Configurable assignment driver

Allow the [assignment] backend to be switched (eg; to LDAP) for
http://docs.openstack.org/developer/keystone/configuration.html#read-only-ldap

Change-Id: I9e4d5a4f4538025c55ebd7db39a78c5135af48e1
Closes-Bug: #1318992

attributes/default.rb

@@ -87,6 +87,7 @@ default['openstack']['identity']['signing']['ca_password'] = nil
 
 # These switches set the various drivers for the different Keystone components
 default['openstack']['identity']['identity']['backend'] = 'sql'
+default['openstack']['identity']['assignment']['backend'] = 'sql'
 default['openstack']['identity']['token']['backend'] = 'sql'
 default['openstack']['identity']['catalog']['backend'] = 'sql'
 default['openstack']['identity']['policy']['backend'] = 'sql'

spec/server_spec.rb

@@ -532,6 +532,13 @@ describe 'openstack-identity::server' do
         end
       end
 
+      describe '[assignment] section' do
+        it 'configures driver' do
+          r = line_regexp('driver = keystone.assignment.backends.sql.Assignment')
+          expect(chef_run).to render_file(path).with_content(r)
+        end
+      end
+
       describe '[catalog] section' do
         # use let() to access Helpers#line_regexp method
         let(:templated) do

templates/default/keystone.conf.erb

@@ -172,6 +172,9 @@ group_allow_delete = <%= @ldap["group_allow_delete"] %>
 [identity]
 driver = keystone.identity.backends.<%= node["openstack"]["identity"]["identity"]["backend"] %>.Identity
 
+[assignment]
+driver = keystone.assignment.backends.<%= node["openstack"]["identity"]["assignment"]["backend"] %>.Assignment
+
 [catalog]
 <% if node["openstack"]["identity"]["catalog"]["backend"] == "templated" -%>
 # templated driver uses different class name :(