Make service_plugins and extensions more configurable

Ease new service_plugins and extension integration as well
as improve code readiness.

Change-Id: I9924de51a70e9342c9ac56113c9fbd148a58c322

ansible/roles/neutron/defaults/main.yml

@@ -299,3 +299,24 @@ extension_drivers:
     enabled: "{{ enable_designate | bool }}"
 
 neutron_extension_drivers: "{{ extension_drivers|selectattr('enabled', 'equalto', true)|list }}"
+
+####################
+# Service Plugins
+####################
+service_plugins:
+  - name: "flow_classifier"
+    enabled: "{{ neutron_plugin_agent == 'sfc' }}"
+  - name: "neutron_lbaas.services.loadbalancer.plugin.LoadBalancerPluginv2"
+    enabled: "{{ enable_neutron_lbaas | bool }}"
+  - name: "neutron.services.firewall.fwaas_plugin.FirewallPlugin"
+    enabled: "{{ enable_neutron_fwaas | bool }}"
+  - name: "neutron_vpnaas.services.vpn.plugin.VPNDriverPlugin"
+    enabled: "{{ enable_neutron_vpnaas | bool }}"
+  - name: "qos"
+    enabled: "{{ enable_neutron_qos | bool }}"
+  - name: "router"
+    enabled: true
+  - name: "sfc"
+    enabled: "{{ neutron_plugin_agent == 'sfc' }}"
+
+neutron_service_plugins: "{{ service_plugins|selectattr('enabled', 'equalto', true)|list }}"

ansible/roles/neutron/templates/neutron.conf.j2

@@ -35,7 +35,8 @@ host = {{ ansible_hostname }}_{{ item }}
 
 allow_overlapping_ips = true
 core_plugin = ml2
-service_plugins = router{% if enable_neutron_lbaas | bool %},neutron_lbaas.services.loadbalancer.plugin.LoadBalancerPluginv2{% endif %}{% if enable_neutron_qos | bool %},qos{% endif %}{% if enable_neutron_vpnaas | bool %},neutron_vpnaas.services.vpn.plugin.VPNDriverPlugin{% endif %}{% if neutron_plugin_agent == "sfc" %}flow_classifier,sfc{% endif %}{% if enable_neutron_fwaas | bool %},neutron.services.firewall.fwaas_plugin.FirewallPlugin{% endif %}
+
+service_plugins = {{ neutron_service_plugins|map(attribute='name')|join(',') }}
 
 {% if enable_neutron_agent_ha | bool %}
 dhcp_agents_per_network = {{ dhcp_agents_per_network }}