Add tkinter.systray.NotificationHandler — a logging handler which shows log records as desktop notifications

Feature or enhancement

The tkinter.systray module (gh-153259) wraps the tk sysnotify command in the notify() function. A natural application of desktop notifications is showing warnings and errors reported via the logging module: a GUI application usually has no console, and a message box for every error is too intrusive.

I propose to add the NotificationHandler class to tkinter.systray. It formats the record with the handler's formatter and sends it as a notification. The title of the notification is the title argument, or the level name of the record (e.g. WARNING) by default. The master argument is the Tk window used to send notifications; by default the default root window is looked up when a record is emitted, so the handler can be created before the root window. Failures are reported via handleError(), as usual for logging handlers.

import logging
import tkinter
from tkinter.systray import NotificationHandler

root = tkinter.Tk()
handler = NotificationHandler('My application')
handler.setLevel(logging.WARNING)
logging.getLogger().addHandler(handler)

The handler belongs to tkinter.systray rather than logging.handlers because it is specific to Tk applications: it needs a Tk root window and follows tkinter's rules for the default root and for calls from other threads. logging.handlers should not depend on an optional GUI package.

Linked PRs

• gh-157760

先从现有的 tkinter.systray 模块及其 notify() 函数开始，然后在进行任何工作之前检查关联的 PR gh-157760。所要求的结果是一个 NotificationHandler，它可以格式化记录，使用标题或级别名称，按描述解析 Tk master，并通过 handleError() 报告失败；没有指定测试文件。