Database in-memory cache

app/database.py

@@ -5,6 +5,10 @@ from contextlib import contextmanager
 import os
 import datetime
 import logging
+from cachetools import cached, TTLCache
+
+
+CACHE_TTL_SECONDS = 600
 
 
 class Base(DeclarativeBase):
@@ -39,7 +43,7 @@ class Source(Base):
 
 
 # get environment variables for database
-USE_TURSO = os.getenv('USE_TURSO')
+USE_TURSO = os.environ.get('USE_TURSO', 'false')
 TURSO_DATABASE_URL = os.getenv('TURSO_DATABASE_URL')
 TURSO_AUTH_TOKEN = os.getenv('TURSO_AUTH_TOKEN')
 
@@ -65,6 +69,10 @@ if not connected_to_turso:
     Base.metadata.create_all(engine)
 
 
+# cache to hold articles
+article_cache = TTLCache(1, ttl=CACHE_TTL_SECONDS)
+
+
 @contextmanager
 def get_session():
     '''
@@ -85,13 +93,22 @@ def add_article(session: Session, article: Article):
     session.add(article)
 
 
-def retrieve_articles(session: Session):
+def _retrieve_articles_from_db(session: Session):
     '''
-    Returns a list containing all articles
+    Returns a list containing all articles from the database
     '''
     return session.query(Article).options(joinedload(Article.sources)).all()
 
 
+@cached(article_cache)
+def get_cached_articles():
+    '''
+    Returns a list containing all articles from the in-memory cache
+    '''
+    with get_session() as session:
+        return _retrieve_articles_from_db(session=session)
+
+
 def clear_articles(session: Session):
     '''
     Deletes all articles and sources in the database

app/main.py

@@ -8,13 +8,13 @@ import os
 import logging
 import itertools
 from datetime import datetime, timedelta
-from .database import get_session, retrieve_articles, Article
+from .database import get_cached_articles, Article
 from .update_news import update_news
 
 
 DEFAULT_UPDATE_HOURS = '0,6,12,18'  # UTC time
 
-if os.getenv('DEBUG') == 'true':
+if os.environ.get('DEBUG', 'false') == 'true':
     root_logger = logging.getLogger()
     root_logger.setLevel(logging.DEBUG)
 
@@ -85,8 +85,7 @@ def group_articles_by_category(articles: list[Article]) -> dict:
 @app.get('/')
 async def read_root(request: Request, background_tasks: BackgroundTasks):
     # retrieve articles from database
-    with get_session() as session:
-        articles = retrieve_articles(session=session)
+    articles = get_cached_articles()
 
     # how many hours since the last update
     last_updated_hours = -1

requirements.txt

@@ -3,6 +3,7 @@ anyio==4.11.0
 APScheduler==3.11.0
 babel==2.17.0
 Brotli==1.1.0
+cachetools==6.2.0
 certifi==2025.8.3
 charset-normalizer==3.4.3
 click==8.1.8