Add Prometheus metrics.

webtest.py

@@ -1,24 +1,37 @@
 #!/usr/bin/python
 from BaseHTTPServer import BaseHTTPRequestHandler,HTTPServer
+from prometheus_client import Gauge
 import serial
 import time
 import json
 
 PORT_NUMBER = 8080
 
+# Setup Prometheus metrics.
+bartem_metric = Gauge('barometer_sensor_temperature_celcius', 'Barometric sensor temperature reading')
+barpres_metric = Gauge('barometer_sensor_pressure_pascals', 'Barometric sensor pressure reading')
+humidity_metric = Gauge('humidity_sensor_percent', 'Humidity sensor humidity reading')
+humidity_temp_metric = Gauge('humidity_sensor_temperature_celcius', 'Humidity sensor temperature reading')
+
+
+# Return the readings from the serial line.
+class readSerial():
+    ser.write('g')
+    bartemp = float(ser.readline())
+    barpres = int(float(ser.readline()))
+    humidity = int(float(ser.readline()))
+    humtemp = int(float(ser.readline()))
+    return bartemp, barpres, humidity, humtemp
+
+
 #This class will handles any incoming request from
 #the browser 
 class myHandler(BaseHTTPRequestHandler):
     #Handler for the GET requests
     def do_GET(self):
         if self.path=="/temp.json":
-            ser.write('g')
-            bartemp = float(ser.readline())
-            barpres = int(float(ser.readline()))
-            humidity = int(float(ser.readline()))
-            humtemp = int(float(ser.readline()))
+            bartemp, barpres, humidity, humtemp = readSerial()
             currenttime = time.time()
-
             data = {'BarometerTemperature':bartemp, 'BarometerPressure':barpres, 'Humidity':humidity, 'HumidityTemperature':humtemp, 'CurrentTime':int(currenttime)}
 
             self.send_response(200)
@@ -27,6 +40,27 @@ def do_GET(self):
             # Send the html message
             self.wfile.write(json.dumps(data))
             return
+        elif self.path=="/metrics":
+            bartemp, barpres, humidity, humtemp = readSerial()
+            bartemp_metric.set(bartemp)
+            barpres_metric.set(barpres)
+            humidity_metric.set(humidity)
+            humidity_temp_metric.set(humtemp)
+
+            registry = core.REGISTRY
+            params = parse_qs(urlparse(self.path).query)
+            if 'name[]' in params:
+                registry = registry.restricted_registry(params['name[]'])
+            try:
+                output = generate_latest(registry)
+            except:
+                self.send_error(500, 'error generating metric output')
+                raise
+            self.send_response(200)
+            self.send_header('Content-Type', CONTENT_TYPE_LATEST)
+            self.end_headers()
+            self.wfile.write(output)
+            return
         else:
             self.send_error(404,'File Not Found: %s' % self.path)
 
@@ -45,4 +79,4 @@ def do_GET(self):
 except KeyboardInterrupt:
     print '^C received, shutting down the web server'
     server.socket.close()
-    ser.close()
+    ser.close()