add command line jobspec

[vsoch]

Problem: we cannot define a shape on the command line to map into a job specification resources section. Solution: first add a command line jobspec that defines this shape.

I've never written one of these before - let me know what I should expand / contract or fix!

[garlick]

Slightly concerned about muddying the terminology here since we already have a jobspec and it contains a different set of information. Maybe we could call this a "short form resource request" or maybe a "job shape specification"? Also, the fact that it fits conveniently on the command line could just be one item in the goals section rather than in the title.

One thing I thought turned out well in some of our other RFCs is to have a Test Vectors section at the end that specifies a table of inputs and outputs. If this is a strict translation from "new thing" to the jobspec v1 Reources section, then maybe that would be applicable here?

Finally just wanted again to mention OAR as I think their --resources option is similar and their choice of characters like using resource=count instead of resource[count] seems like it might be a little easier for users to work with. I do like their use of / to denote hierarchy also.

[vsoch]

Okay I’ll ping - @trws - he suggested the command line job spec (which makes sense to be different I think) and we talked about the design of the shape in slack today.

And I did see oar - very subjectively I don’t think it’s very nice looking / pretty. We could also have count just be an attribute so it would have that format and not put it in the brackets.

[garlick]

OK! Those were just my off the cuff first impressions, so take them with appropriate grains of salt etc

[vsoch]

yeah totally! Here is count as an attribute:

# If it's allowed to go first (and then later)
Node[4]:Slot[count=1+label=default]:Core[count=2]
Node[4]:Slot[label=default+count=1]:Core[count=2]

If I had to guess, the rationale for just using the number is that it's common enough that we shouldn't have to write out count= every time. It's a single number (either present or not) at the beginning of the declaration.