Horde Policies
The idea of Horde Policy is to implement a replacement for the current prefs system, modeled after how Group Policy Objects work in a Microsoft Active Directory. Including a nice administrative GUI, meaning no more editing prefs.php files, and happier admins.
Visualization of a Horde Policy
policy
|-- name
|-- date-updated
|-- attributes
| |-- attribute1
| | |-- value
| | `-- scope
| `-- attribute2
| |-- value
| `-- scope
`-- targets
|-- target1
`-- target2
- each app would have a policy.xml file defining what policy attributes are available.
- A target can consist of one or more:
- entire horde installation
- horde group
- individual user
- guest user
- OU if using LDAP backend
- A target can consist of one or more:
What would need to be done
- build a Horde Policy manager to list, create, edit, delete, etc. policies.
- Store Horde Policies in DB table(s)
- horde_policy table(s)?
- extend the datatree? The data structure fits perfectly with a few performance tweaks
- Store Horde Policies in DB table(s)
Storage
In order to make Horde Policies as generic as possible, it's probably best to specify a new backend for them. Then we can write policy drivers for the various parts of Horde that might use them, such as Prefs.
I'm a big fan of the Datatree structure, slightly simplified, to hold the Policy information. The DataTree itself has proved not to scale very well, but I think by removing a few unneeded fields (for this application, at least), we can reduce the number of JOIN statements, and it should scale just fine. Another thing to think about is how many Horde Policies is a given site going to have? Probably no more than a handful on average.
Anyway, here's a new table structure idea:
horde_policy ------------ policy_id policy_name policy_updated
horde_policy_attributes ----------------------- policy_id attribute_name attribute_scope attribute_overrideable attribute_value
horde_policy_targets -------------------- policy_id target_id target_type <-- maybe
Cache
At login, all applicable Policies should be loaded and cached. We should also try to do something to cache Policies for guest sessions.
Other Thoughts
- all $pref->getValue() calls could be handled on the backend by writing a Policy driver for the Prefs system, giving us a drop-in replacement.
- we'd need a way to clearly define what happens if two Horde Policies have overlapping, conflicting settings.
- there should be a default "root" policy, which cannot be detached from the root installation. This policy would be a site-wide policy that always exists.
Links
http://www.microsoft.com/technet/itsolutions/msit/security/grppolobjectmgmt.mspx - gives a good overview on how MS GPO's work, and a nice graphic that really helped me visualize the internal workings.
Cut & Paste from mailing list until I can better organize my thoughts
- with something like this in place I think it would make more and
more sense to move everything that's at all user-related in conf.php
files to this system. Things like "user capabilities" in both Horde
and IMP - they can even be locked (overridable =3D false?) by default,
but letting people easily manage them on a per-group basis, or
whatever, sounds very good to me.
Just brainstorming here, but we could even go a step further and use =20
this type of system for all of the configs (except for maybe the very =20
basic stuff, like authentication). Doing so would let different =20
groups have different configs, which might be helpful for sites =20
hosting for various groups.
If there were a way to manage, say, IMAP server configs, or other
backend configurations (sieve servers, etc.) using this system, that
would be even better.
Yes! We could put IMAP server configs, etc. in a GPO and assign to =20
targets as necessary. Same way that printers can be assigned in an =20
active directory. "group A uses this IMAP server, group B uses this =20
other IMAP server, group C gets to specify their own IMAP server." The =20
possibilities are endless! I love it!