Multiprocessing.Process Daemonic Behavior

[John L. Stephens]

On 3/15/2011 11:19 PM, James Mills wrote:
> On Wed, Mar 16, 2011 at 12:34 PM, John L. Stephens
> <lists.jkstephens at gmail.com>  wrote:
>> I would have expected the daemonic children processes to terminate with the
>> parent process, regardless of how the parent process terminates, either
>> normally or forcefully.
> As I understand it. If you forcibly kill the parent process
> with the KILL signal then any child procesases that were
> created become zombies. You also can't handle the KILL
> signal in your application (nor can the multiprocessing library)
> and so it therefore cannot cleanup  and terminate any child
> processes in the normal way.
>
> cheers
> James
>
So as I have contemplated this in the wee hours of the morning (risking 
zombie status myself I might add),  my rationale for the behavior I am 
seeing is thus:

As the parent process terminates 'normally' (either through normal 
termination or SIGINT termination), mulitprocessing steps in and 
performs child process cleanup via the x.terminate() method.  If the 
parent terminates any other way, multiprocessing doesn't have the 
opportunity to cleanup.

I would have thought (silly me) the child process would also monitor his 
parent process, and when the child can no longer 'see' or 'sense the 
presence' of its parent, it too would terminate.

I can certainly make the children monitor the parent as well, I was just 
hoping I wouldn't have to put in additional code and overhead.

John