From c07b1dbabd5861ccb710df9da6aadf1f052d2b83 Mon Sep 17 00:00:00 2001
From: Denis-Cosmin Nutiu <denis.nutiu@gmail.com>
Date: Mon, 13 Jun 2022 13:37:49 +0300
Subject: [PATCH] Expose bme680 measurements as prometheus metrics.

---
 requirements.txt |  1 +
 sensors/main.py  | 49 ++++++++++++++++++++++++++++++++++++++----------
 2 files changed, 40 insertions(+), 10 deletions(-)

diff --git a/requirements.txt b/requirements.txt
index 7fe8b29..f541eb4 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -1,2 +1,3 @@
 bme680==1.1.1
 HAP-python==4.4.0
+prometheus-client==0.14.1
diff --git a/sensors/main.py b/sensors/main.py
index a14079e..5833c45 100644
--- a/sensors/main.py
+++ b/sensors/main.py
@@ -3,6 +3,7 @@ from pyhap.accessory import Accessory, Bridge
 import bme680
 from pyhap.accessory_driver import AccessoryDriver
 from pyhap.const import CATEGORY_SENSOR
+from prometheus_client import start_http_server, Gauge
 
 
 class Bme680Sensor(Accessory):
@@ -24,12 +25,27 @@ class Bme680Sensor(Accessory):
         self.sensor.set_temperature_oversample(bme680.OS_8X)
         self.sensor.set_filter(bme680.FILTER_SIZE_3)
 
-        # Add the services that this Accessory will support with add_preload_service here
-        temp_service = self.add_preload_service('TemperatureSensor')
-        humidity_service = self.add_preload_service('HumiditySensor')
+        self._temperature_metric = Gauge(
+            "bme680_tempetaure_celsius", "The temperature measurement in celsius."
+        )
+        self._humidity_metric = Gauge(
+            "bme680_humidity_rh", "The humidity measurement in relative humidity."
+        )
+        self._pressure_metric = Gauge(
+            "bme680_pressure_hpa", "The pressure measurement in hectopascals."
+        )
+        self._gas_resistance_metric = Gauge(
+            "bme860_gas_resistance_ohm", "The gas resistance measurement in ohms."
+        )
 
-        self.temp_value = temp_service.get_characteristic('CurrentTemperature')
-        self.humidity_value = humidity_service.get_characteristic("CurrentRelativeHumidity")
+        # Add the services that this Accessory will support with add_preload_service here
+        temp_service = self.add_preload_service("TemperatureSensor")
+        humidity_service = self.add_preload_service("HumiditySensor")
+
+        self.temp_value = temp_service.get_characteristic("CurrentTemperature")
+        self.humidity_value = humidity_service.get_characteristic(
+            "CurrentRelativeHumidity"
+        )
 
     @Accessory.run_at_interval(3)
     def run(self):
@@ -43,21 +59,34 @@ class Bme680Sensor(Accessory):
             self.temp_value.set_value(self.sensor.data.temperature)
             self.humidity_value.set_value(self.sensor.data.humidity)
 
+            # Update prometheus metrics.
+            self._temperature_metric.set(self.sensor.data.temperature)
+            self._humidity_metric.set(self.sensor.data.humidity)
+            self._pressure_metric.set(self.sensor.data.pressure)
+
+            if self.sensor.data.heat_stable:
+                self._gas_resistance_metric.set(self.sensor.data.gas_resistance)
+
     def stop(self):
         """We override this method to clean up any resources or perform final actions, as
         this is called by the AccessoryDriver when the Accessory is being stopped.
         """
-        print('Stopping accessory.')
+        print("Stopping accessory.")
 
 
 def get_bridge(accessory_driver):
-    bridge = Bridge(accessory_driver, 'Bridge')
-    bridge.add_accessory(Bme680Sensor(accessory_driver, 'Sensor'))
+    bridge = Bridge(accessory_driver, "Bridge")
+    bridge.add_accessory(Bme680Sensor(accessory_driver, "Sensor"))
     return bridge
 
 
-if __name__ == '__main__':
-    driver = AccessoryDriver(port=51826, persist_file="/home/pi/bme680-homekit/sensors/accessory.state")
+if __name__ == "__main__":
+    # Prometheus' metrics server
+    start_http_server(8000)
+    # Python HAP
+    driver = AccessoryDriver(
+        port=51826, persist_file="/home/pi/bme680-homekit/sensors/accessory.state"
+    )
     driver.add_accessory(accessory=get_bridge(driver))
     signal.signal(signal.SIGTERM, driver.signal_handler)
     driver.start()