Retry only once on PartialFailure

When the PowerManager receives a `PartialFailure`, in many cases,
resending the request would fix it, because the power distributor
would have new information on how to redistribute differently.

But this doesn't always work, for example in single battery locations
or if all batteries are in an UNCERTAIN state, in which case the power
distributor has to retry with the same batteries.

For this reason, if we don't have a limit on such retries from the
PowerManager, we'd get into an infinite loop that doesn't have any
delay inbetween retries.

Signed-off-by: Sahas Subramanian <[email protected]>

Author: shsms

src/frequenz/sdk/actor/_power_managing/_power_managing_actor.py

@@ -180,6 +180,7 @@ async def _send_updated_target_power(
     @override
     async def _run(self) -> None:
         """Run the power managing actor."""
+        last_result_partial_failure = False
         async for selected in select(
             self._proposals_receiver,
             self._bounds_subscription_receiver,
@@ -234,9 +235,17 @@ async def _run(self) -> None:
                 self._distribution_results[
                     frozenset(result.request.component_ids)
                 ] = result
+                if not isinstance(result, power_distributing.Success):
+                    _logger.warning(
+                        "PowerManagingActor: PowerDistributing failed: %s", result
+                    )
                 match result:
                     case power_distributing.PartialFailure(request):
-                        await self._send_updated_target_power(
-                            frozenset(request.component_ids), None, must_send=True
-                        )
+                        if not last_result_partial_failure:
+                            last_result_partial_failure = True
+                            await self._send_updated_target_power(
+                                frozenset(request.component_ids), None, must_send=True
+                            )
+                    case power_distributing.Success():
+                        last_result_partial_failure = False
                 await self._send_reports(frozenset(result.request.component_ids))