[HECnet] PyDECnet setup

[Paul Koning]

> On Nov 18, 2021, at 3:53 AM, Brian Hechinger <wonko at 4amlunch.net> wrote:
> 
> On 17/11/21 23:02, Robert Armstrong wrote:
>>> Paul Koning <paulkoning at comcast.net> wrote:
>>> If your PyDECnet is run from Unix startup machinery, typically having it
>>> exit would get it restarted shortly after.
>>   Yeah, Upstart will do this if you want to run pyDECnet as a service.  I
>> often find that annoying and I don't actually do that for pyDECnet. I have
>> my own script for running pyDECnet instead.  If it exits, it won't come back
>> :)
> 
> I think that's his point though. Having it exit is going to have non-consistent behavior depending on how it's setup.
> 
> -brian

Good point.

I'm thinking about whether running all the shutdown code, then cycling back to the startup point, will in fact be a valid implementation of "reload".  If yes that would be fairly easy to do.  In proper Unix fashion it could be triggered by a SIGHUP signal (as well as by some API request).

On the node names bit, if people use the syntax "node @nodenames.dat" in the config, where nodenames.dat is the one in the pydecnet samples directory or equivalent, I could imagine a "copy known nodes" feature that (a) updates the in-memory state and (b) writes a new nodenames.dat with that information.  

A more general "rewrite the config file to reflect volatile changes" would likely be more difficult, but that particular one seems doable.

	paul