[IPython-dev] Behavior of Default Kernel

[Zachary Jones]

Figured it out, with help on Gitter.  I had an old tree.json file in
~/.ipython/<profile>nbconfig

--Zach

On Mon, Dec 22, 2014 at 4:30 PM, Zachary Jones <zach at zacharyjones.us> wrote:

> 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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