[FEATURE] Read and display distance in kilometers to next station

grafana-dashboard.json

@@ -260,7 +260,7 @@
 				"overrides": []
 			},
 			"gridPos": {
-				"h": 7,
+				"h": 5,
 				"w": 5,
 				"x": 19,
 				"y": 2
@@ -349,7 +349,7 @@
 				"h": 3,
 				"w": 5,
 				"x": 19,
-				"y": 9
+				"y": 7
 			},
 			"id": 3,
 			"options": {
@@ -415,10 +415,10 @@
 				"overrides": []
 			},
 			"gridPos": {
-				"h": 5,
+				"h": 4,
 				"w": 5,
 				"x": 19,
-				"y": 12
+				"y": 10
 			},
 			"id": 4,
 			"options": {
@@ -456,6 +456,77 @@
 			],
 			"title": "Next Station",
 			"type": "stat"
+		},
+		{
+			"datasource": {
+				"type": "prometheus",
+				"uid": "prometheus"
+			},
+			"description": "",
+			"fieldConfig": {
+				"defaults": {
+					"color": {
+						"mode": "fixed"
+					},
+					"decimals": 2,
+					"fieldMinMax": true,
+					"mappings": [],
+					"noValue": "0",
+					"thresholds": {
+						"mode": "absolute",
+						"steps": [
+							{
+								"color": "green",
+								"value": null
+							}
+						]
+					},
+					"unit": "lengthkm"
+				},
+				"overrides": []
+			},
+			"gridPos": {
+				"h": 3,
+				"w": 5,
+				"x": 19,
+				"y": 14
+			},
+			"id": 6,
+			"options": {
+				"colorMode": "value",
+				"graphMode": "area",
+				"justifyMode": "auto",
+				"orientation": "auto",
+				"reduceOptions": {
+					"calcs": [
+						"last"
+					],
+					"fields": "",
+					"values": false
+				},
+				"showPercentChange": false,
+				"text": {},
+				"textMode": "auto",
+				"wideLayout": true
+			},
+			"pluginVersion": "10.4.3",
+			"targets": [
+				{
+					"datasource": {
+						"type": "prometheus",
+						"uid": "prometheus"
+					},
+					"editorMode": "code",
+					"exemplar": false,
+					"expr": "train_distance",
+					"instant": true,
+					"legendFormat": "__auto",
+					"range": false,
+					"refId": "A"
+				}
+			],
+			"title": "Distance to Next Station",
+			"type": "stat"
 		}
 	],
 	"refresh": "5s",

metrics_exporter.py

@@ -10,6 +10,7 @@
 import time
 import urllib
 from urllib.request import urlopen
+from geopy.distance import geodesic
 from prometheus_client import start_http_server
 from prometheus_client.core import GaugeMetricFamily, REGISTRY
 
@@ -35,10 +36,14 @@ def collect(self):
             'Delay in minutes of the current trip',
             labels=['train', 'next_station']
         )
+        distance_metric = GaugeMetricFamily(
+            'train_distance',
+            'Distance in km until next station of the current trip'
+        )
 
         # Collect speed and delay information
-        speed = self.collect_speed()
-        train, next_station, delay = self.collect_trip()
+        speed, current_location = self.collect_status()
+        train, next_station, delay, next_station_location = self.collect_trip()
 
         # Handle speed metric
         if speed is not None:
@@ -56,27 +61,50 @@ def collect(self):
         else:
             trip_metric.add_metric(['Unknown', 'Unknown'], 0)
 
+        # Handle distance metric
+        if current_location is not None and next_station_location is not None:
+            distance = self.calculate_distance(current_location, next_station_location)
+            distance_metric.add_metric([], distance)
+            self.logger.debug('Extracted current location from JSON response: %s', current_location)
+            self.logger.debug(
+                'Extracted next station location from JSON response: %s',
+                next_station_location
+            )
+            self.logger.debug('Calculated distance: %.2f', distance)
+        else:
+            distance_metric.add_metric([], 0)
+
         yield speed_metric
         yield trip_metric
+        yield distance_metric
 
-    def collect_speed(self):
+    def collect_status(self):
         """
-        Collect speed metrics from DB onboard status API.
+        Collect status metrics from DB onboard status API.
         """
 
         try:
             with urlopen(self.STATUS_URL, timeout=20) as res:
                 status_response = json.load(res)
         except urllib.error.URLError as error:
             self.logger.error('Error while fetching JSON from %s: %s', self.STATUS_URL, str(error))
-            return None
+            return None, None
         except json.decoder.JSONDecodeError as error:
             self.logger.error('Error while decoding JSON from %s: %s', self.STATUS_URL, str(error))
-            return None
+            return None, None
 
-        return status_response.get('speed', 0.0)
+        speed = status_response.get('speed', 0.0)
+        latitude = status_response.get('latitude')
+        longitude = status_response.get('longitude')
 
-    def collect_trip(self):
+        if latitude is None or longitude is None:
+            coordinates = None
+        else:
+            coordinates = (latitude, longitude)
+
+        return speed, coordinates
+
+    def collect_trip(self): # pylint: disable=too-many-locals
         """
         Collect trip metrics from DB onboard trip API.
         """
@@ -86,10 +114,10 @@ def collect_trip(self):
                 trip_response = json.load(res)
         except urllib.error.URLError as error:
             self.logger.error('Error while fetching JSON from %s: %s', self.TRIP_URL, str(error))
-            return None, None, None
+            return None, None, None, None
         except json.decoder.JSONDecodeError as error:
             self.logger.error('Error while decoding JSON from %s: %s', self.TRIP_URL, str(error))
-            return None, None, None
+            return None, None, None, None
 
         # Fetch train, next station and all stops
         trip = trip_response.get('trip', {})
@@ -101,14 +129,25 @@ def collect_trip(self):
 
         # Early return if next station is not defined
         if next_station is None:
-            return train, None, None
+            return train, None, None, None
 
         for stop in all_stops:
             station = stop.get('station', {})
             eva_nr = station.get('evaNr')
             station_name = station.get('name', '')
             delay = stop.get('timetable', {}).get('arrivalDelay', 0)
 
+            # Get coordinates
+            coordinates = station.get('geocoordinates', {})
+            latitude = coordinates.get('latitude')
+            longitude = coordinates.get('longitude')
+
+            # Handle coordinates
+            if latitude is not None and longitude is not None:
+                location = (latitude, longitude)
+            else:
+                location = None
+
             # Remove leading plus (+) character from delay information
             if isinstance(delay, str) and delay.startswith('+'):
                 delay = int(delay.lstrip('+'))
@@ -117,9 +156,16 @@ def collect_trip(self):
 
             # Return delay data if eva number matches with next station
             if eva_nr == next_station:
-                return train, station_name, delay
+                return train, station_name, delay, location
+
+        return train, None, None, None
+
+    def calculate_distance(self, coordinates_from, coordinates_to):
+        """
+        Calculate distance in kilometers between two coordinates.
+        """
 
-        return train, None, None
+        return geodesic(coordinates_from, coordinates_to).km
 
 def main():
     """

requirements.txt

@@ -1,2 +1,3 @@
+geopy >= 2.4.1, < 3.0
 prometheus_client >= 0.20.0, < 0.21
 requests >= 2.32.2, < 3.0