Re: config library, was GNOME registry

[Andrew Morton <andrewm uow edu au>]

Fascinating discussion, and I'm glad to see Joshua pulling it back from
implementation to requirements.  Carts and horses...

We are confronting what I consider to be Unix's single greatest
weakness: system management.

- Every application has its own specific config files.

- There is no coherent interface by which higher level management
systems can 
manipulate those files.

- There is no coherent mechanism by which an application is informed of
changes to its config (edit/sighup doesn't cut it).

These immaturities are a great barrier to managing large numbers of Unix
machines.

Now I wouldn't expect the gnome team to be able to solve these problems
- a complete solution (definitely CORBA based) would be more complex
than NIS, LDAP and DNS combined...

But if we can identify the end requirements and you folks can implement
a step along the way it'd be a huge contribution to Unix's viability in
the enterprise.

Additional requirements would be:

- That a higher-level management system be able to propagate information
to many hosts, with, of course, per-host variations

- That there be an audit trail of changes.

- Backouts

- When hosts are uncontactable, changes be propagated when they come
back up

- etc.  I assume NDS et al do all this.

- Any host must be able to propagate information to others - not just a
pure top-down hierarchy.

At the client side:

- Persistency (obviously)

- notifications to the running applications. This is _complex_ if the
schema goes much beyond name=value.  You may, for example, require that
a number of information elements be sent, but that they not be committed
until they all have arrived at all hosts.  Otherwise they are backed
out.

- adaptors to/from all those legacy apps which are beyond our control.


So where does it stop, and how far is the gnome team prepared to go??

Within the telecommunications industry (Nortel, at least), we refer to
this problem as "datafill".  Some of the guys here have done quite a bit
of research in this area and I may be able to open up that thinking if
the will is there. I'll keep watching..

Cheers,
Andrew

[ Please, nobody say "this is off topic, take it elsewhere".  It's more
important than gnome itself. ]


"Joshua R. Prismon" wrote:
> 
> Actually, this is where XML would be very usefull.
> 
> I think we are getting ahead of ourselves here. What
> are the requirements for what we want to do?
> 
> 1) Provide a generic/cheap interface to get/set configuration information.
> 
> 2) Provide some mechanism where we can store config information in a
>         number of ways.
> 
> 3) Provide some mechanism where a universal control application could be
>         designed.
> 
> 4) Provide someway to ensure that configuration information is not vunderable.
> 
> So here is what I fleashed out beyond that:
> 
> 1) Provide a generic/cheap interface to get/set configuration information.
> 
> Additional requirements:
>         - Usable from any language (corba?)
>         - Linkable into a exec for non Gnome Applications?
>         - Handle failures (LDAP database going down, for example) gracefully.
> 
> In my opinion, it would be easy to do this in a Unix Library/Corba Service.
> (speaking
> of which, while KDE and GNOME haven't gotten along very well, this would be
> a great
> place to try and unify the two teams. It would ensure that we don't spend
> massive amount
> of time rebuilding each others code. (ie, both control panels could
> configure anything).
> 
> 2) Provide some mechanism where we can store config information in a
>         number of ways.
> Adition Requirements:
>         - Some sort of caching method?
>         - Translators (ala what COAS and LinuxConf are doing).
>         - LDAP/Text/DB formats.
> 
> 3) Provide some mechanism where a universal control application could be
>         designed.
>         - This is where XML would be usefull. We could have applications give
>          us XML structures to desribe the data. using these XML structures, we
>          can create a universal control panel that would be capible of admining
>          anything, so long as it has a XML struct for it.
> 
> 4) Provide someway to ensure that configuration information is not vunderable.
>         - this would be why you would want to store info in a text file. Further, we
>          have to assume that there is some way (a text cache?) to boot up a system
>          even if some of the configuration services (LDAP or a corrupted DB) are
> down.
> 
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