Properly handle missing iSpindel data in Redis (Fixes #621)

docs/source/develop/changelog.rst

@@ -42,6 +42,7 @@ Fixed
 - Resolved issue causing false failures of the connectivity test (Thanks postalbunny!)
 - Fixed issue preventing renaming of BrewPi controllers
 - Dashes now allowed in TiltBridge mDNS IDs
+- Corrected issue where iSpindel data couldn't be loaded if a data point wasn't availble in Redis
 
 
 

gravity/api/sensors.py

@@ -81,7 +81,10 @@ def get_ispindel_extras(req, device_id):
         extras = device.ispindel_configuration.load_extras_from_redis()
         extras['device_name'] = device.name
         extras['device_id'] = device.id
-        extras['log_time'] = device.ispindel_configuration.load_last_log_time_from_redis()
+
+        last_log_time = device.ispindel_configuration.load_last_log_time_from_redis()
+        if last_log_time:
+            extras['log_time'] = last_log_time
     else:
         extras = {}
 

gravity/models.py

@@ -881,13 +881,15 @@ def load_extras_from_redis(self) -> dict:
 
         return extras
 
-    def load_last_log_time_from_redis(self) -> str:
+    def load_last_log_time_from_redis(self) -> str or None:
         r = redis.Redis.from_url(url=settings.REDIS_URL)
-        redis_response = r.get('grav_{}_full'.format(self.sensor_id)).decode(encoding="utf-8")
+        redis_response = r.get('grav_{}_full'.format(self.sensor_id))
 
         if redis_response is None:
             # If we didn't get anything back (i.e. no data has been saved to redis yet) then return None
-            return {}
+            return None
+        else:
+            redis_response = redis_response.decode(encoding="utf-8")
 
         t = json.loads(redis_response)
         if 'fields' in t[0]:
@@ -896,4 +898,4 @@ def load_last_log_time_from_redis(self) -> str:
                 dt = datetime.datetime.fromisoformat( t[0]['fields']['log_time'].replace("Z","") ) 
                 return datetime.datetime.strftime( dt, "%c" )
 
-        return {}
+        return None