[coherence-dev] new option system for backends

[Frank Scholz]

Hi Jean-Michel,

> Sorry i do not participate to the IRC chats.
np, it is actually a mixed blessing to have most discussions
(only) on the irc channel. On one hand feedback/speed process of
opinion-gathering is very fast, on the other hand we lose a lot
of valuable input. :-/

> Any insight on the "options system provided by the backend itself"
> thingy that dev checked in early this week?
> What is the "plan" about this one?
the idea is that each backend should provide information about
its accepted options, so that a configuration UI can provide
the necessary input fields to the user, without having to know
about the specific backend details in advance.

The options are dictionaries, stored in a list, so the backend
has some impact on their presentation order.

So far we've selected these these key-value pairs for the dicts:

option:    name of that option
type:      string,int or bool
default:   default value, should be of type type (optional)
enum:      a tuple/list of possible values (optional)
range:     a dict with min and max elements (optional)
help:      a (short) text describing this option (optional)
level:     the level of this option - normal or advance (optional)
group:     fieldset title, for grouped options (optional) ???

These lists can be easily accessed by either iterating over
all available backends in the dict-like Plugins class or
directly using the backend identifier as the key.

>>> from coherence.base import Plugins
>>> p = Plugins()
>>> p['FSStore'].options
[{'default': 'my media', 'type': 'string', 'option': 'name'}, ...]

Or as a second option via the REST/JSON interface which I'm currently
working on. That especially will allow a very easy access from any
kind of JavaScript frontend.

> And, off-topic, how did Sprint 2 go?
great, already-overdue dedicated email will follow soon.

Regards,
Frank