Fixed database connection handling by reconnecting

src/cpl_core/database/context/__init__.py

@@ -15,7 +15,7 @@ __title__ = 'cpl_core.database.context'
 __author__ = 'Sven Heidemann'
 __license__ = 'MIT'
 __copyright__ = 'Copyright (c) 2020 - 2022 sh-edraft.de'
-__version__ = '2022.7.0.post4'
+__version__ = '2022.7.0.post5'
 
 from collections import namedtuple
 
@@ -25,4 +25,4 @@ from .database_context import DatabaseContext
 from .database_context_abc import DatabaseContextABC
 
 VersionInfo = namedtuple('VersionInfo', 'major minor micro')
-version_info = VersionInfo(major='2022', minor='7', micro='0.post4')
+version_info = VersionInfo(major='2022', minor='7', micro='0.post5')

src/cpl_core/database/context/database_context.py

@@ -1,6 +1,8 @@
 
 from typing import Optional
 
+import mysql
+
 from cpl_core.database.connection.database_connection import DatabaseConnection
 from cpl_core.database.connection.database_connection_abc import \
     DatabaseConnectionABC
@@ -23,12 +25,25 @@ class DatabaseContext(DatabaseContextABC):
 
         self._db: DatabaseConnectionABC = DatabaseConnection()
         self._tables: list[TableABC] = TableABC.__subclasses__()
+        self._settings: Optional[DatabaseSettings] = None
 
     @property
     def cursor(self) -> MySQLCursorBuffered:
+        self._ping_and_reconnect()
         return self._db.cursor
-    
+
+    def _ping_and_reconnect(self):
+        try:
+            self._db.server.ping(reconnect=True, attempts=3, delay=5)
+        except mysql.connector.Error as err:
+            # reconnect your cursor as you did in __init__ or wherever
+            if self._settings is None:
+                raise Exception('Call DatabaseContext.connect first')
+            self.connect(self._settings)
+
     def connect(self, database_settings: DatabaseSettings):
+        if self._settings is None:
+            self._settings = database_settings
         self._db.connect(database_settings)
         for table in self._tables:
             self._db.cursor.execute(table.get_create_string())
@@ -36,8 +51,10 @@ class DatabaseContext(DatabaseContextABC):
         self.save_changes()
 
     def save_changes(self):
+        self._ping_and_reconnect()
         self._db.server.commit()
         
     def select(self, statement: str) -> list[tuple]:
+        self._ping_and_reconnect()
         self._db.cursor.execute(statement)
         return self._db.cursor.fetchall()

src/cpl_core/database/context/database_context_abc.py

@@ -12,8 +12,8 @@ class DatabaseContextABC(ABC):
         pass
 
     @property
-    def cursor(self) -> MySQLCursorBuffered:
-        return self._cursor
+    @abstractmethod
+    def cursor(self) -> MySQLCursorBuffered: pass
     
     @abstractmethod
     def connect(self, database_settings: DatabaseSettings):