Schedule imminent link state verification on link state changes

src/zino/tasks/linkstatetask.py

@@ -4,6 +4,8 @@
 from dataclasses import dataclass
 from typing import Any
 
+from zino.oid import OID
+from zino.scheduler import get_scheduler
 from zino.snmp import SNMP, SparseWalkResponse
 from zino.statemodels import EventState, InterfaceState, Port, PortStateEvent
 from zino.tasks.task import Task
@@ -42,6 +44,10 @@ class LinkStateTask(Task):
 
     sysuptime: int = 0
 
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self._scheduler = get_scheduler()
+
     async def run(self):
         snmp = SNMP(self.device)
         poll_list = [("IF-MIB", column) for column in BASE_POLL_LIST]
@@ -51,6 +57,20 @@ async def run(self):
 
         self._update_interfaces(attrs)
 
+    async def poll_single_interface(self, ifindex: int):
+        """Polls and updates a single interface"""
+        snmp = SNMP(self.device)
+        poll_list = [("IF-MIB", column, str(ifindex - 1)) for column in BASE_POLL_LIST]
+        result = await snmp.getnext2(*poll_list)
+        self.sysuptime = await self._get_uptime(snmp)
+        _logger.debug("poll_single_interface %s result: %r", self.device.name, result)
+
+        assert all(ident.index == OID(f".{ifindex}") for ident, value in result)
+        row = {ident.object: value for ident, value in result}
+
+        self._update_single_interface(row)
+        return row
+
     def _update_interfaces(self, new_attrs: SparseWalkResponse):
         for index, row in new_attrs.items():
             try:
@@ -110,7 +130,19 @@ def _make_or_update_state_event(self, port: Port, new_state: InterfaceState, las
         _logger.info(log)
         event.add_log(log)
 
-        # at this point we should re-schedule a new job in 2 minutes to verify the state change
+        self._schedule_verification_of_single_port(port.ifindex)
+
+    def _schedule_verification_of_single_port(self, ifindex: int):
+        in_two_minutes = datetime.datetime.now() + datetime.timedelta(minutes=2)
+        job_name = f"{self.device.name}-verify-{ifindex}-state"
+        self._scheduler.add_job(
+            func=self.poll_single_interface,
+            args=(ifindex,),
+            trigger="date",
+            run_date=in_two_minutes,
+            name=job_name,
+            id=job_name,
+        )
 
     def _get_or_create_port(self, ifindex: int):
         ports = self.state.devices.get(self.device.name).ports

tests/tasks/test_linkstatetask.py

@@ -3,7 +3,7 @@
 from zino.config.models import PollDevice
 from zino.oid import OID
 from zino.state import ZinoState
-from zino.statemodels import Port
+from zino.statemodels import InterfaceState, Port
 from zino.tasks.linkstatetask import (
     BaseInterfaceRow,
     CollectedInterfaceDataIsNotSaneError,
@@ -90,6 +90,18 @@ def test_when_descr_and_index_are_present_is_sane_should_return_true(self):
         row = BaseInterfaceRow(index=42, descr="x", alias="x", admin_status="x", oper_status="x", last_change=0)
         assert row.is_sane()
 
+    @pytest.mark.asyncio
+    async def test_poll_single_interface_should_update_state(self, linkstatetask_with_one_link_down):
+        target_index = 2
+        await linkstatetask_with_one_link_down.poll_single_interface(target_index)
+        device_state = linkstatetask_with_one_link_down.state.devices.get(linkstatetask_with_one_link_down.device.name)
+
+        assert target_index in device_state.ports, f"no state for port {target_index} was stored"
+        port = device_state.ports[target_index]
+        assert port.state == InterfaceState.DOWN
+        assert port.ifdescr == "2"
+        assert port.ifalias == "from a famous"
+
 
 @pytest.fixture
 def linkstatetask_with_links_up(snmpsim, snmp_test_port):