AW: Graceful Process / Script Termination

[Nachtigall, Jens (I/EK-Z6)]

Thanks for the feedback and for looking into it / opening a ticket!
I have no experience in Perl at all, I'm afraid. This is why I wasn't able to 
dig deeper into your code.

Indeed, my use-case is dependent on the termination sequence. Yet, I can honor 
a fixed termination signal for the toolchain to use.
Can you remind me / document what the default termination signal for remote 
jobs is? What signal does the remote wrapper send to remotely spawned processes 
if not default?

Regarding behavior documentation:
When cancelling GNU Parallel running remote jobs, it returns immediately. 
Indicated on 
https://www.gnu.org/software/parallel/parallel_design.html#The-remote-system-wrapper,
 there is the "Remote Wrapper" which acts as a fallback mechanism to terminate 
remote jobs. Yet, there is no feedback channel for GNU Parallel to know when 
the remote processes actually stopped thus it returns immediately upon CTRL-C. 
This leaves the impression as if nothing happened although I know that 
terminating my remote jobs takes about 20 - 30 seconds while on local instances 
GNU Parallel blocks until the jobs are terminated properly.

As I came across the "parallel_design" page fairly late, maybe linking it here 
https://www.gnu.org/software/parallel/man.html#EXAMPLE:-Using-remote-computers 
would have saved some time on experimenting.

All the best
Jens



INTERNAL

-----Ursprüngliche Nachricht-----
Von: Ole Tange <ole@tange.dk> 
Gesendet: Sonntag, 20. September 2020 00:45
An: Nachtigall, Jens (I/EK-Z6) <jens.nachtigall@audi.de>
Cc: parallel@gnu.org
Betreff: Re: Graceful Process / Script Termination

On Thu, Sep 17, 2020 at 6:07 PM Nachtigall, Jens (I/EK-Z6) 
<jens.nachtigall@audi.de> wrote:

> The only very misleading thing is, that GNU Parallel terminates and returns 
> immediately, regardless.

Please help write what should have been written in the documentation, so you 
would have known this, because absolutely nothing is obvious around the remote 
wrapper.

Re-reading the wrapper I can see, that --termseq is not supported at all for 
remote jobs, so I have created
https://savannah.gnu.org/bugs/index.php?59146


/Ole