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 <[email protected]> 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 <[email protected]> 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 [email protected]. >>> To post to this group, send email to [email protected]. >>> To view this discussion on the web visit https://groups.google.com/d/ms >>> gid/jupyter/97c1bbb1-ada9-44b0-ad68-aff8b1181e94%40googlegroups.com >>> <https://groups.google.com/d/msgid/jupyter/97c1bbb1-ada9-44b0-ad68-aff8b1181e94%40googlegroups.com?utm_medium=email&utm_source=footer> >>> . >>> For more options, visit https://groups.google.com/d/optout. >>> >> >> >> >> -- >> Michael Milligan, Ph.D. | Supercomputing Institute >> Assistant Director for | University of Minnesota >> Application Development | [email protected] >> www.msi.umn.edu/staff/milligan | Phone: 612-624-8857 <(612)%20624-8857> >> > -- > 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 [email protected]. > To post to this group, send email to [email protected]. > To view this discussion on the web visit https://groups.google.com/d/ > msgid/jupyter/8cece011-11eb-4053-86e0-13ca6a0c8cd6%40googlegroups.com > <https://groups.google.com/d/msgid/jupyter/8cece011-11eb-4053-86e0-13ca6a0c8cd6%40googlegroups.com?utm_medium=email&utm_source=footer> > . > > For more options, visit https://groups.google.com/d/optout. > -- Michael Milligan, Ph.D. | Supercomputing Institute Assistant Director for | University of Minnesota Application Development | [email protected] www.msi.umn.edu/staff/milligan | Phone: 612-624-8857 -- 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 [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/jupyter/CAPuy8goJNim%3DFRC-u2tGCvO6fmV3YsXzgBUKXDxL2Op_EmsrNA%40mail.gmail.com. For more options, visit https://groups.google.com/d/optout.
