Deal with missing type info in microgrid API calls

grpc.aio doesn't have type information, and there are all sorts of
tricks in it, so some funtions that look like they are not async really
are (because they return a awaitable). For example [`unary_unary()`]
returns a [`UnaryUnaryMultiCallable`] which returns a [`UnaryUnaryCall`]
which is `awaitable`.

Also there seem to be wrong type info regarding `SetBounds()`, saying
`request_iterator` is a required argument but it is not.
[`stream_unary()`] returns a [`StreamUnaryMultiCallable`] which takes an
optional `request_iterator`.

[`unary_unary()`]: https://github.com/grpc/grpc/blob/v1.51.3/src/python/grpcio/grpc/aio/_base_channel.py#L271-L276
[`UnaryUnaryMultiCallable`]: https://github.com/grpc/grpc/blob/v1.51.3/src/python/grpcio/grpc/aio/_base_channel.py#L28-L41
[`UnaryUnaryCall`]: https://github.com/grpc/grpc/blob/v1.51.3/src/python/grpcio/grpc/aio/_base_call.py#L138-L149
['stream_unary()']: https://github.com/grpc/grpc/blob/v1.51.3/src/python/grpcio/grpc/aio/_base_channel.py#L313-L318
[`StreamUnaryMultiCallable`]: https://github.com/grpc/grpc/blob/v1.51.3/src/python/grpcio/grpc/aio/_base_channel.py#L106-L118

Signed-off-by: Leandro Lucarella <[email protected]>

Author: llucax

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

@@ -6,7 +6,17 @@
 import asyncio
 import logging
 from abc import ABC, abstractmethod
-from typing import Any, Callable, Dict, Iterable, Optional, Set, TypeVar
+from typing import (
+    Any,
+    Awaitable,
+    Callable,
+    Dict,
+    Iterable,
+    Optional,
+    Set,
+    TypeVar,
+    cast,
+)
 
 import grpc
 from frequenz.api.microgrid import common_pb2 as common_pb
@@ -210,10 +220,12 @@ async def components(self) -> Iterable[Component]:
                 when the api call exceeded timeout
         """
         try:
+            # grpc.aio is missing types and mypy thinks this is not awaitable,
+            # but it is
             component_list = await self.api.ListComponents(
                 microgrid_pb.ComponentFilter(),
-                timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
-            )
+                timeout=DEFAULT_GRPC_CALL_TIMEOUT,  # type: ignore[arg-type]
+            )  # type: ignore[misc]
         except grpc.aio.AioRpcError as err:
             msg = f"Failed to list components. Microgrid API: {self.target}. Err: {err.details()}"
             raise grpc.aio.AioRpcError(
@@ -266,8 +278,14 @@ async def connections(
         try:
             valid_components, all_connections = await asyncio.gather(
                 self.components(),
-                self.api.ListConnections(
-                    connection_filter, timeout=int(DEFAULT_GRPC_CALL_TIMEOUT)
+                # grpc.aio is missing types and mypy thinks this is not
+                # awaitable, but it is
+                cast(
+                    Awaitable[microgrid_pb.ConnectionList],
+                    self.api.ListConnections(
+                        connection_filter,
+                        timeout=DEFAULT_GRPC_CALL_TIMEOUT,  # type: ignore[arg-type]
+                    ),
                 ),
             )
         except grpc.aio.AioRpcError as err:
@@ -321,7 +339,9 @@ async def _component_data_task(
                 call = self.api.GetComponentData(
                     microgrid_pb.ComponentIdParam(id=component_id),
                 )
-                async for msg in call:
+                # grpc.aio is missing types and mypy thinks this is not
+                # async iterable, but it is
+                async for msg in call:  # type: ignore[attr-defined]
                     await sender.send(transform(msg))
             except grpc.aio.AioRpcError as err:
                 api_details = f"Microgrid API: {self.target}."
@@ -550,20 +570,24 @@ async def set_power(self, component_id: int, power_w: int) -> Empty:
         """
         try:
             if power_w >= 0:
+                # grpc.aio is missing types and mypy thinks this is not
+                # async iterable, but it is
                 result: Empty = await self.api.Charge(
                     microgrid_pb.PowerLevelParam(
                         component_id=component_id, power_w=power_w
                     ),
-                    timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
-                )
+                    timeout=DEFAULT_GRPC_CALL_TIMEOUT,  # type: ignore[arg-type]
+                )  # type: ignore[misc]
             else:
+                # grpc.aio is missing types and mypy thinks this is not
+                # async iterable, but it is
                 power_w *= -1
                 result = await self.api.Discharge(
                     microgrid_pb.PowerLevelParam(
                         component_id=component_id, power_w=power_w
                     ),
-                    timeout=int(DEFAULT_GRPC_CALL_TIMEOUT),
-                )
+                    timeout=DEFAULT_GRPC_CALL_TIMEOUT,  # type: ignore[arg-type]
+                )  # type: ignore[misc]
         except grpc.aio.AioRpcError as err:
             msg = f"Failed to set power. Microgrid API: {self.target}. Err: {err.details()}"
             raise grpc.aio.AioRpcError(
@@ -600,8 +624,14 @@ async def set_bounds(
         if lower > 0:
             raise ValueError(f"Lower bound {upper} must be less than or equal to 0.")
 
-        set_bounds_call = self.api.SetBounds(timeout=int(DEFAULT_GRPC_CALL_TIMEOUT))
+        # grpc.aio is missing types and mypy thinks request_iterator is
+        # a required argument, but it is not
+        set_bounds_call = self.api.SetBounds(
+            timeout=DEFAULT_GRPC_CALL_TIMEOUT,
+        )  # type: ignore[call-arg]
         try:
+            # grpc.aio is missing types and mypy thinks set_bounds_call can be Empty
+            assert not isinstance(set_bounds_call, Empty)
             await set_bounds_call.write(
                 microgrid_pb.SetBoundsParam(
                     component_id=component_id,