Merge pull request 'Improved database connection and logging' (#4) from feature/improved-db-handling into main

Reviewed-on: #4

src/db.py

@@ -1,59 +1,71 @@
 import mysql.connector
+from mysql.connector import pooling, Error
 import threading
 from secret_handler import return_credentials
 import os
 import time
-import sys
+from logger_handler import setup_logger
 
 db_username = return_credentials("/etc/secrets/db_username")
 db_password = return_credentials("/etc/secrets/db_password")
 db_host = os.getenv("BACKEND_API_INTERNAL_DB_HOST","localhost")
 db_database = os.getenv("BACKEND_API_INTERNAL_DB_DATABASE","app")
 
+logger = setup_logger(__name__)
+
+
 MAX_RETRIES = 5
 RETRY_DELAY = 5
+HEALTHCHECK_INTERVAL = 60
 
 MYSQL_CONFIG = {
 	"host": db_host,
 	"user": db_username,
 	"password": db_password,
-	"database": db_database
+	"database": db_database,
+	"connection_timeout": 10
 }
 
 _pool_lock = threading.Lock()
 _connection_pool = None
+_health_thread = None
+_stop_healthcheck = threading.Event()
 
 
 def create_connection_pool():
 	global _connection_pool
-	for attempt in range(1, MAX_RETRIES+1):
+	with _pool_lock:
+		if _connection_pool is not None:
+			return
+	for attempt in range (1,MAX_RETRIES+1):
 		try:
-			print(f"[MySQL] Attempt {attempt} to connect...")
-			pool  = mysql.connector.pooling.MySQLConnectionPool(
-				pool_name="mypool",
+			logger.info(f"[MySQL] Attempt {attempt} to connect...")
+			pool = pooling.MySQLConnectionPool(
+				pool_name="royalroadPool",
 				pool_size=5,
 				pool_reset_session=True,
 				**MYSQL_CONFIG
 			)
 			with _pool_lock:
 				_connection_pool = pool
-			print("[MySQL] Connection pool created successfully.")
+			logger.info("[MySQL] Pool created", extra={"pool_name": pool.pool_name})
 			return
-		except mysql.connector.Error as e:
-			print(f"[MySQL] Attempt {attempt} failed: {e}")
+
+		except Error as e:
+			logger.warning(f"[MySQL] Attempt {attempt} failed: {e}")
 			if attempt < MAX_RETRIES:
 				time.sleep(RETRY_DELAY)
-	print(f"[MySQL] Failed to connect after {MAX_RETRIES} attempts — exiting.")
-	sys.exit(1)
 
+	logger.critical(f"[MySQL] Failed to connect after {MAX_RETRIES} attempts.")
+	raise RuntimeError("MySQL pool initialization failed")
 
 def close_connection_pool():
 	global _connection_pool
 	with _pool_lock:
 		if _connection_pool:
 			_connection_pool = None
-			print("[MySQL] Connection pool closed.")
-
+			logger.info("[MySQL] Connection pool closed")
+	_stop_healthcheck.set()
 
 def get_connection_pool():
 	global _connection_pool
@@ -62,18 +74,46 @@ def get_connection_pool():
 			create_connection_pool()
 	return _connection_pool
 
-
 def get_db():
 	pool = get_connection_pool()
+	conn = pool.get_connection()
+
 	try:
-		conn = pool.get_connection()
-		if not conn.is_connected():
-			conn.reconnect(attempts=MAX_RETRIES, delay=RETRY_DELAY)
-	except Exception:
+		conn.ping(reconnect=True, attempts=3, delay=1)
+	except Error as e:
+		logger.warning(f"[MySQL] Connection dead, recreating pool: {e}")
 		create_connection_pool()
 		pool = get_connection_pool()
 		conn = pool.get_connection()
+
 	try:
 		yield conn
 	finally:
-		conn.close()
+		if conn and conn.is_connected():
+			conn.close()
+
+def _pool_healthcheck():
+	while not _stop_healthcheck.is_set():
+		time.sleep(HEALTHCHECK_INTERVAL)
+		with _pool_lock:
+			pool = _connection_pool
+		if not pool:
+			continue
+		try:
+			conn = pool.get_connection()
+			conn.ping(reconnect=True, attempts=3, delay=1)
+			conn.close()
+			logger.debug("[MySQL] Pool healthcheck OK.")
+		except Error as e:
+			logger.warning(f"[MySQL] Pool healthcheck failed: {e}")
+			create_connection_pool()
+
+
+def start_healthcheck_thread():
+	global _health_thread
+	if _health_thread and _health_thread.is_alive():
+		return
+	_stop_healthcheck.clear()
+	_health_thread = threading.Thread(target=_pool_healthcheck, daemon=True)
+	_health_thread.start()
+	logger.info("[MySQL] Healthcheck thread started.")

src/main.py

@@ -5,7 +5,7 @@ from starlette.exceptions import HTTPException as StarletteHTTPException
 from typing import Dict
 from pydantic import BaseModel
 from validator import verify_api_key
-from db import get_db, create_connection_pool, close_connection_pool
+from db import get_db, create_connection_pool, close_connection_pool, start_healthcheck_thread
 from logger_handler import setup_logger
 from rabbitmq_handler import send_message_to_rmq, create_connection, close_connection
 import uvicorn
@@ -33,6 +33,9 @@ async def lifespan(app: FastAPI):
 	logger.info("Connecting to RabbitMQ...")
 	app.state.rmq_connection = create_connection()
 
+	start_healthcheck_thread()
+	logger.info("MySQL healthcheck thread started.")
+
 	yield
 	logger.info("Closing RabbitMQ connection...")
 	close_connection(app.state.rmq_connection)