Display duration of current workout

app.py

@@ -56,10 +56,18 @@ def device(device_id):
 def overview(device_id):
     cadences = db.get_all_cadences(device_id)
     last_cadence = cadences[-1]['rpm'] if cadences else 0
+    if cadences:
+        first = cadences[0]['logged_at']
+        last = cadences[-1]['logged_at']
+        duration = str(timedelta(seconds=(last-first).seconds))
 
-    graph_data = generate_sparkline_graph([c['rpm'] for c in cadences])
+        last_cadence = cadences[-1]['rpm']
 
-    return render_template('overview.html', last_cadence=last_cadence, cadences=cadences[-15:], graph_data=graph_data)
+        graph_data = generate_sparkline_graph(
+            [c['rpm'] for c in cadences[-100:]])
+
+        return render_template('overview.html', last_cadence=last_cadence, duration=duration, cadences=cadences[-15:], graph_data=graph_data)
+    return render_template('overview.html', last_cadence=0, duration=duration, cadences=[], graph_data='')
 
 
 @ app.route("/cadence", methods=['POST'])

db.py

@@ -41,7 +41,7 @@ class DataBase():
                      [rpm, device_id], commit=True)
 
     def get_all_cadences(self, device_id):
-        return self.execute("""SELECT LOGGED_AT, RPM FROM cadence WHERE device_id = %s AND (NOW() < (LOGGED_AT + (INTERVAL '3 hour'))) LIMIT 100""", [device_id])
+        return self.execute("""SELECT LOGGED_AT, RPM FROM cadence WHERE device_id = %s AND (NOW() < (LOGGED_AT + (INTERVAL '3 hour')))""", [device_id])
 
     def get_devices(self):
         return self.execute("""

templates/overview.html

@@ -1,6 +1,8 @@
 <h1
     class="mb-4 text-4xl font-extrabold leading-none tracking-tight text-gray-900 md:text-5xl lg:text-6xl dark:text-white text-center">
     {{last_cadence}} rpm</h1>
+<h3 class="mb-4 text-3xl font-extrabold leading-none tracking-tight text-gray-700 md:text-3xl lg:text-3xl dark:text-white text-center">
+{{duration}}</h3>
 
 <div class="flex flex-col items-center">