refactor DB health-check

src/ez_lan_manager/services/DatabaseService.py

@@ -29,6 +29,17 @@ class DatabaseService:
         self._database_config = database_config
         self._connection_pool: Optional[aiomysql.Pool] = None
 
+    async def is_healthy(self) -> bool:
+        try:
+            async with self._connection_pool.acquire() as conn:
+                async with conn.cursor() as _:
+                    return True
+        except aiomysql.OperationalError:
+            return False
+        except Exception as e:
+            logger.error(f"Failed to acquire a connection: {e}")
+            return False
+
     async def init_db_pool(self) -> bool:
         logger.info(
             f"Connecting to database '{self._database_config.db_name}' on "
@@ -42,7 +53,7 @@ class DatabaseService:
                 password=self._database_config.db_password,
                 db=self._database_config.db_name,
                 minsize=1,
-                maxsize=20
+                maxsize=40
             )
         except aiomysql.OperationalError:
             return False
@@ -215,6 +226,7 @@ class DatabaseService:
                 except aiomysql.InterfaceError:
                     pool_init_result = await self.init_db_pool()
                     if not pool_init_result:
+                        print(self._connection_pool)
                         raise NoDatabaseConnectionError
                     return await self.get_news(dt_start, dt_end)
                 except Exception as e: