Merge pull request #166 from mathoudebine/feature/132-use-win32apisetconsolectrlhandler-to-receive-shutdownlogoff-events-from-windows

Catch Windows logoff/shutdown event to do a clean stop, fix Ctrl+C for Windows

Author: mathoudebine

library/log.py

@@ -18,11 +18,13 @@
 
 # Configure logging format
 import logging
+from datetime import datetime
+date = datetime.now().strftime('%Y-%m-%d-%H-%M-%S')
 
 logging.basicConfig(# format='%(asctime)s [%(levelname)s] %(message)s in %(pathname)s:%(lineno)d',
                     format="%(asctime)s [%(levelname)s] %(message)s",
                     handlers=[
-                        # logging.FileHandler("log.log", mode='w'),  # Log in textfile (erased at each start)
+                        # logging.FileHandler("log_"+date+".log", mode='w'),  # Log in textfile
                         logging.StreamHandler()  # Log also in console
                     ],
                     datefmt='%H:%M:%S')

main.py

@@ -22,12 +22,8 @@
 # along with this program.  If not, see <https://www.gnu.org/licenses/>.
 
 # This file is the system monitor main program to display HW sensors on your screen using themes (see README)
-import locale
 import os
-import platform
-import signal
 import sys
-import time
 
 MIN_PYTHON = (3, 7)
 if sys.version_info < MIN_PYTHON:
@@ -37,8 +33,18 @@
     except:
         os._exit(0)
 
+import atexit
+import locale
+import platform
+import signal
+import time
 from PIL import Image
 
+if platform.system() == 'Windows':
+    import win32api
+    import win32con
+    import win32gui
+
 try:
     import pystray
 except:
@@ -86,7 +92,7 @@ def clean_stop(tray_icon=None):
             os._exit(0)
 
 
-    def sighandler(signum, frame=None):
+    def on_signal_caught(signum, frame=None):
         logger.info("Caught signal %d, exiting" % signum)
         clean_stop()
 
@@ -96,6 +102,25 @@ def on_exit_tray(tray_icon, item):
         clean_stop(tray_icon)
 
 
+    def on_clean_exit(*args):
+        logger.info("Program will now exit")
+        clean_stop()
+
+
+    if platform.system() == "Windows":
+        def on_win32_ctrl_event(event):
+            """Handle Windows console control events (like Ctrl-C)."""
+            if event in (win32con.CTRL_C_EVENT, win32con.CTRL_BREAK_EVENT, win32con.CTRL_CLOSE_EVENT):
+                logger.info("Caught Windows control event %s, exiting" % event)
+                clean_stop()
+            return 0
+
+
+        def on_win32_wm_event(hWnd, msg, wParam, lParam):
+            """Handle Windows window message events (like ENDSESSION, CLOSE, DESTROY)."""
+            logger.debug("Caught Windows window message event %s, exiting" % msg)
+            clean_stop()
+
     # Create a tray icon for the program, with an Exit entry in menu
     try:
         tray_icon = pystray.Icon(
@@ -116,12 +141,15 @@ def on_exit_tray(tray_icon, item):
         tray_icon = None
         logger.warning("Tray icon is not supported on your platform")
 
-    # Set the signal handlers, to send a complete frame to the LCD before exit
-    signal.signal(signal.SIGINT, sighandler)
-    signal.signal(signal.SIGTERM, sighandler)
+    # Set the different stopping event handlers, to send a complete frame to the LCD before exit
+    atexit.register(on_clean_exit)
+    signal.signal(signal.SIGINT, on_signal_caught)
+    signal.signal(signal.SIGTERM, on_signal_caught)
     is_posix = os.name == 'posix'
     if is_posix:
-        signal.signal(signal.SIGQUIT, sighandler)
+        signal.signal(signal.SIGQUIT, on_signal_caught)
+    if platform.system() == "Windows":
+        win32api.SetConsoleCtrlHandler(on_win32_ctrl_event, True)
 
     # Initialize the display
     display.initialize_display()
@@ -150,13 +178,49 @@ def on_exit_tray(tray_icon, item):
     scheduler.DateStats()
     scheduler.QueueHandler()
 
-    if tray_icon and platform.system() == "Darwin":
-        from AppKit import NSBundle, NSApp, NSAutoreleasePool, NSApplicationActivationPolicyRegular, NSApplicationActivationPolicyProhibited
+    if tray_icon and platform.system() == "Darwin":  # macOS-specific
+        from AppKit import NSBundle, NSApp, NSApplicationActivationPolicyProhibited
 
-        # Hide Python Launcher icon from MacOS dock
+        # Hide Python Launcher icon from macOS dock
         info = NSBundle.mainBundle().infoDictionary()
         info["LSUIElement"] = "1"
         NSApp.setActivationPolicy_(NSApplicationActivationPolicyProhibited)
 
         # For macOS: display the tray icon now with blocking function
         tray_icon.run()
+
+    elif platform.system() == "Windows":  # Windows-specific
+        # Create a hidden window just to be able to receive window message events (for shutdown/logoff clean stop)
+        hinst = win32api.GetModuleHandle(None)
+        wndclass = win32gui.WNDCLASS()
+        wndclass.hInstance = hinst
+        wndclass.lpszClassName = "turingEventWndClass"
+        messageMap = {win32con.WM_QUERYENDSESSION: on_win32_wm_event,
+                      win32con.WM_ENDSESSION: on_win32_wm_event,
+                      win32con.WM_QUIT: on_win32_wm_event,
+                      win32con.WM_DESTROY: on_win32_wm_event,
+                      win32con.WM_CLOSE: on_win32_wm_event}
+
+        wndclass.lpfnWndProc = messageMap
+
+        try:
+            myWindowClass = win32gui.RegisterClass(wndclass)
+            hwnd = win32gui.CreateWindowEx(win32con.WS_EX_LEFT,
+                                           myWindowClass,
+                                           "turingEventWnd",
+                                           0,
+                                           0,
+                                           0,
+                                           win32con.CW_USEDEFAULT,
+                                           win32con.CW_USEDEFAULT,
+                                           0,
+                                           0,
+                                           hinst,
+                                           None)
+            while True:
+                # Receive and dispatch window messages
+                win32gui.PumpWaitingMessages()
+                time.sleep(0.5)
+
+        except Exception as e:
+            logger.error("Exception while creating event window: %s" % str(e))