將 uvicorn 作為 WindowsService 運行，信號僅在主線程中有效

Question

在 Windows 服務中啟動 uvicorn 應用程序時，該服務無法啟動，錯誤指示信號只能在主線程中處理。

這是事件日志中捕獲的錯誤消息：

Traceback (most recent call last):
  File "site-packages\win32\lib\win32serviceutil.py", line 839, in SvcRun
  File "WindowsService.py", line 49, in SvcDoRun
  File "site-packages\uvicorn\main.py", line 279, in run
  File "site-packages\uvicorn\main.py", line 307, in run
  File "asyncio\base_events.py", line 584, in run_until_complete
  File "site-packages\uvicorn\main.py", line 319, in serve
  File "site-packages\uvicorn\main.py", line 459, in install_signal_handlers
  File "signal.py", line 47, in signal
ValueError: signal only works in main thread

該項目在 fin un 調試模式下工作。

.\dist\WindowsService.exe debug

沒有參數允許我指定不處理信號。

以下是我如何以編程方式啟動 uvicorn 應用程序：

        uvicorn.run(app.main, 
                    host=config['server']['host'], 
                    port=config['server']['port'], 
                    log_level=config['server']['loglevel'], 
                    reload=False)

該應用程序使用win32serviceutil.ServiceFramework編譯為凍結的可執行文件

pyinstaller -F --hidden-import=win32timezone --additional-hooks-dir pyinstaller-hooks WindowsService.py

我希望啟動 Windows 服務並運行 uvicorn 應用程序。

Answer 1

我找到了一個解決方案，這意味着有一個由 Windows 服務調用的控制台應用程序。 在我的控制台應用程序中，我有機會在主線程上工作並根據要求啟動 uvicorn。

子進程調用由：

 def SvcDoRun(self):
        _log('has started')

        # determine if application is a script file or frozen exe
        if getattr(sys, 'frozen', False):
            application_path = os.path.dirname(sys.executable)
        elif __file__:
            application_path = os.path.dirname(__file__)

        exe_name = os.path.join(application_path, self._app_exe_name_)
        _log('launchin subprocess for {exe_name}'.format(exe_name=exe_name))
        p = subprocess.Popen([exe_name])

        _log('is running in subprocess id {process_id}'.format(process_id=p.pid))

        while True:               
            result = win32event.WaitForSingleObject(self._stop_event, 5000)

            if result == win32event.WAIT_OBJECT_0:
                # stop requested                  
                _log('is stopping')
                p.kill()
                break

        _log('has stopped')  

Answer 2

我有同樣的問題，不喜歡你運行子進程的解決方案。 我發現https://github.com/encode/uvicorn/issues/526解釋了這個問題。 我的解決方法：

config = uvicorn.Config(app, ...)
server = uvicorn.Server(config=config)
# According to https://github.com/encode/uvicorn/issues/526, on Python 3.8+ you MIGHT also need:
# asyncio.set_event_loop_policy(asyncio.WindowsSelectorEventLoopPolicy())
# But in my case it didn't seem to be necessary
server.install_signal_handlers = lambda: None  # this is the necessary workaround
server.run()