Add $lastSeen and prometheus metrics endpoint

main.py

@@ -31,6 +31,40 @@ def index():
 
     return flask.render_template('index.html', devices=manager.devices)
 
+def prometheus_sanitize(v):
+    return v.encode('unicode_escape').decode('utf-8')
+
+def prometheus_value(v):
+    return float(v)
+
+@app.route('/metrics')
+def metrics():
+    proplist = []
+
+    for _, dev in manager.devices.items():
+        if not dev.online:
+            continue
+
+        for endpoint_id, props in dev.endpoints.items():
+            for property_id, value in props.items():
+                if property_id.startswith('$'):
+                    continue
+                try:
+                    proplist.append('spejsiot{node_id="%s", name="%s", ' \
+                                    'endpoint="%s", property="%s"} %s' % (
+                        prometheus_sanitize(dev.node_id),
+                        prometheus_sanitize(dev.name),
+                        prometheus_sanitize(endpoint_id),
+                        prometheus_sanitize(property_id),
+                        prometheus_value(value),
+                        ))
+                except ValueError:
+                    # This is most probably just a string value
+                    continue
+    return '\n'.join(proplist), 200, {
+        'Content-Type': 'text/plain; version=0.0.4',
+        }
+
 @app.route('/api/1/devices/')
 def api_devices():
     """Lists all known devices.

spejsiot/manager.py

@@ -1,6 +1,7 @@
 import paho.mqtt.client as mqtt
 from collections import defaultdict
 import logging
+import time
 
 class SpejsiotDevice(object):
     node_id = None
@@ -27,6 +28,15 @@ class SpejsiotDevice(object):
 
         return True
 
+    @property
+    def online(self):
+        return self.properties.get('$online', False)
+
+    @property
+    def name(self):
+        return self.properties.get('$name', '')
+
+
 class SpejsiotManager(mqtt.Client):
     devices = dict()
     logger = logging.getLogger('manager')
@@ -60,6 +70,8 @@ class SpejsiotManager(mqtt.Client):
             else:
                 value = msg.payload.decode('utf-8')
 
+            self.devices[node_id].properties['$lastSeen'] = int(time.time())
+
             if topic.startswith('$'):
                 self.devices[node_id].properties[topic] = value
             else: