Merge pull request #427 from kytos-ng/disjointment

Adding switches to disjointedness algorithm

CHANGELOG.rst

@@ -28,6 +28,7 @@ Changed
 - Improved log for invalid traces by adding ``From EVC(evc_id) named 'evc_name'``
 - An inactive and enabled EVC will be redeploy if an attribute from ``attributes_requiring_redeploy`` is updated.
 - If a KytosEvent can't be put on ``buffers.app`` during ``setup()``, it'll make the NApp to fail to start
+- Disjointedness algorithm now takes into account switches, excepting the UNIs switches. Unwanted switches have the same value as the unwanted links.
 
 Deprecated
 ==========

models/path.py

@@ -185,16 +185,17 @@ def get_disjoint_paths(
         """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
+        source node to the target node that share the minimum number of links
+        and switches 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 and
+        switches between them. As an example, if the unwanted_path has 3
+        links and 2 switches, a given path P1 has 1 link shared with
+        unwanted_path, and a given path P2 has 2 links and 1 switch shared
+        with unwanted_path, then the disjointness of P1 is 0.8 and the
+        disjointness of P2 is 0.4. 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
@@ -222,28 +223,56 @@ def get_disjoint_paths(
         unwanted_links = [
             (link.endpoint_a.id, link.endpoint_b.id) for link in unwanted_path
         ]
-        if not unwanted_links:
+        unwanted_switches = set()
+        for link in unwanted_path:
+            unwanted_switches.add(link.endpoint_a.switch.id)
+            unwanted_switches.add(link.endpoint_b.switch.id)
+        unwanted_switches.discard(circuit.uni_a.interface.switch.id)
+        unwanted_switches.discard(circuit.uni_z.interface.switch.id)
+
+        length_unwanted = (len(unwanted_links) + len(unwanted_switches))
+        if not unwanted_links or not unwanted_switches:
             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)
+            links_n, switches_n = cls.get_shared_components(
+                path, unwanted_links, unwanted_switches
+            )
+            shared_components = links_n + switches_n
+            path["disjointness"] = 1 - shared_components / length_unwanted
         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
 
+    @staticmethod
+    def get_shared_components(
+        path: Path,
+        unwanted_links: list[tuple[str, str]],
+        unwanted_switches: set[str]
+    ) -> tuple[int, int]:
+        """Return the number of shared links
+        and switches found in path."""
+        head = path["hops"][:-1]
+        tail = path["hops"][1:]
+        shared_links = 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_links += 1
+        copy_switches = unwanted_switches.copy()
+        shared_switches = 0
+        for component in path["hops"]:
+            if component in copy_switches:
+                shared_switches += 1
+                copy_switches.remove(component)
+        return shared_links, shared_switches
+
     @classmethod
     def create_path(cls, path):
         """Return the path containing only the interfaces."""

tests/helpers.py

@@ -23,6 +23,7 @@ def id_to_interface_mock(interface_id):
     switch_id = ":".join(interface_id.split(":")[:-1])
     port_id = int(interface_id.split(":")[-1])
     switch = get_switch_mock(switch_id, 0x04)
+    switch.id = switch_id
     interface = get_interface_mock(port_id, port_id, switch)
     return interface
 

tests/unit/models/test_path.py

@@ -488,8 +488,14 @@ def test_get_best_paths_error(self, mock_requests_post, mock_log):
         assert isinstance(res_paths, list)
         assert mock_log.error.call_count == 1
 
+    # pylint: disable=too-many-statements, too-many-locals
+    @patch.object(
+        DynamicPathManager,
+        "get_shared_components",
+        side_effect=DynamicPathManager.get_shared_components
+    )
     @patch("requests.post")
-    def test_get_disjoint_paths(self, mock_requests_post):
+    def test_get_disjoint_paths(self, mock_requests_post, mock_shared):
         """Test get_disjoint_paths method."""
 
         controller = MagicMock()
@@ -506,6 +512,8 @@ def test_get_disjoint_paths(self, mock_requests_post):
         }
         evc.uni_a.interface.id = "1"
         evc.uni_z.interface.id = "2"
+        evc.uni_a.interface.switch.id = "00:00:00:00:00:00:00:01"
+        evc.uni_z.interface.switch.id = "00:00:00:00:00:00:00:05"
 
         # Topo0
         paths1 = {
@@ -633,12 +641,25 @@ def test_get_disjoint_paths(self, mock_requests_post):
                 id_to_interface_mock("00:00:00:00:00:00:00:05:2")
             ),
         ]
+        path_links = [
+            ("00:00:00:00:00:00:00:01:2", "00:00:00:00:00:00:00:02:2"),
+            ("00:00:00:00:00:00:00:02:3", "00:00:00:00:00:00:00:04:2"),
+            ("00:00:00:00:00:00:00:04:3", "00:00:00:00:00:00:00:05:2")
+        ]
+        path_switches = {
+            "00:00:00:00:00:00:00:04",
+            "00:00:00:00:00:00:00:02"
+        }
 
         # only one path available from pathfinder (precesilly the
         # current_path), so the maximum disjoint path will be empty
         mock_response.json.return_value = {"paths": paths1["paths"][0:1]}
         mock_requests_post.return_value = mock_response
         paths = list(DynamicPathManager.get_disjoint_paths(evc, current_path))
+        args = mock_shared.call_args[0]
+        assert args[0] == paths1["paths"][0]
+        assert args[1] == path_links
+        assert args[2] == path_switches
         assert len(paths) == 0
 
         expected_disjoint_path = [
@@ -664,6 +685,13 @@ def test_get_disjoint_paths(self, mock_requests_post):
         mock_response.json.return_value = paths1
         mock_requests_post.return_value = mock_response
         paths = list(DynamicPathManager.get_disjoint_paths(evc, current_path))
+        args = mock_shared.call_args[0]
+        assert args[0] == paths1["paths"][-1]
+        assert args[1] == path_links
+        assert args[2] == {
+            "00:00:00:00:00:00:00:04",
+            "00:00:00:00:00:00:00:02"
+        }
         assert len(paths) == 4
         # for more information on the paths please refer to EP029
         assert len(paths[0]) == 4  # path S-Z-W-I-D
@@ -692,6 +720,8 @@ def test_get_disjoint_paths(self, mock_requests_post):
         mock_requests_post.assert_has_calls([expected_call])
 
         # EP029 Topo2
+        evc.uni_a.interface.switch.id = "00:00:00:00:00:00:00:01"
+        evc.uni_z.interface.switch.id = "00:00:00:00:00:00:00:07"
         paths2 = {
             "paths": [
                 {
@@ -758,6 +788,17 @@ def test_get_disjoint_paths(self, mock_requests_post):
                 id_to_interface_mock("00:00:00:00:00:00:00:07:2")
             ),
         ]
+        path_interfaces = [
+            ("00:00:00:00:00:00:00:01:2", "00:00:00:00:00:00:00:02:1"),
+            ("00:00:00:00:00:00:00:02:2", "00:00:00:00:00:00:00:03:1"),
+            ("00:00:00:00:00:00:00:03:2", "00:00:00:00:00:00:00:04:1"),
+            ("00:00:00:00:00:00:00:04:2", "00:00:00:00:00:00:00:07:2")
+        ]
+        path_switches = {
+            "00:00:00:00:00:00:00:02",
+            "00:00:00:00:00:00:00:03",
+            "00:00:00:00:00:00:00:04"
+        }
 
         expected_disjoint_path = [
             Link(
@@ -785,8 +826,39 @@ def test_get_disjoint_paths(self, mock_requests_post):
         mock_response.json.return_value = {"paths": paths2["paths"]}
         mock_requests_post.return_value = mock_response
         paths = list(DynamicPathManager.get_disjoint_paths(evc, current_path))
+        args = mock_shared.call_args[0]
+        assert args[0] == paths2["paths"][-1]
+        assert args[1] == path_interfaces
+        assert args[2] == path_switches
         assert len(paths) == 1
         assert (
             [link.id for link in paths[0]] ==
             [link.id for link in expected_disjoint_path]
         )
+
+    def test_get_shared_components(self):
+        """Test get_shared_components"""
+        mock_path = {"hops": [
+            '00:00:00:00:00:00:00:01:1',
+            '00:00:00:00:00:00:00:01',
+            '00:00:00:00:00:00:00:01:4',
+            '00:00:00:00:00:00:00:05:2',
+            '00:00:00:00:00:00:00:05',
+            '00:00:00:00:00:00:00:05:3',
+            '00:00:00:00:00:00:00:02:4',
+            '00:00:00:00:00:00:00:02',
+            '00:00:00:00:00:00:00:02:3',
+            '00:00:00:00:00:00:00:03:2',
+            '00:00:00:00:00:00:00:03',
+            '00:00:00:00:00:00:00:03:1'
+        ]}
+        mock_links = [
+            ("00:00:00:00:00:00:00:01:2", "00:00:00:00:00:00:00:02:2"),
+            ("00:00:00:00:00:00:00:02:3", "00:00:00:00:00:00:00:03:2")
+        ]
+        mock_switches = {"00:00:00:00:00:00:00:02"}
+        actual_lk, actual_sw = DynamicPathManager.get_shared_components(
+            mock_path, mock_links, mock_switches
+        )
+        assert actual_lk == 1
+        assert actual_sw == 1