Move ComponentMetricRequest structure to avoid cyclic imports

Signed-off-by: Mathias L. Baumann <[email protected]>

Author: Marenz

src/frequenz/sdk/actor/_data_sourcing/__init__.py

@@ -3,8 +3,8 @@
 
 """The DataSourcingActor."""
 
+from ._component_metric_request import ComponentMetricRequest
 from .data_sourcing import DataSourcingActor
-from .microgrid_api_source import ComponentMetricRequest
 
 __all__ = [
     "ComponentMetricRequest",

src/frequenz/sdk/actor/_data_sourcing/_component_metric_request.py

@@ -0,0 +1,51 @@
+# License: MIT
+# Copyright © 2023 Frequenz Energy-as-a-Service GmbH
+
+"""The ComponentMetricRequest class."""
+
+from dataclasses import dataclass
+from datetime import datetime
+
+from ...microgrid.component._component import ComponentMetricId
+
+
+@dataclass
+class ComponentMetricRequest:
+    """A request object to start streaming a metric for a component."""
+
+    namespace: str
+    """The namespace that this request belongs to.
+
+    Metric requests with a shared namespace enable the reuse of channels within
+    that namespace.
+
+    If for example, an actor making a multiple requests, uses the name of the
+    actor as the namespace, then requests from the actor will get reused when
+    possible.
+    """
+
+    component_id: int
+    """The ID of the requested component."""
+
+    metric_id: ComponentMetricId
+    """The ID of the requested component's metric."""
+
+    start_time: datetime | None
+    """The start time from which data is required.
+
+    When None, we will stream only live data.
+    """
+
+    def get_channel_name(self) -> str:
+        """Return a channel name constructed from Self.
+
+        This channel name can be used by the sending side and receiving sides to
+        identify the right channel from the ChannelRegistry.
+
+        Returns:
+            A string denoting a channel name.
+        """
+        return (
+            f"component-stream::{self.component_id}::{self.metric_id.name}::"
+            f"{self.start_time}::{self.namespace}"
+        )

src/frequenz/sdk/actor/_data_sourcing/data_sourcing.py

@@ -7,7 +7,8 @@
 
 from .._actor import Actor
 from .._channel_registry import ChannelRegistry
-from .microgrid_api_source import ComponentMetricRequest, MicrogridApiSource
+from ._component_metric_request import ComponentMetricRequest
+from .microgrid_api_source import MicrogridApiSource
 
 
 class DataSourcingActor(Actor):

src/frequenz/sdk/actor/_data_sourcing/microgrid_api_source.py

@@ -5,8 +5,6 @@
 
 import asyncio
 import logging
-from dataclasses import dataclass
-from datetime import datetime
 from typing import Any, Callable, Dict, List, Optional, Tuple
 
 from frequenz.channels import Receiver, Sender
@@ -23,49 +21,7 @@
 from ...timeseries import Sample
 from ...timeseries._quantities import Quantity
 from .._channel_registry import ChannelRegistry
-
-
-@dataclass
-class ComponentMetricRequest:
-    """A request object to start streaming a metric for a component."""
-
-    namespace: str
-    """The namespace that this request belongs to.
-
-    Metric requests with a shared namespace enable the reuse of channels within
-    that namespace.
-
-    If for example, an actor making a multiple requests, uses the name of the
-    actor as the namespace, then requests from the actor will get reused when
-    possible.
-    """
-
-    component_id: int
-    """The ID of the requested component."""
-
-    metric_id: ComponentMetricId
-    """The ID of the requested component's metric."""
-
-    start_time: Optional[datetime]
-    """The start time from which data is required.
-
-    When None, we will stream only live data.
-    """
-
-    def get_channel_name(self) -> str:
-        """Return a channel name constructed from Self.
-
-        This channel name can be used by the sending side and receiving sides to
-        identify the right channel from the ChannelRegistry.
-
-        Returns:
-            A string denoting a channel name.
-        """
-        return (
-            f"component-stream::{self.component_id}::{self.metric_id.name}::"
-            f"{self.start_time}::{self.namespace}"
-        )
-
+from ._component_metric_request import ComponentMetricRequest
 
 _MeterDataMethods: Dict[ComponentMetricId, Callable[[MeterData], float]] = {
     ComponentMetricId.ACTIVE_POWER: lambda msg: msg.active_power,