switch to debian in docker

app/__init__.py

@@ -1,11 +1,12 @@
-from dotenv import load_dotenv
+import time
 from pathlib import Path
+
+from dotenv import load_dotenv
 from flask import Flask, render_template, request, url_for
 from flask_login import current_user
-from werkzeug.middleware.proxy_fix import ProxyFix
-from dotenv import load_dotenv
 from sqlalchemy import inspect, text
-from sqlalchemy.exc import SQLAlchemyError
+from sqlalchemy.exc import OperationalError, SQLAlchemyError
+from werkzeug.middleware.proxy_fix import ProxyFix
 from config import Config
 from redis.exceptions import RedisError
 from app.cli import register_cli
@@ -30,7 +31,25 @@ def _ensure_column(table_name: str, column_name: str, ddl: str):
         db.session.commit()
 
 
+
+def _wait_for_database(app, attempts: int = 30, delay: float = 1.0) -> bool:
+    for attempt in range(1, attempts + 1):
+        try:
+            with db.engine.connect() as conn:
+                conn.execute(text('SELECT 1'))
+            if attempt > 1:
+                app.logger.info('Database became available after %s attempt(s).', attempt)
+            return True
+        except OperationalError:
+            app.logger.warning('Database not ready yet (%s/%s). Waiting...', attempt, attempts)
+            time.sleep(delay)
+    return False
+
 def _bootstrap_database(app):
+    if not _wait_for_database(app):
+        app.logger.error('Database is still unavailable after waiting. Skipping bootstrap.')
+        return
+
     try:
         db.create_all()
         patches = [