add a 'ping' endpoint, redirect stderr to stdout

Dockerfile

@@ -41,4 +41,5 @@ RUN chown -R myuser:myuser /app
 USER myuser
 
 # Start gunicorn with the appropriate options
-CMD ["gunicorn", "-b", "0.0.0.0:3000", "--log-level=debug", "--workers=1", "app:app"]
+# Without "2>&1" the gunicorn internal logging shows in 'docker logs' but doesn't go to stdout like our 'printf' commands.
+CMD ["gunicorn", "-b", "0.0.0.0:3000", "--log-level=debug", "--workers=1", "app:app", "2>&1"]

README.md

@@ -240,6 +240,7 @@ Run the app:
 ```commandline
 sh <(curl https://pkgx.sh) +python.org +virtualenv.pypa.io sh
 
+# first time
 python -m venv .
 
 source bin/activate
@@ -249,6 +250,8 @@ pip install -r requirements.txt
 
 cp data/webpush.db.empty data/webpush.db
 
+# For DB access, you'll have to uncomment the local path for `db_uri`.
+
 # 3 workers would trigger 3 daily subscription runs
 gunicorn -b 0.0.0.0:3000 --log-level=debug --workers=1 app:app
 

app.py

@@ -23,7 +23,11 @@ CONTACT_EMAIL = "mailto:info@timesafari.app"
 
 app = Flask(__name__)
 
+
 class WebPushService():
+
+    latest_subscription_run = None
+
     """
     This class provides services for sending web push notifications.
     """
@@ -44,10 +48,12 @@ class WebPushService():
         # Setting the application instance
         self.app = app
         self.app.add_url_rule('/web-push/regenerate-vapid', view_func=self.regenerate_vapid, methods=['POST'])
+        self.app.add_url_rule('/web-push/ping', view_func=self.ping, methods=['GET'])
 
         # Setting the database URI for the application
         db_uri = os.getenv('SQLALCHEMY_DATABASE_URI', 'sqlite:////app/instance/data/webpush.db')
         # This relative path works in docker-compose
+        # This relative path works on a local run if you link to this dir from "var/app-instance"
         #db_uri = os.getenv('SQLALCHEMY_DATABASE_URI', 'sqlite:///data/webpush.db')
         self.app.config['SQLALCHEMY_DATABASE_URI'] = db_uri
 
@@ -230,10 +236,24 @@ class WebPushService():
                     print(f"Result from sub {subscription.id}: success={result['success']} text={result['message']}", flush=True)
                 print(f"{now} - Finished sending {len(all_subscriptions)} subscriptions.", flush=True)
 
+            self.latest_subscription_run = now
+
             # Sleeping for 24 hours before sending the next set of notifications
             time.sleep(24 * 60 * 60)
 
 
+    # This is an endpoint, routed in __init__
+    def ping(self) -> Response:
+        """
+        Endpoint to show liveness info
+
+        Returns:
+        - Response: Text with some subscription-run info
+        """
+
+        return f"pong ... with latest subscription run at {self.latest_subscription_run}"
+
+
     # This is an endpoint, routed in __init__
     def regenerate_vapid(self) -> Tuple[str, int]:
         """