Run weather updates in a separate thread

.gitignore

@@ -1,3 +1,4 @@
 __pycache__/
 *.swp
 chutney.cfg
+weather.txt

chutney.py

@@ -1,10 +1,12 @@
 import sys
+import threading
 
 from character_display import CharacterDisplay
 from signal import signal, SIGTERM
 from time import sleep
 from time_display import TimeDisplay
 from weather_display import WeatherDisplay
+from weather_updater import WeatherUpdater
 
 try:
     import unicornhathd as unicorn
@@ -14,34 +16,44 @@ except ImportError:
     unicorn.rotation(180)
 
 
-def cleanExit(unicorn):
+WEATHER_UPDATE_INTERVAL_IN_SECONDS = 10
+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():
-    signal(SIGTERM, cleanExit(unicorn))
+    haltEvent = threading.Event()
+    signal(SIGTERM, cleanExit(unicorn, haltEvent))
     unicorn.brightness(0.3)
 
+    weatherThread = threading.Thread(target=weatherLoop, args=[haltEvent])
+    weatherThread.start()
+
     characterDisplay = CharacterDisplay(unicorn)
     timeDisplay = TimeDisplay(characterDisplay, topRow=15)
-    weatherDisplay = WeatherDisplay(characterDisplay, topRow=9, configFile='chutney.cfg')
-
-    x = 0
+    weatherDisplay = WeatherDisplay(characterDisplay, topRow=9)
 
     while True:
         timeDisplay.showTime()
-
-        if (x == 0):
         weatherDisplay.showWeather()
-
-        x = x + 1
-        x = x % 120
-
-        sleep(1)
+        sleep(DISPLAY_UPDATE_INTERVAL_IN_SECONDS)
 
 
 if __name__ == '__main__':

time_display.py

@@ -16,15 +16,11 @@ class TimeDisplay:
         self.timeDotsColumn = 7
         self.minuteStartColumn = 9
 
-        self.characterDisplay.displayTimeDots(
-            x=self.timeDotsColumn,
-            y=self.topRow,
-            color=self.color
-        )
-
     def showTime(self):
         self.showHour(self.getHourDigits())
+        self.showTimeDots()
         self.showMinute(self.getMinuteDigits())
+        self.currentColor = self.color
 
     def showHour(self, hour):
         if hour[0] != self.currentHour[0]:
@@ -39,6 +35,14 @@ class TimeDisplay:
             self.currentHour[1] = hour[1]
             self.showDigit(self.hourStartColumn + 4, hour[1])
 
+    def showTimeDots(self):
+        if self.color != self.currentColor:
+            self.characterDisplay.displayTimeDots(
+                x=self.timeDotsColumn,
+                y=self.topRow,
+                color=self.color
+            )
+
     def showMinute(self, minute):
         if minute[0] != self.currentMinute[0]:
             self.currentMinute[0] = minute[0]

weather_display.py

@@ -1,37 +1,24 @@
 import colors
 import requests
 
-from configparser import ConfigParser
-
 
 class WeatherDisplay:
-    def __init__(self, characterDisplay, topRow, configFile):
+    def __init__(self, characterDisplay, topRow):
         self.characterDisplay = characterDisplay
         self.topRow = topRow
         self.currentTemperature = [9, 9]
         self.color = colors.BLUE
-
-        config = ConfigParser()
-        config.read(configFile)
-
-        host = config['weather'].get('host')
-        user = config['weather'].get('user')
-        password = config['weather'].get('pass')
-        lat = config['weather'].get('lat')
-        lon = config['weather'].get('lon')
-
-        self.uri = f'https://{host}/api/weather?lat={lat}&lon={lon}&units=metric'
-        self.auth = (user, password)
+        self.weatherFile = 'weather.txt'
 
     def showWeather(self):
         try:
             self.showTemperature(
                 self.getTemperatureCharacters(self.getTemperature()))
         except requests.exceptions.ConnectionError:
-            print("connection error", flush=True)
+            print('connection error', flush=True)
             self.characterDisplay.clearRow(self.topRow)
         except requests.exceptions.Timeout:
-            print("timeout", flush=True)
+            print('timeout', flush=True)
             self.characterDisplay.clearRow(self.topRow)
 
     def showTemperature(self, temperature):
@@ -53,7 +40,14 @@ class WeatherDisplay:
             self.currentTemperature = temperature
 
     def getTemperature(self):
-        return list(filter(lambda t: t["timestep"] == 'current', requests.get(self.uri, auth=self.auth, timeout=2).json()["tomorrow"]["data"]['timelines']))[0]["intervals"][0]["values"]["temperature"]
+        # 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

@@ -0,0 +1,54 @@
+import os
+import requests
+
+from configparser import ConfigParser
+
+
+class WeatherUpdater:
+    def __init__(self, configFile):
+        config = ConfigParser()
+        config.read(configFile)
+
+        host = config['weather'].get('host')
+        user = config['weather'].get('user')
+        password = config['weather'].get('pass')
+        lat = config['weather'].get('lat')
+        lon = config['weather'].get('lon')
+
+        self.uri = f'https://{host}/api/weather?lat={lat}&lon={lon}&units=metric'
+        self.auth = (user, password)
+        self.weatherTempFile = 'weather.tmp'
+        self.weatherFile = 'weather.txt'
+
+        # TODO - clear weather file on init and on failure
+
+    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)
+
+    def getTemperature(self):
+        weather = self.getWeather()
+        currentWeather = list(
+            filter(
+                lambda t: t['timestep'] == 'current',
+                weather['tomorrow']['data']['timelines']
+            )
+        )
+
+        return currentWeather[0]['intervals'][0]['values']['temperature']
+
+    def getWeather(self):
+        return requests.get(self.uri, auth=self.auth).json()
+
+    def persistTemperature(self, temperature):
+        with open(self.weatherTempFile, 'w') as file:
+            file.write(str(temperature))
+
+        os.replace(self.weatherTempFile, self.weatherFile)