build.models.path.DynamicPathManager.set_controller() - Code Metrics - Inspection of "Merge pull request #355 from kytos-ng/feat/setting..." - kytos-ng/mef_eline - Measure and Improve Code Quality continuously with Scrutinizer

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by Vinicius

created 2023-07-13 20:03 UTC

DynamicPathManager.set_controller() A

↳ Parent: build.models.path

Complexity

Conditions

Size

Total Lines	4
Code Lines	3

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	3
CRAP Score	1

Importance

Changes

Metric	Value
cc	1
eloc	3
nop	2
dl	0
loc	4
ccs	3
cts	3
cp	1
crap	1
rs	10
c	0
b	0
f	0

"""Classes related to paths"""
import requests

from kytos.core import log
from kytos.core.common import EntityStatus, GenericEntity
from kytos.core.link import Link
from napps.kytos.mef_eline import settings
from napps.kytos.mef_eline.exceptions import InvalidPath


class Path(list, GenericEntity):
    """Class to represent a Path."""

    def __eq__(self, other=None):
        """Compare paths."""
        if not other or not isinstance(other, Path):
            return False
        return super().__eq__(other)

    def is_affected_by_link(self, link=None):
        """Verify if the current path is affected by link."""
        if not link:
            return False
        return link in self

    def link_affected_by_interface(self, interface=None):
        """Return the link using this interface, if any, or None otherwise."""
        if not interface:
            return None
        for link in self:
            if interface in (link.endpoint_a, link.endpoint_b):
                return link
        return None

    def choose_vlans(self):
        """Choose the VLANs to be used for the circuit."""
        for link in self:
            tag = link.get_next_available_tag()
            link.add_metadata("s_vlan", tag)

    def make_vlans_available(self):
        """Make the VLANs used in a path available when undeployed."""
        for link in self:
            link.make_tag_available(link.get_metadata("s_vlan"))
            link.remove_metadata("s_vlan")

    def is_valid(self, switch_a, switch_z, is_scheduled=False):
        """Check if this is a valid path."""
        if not self:
            return True
        previous = visited = {switch_a}
        for link in self:
            current = {link.endpoint_a.switch, link.endpoint_b.switch} \
                      - previous
            if len(current) != 1:
                raise InvalidPath(
                    f"Previous switch {previous} is not connected to "
                    f"current link with switches {current}."
                )
            if current & visited:
                raise InvalidPath(
                    f"Loop detected in path, switch {current} was visited"
                    f" more than once."
                )
            if is_scheduled is False and (
                link.endpoint_a.link is None
                or link.endpoint_a.link != link
                or link.endpoint_b.link is None
                or link.endpoint_b.link != link
            ):
                raise InvalidPath(f"Link {link} is not available.")
            previous = current
            visited |= current
        if previous & {switch_z}:
            return True
        raise InvalidPath("Last link does not contain uni_z switch")

    @property
    def status(self):
        """Check for the  status of a path.

        If any link in this path is down, the path is considered down.
        """
        if not self:
            return EntityStatus.DISABLED

        endpoint = f"{settings.TOPOLOGY_URL}/links"
        api_reply = requests.get(endpoint)
        if api_reply.status_code != getattr(requests.codes, "ok"):
            log.error(
                "Failed to get links at %s. Returned %s",
                endpoint,
                api_reply.status_code,
            )
            return None
        links = api_reply.json()["links"]
        return_status = EntityStatus.UP
        for path_link in self:
            try:
                link = links[path_link.id]
            except KeyError:
                return EntityStatus.DISABLED
            if link["enabled"] is False:
                return EntityStatus.DISABLED
            if link["active"] is False:
                return_status = EntityStatus.DOWN
        return return_status

    def as_dict(self):
        """Return list comprehension of links as_dict."""
        return [link.as_dict() for link in self if link]


class DynamicPathManager:
    """Class to handle and create paths."""

    controller = None

    @classmethod
    def set_controller(cls, controller=None):
        """Set the controller to discovery news paths."""
        cls.controller = controller

    @staticmethod
    def get_paths(circuit, max_paths=2, **kwargs):
        """Get a valid path for the circuit from the Pathfinder."""
        endpoint = settings.PATHFINDER_URL
        spf_attribute = kwargs.get("spf_attribute") or settings.SPF_ATTRIBUTE
        request_data = {
            "source": circuit.uni_a.interface.id,
            "destination": circuit.uni_z.interface.id,
            "spf_max_paths": max_paths,
            "spf_attribute": spf_attribute
        }
        request_data.update(kwargs)
        api_reply = requests.post(endpoint, json=request_data)

        if api_reply.status_code != getattr(requests.codes, "ok"):
            log.error(
                "Failed to get paths at %s. Returned %s",
                endpoint,
                api_reply.text,
            )
            return None
        reply_data = api_reply.json()
        return reply_data.get("paths")

    @staticmethod
    def _clear_path(path):
        """Remove switches from a path, returning only interfaces."""
        return [endpoint for endpoint in path if len(endpoint) > 23]

    @classmethod
    def get_best_path(cls, circuit):
        """Return the best path available for a circuit, if exists."""
        paths = cls.get_paths(circuit)
        if paths:
            return cls.create_path(cls.get_paths(circuit)[0]["hops"])
        return None

    @classmethod
    def get_best_paths(cls, circuit, **kwargs):
        """Return the best paths available for a circuit, if they exist."""
        for path in cls.get_paths(circuit, **kwargs):
            yield cls.create_path(path["hops"])

    @classmethod
    def get_disjoint_paths(
        cls, circuit, unwanted_path, cutoff=settings.DISJOINT_PATH_CUTOFF
    ):
        """Computes the maximum disjoint paths from the unwanted_path for a EVC

        Maximum disjoint paths from the unwanted_path are the paths from the
        source node to the target node that share the minimum number os links
        contained in unwanted_path. In other words, unwanted_path is the path
        we want to avoid: we want the maximum possible disjoint path from it.
        The disjointness of a path in regards to unwanted_path is calculated
        by the complementary percentage of shared links between them. As an
        example, if the unwanted_path has 3 links, a given path P1 has 1 link
        shared with unwanted_path, and a given path P2 has 2 links shared with
        unwanted_path, then the disjointness of P1 is 0.67 and the disjointness
        of P2 is 0.33. In this example, P1 is preferable over P2 because it
        offers a better disjoint path. When two paths have the same
        disjointness they are ordered by 'cost' attributed as returned from
        Pathfinder. When the disjointness of a path is equal to 0 (i.e., it
        shares all the links with unwanted_path), that particular path is not
        considered a candidate.

        Parameters:
        -----------

        circuit : EVC
            The EVC providing source node (uni_a) and target node (uni_z)

        unwanted_path : Path
            The Path which we want to avoid.

        cutoff: int
            Maximum number of paths to consider when calculating the disjoint
            paths (number of paths to request from pathfinder)

        Returns:
        --------
        paths : generator
            Generator of unwanted_path disjoint paths. If unwanted_path is
            not provided or empty, we return an empty list.
        """
        unwanted_links = [
            (link.endpoint_a.id, link.endpoint_b.id) for link in unwanted_path
        ]
        if not unwanted_links:
            return None

        paths = cls.get_paths(circuit, max_paths=cutoff,
                              **circuit.secondary_constraints)
        for path in paths:
            head = path["hops"][:-1]
            tail = path["hops"][1:]
            shared_edges = 0
            for (endpoint_a, endpoint_b) in unwanted_links:
                if ((endpoint_a, endpoint_b) in zip(head, tail)) or (
                    (endpoint_b, endpoint_a) in zip(head, tail)
                ):
                    shared_edges += 1
            path["disjointness"] = 1 - shared_edges / len(unwanted_links)
        paths = sorted(paths, key=lambda x: (-x['disjointness'], x['cost']))
        for path in paths:
            if path["disjointness"] == 0:
                continue
            yield cls.create_path(path["hops"])
        return None

    @classmethod
    def create_path(cls, path):
        """Return the path containing only the interfaces."""
        new_path = Path()
        clean_path = cls._clear_path(path)

        if len(clean_path) % 2:
            return None

        for link in zip(clean_path[1:-1:2], clean_path[2::2]):
            interface_a = cls.controller.get_interface_by_id(link[0])
            interface_b = cls.controller.get_interface_by_id(link[1])
            if interface_a is None or interface_b is None:
                return None
            new_path.append(Link(interface_a, interface_b))

        return new_path


1		"""Classes related to paths"""
2	1	import requests
3
4	1	from kytos.core import log
5	1	from kytos.core.common import EntityStatus, GenericEntity
6	1	from kytos.core.link import Link
7	1	from napps.kytos.mef_eline import settings
8	1	from napps.kytos.mef_eline.exceptions import InvalidPath
9
10
11	1	class Path(list, GenericEntity):
12		"""Class to represent a Path."""
13
14	1	def __eq__(self, other=None):
15		"""Compare paths."""
16	1	if not other or not isinstance(other, Path):
17	1	return False
18	1	return super().__eq__(other)
19
20	1	def is_affected_by_link(self, link=None):
21		"""Verify if the current path is affected by link."""
22	1	if not link:
23	1	return False
24	1	return link in self
25
26	1	def link_affected_by_interface(self, interface=None):
27		"""Return the link using this interface, if any, or None otherwise."""
28	1	if not interface:
29	1	return None
30	1	for link in self:
31	1	if interface in (link.endpoint_a, link.endpoint_b):
32	1	return link
33		return None
34
35	1	def choose_vlans(self):
36		"""Choose the VLANs to be used for the circuit."""
37	1	for link in self:
38	1	tag = link.get_next_available_tag()
39	1	link.add_metadata("s_vlan", tag)
40
41	1	def make_vlans_available(self):
42		"""Make the VLANs used in a path available when undeployed."""
43	1	for link in self:
44	1	link.make_tag_available(link.get_metadata("s_vlan"))
45	1	link.remove_metadata("s_vlan")
46
47	1	def is_valid(self, switch_a, switch_z, is_scheduled=False):
48		"""Check if this is a valid path."""
49	1	if not self:
50	1	return True
51	1	previous = visited = {switch_a}
52	1	for link in self:
53	1	current = {link.endpoint_a.switch, link.endpoint_b.switch} \
54		- previous
55	1	if len(current) != 1:
56	1	raise InvalidPath(
57		f"Previous switch {previous} is not connected to "
58		f"current link with switches {current}."
59		)
60	1	if current & visited:
61	1	raise InvalidPath(
62		f"Loop detected in path, switch {current} was visited"
63		f" more than once."
64		)
65	1	if is_scheduled is False and (
66		link.endpoint_a.link is None
67		or link.endpoint_a.link != link
68		or link.endpoint_b.link is None
69		or link.endpoint_b.link != link
70		):
71		raise InvalidPath(f"Link {link} is not available.")
72	1	previous = current
73	1	visited \|= current
74	1	if previous & {switch_z}:
75	1	return True
76		raise InvalidPath("Last link does not contain uni_z switch")
77
78	1	@property
79	1	def status(self):
80		"""Check for the status of a path.
81
82		If any link in this path is down, the path is considered down.
83		"""
84	1	if not self:
85	1	return EntityStatus.DISABLED
86
87	1	endpoint = f"{settings.TOPOLOGY_URL}/links"
88	1	api_reply = requests.get(endpoint)
89	1	if api_reply.status_code != getattr(requests.codes, "ok"):
90		log.error(
91		"Failed to get links at %s. Returned %s",
92		endpoint,
93		api_reply.status_code,
94		)
95		return None
96	1	links = api_reply.json()["links"]
97	1	return_status = EntityStatus.UP
98	1	for path_link in self:
99	1	try:
100	1	link = links[path_link.id]
101		except KeyError:
102		return EntityStatus.DISABLED
103	1	if link["enabled"] is False:
104	1	return EntityStatus.DISABLED
105	1	if link["active"] is False:
106	1	return_status = EntityStatus.DOWN
107	1	return return_status
108
109	1	def as_dict(self):
110		"""Return list comprehension of links as_dict."""
111	1	return [link.as_dict() for link in self if link]
112
113
114	1	class DynamicPathManager:
115		"""Class to handle and create paths."""
116
117	1	controller = None
118
119	1	@classmethod
120	1	def set_controller(cls, controller=None):
121		"""Set the controller to discovery news paths."""
122	1	cls.controller = controller
123
124	1	@staticmethod
125	1	def get_paths(circuit, max_paths=2, **kwargs):
126		"""Get a valid path for the circuit from the Pathfinder."""
127	1	endpoint = settings.PATHFINDER_URL
128	1	spf_attribute = kwargs.get("spf_attribute") or settings.SPF_ATTRIBUTE
129	1	request_data = {
130		"source": circuit.uni_a.interface.id,
131		"destination": circuit.uni_z.interface.id,
132		"spf_max_paths": max_paths,
133		"spf_attribute": spf_attribute
134		}
135	1	request_data.update(kwargs)
136	1	api_reply = requests.post(endpoint, json=request_data)
137
138	1	if api_reply.status_code != getattr(requests.codes, "ok"):
139	1	log.error(
140		"Failed to get paths at %s. Returned %s",
141		endpoint,
142		api_reply.text,
143		)
144	1	return None
145	1	reply_data = api_reply.json()
146	1	return reply_data.get("paths")
147
148	1	@staticmethod
149	1	def _clear_path(path):
150		"""Remove switches from a path, returning only interfaces."""
151	1	return [endpoint for endpoint in path if len(endpoint) > 23]
152
153	1	@classmethod
154	1	def get_best_path(cls, circuit):
155		"""Return the best path available for a circuit, if exists."""
156	1	paths = cls.get_paths(circuit)
157	1	if paths:
158	1	return cls.create_path(cls.get_paths(circuit)[0]["hops"])
159	1	return None
160
161	1	@classmethod
162	1	def get_best_paths(cls, circuit, **kwargs):
163		"""Return the best paths available for a circuit, if they exist."""
164	1	for path in cls.get_paths(circuit, **kwargs):
165	1	yield cls.create_path(path["hops"])
166
167	1	@classmethod
168	1	def get_disjoint_paths(
169		cls, circuit, unwanted_path, cutoff=settings.DISJOINT_PATH_CUTOFF
170		):
171		"""Computes the maximum disjoint paths from the unwanted_path for a EVC
172
173		Maximum disjoint paths from the unwanted_path are the paths from the
174		source node to the target node that share the minimum number os links
175		contained in unwanted_path. In other words, unwanted_path is the path
176		we want to avoid: we want the maximum possible disjoint path from it.
177		The disjointness of a path in regards to unwanted_path is calculated
178		by the complementary percentage of shared links between them. As an
179		example, if the unwanted_path has 3 links, a given path P1 has 1 link
180		shared with unwanted_path, and a given path P2 has 2 links shared with
181		unwanted_path, then the disjointness of P1 is 0.67 and the disjointness
182		of P2 is 0.33. In this example, P1 is preferable over P2 because it
183		offers a better disjoint path. When two paths have the same
184		disjointness they are ordered by 'cost' attributed as returned from
185		Pathfinder. When the disjointness of a path is equal to 0 (i.e., it
186		shares all the links with unwanted_path), that particular path is not
187		considered a candidate.
188
189		Parameters:
190		-----------
191
192		circuit : EVC
193		The EVC providing source node (uni_a) and target node (uni_z)
194
195		unwanted_path : Path
196		The Path which we want to avoid.
197
198		cutoff: int
199		Maximum number of paths to consider when calculating the disjoint
200		paths (number of paths to request from pathfinder)
201
202		Returns:
203		--------
204		paths : generator
205		Generator of unwanted_path disjoint paths. If unwanted_path is
206		not provided or empty, we return an empty list.
207		"""
208	1	unwanted_links = [
209		(link.endpoint_a.id, link.endpoint_b.id) for link in unwanted_path
210		]
211	1	if not unwanted_links:
212	1	return None
213
214	1	paths = cls.get_paths(circuit, max_paths=cutoff,
215		**circuit.secondary_constraints)
216	1	for path in paths:
217	1	head = path["hops"][:-1]
218	1	tail = path["hops"][1:]
219	1	shared_edges = 0
220	1	for (endpoint_a, endpoint_b) in unwanted_links:
221	1	if ((endpoint_a, endpoint_b) in zip(head, tail)) or (
222		(endpoint_b, endpoint_a) in zip(head, tail)
223		):
224	1	shared_edges += 1
225	1	path["disjointness"] = 1 - shared_edges / len(unwanted_links)
226	1	paths = sorted(paths, key=lambda x: (-x['disjointness'], x['cost']))
227	1	for path in paths:
228	1	if path["disjointness"] == 0:
229	1	continue
230	1	yield cls.create_path(path["hops"])
231	1	return None
232
233	1	@classmethod
234	1	def create_path(cls, path):
235		"""Return the path containing only the interfaces."""
236	1	new_path = Path()
237	1	clean_path = cls._clear_path(path)
238
239	1	if len(clean_path) % 2:
240	1	return None
241
242	1	for link in zip(clean_path[1:-1:2], clean_path[2::2]):
243	1	interface_a = cls.controller.get_interface_by_id(link[0])
244	1	interface_b = cls.controller.get_interface_by_id(link[1])
245	1	if interface_a is None or interface_b is None:
246	1	return None
247	1	new_path.append(Link(interface_a, interface_b))
248
249		return new_path
250

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DynamicPathManager.set_controller() A

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