Support to inject config-flags for neutron-api charm

This patch is just to enable adding custom options to
neutron.conf by the following command:

juju set neutron-api config-flags='key1=val1, ...'

Change-Id: I46bc32c250295a511508ced4cbca8f9748229415
Closes-Bug: #1585508

config.yaml

@@ -597,3 +597,20 @@ options:
     description: |
       Apply system hardening. Supports a space-delimited list of modules
       to run. Supported modules currently include os, ssh, apache and mysql.
+  config-flags:
+    type: string
+    default:
+    description: |
+      Comma-separated list of key=value config flags. These values will be
+      placed in the neutron.conf [DEFAULT] section.
+      .
+      WARNING: this is not the recommended way to configure the underlying
+      services that this charm installs and is used at the user's own risk.
+      This option is mainly provided as a stop-gap for users that either
+      want to test the effect of modifying some config or who have found
+      a critical bug in the way the charm has configured their services
+      and need it fixed immediately. We ask that whenever this is used,
+      that the user consider opening a bug on this charm at
+      http://bugs.launchpad.net/charms providing an explanation of why the
+      config was needed so that we may consider it for inclusion as a
+      natively supported config in the the charm.

hooks/neutron_api_utils.py

@@ -163,6 +163,7 @@ BASE_RESOURCE_MAP = OrderedDict([
                      neutron_api_context.IdentityServiceContext(
                          service='neutron',
                          service_user='neutron'),
+                     context.OSConfigFlagContext(),
                      neutron_api_context.NeutronCCContext(),
                      context.SyslogContext(),
                      context.ZeroMQContext(),

templates/icehouse/neutron.conf

@@ -70,6 +70,12 @@ nova_admin_auth_url = {{ auth_protocol }}://{{ auth_host }}:{{ auth_port }}/v2.0
 {% endfor -%}
 {% endif %}
 
+{% if user_config_flags -%}
+{% for key, value in user_config_flags.iteritems() -%}
+{{ key }} = {{ value }}
+{% endfor -%}
+{% endif -%}
+
 [quotas]
 {% if quota_driver -%}
 quota_driver = {{ quota_driver }}

templates/juno/neutron.conf

@@ -70,6 +70,12 @@ nova_admin_auth_url = {{ auth_protocol }}://{{ auth_host }}:{{ auth_port }}/v2.0
 {% endfor -%}
 {% endif %}
 
+{% if user_config_flags -%}
+{% for key, value in user_config_flags.iteritems() -%}
+{{ key }} = {{ value }}
+{% endfor -%}
+{% endif -%}
+
 [quotas]
 {% if quota_driver -%}
 quota_driver = {{ quota_driver }}

templates/kilo/neutron.conf

@@ -72,6 +72,12 @@ nova_admin_auth_url = {{ auth_protocol }}://{{ auth_host }}:{{ auth_port }}/v2.0
 {% endfor -%}
 {% endif %}
 
+{% if user_config_flags -%}
+{% for key, value in user_config_flags.iteritems() -%}
+{{ key }} = {{ value }}
+{% endfor -%}
+{% endif -%}
+
 {% include "section-zeromq" %}
 
 [quotas]

templates/liberty/neutron.conf

@@ -67,6 +67,12 @@ notify_nova_on_port_data_changes = True
 {% endfor -%}
 {% endif %}
 
+{% if user_config_flags -%}
+{% for key, value in user_config_flags.iteritems() -%}
+{{ key }} = {{ value }}
+{% endfor -%}
+{% endif -%}
+
 {% include "section-zeromq" %}
 
 [quotas]

templates/mitaka/neutron.conf

@@ -62,6 +62,12 @@ notify_nova_on_port_data_changes = True
 {% endfor -%}
 {% endif %}
 
+{% if user_config_flags -%}
+{% for key, value in user_config_flags.iteritems() -%}
+{{ key }} = {{ value }}
+{% endfor -%}
+{% endif -%}
+
 {% include "section-zeromq" %}
 
 [quotas]