Jupyter Lab 和 Notebook 问题：内核错误

Question

看来我的一个内核被删除了。也许这就是我收到此错误的原因。我怎么可能修复它？我可以重新安装一些东西（也许是基础环境中的内核）？

如果没有更好的选择，我会尝试完全重新安装 anaconda 作为最后的手段，根据：Default kernel in jupyter Notebook (Python3) not working。

我尝试过使用以下内容：

1. Jupyter实验室的安装：requirements already satisfied
2. 运行“jupyter lab”时内核不显示
3. UI 说“没有内核”，而我确实有一个
4. 在 Python3 中运行 Jupyter Notebook 时出现内核错误
5. https://ipython.readthedocs.io/en/latest/install/kernel_install.html
6. https://medium.com/flatiron-engineering/recovering-from-a-jupyter-disaster-27401677aeeb

当前内核列表

jupyter kernelspec list

输出：

Available kernels:
  python3    C:\Users\raysu\AppData\Roaming\jupyter\kernels\python3
  vpython    C:\ProgramData\jupyter\kernels\vpython

但我必须有另一个与我的基本环境相关联的内核（我想它以某种方式被删除了）。

C:\Users\raysu\Documents>conda env list
# conda environments:
#
base                  *  C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64
astra_env                C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\envs\astra_env
bokeh_env                C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\envs\bokeh_env
sound_env                C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\envs\sound_env
tf_env                   C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\envs\tf_env
                         C:\Users\raysu\Anaconda3
                         C:\Users\raysu\Anaconda3\envs\pyforge
opencv_env               C:\Users\raysu\AppData\Local\conda\conda\envs\opencv_env
test_env                 C:\Users\raysu\AppData\Local\conda\conda\envs\test_env

错误

Traceback (most recent call last):
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\tornado\web.py", line 1699, in _execute
    result = await result
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\tornado\gen.py", line 742, in run
    yielded = self.gen.throw(*exc_info)  # type: ignore
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\notebook\services\sessions\handlers.py", line 72, in post
    type=mtype))
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\tornado\gen.py", line 735, in run
    value = future.result()
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\tornado\gen.py", line 742, in run
    yielded = self.gen.throw(*exc_info)  # type: ignore
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\notebook\services\sessions\sessionmanager.py", line 88, in create_session
    kernel_id = yield self.start_kernel_for_session(session_id, path, name, type, kernel_name)
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\tornado\gen.py", line 735, in run
    value = future.result()
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\tornado\gen.py", line 742, in run
    yielded = self.gen.throw(*exc_info)  # type: ignore
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\notebook\services\sessions\sessionmanager.py", line 101, in start_kernel_for_session
    self.kernel_manager.start_kernel(path=kernel_path, kernel_name=kernel_name)
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\tornado\gen.py", line 735, in run
    value = future.result()
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\tornado\gen.py", line 209, in wrapper
    yielded = next(result)
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\site-packages\notebook\services\kernels\kernelmanager.py", line 168, in start_kernel
    super(MappingKernelManager, self).start_kernel(**kwargs)
  File "C:\Users\raysu\AppData\Roaming\Python\Python36\site-packages\jupyter_client\multikernelmanager.py", line 110, in start_kernel
    km.start_kernel(**kwargs)
  File "C:\Users\raysu\AppData\Roaming\Python\Python36\site-packages\jupyter_client\manager.py", line 240, in start_kernel
    self.write_connection_file()
  File "C:\Users\raysu\AppData\Roaming\Python\Python36\site-packages\jupyter_client\connect.py", line 476, in write_connection_file
    kernel_name=self.kernel_name
  File "C:\Users\raysu\AppData\Roaming\Python\Python36\site-packages\jupyter_client\connect.py", line 141, in write_connection_file
    with secure_write(fname) as f:
  File "C:\Program Files (x86)\Microsoft Visual Studio\Shared\Anaconda3_64\lib\contextlib.py", line 81, in __enter__
    return next(self.gen)
  File "C:\Users\raysu\AppData\Roaming\Python\Python36\site-packages\jupyter_core\paths.py", line 404, in secure_write
    win32_restrict_file_to_user(fname)
  File "C:\Users\raysu\AppData\Roaming\Python\Python36\site-packages\jupyter_core\paths.py", line 359, in win32_restrict_file_to_user
    import win32api
ImportError: DLL load failed: The specified procedure could not be found.

Answer 1

通过在全新安装 Anaconda 后编辑相关的kernelspec:文件解决了该问题。kernel.json

详细解决方案

正如之前报道的，我发现我有两个 kernelspecs. （命令：jupyter kernelspec list）

1. 蟒蛇3: C:\Users\raysu\AppData\Roaming\jupyter\kernels\python3
2. 虚拟蟒蛇： C:\ProgramData\jupyter\kernels\vpython

该kernelspec文件.json维护 jupyter-notebook/lab 启动特定内核的内核规范。幸运的是，内核vpython正在运行，这帮助我缩小了内部问题的根源kernelpsec: python3。我必须更正 python 可执行文件 ( ) 的路径python.exe，这解决了问题。

我想提一下，在这种情况下，以下两个资源就派上用场了。在看到文档的典型结构后，我更清楚地了解了问题所在kernelspec。

注意：但是，由于我无法测试这个理论，因此我会要求遇到类似问题的其他人首先复制旧文件kernel.json，然后更新文件的路径python.exe。如果这解决了内核错误，则可能不需要完全重新安装 Anaconda。

长话短说：

如果您的 jupyter 笔记本/实验室环境显示kernel error，则问题的根源很可能是在 kernelspec 文件内部：kernel.json并且路径python.exe不正确。kernel error如果即使在重新安装 anaconda/jupyter-notebook/lab 后仍然存在同样的情况，这可能是更可能的情况。

例如，就我而言，该位置python3-kernelspec位于：

"C:\Users\raysu\AppData\Roaming\jupyter\kernels\python3"

位于python.exe：

"C:\Users\raysu\Anaconda3\python.exe"

但是， python 可执行文件的路径是错误的：它仍然显示旧安装的路径。重新安装 anaconda 后，这条路径发生了变化。因此，我必须通过编辑kernel.json文件来更新 python3 的内核规范。

# kernel.json file
{
 "argv": [
  "C:\\Users\\raysu\\Anaconda3\\python.exe",
  "-m",
  "ipykernel_launcher",
  "-f",
  "{connection_file}"
 ],
 "display_name": "Python 3",
 "language": "python"
}

如果这不能解决您的问题，请查阅以下两个文档。我就因为这个浪费了4天的时间。希望这个答案能对将来的人有所帮助。

什么东西派上用场了？

1. https://jupyter-notebook.readthedocs.io/en/stable/troubleshooting.html
2. https://jupyter-client.readthedocs.io/en/stable/kernels.html