[Fix][cherry-pick] Handle error when switch is not connected

exceptions.py

@@ -3,3 +3,7 @@
 
 class InvalidCommandError(Exception):
     """Command has an invalid value."""
+
+
+class SwitchNotConnectedError(Exception):
+    """Exception raised when a switch's connection isn't connected."""

main.py

@@ -14,12 +14,17 @@
 from pyof.foundation.base import UBIntBase
 from pyof.v0x01.asynchronous.error_msg import BadActionCode
 from pyof.v0x01.common.phy_port import PortConfig
-from werkzeug.exceptions import BadRequest, NotFound, UnsupportedMediaType
+from werkzeug.exceptions import (
+    BadRequest,
+    FailedDependency,
+    NotFound,
+    UnsupportedMediaType,
+)
 
 from kytos.core import KytosEvent, KytosNApp, log, rest
 from kytos.core.helpers import get_time, listen_to, now
 
-from .exceptions import InvalidCommandError
+from .exceptions import InvalidCommandError, SwitchNotConnectedError
 from .settings import (
     CONSISTENCY_COOKIE_IGNORED_RANGE,
     CONSISTENCY_TABLE_ID_IGNORED_RANGE,
@@ -470,21 +475,25 @@ def _send_flow_mods_from_request(self, dpid, command, flows_dict=None):
             f"Send FlowMod from request dpid: {dpid} command: {command}"
             f" flows_dict: {flows_dict}"
         )
-        if dpid:
+        try:
+            if not dpid:
+                self._install_flows(
+                    command, flows_dict, self._get_all_switches_enabled()
+                )
+                return jsonify({"response": "FlowMod Messages Sent"}), 202
+
             switch = self.controller.get_switch_by_dpid(dpid)
             if not switch:
                 return jsonify({"response": "dpid not found."}), 404
-            elif switch.is_enabled() is False:
-                if command == "delete":
-                    self._install_flows(command, flows_dict, [switch])
-                else:
-                    return jsonify({"response": "switch is disabled."}), 404
-            else:
-                self._install_flows(command, flows_dict, [switch])
-        else:
-            self._install_flows(command, flows_dict, self._get_all_switches_enabled())
 
-        return jsonify({"response": "FlowMod Messages Sent"}), 202
+            if not switch.is_enabled() and command == "add":
+                return jsonify({"response": "switch is disabled."}), 404
+
+            self._install_flows(command, flows_dict, [switch])
+            return jsonify({"response": "FlowMod Messages Sent"}), 202
+
+        except SwitchNotConnectedError as error:
+            raise FailedDependency(str(error))
 
     def _install_flows(self, command, flows_dict, switches=[], save=True):
         """Execute all procedures to install flows in the switches.
@@ -523,8 +532,10 @@ def _add_flow_mod_sent(self, xid, flow, command):
         self._flow_mods_sent[xid] = (flow, command)
 
     def _send_flow_mod(self, switch, flow_mod):
-        event_name = "kytos/flow_manager.messages.out.ofpt_flow_mod"
+        if not switch.is_connected():
+            raise SwitchNotConnectedError(f"switch {switch.id} isn't connected")
 
+        event_name = "kytos/flow_manager.messages.out.ofpt_flow_mod"
         content = {"destination": switch.connection, "message": flow_mod}
 
         event = KytosEvent(name=event_name, content=content)

setup.cfg

@@ -6,7 +6,7 @@ add-ignore = D105
 
 [yala]
 radon mi args = --min C
-pylint args = --disable==too-many-arguments,too-many-locals,too-few-public-methods,too-many-instance-attributes,no-else-return,dangerous-default-value,duplicate-code --ignored-modules=napps.kytos.topology
+pylint args = --disable==too-many-arguments,too-many-locals,too-few-public-methods,too-many-instance-attributes,no-else-return,dangerous-default-value,duplicate-code,raise-missing-from --ignored-modules=napps.kytos.topology
 
 [flake8]
 max-line-length = 88

tests/unit/test_main.py

@@ -13,6 +13,7 @@
     get_switch_mock,
     get_test_client,
 )
+from napps.kytos.flow_manager.exceptions import SwitchNotConnectedError
 
 
 # pylint: disable=protected-access, too-many-public-methods
@@ -163,6 +164,17 @@ def test_rest_add_and_delete_with_dpi_fail(self, mock_install_flows):
 
         self.assertEqual(mock_install_flows.call_count, 0)
 
+    @patch("napps.kytos.flow_manager.main.Main._install_flows")
+    def test_rest_flow_mod_add_switch_not_connected(self, mock_install_flows):
+        """Test sending a flow mod when a swith isn't connected."""
+        api = get_test_client(self.napp.controller, self.napp)
+        mock_install_flows.side_effect = SwitchNotConnectedError
+
+        url = f"{self.API_URL}/v2/flows"
+        response = api.post(url, json={"flows": [{"priority": 25}]})
+
+        self.assertEqual(response.status_code, 424)
+
     def test_get_all_switches_enabled(self):
         """Test _get_all_switches_enabled method."""
         switches = self.napp._get_all_switches_enabled()
@@ -278,6 +290,18 @@ def test_send_flow_mod(self, mock_buffers_put):
 
         mock_buffers_put.assert_called()
 
+    @patch("kytos.core.buffers.KytosEventBuffer.put")
+    def test_send_flow_mod_error(self, mock_buffers_put):
+        """Test _send_flow_mod method error."""
+        switch = get_switch_mock("00:00:00:00:00:00:00:01", 0x04)
+        switch.is_connected = MagicMock(return_value=False)
+        flow_mod = MagicMock()
+
+        with self.assertRaises(SwitchNotConnectedError):
+            self.napp._send_flow_mod(switch, flow_mod)
+
+        mock_buffers_put.assert_not_called()
+
     @patch("kytos.core.buffers.KytosEventBuffer.put")
     def test_send_napp_event(self, mock_buffers_put):
         """Test _send_napp_event method."""