Re: [jupyter] Invalidate spawn in pre_spawn_hook?

2018-01-20 Thread Michael Milligan 
I'm surprised to hear that throwing an exception there causes any havoc; in
the code there is a generic exception handler that shouldn't let any
uncaught exceptions leak through. There is potential for trouble, though,
if you are using a spawner that does some vial initialization during the
start() call, such that calling stop() or start_polling() throws an
exception if start() was not previously called. If that is what's
happening, it would be a bug in the spawner class and you would want to
file an issue with the corresponding project.

Michael

On Fri, Jan 19, 2018 at 12:51 PM, Tim Harsch  wrote:

> Thank you Michael, that is very helpful. In this case I am using
> pre_spawn_hook, in lieu of a spawner options form.   So I think the
> exceptions are causing havoc to the server.
> I went the route of the pre_spawn_hook because in my case because the user
> doesn't need to inform the hub of the docker image, it can be done in the
> hook.   But that's where an issue could arise..  and I'm not sure to handle
> it gracefully.
>
> Tim
>
>
> On Friday, January 19, 2018 at 9:44:34 AM UTC-8, Michael Milligan wrote:
>>
>> Hi,
>>
>> The Spawner's start() function is called unconditionally after
>> pre_spawn_hook() returns, so you're correct that the return value will have
>> no effect. However, if you raise an exception, it will be caught by the app
>> and the associated error message will be logged. There are some cases where
>> exception error messages are displayed to the user. If I'm correctly
>> interpreting the code, in this case a message will be displayed *if* you
>> have a spawner options form set up.
>>
>> Michael
>>
>> On Fri, Jan 19, 2018 at 11:06 AM, Tim Harsch  wrote:
>>
>>> Hi all,
>>> Is there a way in the pre_spawn_hook I could invalidate the spawn?
>>>  return True/False doesn't work.   I'd like it to ultimately produce a user
>>> friendly result to the user if an issue occurs
>>>
>>> Thanks,
>>> Tim
>>>
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>>
>>
>>
>> --
>> Michael Milligan, Ph.D. | Supercomputing Institute
>> Assistant Director for  | University of Minnesota
>>Application Development  | mill...@umn.edu
>> www.msi.umn.edu/staff/milligan  | Phone: 612-624-8857 <(612)%20624-8857>
>>
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-- 
Michael Milligan, Ph.D. | Supercomputing Institute
Assistant Director for  | University of Minnesota
   Application Development  | milli...@umn.edu
www.msi.umn.edu/staff/milligan  | Phone: 612-624-8857

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Re: [jupyter] Invalidate spawn in pre_spawn_hook?

2018-01-19 Thread Tim Harsch 
Thank you Michael, that is very helpful. In this case I am using 
pre_spawn_hook, in lieu of a spawner options form.   So I think the 
exceptions are causing havoc to the server.   
I went the route of the pre_spawn_hook because in my case because the user 
doesn't need to inform the hub of the docker image, it can be done in the 
hook.   But that's where an issue could arise..  and I'm not sure to handle 
it gracefully.

Tim


On Friday, January 19, 2018 at 9:44:34 AM UTC-8, Michael Milligan wrote:
>
> Hi,
>
> The Spawner's start() function is called unconditionally after 
> pre_spawn_hook() returns, so you're correct that the return value will have 
> no effect. However, if you raise an exception, it will be caught by the app 
> and the associated error message will be logged. There are some cases where 
> exception error messages are displayed to the user. If I'm correctly 
> interpreting the code, in this case a message will be displayed *if* you 
> have a spawner options form set up.
>
> Michael
>
> On Fri, Jan 19, 2018 at 11:06 AM, Tim Harsch  > wrote:
>
>> Hi all,
>> Is there a way in the pre_spawn_hook I could invalidate the spawn?  
>>  return True/False doesn't work.   I'd like it to ultimately produce a user 
>> friendly result to the user if an issue occurs
>>
>> Thanks,
>> Tim
>>
>> -- 
>> You received this message because you are subscribed to the Google Groups 
>> "Project Jupyter" group.
>> To unsubscribe from this group and stop receiving emails from it, send an 
>> email to jupyter+u...@googlegroups.com .
>> To post to this group, send email to jup...@googlegroups.com 
>> .
>> To view this discussion on the web visit 
>> https://groups.google.com/d/msgid/jupyter/97c1bbb1-ada9-44b0-ad68-aff8b1181e94%40googlegroups.com
>>  
>> 
>> .
>> For more options, visit https://groups.google.com/d/optout.
>>
>
>
>
> -- 
> Michael Milligan, Ph.D. | Supercomputing Institute
> Assistant Director for  | University of Minnesota
>Application Development  | mill...@umn.edu 
> www.msi.umn.edu/staff/milligan  | Phone: 612-624-8857
>

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Re: [jupyter] Invalidate spawn in pre_spawn_hook?

2018-01-19 Thread Michael Milligan 
Hi,

The Spawner's start() function is called unconditionally after
pre_spawn_hook() returns, so you're correct that the return value will have
no effect. However, if you raise an exception, it will be caught by the app
and the associated error message will be logged. There are some cases where
exception error messages are displayed to the user. If I'm correctly
interpreting the code, in this case a message will be displayed *if* you
have a spawner options form set up.

Michael

On Fri, Jan 19, 2018 at 11:06 AM, Tim Harsch  wrote:

> Hi all,
> Is there a way in the pre_spawn_hook I could invalidate the spawn?
>  return True/False doesn't work.   I'd like it to ultimately produce a user
> friendly result to the user if an issue occurs
>
> Thanks,
> Tim
>
> --
> You received this message because you are subscribed to the Google Groups
> "Project Jupyter" group.
> To unsubscribe from this group and stop receiving emails from it, send an
> email to jupyter+unsubscr...@googlegroups.com.
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> To view this discussion on the web visit https://groups.google.com/d/
> msgid/jupyter/97c1bbb1-ada9-44b0-ad68-aff8b1181e94%40googlegroups.com
> 
> .
> For more options, visit https://groups.google.com/d/optout.
>



-- 
Michael Milligan, Ph.D. | Supercomputing Institute
Assistant Director for  | University of Minnesota
   Application Development  | milli...@umn.edu
www.msi.umn.edu/staff/milligan  | Phone: 612-624-8857

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