Multiple measurements support (volts, amperes, watts).

Drivers send dictionaries dumped in JSON format (instead of probe_id:value format).
Driver method "send_value" is renamed to "send_measurements".

kwapi/api/collector.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 
+import json
 import threading
 import time
 
@@ -90,8 +91,8 @@ class Collector:
             self.timer.start()
     
     def listen(self, conf):
-        """Subscribes to ZeroMQ messages, and adds received values to the database.
-        Message format is "probe:value".
+        """Subscribes to ZeroMQ messages, and adds received measurements to the database.
+        Messages are dictionaries dumped in JSON format.
         
         """
         LOG.info('Collector listenig to %s' % conf.probes_endpoint)
@@ -103,11 +104,11 @@ class Collector:
         
         while True:
             message = subscriber.recv()
-            data = message.split(':')
-            if len(data) == 2:
-                try:
-                    self.add(data[0], float(data[1]))
-                except:
-                    LOG.error('Message format error: %s' % message)
+            measurements = json.loads(message)
+            if not isinstance(measurements, dict):
+                LOG.error('Bad message type (not a dict)')
             else:
-                LOG.error('Malformed message: %s' % message)
+                try:
+                    self.add(measurements['probe_id'], float(measurements['w']))
+                except KeyError:
+                    LOG.error('Malformed message (missing required key)')

kwapi/drivers/driver.py

@@ -1,5 +1,6 @@
 # -*- coding: utf-8 -*-
 
+import json
 from threading import Thread, Event
 
 import zmq
@@ -35,9 +36,10 @@ class Driver(Thread):
         """Returns true if a stop request is pending."""
         return self.stop_request.is_set()
     
-    def send_value(self, probe_id, value):
-        """Sends a message via ZeroMQ with the following format: probe_id, value."""
-        self.publisher.send(probe_id + ':' + str(value))
+    def send_measurements(self, probe_id, measurements):
+        """Sends a message via ZeroMQ (dictionary dumped in JSON format)."""
+        measurements['probe_id'] = probe_id
+        self.publisher.send(json.dumps(measurements))
     
     def subscribe(self, observer):
         """Appends the observer (callback method) to the observers list."""

kwapi/drivers/dummy.py

@@ -24,6 +24,9 @@ class Dummy(Driver):
         """Starts the driver thread."""
         while not self.stop_request_pending():
             for probe_id in self.probe_ids:
-                value = randrange(self.min_value, self.max_value)
-                self.send_value(probe_id, value)
+                measurements = {}
+                measurements['w'] = randrange(self.min_value, self.max_value)
+                measurements['v'] = 230.0
+                measurements['a'] = measurements['w'] / measurements['v']
+                self.send_measurements(probe_id, measurements)
             time.sleep(1)

kwapi/drivers/wattsup.py

@@ -44,8 +44,9 @@ class Wattsup(Driver):
             except SerialException:
                 self.serial.close()
                 self.stop()
-            value = self.extract_watts(packet)
-            self.send_value(self.probe_ids[0], value)
+            measurements = {}
+            measurements['w'] = self.extract_watts(packet)
+            self.send_measurements(self.probe_ids[0], measurements)
     
     def get_packet(self):
         """Returns the next packet sent by the wattmeter."""