[erlang-questions] supervisor woes

Jared Nance <>
Wed Sep 8 22:50:04 CEST 2010


Thanks for the sasl hint, it's definitely nice to have slightly more verbose error messages.

The supervisor calling my supervisor is the top level supervisor, started via an application behavior that calls ios_overlord:start_link/1, which in turn invokes supervisor:start_link/3.

On Sep 8, 2010, at 1:43 PM, Anthony Molinaro wrote:

> 
> What does the child spec for the supervisor calling your supervisor look like?
> Maybe you are calling your supervisor a worker in that spec?
> 
> -Anthony
> 
> On Wed, Sep 08, 2010 at 01:21:27PM -0700, Jared Nance wrote:
>> Also, as a point of clarification:  If I start the ios_card_super manually with the multiple children, it works without a hitch - all of the ios_faux_cards get registered correctly and behave normally.  It's only when I try to start the ios_card_super as a supervised node in a supervision tree that I have the problem.
>> 
>> On Sep 8, 2010, at 11:59 AM, Adam Kocoloski wrote:
>> 
>>> On Sep 8, 2010, at 11:36 AM, Jared Nance wrote:
>>> 
>>>> Hello List-
>>>> Thanks in advance for whatever help you can offer.  I'm putting together a supervision tree which is rather simple - at the moment, there is a supervisor that manages several other supervisors, and those supervisors each manage only worker nodes.  The problem I am having is with one of my supervisors which manages 4 worker nodes.  Each node is a gen_server that uses the same callback module, but with different arguments to start_link.  The childspec for the worker nodes looks like
>>>> 
>>>> {cardA, {ios_faux_card, start_link, [cardA]}, permanent, brutal_kill, worker, [ios_faux_card]}
>>>> 
>>>> and so the supervisor for these workers is started with a child spec that looks like
>>>> 
>>>> {{one_for_one, 5, 10}, [{ios_card_super, {ios_card_super, start_link, [{cardA, {ios_faux_card, start_link, [cardA]}, permanent, brutal_kill, worker, [ios_faux_card]}], permanent, infinity, supervisor, [ios_card_super]}
>>>> 
>>>> and that works just fine.  the problem arises when i try to add a second (or third, or fourth) gen_server to the list of processes that the ios_card_super is supervising.  if i try starting it with this child spec instead:
>>>> 
>>>> {{one_for_one, 5, 10}, [{ios_card_super, {ios_card_super, start_link, [{cardA, {ios_faux_card, start_link, [cardA]}, permanent, brutal_kill, worker, [ios_faux_card]},{cardB,{ios_faux_card, start_link, [cardB]}, permanent, brutal_kill, worker, [ios_faux_card]}], permanent, infinity, supervisor, [ios_card_super]}
>>>> 
>>>> it refuses to start.  what's more, the only response I get out of it is {error, shutdown}.  I have put io:format debug statements in the ios_faux_card module and it's clear that start_link/1is never being called when there are 2+ workers to supervise.
>>>> 
>>>> Thanks for whatever help you can offer on this very frustrating issue.
>>>> 
>>>> Jared N
>>> 
>>> Hi Jared, you wouldn't happen to be trying to register the process in ios_faux_card, would you?
>>> 
>>> Adam
>>> 
>>> 
>>> 
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> -- 
> ------------------------------------------------------------------------
> Anthony Molinaro                           <>



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