将编写的Sanic程序导入另一个程序后发生的“上下文已设置”错误，如何解决？

Question

• python version: 3.10
• Sanic-Cors version: 2.2.0
• sanic version: 24.6.0

• OS: Win 11
  首先我尝试直接运行了api.py，没有发生任何错误，但是当我再尝试运行main.py的时候，发生了:
  

  PS E:\project>python main.py
  Main  2024-08-15 21:58:44 +0800 INFO: Sanic v24.6.0
  Main  2024-08-15 21:58:44 +0800 INFO: Goin' Fast @ http://127.0.0.1:5050
  Main  2024-08-15 21:58:44 +0800 INFO: app: ip
  Main  2024-08-15 21:58:44 +0800 INFO: mode: production, single worker
  Main  2024-08-15 21:58:44 +0800 INFO: server: sanic, HTTP/1.1
  Main  2024-08-15 21:58:44 +0800 INFO: python: 3.12.4
  Main  2024-08-15 21:58:44 +0800 INFO: platform: Windows-11-10.0.22631-SP0
  Main  2024-08-15 21:58:44 +0800 INFO: packages: sanic-routing==23.12.0
  Traceback (most recent call last):
  File "<string>", line 1, in <module>
  File "xxx\Python\Python312\Lib\multiprocessing\spawn.py", line 122, in spawn_main
  exitcode = _main(fd, parent_sentinel)
  ^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "xxx\Python\Python312\Lib\multiprocessing\spawn.py", line 131, in _main
  prepare(preparation_data)
  File "xxx\Python\Python312\Lib\multiprocessing\spawn.py", line 246, in prepare
  _fixup_main_from_path(data['init_main_from_path'])
  File "xxx \Python\Python312\Lib\multiprocessing\spawn.py", line 297, in _fixup_main_from_path
  main_content = runpy.run_path(main_path,
  ^^^^^^^^^^^^^^^^^^^^^^^^^
  File "<frozen runpy>", line 286, in run_path
  File "<frozen runpy>", line 98, in _run_module_code
  File "<frozen runpy>", line 88, in _run_code
  File "xxx\test\main.py", line 3, in <module>
  api.start_server()
  File "xxx\test\api.py", line 16, in start_server
  app.run(host="127.0.0.1", port=5050)
  File "xxx\Python\Python312\Lib\site-packages\sanic\mixins\startup.py", line 291, in run
  serve(primary=self)  # type: ignore
  ^^^^^^^^^^^^^^^^^^^
  File "xxx\Python\Python312\Lib\site-packages\sanic\mixins\startup.py", line 1003, in serve
  cls._set_startup_method()
  File "xxx\Python\Python312\Lib\site-packages\sanic\mixins\startup.py", line 932, in _set_startup_method
  set_start_method(method, force=cls.test_mode)
  File "xxx\Python\Python312\Lib\multiprocessing\context.py", line 247, in set_start_method
  raise RuntimeError('context has already been set')
  RuntimeError: context has already been set

  
  这是第一个python文件 (api.py):
  

  # api.py
  from sanic import Sanic, json
  from sanic_cors import CORS
  
  app = Sanic("ip")
  CORS(app)
  
  
  @app.route("/get_proxy")
  async def ip_api(request):
    ip = "XXXXXX"
    return json({"ip": ip})
  
  
  def start_server():
    app.run(host="127.0.0.1", port=5050)
  
  
  if __name__ == '__main__':
    start_server()

  
  这是第二个python文件 (main.py):
  

  # main.py
  import api
  
  api.start_server()

  
  感谢您提供的帮助。
  

我原本怀疑时主模块检查因为某些原因自己运行了，于是删除了那段代码，但并没有任何效果。

Answer 1

感谢各位，本贴已于 Stackoverflow 上解决，这是解决方法，希望能帮助到更多朋友。

This has something to do with the fact that Sanic has to start in main, but the routes can be defined anywhere else.
Sanic 必须在__main__中启动，因为Sanic需要在其中做一些事情，但是相关路由可以定义在任何地方。

This works:
这样做就可以正常运行了：

# api.py
from sanic import Sanic, json
from sanic_cors import CORS

app = Sanic("ip")
CORS(app)


@app.route("/get_proxy")
async def ip_api(request):
    ip = "XXXXXX"
    return json({"ip": ip})

if __name__ == '__main__':
    app.run(host="127.0.0.1", port=5050)

Or try this:
或者试试这样做：

# main.py
from api import start_server

if __name__ == "__main__":
    start_server()