Improve docs about Horizon Settings

[Julie Pichon]

http://docs.openstack.org/developer/horizon/topics/settings.html could use an update, local_settings.py.example is nice but sometimes it is more handy to point people to the docs.

Missing ones I can see:

* Horizon section

auto-fade alerts?

I wonder if we might want to add a warning about the 'exceptions' attribute, or probably the HORIZON_CONFIG dictionary in general. I've seen issues where people define only one attribute that they want to override (e.g. help_url) thinking the rest would remain at the defaults, and then wonder why exceptions/HTTP 401 bring up an Internal Server Error.

* Openstack section

SESSION_TIMEOUT

OPENSTACK_NEUTRON_NETWORK should talk about security groups, quotas, profile support.

OPENSTACK_API_VERSIONS

SECONDARY_ENDPOINT_TYPE

OPENSTACK_KEYSTONE_MULTIDOMAIN_SUPPORT
OPENSTACK_KEYSTONE_DEFAULT_DOMAIN = 'Default'
OPENSTACK_KEYSTONE_BACKEND

CONSOLE_TYPE

OPENSTACK_SSL_CACERT

OPENSTACK_IMAGE_BACKEND and SECURITY_GROUPS_RULES?

CREATE_INSTANCE_FLAVOR_SORT

TROVE_ADD_USER_PERMS
TROVE_ADD_DATABASE_PERMS

* Django settings

Perhaps it would be nice to add something about ALLOWED_HOSTS, I know I got caught upgrading to Django 1.5 and it's difficult to debug.

This is also another place where we could highlight the SECRET_KEY issue.

...There were more than I initially expected.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/56299

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/56299
Committed: http://github.com/openstack/horizon/commit/ca014eba80f61c934238584915922ba5cc3a48ac
Submitter: Jenkins
Branch: master

commit ca014eba80f61c934238584915922ba5cc3a48ac
Author: David Lyle <email address hidden>
Date: Wed Nov 13 16:59:29 2013 -0700

    Documenting OPENSTACK_SSL_CACERT

    Partial-bug: #1221115

    Change-Id: I0aa0ed1d871cd72fe3375ec8afdf0588073a382f

[Matthias Runge (mrunge)]

Logging options should be added as well.

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/65074

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/65074
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=95565286bf8cf153209a54707fa08c5e5f261adc
Submitter: Jenkins
Branch: master

commit 95565286bf8cf153209a54707fa08c5e5f261adc
Author: Matthias Runge <email address hidden>
Date: Mon Jan 6 14:17:50 2014 +0100

    Improve docs about horizon settings

    added ALLOWED_HOSTS
    added SESSION_TIMEOUT

    Since settings become longer and longer, I re-arranged the options
    in alphabetical order.

    Change-Id: I4424cc178ec0cd7892b0f07cb0192b5af5b2ee0d
    Partial-bug: #1221115

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/68639

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/68639
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=6cb164f262abe122a41e2511dd0e3202dccaf93b
Submitter: Jenkins
Branch: master

commit 6cb164f262abe122a41e2511dd0e3202dccaf93b
Author: Julie Pichon <email address hidden>
Date: Thu Jan 23 13:26:47 2014 +0000

    Document the IMAGE_LIST_FILTER_TENANTS setting

    This has been around since Grizzly.

    Change-Id: I1e3d3f3aaf2c0d6d7698572a1efbae9acb3e0a3e
    Partial-Bug: #1221115

[Anne Gentle (annegentle)]

Just wanted to say, we already automate the 2500+ config options for <project>.conf files (for ceilometer cinder glance keystone nova neutron), but I don't know how to automate horizon config options. If anyone has ideas, let the docs team know!

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/74437
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=69a299c70bb8ac5c99825be483a40a8810cbde1d
Submitter: Jenkins
Branch: master

commit 69a299c70bb8ac5c99825be483a40a8810cbde1d
Author: Kevin Kirkpatrick <email address hidden>
Date: Tue Feb 18 08:31:53 2014 -0800

    Documented Flavor Sorting Options

    Documented with examples to add a sorting mechanisms to hardware template flavors.

    Change-Id: Ic42b4f7b9e1fe8a59aaa548bd2883e6eef450e98
    Partial-Bug: #1221115

[Julie Pichon (jpichon)]

Thanks for the tips Anne. Our current issue is that we don't have a canonical location where settings live, some are documented in the dev docs, some are documented in the example local settings file and some only exists in the code and no one even remember they exist. Definitely some space for us to improve here!

[OpenStack Infra (hudson-openstack)]

Change abandoned by Denise Hale (<email address hidden>) on branch: master
Review: https://review.openstack.org/117544
Reason: Issue with merged code

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/117653
Committed: https://git.openstack.org/cgit/openstack/horizon/commit/?id=8c3e36e6ce1d9f292f7369705425dbb4b6631cd6
Submitter: Jenkins
Branch: master

commit 8c3e36e6ce1d9f292f7369705425dbb4b6631cd6
Author: Denise Hale <email address hidden>
Date: Thu Aug 28 16:54:50 2014 -0700

    Updates to horizon settings.rst

    Added documentation for auto_fade_alerts.

    Also added to the OpenStack section documentation for:
    OPENSTACK_API_VERSIONS,
    OPENSTACK_KEYSTONE_MULTIDOMAIN_SUPPORT,
    OPENSTACK_KEYSTONE_DEFAULT_DOMAIN,
    OPENSTACK_KEYSTONE_BACKEND,
    CONSOLE_TYPE,
    TROVE_ADD_USER_PERMS,
    TROVE_ADD_DATABASE_PERMS.

    In the Django section, added ALLOWED_HOSTS
    and a note about use of SECRET_KEY.

    Closes-Bug: #1221115
    Change-Id: I16596fef2af62b892cef00ab25e2bfe4a80e1c65