feat: add slave_id per metric group

Author: bmario

metricq_source_modbus/config_model.py

@@ -48,6 +48,9 @@ def metrics_not_empty(cls, v: dict[str, Metric]) -> dict[str, Metric]:
             raise ValueError("Group must have at least one metric")
         return v
 
+    slave_id: int | None = None
+    """Slave ID to query"""
+
     double_sample: bool = False
     """
     If set to true, the metric will be sampled twice per configured interval.

metricq_source_modbus/source.py

@@ -154,6 +154,7 @@ class MetricGroup:
     Represents a set of metrics
     - same host (implicitly)
     - same interval (implicitly)
+    - same slave id
     - common address space (based on addresses within the metrics)
     """
 
@@ -181,6 +182,10 @@ def __init__(self, host: "Host", config: config_model.Group) -> None:
                 raise ConfigError("missing interval")
         self.interval: Timedelta = interval
 
+        self.slave_id = (
+            config.slave_id if config.slave_id is not None else host.slave_id
+        )
+
         # Must be exactly here because we initialize `self.interval` before
         # and use `self._metrics` later
         self._metrics = self._create_metrics(config.metrics)
@@ -249,7 +254,7 @@ async def _update(
         async with lock:
             timestamp = Timestamp.now()
             raw_values = await client.read_input_registers(
-                self.host.slave_id, self.base_address, self._num_registers
+                self.slave_id, self.base_address, self._num_registers
             )
         assert len(raw_values) == self._num_registers
         buffer = struct.pack(f">{len(raw_values)}H", *raw_values)