[IPython-dev] Behavior of Default Kernel

[Zachary Jones]

To follow up on this...
After stepping through code, I found my way to this URL:
http://localhost:80000/api/config/tree

Which returns: {"NewNotebookWidget": {"default_kernel": "python3"}}

While  http://localhost:8000/api/kernelspecs

returns {"default": "na_python2", ...}

So it looks like something is off with the code path for '/api/config/tree'

Thanks,
Zach

On Fri, Dec 19, 2014 at 6:03 PM, Zachary Jones <zach at zacharyjones.us> wrote:

> Hi everyone,
>
> I have a question about the behavior of default kernels
>
> I was testing IPython from github today (commit hash: dc60d34) and wanted
> to understand if the behavior I am seeing is expected.
>
> The IPython notebook server is running under Python3.4, but I would the
> default kernel to be a custom Python 2 stack.
>
> Running "ipython kernelspec list" from the CLI returns:
> Available kernels:
>   python3
>   my_python2
>
> I invoked IPython notebook using the default_kernel_name:
> '--MappingKernelManager.default_kernel_name=my_python2'
>
> The API call to http://localhost:8000/api/kernelspecs returns:
> {
>     "default": "my_python2",
>     "kernelspecs": {
>         "my_python2": {
>              "env": {},
>              "argv": [*omitted*],
>              "name": "my_python2",
>              "display_name": "My Python2 Stack"
>         },
>         "python3": {
>              "env": {},
>              "argv": [*omitted*],
>              "name": "python3",
>              "display_name": "IPython (Python 3)"
>         }
>     }
> }
>
> With this configuration, I observed the following:
>
>    - When I go to to the notebook dashboard, next to the "New Notebook"
>    button is "IPython (Python 3)" and the hover over says "IPython (Python 3)
>    is the default kernel for new notebooks".
>    - When I click on "New Notebook", the notebook opened uses "IPython
>    (Python 3)" kernel.
>    - When I open existing notebooks that are being converted from v3 to
>    v4, the notebooks open using "My Python 2 Stack" kernel.
>    - When I open an existing notebook that has had the kernel spec
>    inserted into metadata, that kernel is used.
>
>
> *Finally to my questions..*
> Is the default_kernel_name supposed to be used when the "New Notebook"
> button is pressed? and is it suppose to be shown next to the "New Notebook"
> button?
>
> If the answers are yes, should I open an Issue in GitHub? I tried looking
> for an existing issue, but did not turn up anything.
>
>
> Thanks for your help,
> Zach Jones
>
>
>
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