Allow clients to debug code from command line, like pdb or epdb

从 debugpy/main.py 和 server/cli.py 开始，然后通过 server/api.py 和 vendored 的 pydevd 文件跟踪报告的路径。重现 OutputEvent/command 失败，并确定是否支持命令行调试和交互式 shell 调试。当约定的命令行工作流能够正常运行且不再出现此失败，并且其用法已记录在文档中时，即视为完成。

Hi there,
in my company many don't use VSCode. For this reason our main guidelines to debug are to use pdb or epdb. (https://pypi.org/project/epdb/)
However, in an effort to have just one library that works for all use cases, I'd like to have debugpy to work from command line too.

I have tried this:

python -m debugpy --connect 5678 <path of the file with debugpy.listen()> 

Traceback (most recent call last):
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_comm.py", line 252, in _on_run
    self.process_net_command_json(self.py_db, json_contents)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_process_net_command_json.py", line 171, in process_net_command_json
    method_name = 'on_%s_request' % (request.command.lower(),)
AttributeError: 'OutputEvent' object has no attribute 'command'
^CTraceback (most recent call last):
  File "/usr/local/lib/python3.8/runpy.py", line 194, in _run_module_as_main
    return _run_code(code, main_globals, None,
  File "/usr/local/lib/python3.8/runpy.py", line 87, in _run_code
    exec(code, run_globals)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/__main__.py", line 39, in <module>
    cli.main()
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/server/cli.py", line 430, in main
    run()
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/server/cli.py", line 268, in run_file
    start_debugging(target)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/server/cli.py", line 258, in start_debugging
    debugpy.connect(options.address, access_token=options.adapter_access_token)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/public_api.py", line 31, in wrapper
    return wrapped(*args, **kwargs)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/server/api.py", line 141, in debug
    return func(address, settrace_kwargs, **kwargs)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/server/api.py", line 297, in connect
    _settrace(host=host, port=port, client_access_token=access_token, **settrace_kwargs)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/server/api.py", line 45, in _settrace
    return pydevd.settrace(*args, **kwargs)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/_vendored/pydevd/pydevd.py", line 2821, in settrace
    _locked_settrace(
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/_vendored/pydevd/pydevd.py", line 2929, in _locked_settrace
    py_db.wait_for_ready_to_run()
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/_vendored/pydevd/pydevd.py", line 838, in wait_for_ready_to_run
    self._py_db_command_thread_event.wait(0.1)
  File "/usr/local/lib/python3.8/threading.py", line 558, in wait
    signaled = self._cond.wait(timeout)
  File "/usr/local/lib/python3.8/threading.py", line 306, in wait
    gotit = waiter.acquire(True, timeout)

doesn't stop in debug.

I've also tried to use debugpy in python shell:

>>> import debugpy
>>> debugpy.connect(5678)
Traceback (most recent call last):
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_comm.py", line 252, in _on_run
    self.process_net_command_json(self.py_db, json_contents)
  File "/root/.cache/pypoetry/virtualenvs/viralize-adserver-9TtSrW0h-py3.8/lib/python3.8/site-packages/debugpy/_vendored/pydevd/_pydevd_bundle/pydevd_process_net_command_json.py", line 171, in process_net_command_json
    method_name = 'on_%s_request' % (request.command.lower(),)
AttributeError: 'OutputEvent' object has no attribute 'command'

What is supposed to be this "command"?

Also, am I doing something that is intended to be used like this, or what? I think no, because there is no such reference on the web.