Introduce macro to remove Py3 only plugins on CentOS 7

As CentOS 7 is Python 2 we need a way to remove plugins used in
OpenStack components once they switch to be Python 3 only.

'remove_py3_only_plugins_for_py2' macro does exactly that.

This change also disables networking-bgpvpn for python 2.

Change-Id: Ib90aabc485f1c831d3d41cc0f70052f8fffc3fe6
Related: blueprint drop-py2-support

docker/horizon/Dockerfile.j2

@@ -163,10 +163,7 @@ RUN ln -s horizon-source/* horizon \
     && cp -r /horizon/openstack_dashboard/conf/* /etc/openstack-dashboard/ \
     && cp /horizon/openstack_dashboard/local/local_settings.py.example /etc/openstack-dashboard/local_settings \
     && cp /horizon/manage.py /var/lib/kolla/venv/bin/manage.py \
-    {# NOTE(hrw) some plugins already moved to Python 3 and CentOS 7 uses Python 2 #}
-    {% if base_package_type == 'rpm' and base_distro_tag.startswith('7') %}
-    && rm -rf /plugins/searchlight-ui* /plugins/neutron-vpnaas-dashboard* \
-    {% endif %}
+    {{ macros.remove_py3_only_plugins_for_py2(['searchlight-ui', 'neutron-vpnaas-dashboard']) }}
     && if [ "$(ls /plugins)" ]; then \
            {{ macros.install_pip(horizon_plugins_pip_packages) }}; \
        fi \

docker/macros.j2

@@ -97,3 +97,13 @@ RUN usermod --append --home {{ homedir }} --groups kolla {{ name }} \
 {{ enable_repos(repos) }}
 
 {% endmacro %}
+
+# NOTE(hrw): ending \ has to be at the end as we generate one line and there
+# can be multiple plugins to remove
+{% macro remove_py3_only_plugins_for_py2(plugins_to_remove) -%}
+    {% if distro_python_version == '2.7' -%}
+        {% for plugin in plugins_to_remove %}&& rm -rf /plugins/{{ plugin }}* {% endfor %} \
+    {%- else -%}
+    \
+    {%- endif %}
+{%- endmacro %}

docker/neutron/neutron-server-opendaylight/Dockerfile.j2

@@ -18,8 +18,6 @@ USER root
         ] %}
         {% else %}
         {% set neutron_server_opendaylight_packages = [
-            'python-networking-bgpvpn',
-            'python-networking-bgpvpn-heat',
             'python-networking-l2gw',
             'python-networking-odl'
         ] %}
@@ -58,6 +56,7 @@ ADD plugins-archive /
 
 RUN if [ "$(ls /plugins)" ]; then \
         sed -i 's|^ceilometer===.*$||g' requirements/upper-constraints.txt \
+        {{ macros.remove_py3_only_plugins_for_py2(['networking-bgpvpn']) }}
         && {{ macros.install_pip(neutron_server_opendaylight_plugins_pip_packages) }}; \
     fi