Allow defining per-sensor offsets within the configuration file

CHANGES.md

@@ -7,6 +7,8 @@
   @bee-mois.
 - Data Model: Make MQTT settings optional, to allow running the
   data logger without configuring them.
+- Allow defining per-sensor offsets within the configuration
+  file. Thanks, @bee-mois.
 
 ## v0.0.3 - 2024-04-20
 - Tests: Make sensor tests work, using a fake sysfs filesystem

ds18b20_datalogger/core.py

@@ -73,5 +73,7 @@ def read_ds18b20_sensor_matrix(devicemap: DeviceMap) -> Reading:
     reading = Reading()
     for device in devicemap.devices:
         value = read_temp(device.path)
+        if value is not None and device.offset is not None:
+            value += device.offset
         reading.add_measurement(name=device.name, value=value)
     return reading

ds18b20_datalogger/datalogger.yaml

@@ -19,13 +19,19 @@ mqtt:
 one-wire:
   - name: temp-ir-1-1
     path: /sys/bus/w1/devices/28-0346d4430b06
+    offset: null
   - name: temp-ir-1-2
     path: /sys/bus/w1/devices/28-0cf3d443ba40
+    offset: null
   - name: temp-ir-1-3
     path: /sys/bus/w1/devices/28-0e49d44343bd
+    offset: null
   - name: temp-ir-2-1
     path: /sys/bus/w1/devices/28-2231d443d266
+    offset: null
   - name: temp-ir-2-2
     path: /sys/bus/w1/devices/28-282bd4430f5e
+    offset: null
   - name: temp-ir-2-3
     path: /sys/bus/w1/devices/28-2846d443e4f2
+    offset: null

ds18b20_datalogger/model.py

@@ -16,6 +16,7 @@ class Device:
 
     name: str
     path: str
+    offset: t.Union[float, None] = None
 
 
 class DeviceMap:

tests/datalogger-offset.yaml

@@ -0,0 +1,11 @@
+# Test configuration file for validating per-sensor offsets.
+
+one-wire:
+  - name: temp-ir-1-1
+    path: /sys/bus/w1/devices/28-0346d4430b06
+    offset: -0.5
+  - name: temp-ir-1-2
+    path: /sys/bus/w1/devices/28-0cf3d443ba40
+    offset: null
+  - name: temp-ir-1-3
+    path: /sys/bus/w1/devices/28-0e49d44343bd

tests/test_core.py

@@ -109,3 +109,18 @@ def test_sensors_none(settings):
 def test_telemetry(settings):
     reading = read_ds18b20_sensor_matrix(settings.devicemap)
     send_measurement_mqtt(settings.mqtt, reading)
+
+
+@pytest.fixture
+def offset_settings() -> Settings:
+    configfile = Path("tests") / "datalogger-offset.yaml"
+    return Settings.from_file(configfile)
+
+
+def test_sensors_offset(offset_settings, fake_hardware_success):
+    reading = read_ds18b20_sensor_matrix(offset_settings.devicemap)
+    assert reading.to_dict() == {
+        "temp-ir-1-1": -0.499,
+        "temp-ir-1-2": 0.002,
+        "temp-ir-1-3": 0.003,
+    }