Some EV charger pool cleanup and fixes (#919)

Author: shsms

src/frequenz/sdk/actor/power_distributing/_component_managers/_ev_charger_manager/_ev_charger_manager.py

@@ -10,7 +10,6 @@
 
 import grpc
 from frequenz.channels import Broadcast, Sender, merge, select, selected_from
-from frequenz.channels.timer import SkipMissedAndDrift, Timer
 from frequenz.client.microgrid import ApiClient, ComponentCategory, EVChargerData
 from typing_extensions import override
 
@@ -20,8 +19,6 @@
 from ....._internal._math import is_close_to_zero
 from .....timeseries import Power, Sample3Phase, Voltage
 from ..._component_pool_status_tracker import ComponentPoolStatusTracker
-
-# from .._component_pool_status_tracker import ComponentPoolStatusTracker
 from ..._component_status import ComponentPoolStatus, EVChargerStatusTracker
 from ...request import Request
 from ...result import PartialFailure, Result, Success
@@ -32,7 +29,6 @@
 _logger = logging.getLogger(__name__)
 
 _DEFAULT_API_REQUEST_TIMEOUT = timedelta(seconds=5.0)
-_TGT_POWER_RESEND_INTERVAL = timedelta(seconds=5.0)
 
 
 class EVChargerManager(ComponentManager):
@@ -79,7 +75,9 @@ def component_ids(self) -> collections.abc.Set[int]:
     @override
     async def start(self) -> None:
         """Start the ev charger data manager."""
-        self._task = asyncio.create_task(self._run_forever())
+        # Need to start a task only if there are EV chargers in the component graph.
+        if self._ev_charger_ids:
+            self._task = asyncio.create_task(self._run_forever())
 
     @override
     async def distribute_power(self, request: Request) -> None:
@@ -88,7 +86,8 @@ async def distribute_power(self, request: Request) -> None:
         Args:
             request: Request to get the distribution for.
         """
-        await self._target_power_tx.send(request)
+        if self._ev_charger_ids:
+            await self._target_power_tx.send(request)
 
     @override
     async def stop(self) -> None:
@@ -222,10 +221,8 @@ async def _run(self) -> None:  # pylint: disable=too-many-locals
         )
         target_power_rx = self._target_power_channel.new_receiver()
         api_request_timeout = _DEFAULT_API_REQUEST_TIMEOUT
-        resend_timer = Timer(_TGT_POWER_RESEND_INTERVAL, SkipMissedAndDrift())
         latest_target_powers: dict[int, Power] = {}
-        async for selected in select(ev_charger_data_rx, target_power_rx, resend_timer):
-            resending = False
+        async for selected in select(ev_charger_data_rx, target_power_rx):
             target_power_changes = {}
             now = datetime.now(tz=timezone.utc)
 
@@ -276,21 +273,14 @@ async def _run(self) -> None:  # pylint: disable=too-many-locals
                     diff_power = allocated_power - self._target_power
                     target_power_changes = self._deallocate_unused_power(diff_power)
 
-            elif selected_from(selected, resend_timer):
-                target_power_changes = latest_target_powers
-                resending = True
-
             if target_power_changes:
                 _logger.debug("Setting power to EV chargers: %s", target_power_changes)
             else:
                 continue
-            if not resending:
-                for component_id, power in target_power_changes.items():
-                    self._evc_states.get(component_id).update_last_allocation(
-                        power, now
-                    )
+            for component_id, power in target_power_changes.items():
+                self._evc_states.get(component_id).update_last_allocation(power, now)
 
-                latest_target_powers.update(target_power_changes)
+            latest_target_powers.update(target_power_changes)
             result = await self._set_api_power(
                 api, target_power_changes, api_request_timeout
             )

src/frequenz/sdk/timeseries/ev_charger_pool/_ev_charger_pool.py

@@ -115,7 +115,14 @@ async def propose_power(
                 actors with a higher priority.  If None, the power bounds will be set to
                 the maximum power of the batteries in the pool.  This is currently and
                 experimental feature.
+
+        Raises:
+            EVChargerPoolError: If a discharge power for EV chargers is requested.
         """
+        if power is not None and power < Power.zero():
+            raise EVChargerPoolError(
+                "Discharging from EV chargers is currently not supported."
+            )
         await self._ev_charger_pool.power_manager_requests_sender.send(
             _power_managing.Proposal(
                 source_id=self._source_id,

tests/timeseries/_ev_charger_pool/test_ev_charger_pool_control_methods.py

@@ -163,8 +163,6 @@ async def _init_ev_chargers(self, mocks: _Mocks) -> None:
                 0.05,
             )
 
-        await asyncio.sleep(1)
-
     def _assert_report(  # pylint: disable=too-many-arguments
         self,
         report: EVChargerPoolReport,