Add maxsize argument when subscribing for the component data

Default maxsize=50 is not working in case when user is interested
in the latest component data only.
maxsize has default constant argument specified outsided.
That way this constanst can be reused and this PR is not
breaking change.

Signed-off-by: ela-kotulska-frequenz <[email protected]>

Author: ela-kotulska-frequenz

src/frequenz/sdk/_internal/_constants.py

@@ -0,0 +1,10 @@
+# License: MIT
+# Copyright © 2023 Frequenz Energy-as-a-Service GmbH
+
+"""Module with constants shared between instances of the sdk.
+
+To be replaced by ConfigManager.
+"""
+
+RECEIVER_MAX_SIZE = 50
+"""Default buffer size of the receiver."""

src/frequenz/sdk/microgrid/client/_client.py

@@ -25,6 +25,7 @@
 from frequenz.channels import Broadcast, Receiver, Sender
 from google.protobuf.empty_pb2 import Empty  # pylint: disable=no-name-in-module
 
+from ..._internal._constants import RECEIVER_MAX_SIZE
 from ..component import (
     BatteryData,
     Component,
@@ -90,6 +91,7 @@ async def connections(
     async def meter_data(
         self,
         component_id: int,
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[MeterData]:
         """Return a channel receiver that provides a `MeterData` stream.
 
@@ -99,6 +101,7 @@ async def meter_data(
 
         Args:
             component_id: id of the meter to get data for.
+            maxsize: Size of the receiver's buffer.
 
         Returns:
             A channel receiver that provides realtime meter data.
@@ -108,6 +111,7 @@ async def meter_data(
     async def battery_data(
         self,
         component_id: int,
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[BatteryData]:
         """Return a channel receiver that provides a `BatteryData` stream.
 
@@ -117,6 +121,7 @@ async def battery_data(
 
         Args:
             component_id: id of the battery to get data for.
+            maxsize: Size of the receiver's buffer.
 
         Returns:
             A channel receiver that provides realtime battery data.
@@ -126,6 +131,7 @@ async def battery_data(
     async def inverter_data(
         self,
         component_id: int,
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[InverterData]:
         """Return a channel receiver that provides an `InverterData` stream.
 
@@ -135,6 +141,7 @@ async def inverter_data(
 
         Args:
             component_id: id of the inverter to get data for.
+            maxsize: Size of the receiver's buffer.
 
         Returns:
             A channel receiver that provides realtime inverter data.
@@ -144,6 +151,7 @@ async def inverter_data(
     async def ev_charger_data(
         self,
         component_id: int,
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[EVChargerData]:
         """Return a channel receiver that provides an `EvChargeData` stream.
 
@@ -153,6 +161,7 @@ async def ev_charger_data(
 
         Args:
             component_id: id of the ev charger to get data for.
+            maxsize: Size of the receiver's buffer.
 
         Returns:
             A channel receiver that provides realtime ev charger data.
@@ -440,6 +449,7 @@ async def _expect_category(
     async def meter_data(
         self,
         component_id: int,
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[MeterData]:
         """Return a channel receiver that provides a `MeterData` stream.
 
@@ -452,6 +462,7 @@ async def meter_data(
 
         Args:
             component_id: id of the meter to get data for.
+            maxsize: Size of the receiver's buffer.
 
         Returns:
             A channel receiver that provides realtime meter data.
@@ -463,11 +474,12 @@ async def meter_data(
         return self._get_component_data_channel(
             component_id,
             MeterData.from_proto,
-        ).new_receiver()
+        ).new_receiver(maxsize=maxsize)
 
     async def battery_data(
         self,
         component_id: int,
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[BatteryData]:
         """Return a channel receiver that provides a `BatteryData` stream.
 
@@ -480,6 +492,7 @@ async def battery_data(
 
         Args:
             component_id: id of the battery to get data for.
+            maxsize: Size of the receiver's buffer.
 
         Returns:
             A channel receiver that provides realtime battery data.
@@ -491,11 +504,12 @@ async def battery_data(
         return self._get_component_data_channel(
             component_id,
             BatteryData.from_proto,
-        ).new_receiver()
+        ).new_receiver(maxsize=maxsize)
 
     async def inverter_data(
         self,
         component_id: int,
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[InverterData]:
         """Return a channel receiver that provides an `InverterData` stream.
 
@@ -508,6 +522,7 @@ async def inverter_data(
 
         Args:
             component_id: id of the inverter to get data for.
+            maxsize: Size of the receiver's buffer.
 
         Returns:
             A channel receiver that provides realtime inverter data.
@@ -519,11 +534,12 @@ async def inverter_data(
         return self._get_component_data_channel(
             component_id,
             InverterData.from_proto,
-        ).new_receiver()
+        ).new_receiver(maxsize=maxsize)
 
     async def ev_charger_data(
         self,
         component_id: int,
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[EVChargerData]:
         """Return a channel receiver that provides an `EvChargeData` stream.
 
@@ -536,6 +552,7 @@ async def ev_charger_data(
 
         Args:
             component_id: id of the ev charger to get data for.
+            maxsize: Size of the receiver's buffer.
 
         Returns:
             A channel receiver that provides realtime ev charger data.
@@ -547,7 +564,7 @@ async def ev_charger_data(
         return self._get_component_data_channel(
             component_id,
             EVChargerData.from_proto,
-        ).new_receiver()
+        ).new_receiver(maxsize=maxsize)
 
     async def set_power(self, component_id: int, power_w: int) -> Empty:
         """Send request to the Microgrid to set power for component.

tests/utils/mock_microgrid.py

@@ -10,6 +10,7 @@
 from google.protobuf.empty_pb2 import Empty  # pylint: disable=no-name-in-module
 from pytest_mock import MockerFixture
 
+from frequenz.sdk._internal._constants import RECEIVER_MAX_SIZE
 from frequenz.sdk.microgrid import ConnectionManager
 from frequenz.sdk.microgrid._graph import ComponentGraph, _MicrogridComponentGraph
 from frequenz.sdk.microgrid.client import Connection
@@ -264,6 +265,7 @@ def _get_battery_receiver(
         self,
         component_id: int,
         channels: Dict[int, Broadcast[BatteryData]],
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[BatteryData]:
         """Return receiver of the broadcast channel for given component_id.
 
@@ -274,12 +276,15 @@ def _get_battery_receiver(
         Returns:
             Receiver from the given channels.
         """
-        return channels[component_id].new_receiver("component" + str(component_id))
+        return channels[component_id].new_receiver(
+            "component" + str(component_id), maxsize=maxsize
+        )
 
     def _get_meter_receiver(
         self,
         component_id: int,
         channels: Dict[int, Broadcast[MeterData]],
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[MeterData]:
         """Return receiver of the broadcast channel for given component_id.
 
@@ -290,12 +295,15 @@ def _get_meter_receiver(
         Returns:
             Receiver from the given channels.
         """
-        return channels[component_id].new_receiver("component" + str(component_id))
+        return channels[component_id].new_receiver(
+            "component" + str(component_id), maxsize=maxsize
+        )
 
     def _get_ev_charger_receiver(
         self,
         component_id: int,
         channels: Dict[int, Broadcast[EVChargerData]],
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[EVChargerData]:
         """Return receiver of the broadcast channel for given component_id.
 
@@ -306,12 +314,15 @@ def _get_ev_charger_receiver(
         Returns:
             Receiver from the given channels.
         """
-        return channels[component_id].new_receiver("component" + str(component_id))
+        return channels[component_id].new_receiver(
+            "component" + str(component_id), maxsize=maxsize
+        )
 
     def _get_inverter_receiver(
         self,
         component_id: int,
         channels: Dict[int, Broadcast[InverterData]],
+        maxsize: int = RECEIVER_MAX_SIZE,
     ) -> Receiver[InverterData]:
         """Return receiver of the broadcast channel for given component_id.
 
@@ -322,4 +333,6 @@ def _get_inverter_receiver(
         Returns:
             Receiver from the given channels.
         """
-        return channels[component_id].new_receiver("component" + str(component_id))
+        return channels[component_id].new_receiver(
+            "component" + str(component_id), maxsize=maxsize
+        )