A Logging Handler that allows logging to a Tkinter Text Widget

TextHandler.py

#!/usr/bin/env python

# Built-in modules
import logging
import Tkinter
import threading

class TextHandler(logging.Handler):
    """This class allows you to log to a Tkinter Text or ScrolledText widget"""
    def __init__(self, text):
        # run the regular Handler __init__
        logging.Handler.__init__(self)
        # Store a reference to the Text it will log to
        self.text = text

    def emit(self, record):
        msg = self.format(record)
        def append():
            self.text.configure(state='normal')
            self.text.insert(Tkinter.END, msg + '\n')
            self.text.configure(state='disabled')
            # Autoscroll to the bottom
            self.text.yview(Tkinter.END)
        # This is necessary because we can't modify the Text from other threads
        self.text.after(0, append)


# Sample usage
if __name__ == '__main__':
    # Create the GUI
    root = Tkinter.Tk()
    
    import ScrolledText
    st = ScrolledText.ScrolledText(root, state='disabled')
    st.configure(font='TkFixedFont')
    st.pack()

    # Create textLogger
    text_handler = TextHandler(st)

    # Add the handler to logger
    logger = logging.getLogger()
    logger.addHandler(text_handler)

    # Log some messages
    logger.debug('debug message')
    logger.info('info message')
    logger.warn('warn message')
    logger.error('error message')
    logger.critical('critical message')

    root.mainloop()

This is a nice simple example but it is not thread safe. Look here for a thread safe example that sets up a logging.Handler with a Queue to receive messages from other TK threads: https://github.com/beenje/tkinter-logging-text-widget

That would require custom styling.

…

On Thu, Feb 8, 2024, 4:56 PM lunaeidi ***@***.***> wrote: ***@***.**** commented on this gist. ------------------------------ Are the info/warn/error supposed to show up as different colors by default? Or do you have to add custom styling for that? Thanks! — Reply to this email directly, view it on GitHub <https://gist.github.com/moshekaplan/c425f861de7bbf28ef06#gistcomment-4884726> or unsubscribe <https://github.com/notifications/unsubscribe-auth/AAGF2J6YMSIT6Y65YWUK7TTYSVCYFBFKMF2HI4TJMJ2XIZLTSKBKK5TBNR2WLJDUOJ2WLJDOMFWWLO3UNBZGKYLEL5YGC4TUNFRWS4DBNZ2F6YLDORUXM2LUPGBKK5TBNR2WLJDHNFZXJJDOMFWWLK3UNBZGKYLEL52HS4DFVRZXKYTKMVRXIX3UPFYGLK2HNFZXIQ3PNVWWK3TUUZ2G64DJMNZZDAVEOR4XAZNEM5UXG5FFOZQWY5LFVAYTIMRTG42TMNVHORZGSZ3HMVZKMY3SMVQXIZI> . You are receiving this email because you authored the thread. Triage notifications on the go with GitHub Mobile for iOS <https://apps.apple.com/app/apple-store/id1477376905?ct=notification-email&mt=8&pt=524675> or Android <https://play.google.com/store/apps/details?id=com.github.android&referrer=utm_campaign%3Dnotification-email%26utm_medium%3Demail%26utm_source%3Dgithub> .

Hello, I'm wondering if you know if this could cause the GUI to freeze? perhaps because of not multithreading? Thanks!

I am not aware of any issues, but I haven't had to use this code in nearly a decade, so it's possible Python 3 has changed something significant that I'm unaware of.