Question

在Windows服务中启动uvicorn应用程序时，该服务无法启动，并显示错误消息，表明该信号只能在主线程中处理。

这是事件日志中捕获的错误消息：

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

项目在最终调试模式下工作。

.\dist\WindowsService.exe debug

没有参数允许我指定不处理信号。

这是我实用地启动uvicorn应用程序的方式：

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

使用 win32serviceutil.ServiceFramework

将应用程序编译为冻结的可执行文件

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

我希望启动Windows服务并运行uvicorn应用程序。

Answer 1

我找到了一个解决方案，这意味着要有一个Windows服务调用的控制台应用程序。在控制台应用程序中使用它后，我就有机会在主线程上工作并按要求启动uvicorn。

子流程调用是通过以下方式进行的：

 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

我遇到了同样的问题，不喜欢您运行子流程的解决方案。我发现https://github.com/encode/uvicorn/issues/526可以解释问题。我的解决方法：

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()

将uvicorn作为WindowsService运行，信号仅在主线程中有效

2 个答案: