Update news at set hours

app/main.py

@@ -12,7 +12,7 @@ from .database import get_session, retrieve_articles, Article
 from .update_news import update_news
 
 
-DEFAULT_UPDATE_INTERVAL = 6  # in hours
+DEFAULT_UPDATE_HOURS = '0,6,12,18'  # UTC time
 
 if os.getenv('DEBUG') == 'true':
     root_logger = logging.getLogger()
@@ -20,15 +20,7 @@ if os.getenv('DEBUG') == 'true':
 
 
 # set update interval from environment variable if available
-try:
-    update_interval_str = os.getenv('UPDATE_INTERVAL')
-    if update_interval_str is not None:
-        update_interval = int(update_interval_str)
-    else:
-        update_interval = DEFAULT_UPDATE_INTERVAL
-except (ValueError, TypeError):
-    update_interval = DEFAULT_UPDATE_INTERVAL
-
+update_schedule_hours = os.environ.get('UPDATE_HOURS', DEFAULT_UPDATE_HOURS)
 
 # for updating the news feed periodically
 scheduler = BackgroundScheduler()
@@ -51,7 +43,14 @@ def safe_update_news():
 @asynccontextmanager
 async def lifespan(app: FastAPI):
     # update news periodically
-    scheduler.add_job(safe_update_news, 'interval', hours=update_interval)
+    scheduler.add_job(
+        safe_update_news,
+        'cron',
+        hour=update_schedule_hours,
+        minute=0,
+        id='update_task',
+        replace_existing=True
+    )
     scheduler.start()
     yield
     # stop the scheduler when closing the server