[Pipet Devel] Re: Booting and shutting down piper

[jarl]

> 
> The approach Jarl and I have settled on for the time being (it's not the best,
> but it will work for the pilot), is to put the PID's of each Piper process in
> the user's $HOME/piper_info/pids directory, then from UIL->DL->BL->PL (top to
> bottom) send a "kill <PID>" (not "kill -9") to the next lower layer.  This
> will allow each layer to begin its own shutdown, and that should be that
> (unless a layer can't die).
> 
> The other benefit of storing the PID's is to determine what is running, or
> what has crashed, should things be re-started.
> 
> I was a bit confused about what Jarl wanted me to do in the UIL and DL,
> because I knew that Brad had already developed a shutdown/crash recovery
> mechanism.  Brad explained his mechanism in a recent message and suggested
> that Jarl use the same approach for the other layers (all layers).
> 
> My question at this point is for Jarl: Do you understand what Brad is
> proposing for the whole system (that which is implemented in the UIL and DL)? 
> What do you think?
I understand and I agree. The meganism between the BL and PL already IS like Brad proposed, and in my reply on Brads email I asked him to point me out where I should work on in the Python code to add such a meganism to the DL->BL communications.
Also I must add that this corbatized pinging is not enough, you cant tell if a layer is crashed or termintated correctly.
> 
> Jarl also brought up a problem with sending network information (an XML
> "document") from the UIL to the PL.  He has been getting errors from the PL. 
> Jarl, can you send copies of those errors to this list so that Brad and
> Jean-Marc can see them?
> 
I could, but I would like to see JeanMarc and Brad give it a try themselfs, because I dont really know what is an error and what is not. 

bye,
jarl