differentiate b/t readonly and readwrite config files

config.py

@@ -5,23 +5,33 @@ Presents an interface for yaml files as a dict-like object
 import yaml
 from threading import Lock
 
-class _ConfigFile():
+class _ReadOnlyFile():
+	'''
+	Opens a yaml file for reading. Intended for config files.
+	'''
 	def __init__(self, path):
 		self._path = path
-		self._lock = Lock()
 		with open(self._path, 'r') as f:
 			self._dict = yaml.safe_load(f)
 
 	def __getitem__(self, key):
 		return self._dict[key]
 	
+class _ReadWriteFile(_ReadOnlyFile):
+	'''
+	Same as above but adds write functionality. Intended for files that retain
+	program state so that it may return to the same state when recovering from
+	a crash (eg someone can't crash the system to disarm it)
+	'''
+	def __init__(self, path):
+		super().__init__(path)
+		self._lock = Lock()
+		
 	def __setitem__(self, key, value):
 		with self._lock:
 			self._dict[key] = value
-			self._sync()
+			with open(self._path, 'w') as f:
+				yaml.dump(self._dict, f, default_flow_style=False)
 
-	def _sync(self):
+configFile = _ReadOnlyFile('config/pyledriver.yaml')
-		with open(self._path, 'w') as f:
+stateFile = _ReadWriteFile('config/state.yaml')
-			yaml.dump(self._dict, f, default_flow_style=False)
-
-configFile = _ConfigFile('config.yaml')

config/pyledriver.yaml

@@ -3,4 +3,3 @@ gmail:
   recipientList:
   - natedwarshuis@gmail.com
   username: natedwarshuis@gmail.com
-state: disarmed

stateMachine.py

@@ -5,7 +5,7 @@ from functools import partial
 from collections import namedtuple
 
 from auxilary import CountdownTimer, resetUSBDevice
-from config import configFile
+from config import stateFile
 from sensors import setupDoorSensor, setupMotionSensor
 from gmail import intruderAlert
 from listeners import KeypadListener, PipeListener
@@ -110,7 +110,7 @@ class StateMachine:
 			)
 		)
 
-		self.currentState = getattr(self.states, configFile['state'])
+		self.currentState = getattr(self.states, stateFile['state'])
 		
 		self.transitionTable = {
 			(self.states.disarmed, 			SIGNALS.ARM): 			self.states.disarmedCountdown,
@@ -198,7 +198,7 @@ class StateMachine:
 				self.currentState = nextState
 				self.currentState.entry()
 			
-			configFile['state'] = self.currentState.name
+			stateFile['state'] = self.currentState.name
 			
 			logger.info('state changed to %s', self.currentState)