scripts/python/app/NUT-Monitor-py2gtk2.in: propose a fix for reconnection modeled after PR #3523 for Python3 siblings [#3509]

Co-Authored-By: Programer <developer.sorli@gmail.com>
Signed-off-by: Jim Klimov <jimklimov+nut@gmail.com>

Author: jimklimov

NEWS.adoc

@@ -190,7 +190,7 @@ https://github.com/networkupstools/nut/milestone/13
     * Fixed Qt tray tooltips to render in plain text, not rich text which
       ended up as literal HTML on KDE Plasma 6; now that rich text formatting
       is only used for main window status labels. [PR #3430]
-    * Fixed Qt (Python 3) variants to handle automatic client reconnection
+    * Fixed both Python 2 and 3 variants to handle automatic client reconnection
       (e.g. after system suspend/resume, network interruption, or NUT server
       restart). [issue #3509, PR #3523]
 

scripts/python/app/NUT-Monitor-py2gtk2.in

@@ -34,6 +34,7 @@
 
 import gtk, gtk.glade, gobject
 import sys
+import socket
 import base64
 import os, os.path
 import stat
@@ -116,6 +117,7 @@ class interface :
     __ups_rw_vars                    = None
     __gui_thread                     = None
     __current_ups                    = None
+    __reconnect_attempted            = False
 
     def __init__( self ) :
 
@@ -389,8 +391,11 @@ class interface :
     def quit( self, widget=None ) :
         # If we are connected to an UPS, disconnect first...
         if self.__connected :
-            self.gui_status_message( _("Disconnecting from device") )
-            self.disconnect_from_ups()
+            try:
+                self.gui_status_message( _("Disconnecting from device") )
+                self.disconnect_from_ups()
+            except Exception:
+                pass
 
         gtk.main_quit()
 
@@ -746,6 +751,7 @@ class interface :
     # Connect to the selected UPS using parameters (host,port,login,pass)
     def connect_to_ups( self, widget=None ) :
 
+        self.__reconnect_attempted = False
         host     = self.__widgets["ups_host_entry"].get_text()
         port     = int( self.__widgets["ups_port_entry"].get_value() )
         login    = None
@@ -862,6 +868,7 @@ class gui_updater( threading.Thread ) :
     __parent_class = None
     __stop_thread  = False
     was_online = True
+    __reconnect_attempted = False
 
     def __init__( self, parent_class ) :
         threading.Thread.__init__( self )
@@ -977,12 +984,91 @@ class gui_updater( threading.Thread ) :
                 # Display UPS status as tooltip for tray icon
                 self.__parent_class._interface__widgets["status_icon"].set_tooltip_markup( status_text )
 
-            except :
-                self.__parent_class.gui_status_message( _("Error from '{0}' ({1})").format( ups, sys.exc_info()[1] ) )
-                self.__parent_class.gui_status_notification( _("Error from '{0}'\n{1}").format( ups, sys.exc_info()[1] ), "warning.png" )
+            except (socket.error, EOFError, PyNUT.PyNUTError) as e:
+                # Connection error detected - attempt automatic reconnection
+                if not self.__reconnect_attempted and self.__parent_class._interface__connected:
+                    self.__reconnect_attempted = True
+                    self.__parent_class.gui_status_message( _("Connection lost - attempting to reconnect...") )
+                    self.__parent_class.gui_status_notification( _("Connection lost"), "warning.png" )
+
+                    # Wait for 2 seconds before attempting reconnection
+                    time.sleep( 2 )
+                    self.__attempt_reconnect()
+                else:
+                    self.__parent_class.gui_status_message( _("Error from '{0}' ({1})").format( ups, sys.exc_info()[1] ) )
+                    self.__parent_class.gui_status_notification( _("Error from '{0}'\n{1}").format( ups, sys.exc_info()[1] ), "warning.png" )
 
             time.sleep( 1 )
 
+    def __attempt_reconnect( self ) :
+        """Attempt to reconnect to the UPS after a connection loss."""
+        if self.__stop_thread:
+            return
+
+        try:
+            # Get connection parameters from the parent class
+            host = self.__parent_class._interface__widgets["ups_host_entry"].get_text()
+            port = int(self.__parent_class._interface__widgets["ups_port_entry"].get_value())
+            login = None
+            password = None
+
+            if self.__parent_class._interface__widgets["ups_authentication_check"].get_active():
+                login = self.__parent_class._interface__widgets["ups_authentication_login"].get_text()
+                password = self.__parent_class._interface__widgets["ups_authentication_password"].get_text()
+
+            # Teardown old connection handler properly
+            old_handler = self.__parent_class._interface__ups_handler
+            if old_handler is not None:
+                try:
+                    # Close the underlying telnet connection if it exists
+                    if hasattr(old_handler, '_PyNUTClient__tn') and old_handler._PyNUTClient__tn is not None:
+                        old_handler._PyNUTClient__tn.close()
+                    elif hasattr(old_handler, 'tn') and old_handler.tn is not None:
+                        old_handler.tn.close()
+                except Exception:
+                    pass  # Best effort cleanup
+                del old_handler
+
+            # Create a new connection handler
+            ups_handler = PyNUT.PyNUTClient(host=host, port=port, login=login, password=password)
+
+            # Verify the UPS is available
+            ups = self.__parent_class._interface__current_ups
+            srv_upses = ups_handler.GetUPSList()
+
+            if ups not in srv_upses:
+                self.__parent_class.gui_status_message( _("UPS '{0}' not found after reconnection").format(ups) )
+                self.__reconnect_attempted = False
+                return
+
+            if not ups_handler.CheckUPSAvailable(ups):
+                self.__parent_class.gui_status_message( _("UPS '{0}' is still not reachable").format(ups) )
+                self.__reconnect_attempted = False
+                return
+
+            # Connection successful - update the parent class
+            self.__parent_class._interface__ups_handler = ups_handler
+            self.__parent_class._interface__connected = True
+            self.__reconnect_attempted = False
+
+            # Refresh UPS data
+            commands = ups_handler.GetUPSCommands(ups)
+            self.__parent_class._interface__ups_commands = list(commands.keys())
+            self.__parent_class._interface__ups_commands.sort()
+
+            self.__parent_class._interface__ups_vars = ups_handler.GetUPSVars(ups)
+            self.__parent_class._interface__ups_rw_vars = ups_handler.GetRWVars(ups)
+
+            # Update the GUI (must be done on the main thread in GTK)
+            gobject.idle_add( self.__parent_class._interface__gui_update_ups_vars_view )
+            gobject.idle_add( self.__parent_class.change_status_icon, "on_line", False )
+            self.__parent_class.gui_status_message( _("Reconnected to '{0}' on {1}").format(ups, host) )
+            self.__parent_class.gui_status_notification( _("Reconnected to UPS"), "on_line.png" )
+
+        except (socket.error, EOFError, PyNUT.PyNUTError) as e:
+            self.__parent_class.gui_status_message( _("Reconnection failed: {0}").format(str(e)) )
+            self.__reconnect_attempted = False
+
     def stop_thread( self ) :
         self.__stop_thread = True