Switch to multiprocessing

chutney.py

@@ -1,8 +1,10 @@
 import sys
-import threading
 
 from character_display import CharacterDisplay
-from signal import signal, SIGTERM
+from multiprocessing import Event
+from multiprocessing import Process
+from signal import signal
+from signal import SIGTERM
 from time import sleep
 from time_display import TimeDisplay
 from weather_display import WeatherDisplay
@@ -16,34 +18,17 @@ except ImportError:
     unicorn.rotation(180)
 
 
-WEATHER_UPDATE_INTERVAL_IN_SECONDS = 10
+WEATHER_UPDATE_INTERVAL_IN_SECONDS = 60
 DISPLAY_UPDATE_INTERVAL_IN_SECONDS = 0.5
 CONFIG_FILE = 'chutney.cfg'
 
 
-def cleanExit(unicorn, haltEvent):
-    def _exit_(signum, frame):
-        unicorn.off()
-        haltEvent.set()
-        sys.exit(0)
-
-    return _exit_
-
-
-def weatherLoop(haltEvent):
-    weatherUpdater = WeatherUpdater(configFile=CONFIG_FILE)
-
-    while not haltEvent.is_set():
-        weatherUpdater.updateWeather()
-        sleep(WEATHER_UPDATE_INTERVAL_IN_SECONDS)
-
-
 def main():
-    haltEvent = threading.Event()
+    haltEvent = Event()
     signal(SIGTERM, cleanExit(unicorn, haltEvent))
     unicorn.brightness(0.3)
 
-    weatherThread = threading.Thread(target=weatherLoop, args=[haltEvent])
+    weatherThread = Process(target=weatherLoop, args=[haltEvent])
     weatherThread.start()
 
     characterDisplay = CharacterDisplay(unicorn)
@@ -56,5 +41,24 @@ def main():
         sleep(DISPLAY_UPDATE_INTERVAL_IN_SECONDS)
 
 
+def weatherLoop(haltEvent):
+    weatherUpdater = WeatherUpdater(configFile=CONFIG_FILE)
+
+    while not haltEvent.is_set():
+        weatherUpdater.updateWeather()
+        haltEvent.wait(timeout=WEATHER_UPDATE_INTERVAL_IN_SECONDS)
+
+    weatherUpdater.clearWeather()
+
+
+def cleanExit(unicorn, haltEvent):
+    def _exit_(signum, frame):
+        unicorn.off()
+        haltEvent.set()
+        sys.exit(0)
+
+    return _exit_
+
+
 if __name__ == '__main__':
     main()

weather_display.py

@@ -11,15 +11,23 @@ class WeatherDisplay:
         self.weatherFile = 'weather.txt'
 
     def showWeather(self):
+        temperature = self.getTemperature()
+
+        if self.isTemperatureMissing(temperature):
+            self.characterDisplay.clearRow(self.topRow)
+        else:
+            self.showTemperature(list(temperature))
+
+    def getTemperature(self):
         try:
-            self.showTemperature(
-                self.getTemperatureCharacters(self.getTemperature()))
-        except requests.exceptions.ConnectionError:
-            print('connection error', flush=True)
-            self.characterDisplay.clearRow(self.topRow)
-        except requests.exceptions.Timeout:
-            print('timeout', flush=True)
-            self.characterDisplay.clearRow(self.topRow)
+            with open(self.weatherFile) as file:
+                return file.readline().strip()
+        except Exception as e:
+            print(e, flush=True)
+            return 'error'
+
+    def isTemperatureMissing(self, temperature):
+        return temperature == 'error' or temperature == 'init' or temperature == 'halted'
 
     def showTemperature(self, temperature):
         if temperature != self.currentTemperature:
@@ -38,16 +46,3 @@ class WeatherDisplay:
                     start = start + 4
 
             self.currentTemperature = temperature
-
-    def getTemperature(self):
-        # TODO - don't use a file left around from a previous run
-        # TODO - clear temp on errors from updater
-        try:
-            with open(self.weatherFile) as file:
-                return int(file.readline().strip())
-        except Exception as e:
-            print(e)
-            return 0
-
-    def getTemperatureCharacters(self, temperature):
-        return list(str(round(temperature)))

weather_updater.py

@@ -19,19 +19,21 @@ class WeatherUpdater:
         self.auth = (user, password)
         self.weatherTempFile = 'weather.tmp'
         self.weatherFile = 'weather.txt'
-
-        # TODO - clear weather file on init and on failure
+        self.persistTemperature('init')
 
     def updateWeather(self):
         try:
             temperature = round(self.getTemperature())
             self.persistTemperature(temperature)
-        except requests.exceptions.ConnectionError:
-            print('connection error', flush=True)
-            self.characterDisplay.clearRow(self.topRow)
-        except requests.exceptions.Timeout:
-            print('timeout', flush=True)
-            self.characterDisplay.clearRow(self.topRow)
+        except requests.exceptions.ConnectionError as e:
+            print(e, flush=True)
+            self.persistTemperature('error')
+        except requests.exceptions.Timeout as e:
+            print(e, flush=True)
+            self.persistTemperature('error')
+
+    def clearWeather(self):
+        self.persistTemperature('halted')
 
     def getTemperature(self):
         weather = self.getWeather()