Re: [BuildStream] CAS server resource names & instance names

[Jim MacArthur <jim macarthur codethink co uk>]

On 10/12/2018 12:46, Jürg Billeter wrote:

> > Remote execution storage will take an optional instance name and not
> > provide it or the initial slash if it's not provided, although I will
> > allow specification of "" as a valid instance name, distinct from not
> > specifying one.
> I don't understand this. In the protocol there is no difference between
> an empty instance name and not specifying an instance name (as in
> protobuf it's the same). Why (and how) would we treat these two cases
> differently in BuildStream, possibly violating the spec?
>
> Cheers,
> Jürg
I don't see how you've got to the conclusion that empty instance and no 
instance are the same thing. The Bazel protocol does say "For servers 
which do not support multiple instances, then the `instance_name` is the 
empty path" but that doesn't necessary imply behaviour for servers which 
do support it. I can also see mappings to http URLs which look like 
they'll always include an instance name or empty string, but I wasn't 
considering them authoritative specifications.

Jim