[equinox-dev] [prov] Is the director a constraint solver

[Pascal Rapicault <Pascal_Rapicault@xxxxxxxxxx>]

Hello,

Our provisioning system is made of installable units (things that can be
installed by a user). These installable units have "capabilities" and
"requirements". The capabilities are what satisfy the requirements. The
installation of an installable unit can only be successful if all the
"requirements" of this IU are satisfied, and thus recursively. Therefore it
looks like any operation installing, uninstalling, updating, etc is
equivalent to solving a constraint system.

That said, the few readings I have done on the topic of CSP seem to
indicate that the variables, constraints and domains constituting the
system to be satisfied are fixed. However it seems this approach would not
really work in our case since entities available in the domain may be
incompatible with each others (for example we could have installable unit
for multiple versions of eclipse in the repository). Therefore, I was
thinking of a more incremental approach where constraints and variables
would be added as new elements for the domain are being instantiated, but I
have not seen anything related to that in the literature.

So here are the questions:
- Is CSP applicable to this problem?
- Is there any algorithm that I should take a close look at (note that
there can be cycles between installable units) ?
- How scalable are the constraint solvers in presence of tens of thousands
of constraints and variables?

If you know someone (who know someone)* who can help, please pass it on.

Thanks in advance,

PaScaL