Move sensor management to separate module

Create a `sensor` module that will handle the interaction with coolr and
return updated machine information regularly.

The code code is as dumb as the previous one, but the structure is
improved, which should help for the next round of updates with coolr.

nrm/daemon.py

@@ -6,6 +6,7 @@ import re
 import signal
 import zmq
 from zmq.eventloop import ioloop, zmqstream
+import sensor
 
 application_fsm_table = {'stable': {'i': 's_ask_i', 'd': 's_ask_d'},
                          's_ask_i': {'done': 'stable', 'max': 'max'},
@@ -70,7 +71,6 @@ class Daemon(object):
         self.applications = {}
         self.buf = ''
         self.logger = logging.getLogger(__name__)
-        self.current = 1
         self.target = 1
 
     def do_application_receive(self, parts):
@@ -97,19 +97,20 @@ class Daemon(object):
                                      application.state)
 
     def do_sensor(self):
-        self.current = random.randrange(0, 34)
-        self.logger.info("current measure: " + str(self.current))
+        self.sensor_state = self.sensor.do_update()
+        self.logger.info("current state: %r" % self.sensor_state)
 
     def do_control(self):
+        total_power = self.sensor_state['total_power']
         self.target = random.randrange(0, 34)
         self.logger.info("target measure: " + str(self.target))
 
         for identity, application in self.applications.iteritems():
-            if self.current < self.target:
+            if total_power < self.target:
                 if 'i' in application.get_allowed_requests():
                     self.stream.send_multipart([identity, 'i'])
                     application.do_transition('i')
-            elif self.current > self.target:
+            elif total_power > self.target:
                 if 'd' in application.get_allowed_requests():
                     self.stream.send_multipart([identity, 'd'])
                     application.do_transition('d')
@@ -137,8 +138,13 @@ class Daemon(object):
         self.stream = zmqstream.ZMQStream(socket)
         self.stream.on_recv(self.do_application_receive)
 
-        self.sensor = ioloop.PeriodicCallback(self.do_sensor, 1000)
-        self.sensor.start()
+        # create sensor manager and make first measurement
+        self.sensor = sensor.SensorManager()
+        self.sensor_state = self.sensor.do_update()
+
+        # setup periodic sensor updates
+        self.sensor_cb = ioloop.PeriodicCallback(self.do_sensor, 1000)
+        self.sensor_cb.start()
 
         self.control = ioloop.PeriodicCallback(self.do_control, 1000)
         self.control.start()

nrm/sensor.py

+"""Sensor Module:
+    provide the core functionalities related to measuring power, energy,
+    temperature and other information about the local node, using our internal
+    version of the coolr code.
+
+    This module should be the only one interfacing with coolr.
+"""
+import random
+
+
+class SensorManager:
+    """Performs sensor reading and basic data aggregation."""
+
+    def __init__(self):
+        pass
+
+    def do_update(self):
+        return {'total_power': random.randrange(0, 34)}