shortest_path(self): |
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"""Calculate the best path between the source and destination.""" |
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data = request.get_json() |
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data = self._validate_payload(data) |
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desired = data.get("desired_links") |
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undesired = data.get("undesired_links") |
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spf_attr = data.get("spf_attribute") |
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spf_max_paths = data.get("spf_max_paths") |
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spf_max_path_cost = data.get("spf_max_path_cost") |
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mandatory_metrics = data.get("mandatory_metrics") |
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flexible_metrics = data.get("flexible_metrics") |
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minimum_hits = data.get("minimum_flexible_hits") |
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log.debug(f"POST v2/ payload data: {data}") |
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try: |
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with self._lock: |
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if any([mandatory_metrics, flexible_metrics]): |
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paths = self.graph.constrained_k_shortest_paths( |
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data["source"], |
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data["destination"], |
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weight=self.graph.spf_edge_data_cbs[spf_attr], |
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k=spf_max_paths, |
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minimum_hits=minimum_hits, |
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mandatory_metrics=mandatory_metrics, |
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flexible_metrics=flexible_metrics, |
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) |
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else: |
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paths = self.graph.k_shortest_paths( |
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data["source"], |
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data["destination"], |
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weight=self.graph.spf_edge_data_cbs[spf_attr], |
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k=spf_max_paths, |
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) |
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paths = self.graph.path_cost_builder( |
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paths, |
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weight=spf_attr, |
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) |
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log.debug(f"Found paths: {paths}") |
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except TypeError as err: |
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raise BadRequest(str(err)) |
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paths = self._filter_paths_le_cost(paths, max_cost=spf_max_path_cost) |
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paths = self._filter_paths_undesired_links(paths, undesired) |
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paths = self._filter_paths_desired_links(paths, desired) |
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log.debug(f"Filtered paths: {paths}") |
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return jsonify({"paths": paths}) |
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@listen_to("kytos.topology.updated", "kytos/topology.topology_loaded") |
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def on_topology_updated(self, event): |
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"""Update the graph when the network topology is updated.""" |
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self.update_topology(event) |
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def update_topology(self, event): |
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"""Update the graph when the network topology is updated.""" |
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if "topology" not in event.content: |
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return |
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topology = event.content["topology"] |
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with self._lock: |
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self._topology = topology |
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self.graph.update_topology(topology) |
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log.debug("Topology graph updated.") |
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@listen_to("kytos/topology.links.metadata.(added|removed)") |
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def on_links_metadata_changed(self, event): |
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"""Update the graph when links' metadata are added or removed.""" |
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link = event.content["link"] |
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with self._lock: |
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self.graph.update_link_metadata(link) |
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metadata = event.content["metadata"] |
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log.debug(f"Topology graph updated link id: {link.id} metadata: {metadata}") |
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kytos-ng /
pathfinder
