Creates a router if one doesn't exist

If it doesn't find a router by the name specified in router_name
in murano.conf, create a router with that name. Uses
external_network_id or external_network_name as the
external_gateway_info ID. Requires:
https://review.openstack.org/#/c/119800

Change-Id: If8b966a7d43eb2af485113de2a0708e554605725

etc/murano/murano.conf.sample

@@ -760,10 +760,18 @@
 # (string value)
 #default_dns=8.8.8.8
 
+# ID or name of the external network for routers to connect to
+# (string value)
+#external_network=ext-net
+
 # Name of the router that going to be used in order to join
 # all networks created by Murano (string value)
 #router_name=murano-default-router
 
+# This option will create a router when one with "router_name"
+# does not exist (boolean value)
+#create_router=true
+
 
 [neutron]
 

murano/common/config.py

@@ -160,9 +160,17 @@ networking_opts = [
                help='Default DNS nameserver to be assigned to '
                'created Networks'),
 
+    cfg.StrOpt('external_network', default='ext-net',
+               help='ID or name of the external network for routers '
+                    'to connect to'),
+
     cfg.StrOpt('router_name', default='murano-default-router',
                help='Name of the router that going to be used in order to '
-                    'join all networks created by Murano')
+                    'join all networks created by Murano'),
+
+    cfg.BoolOpt('create_router', default=True,
+                help='This option will create a router when one with '
+                     '"router_name" does not exist'),
 ]
 stats_opt = [
     cfg.IntOpt('period', default=5,

murano/engine/system/net_explorer.py

@@ -24,6 +24,11 @@ import murano.common.config as config
 import murano.dsl.helpers as helpers
 import murano.dsl.murano_class as murano_class
 import murano.dsl.murano_object as murano_object
+from murano.openstack.common import log as logging
+import muranoclient.openstack.common.uuidutils as uuidutils
+
+
+LOG = logging.getLogger(__name__)
 
 
 @murano_class.classname('io.murano.system.NetworkExplorer')
@@ -69,7 +74,37 @@ class NetworkExplorer(murano_object.MuranoObject):
             list_routers(tenant_id=self._tenant_id, name=router_name).\
             get('routers')
         if len(routers) == 0:
-            raise KeyError('Router %s was not found' % router_name)
+            LOG.debug('Router {0} not found'.format(router_name))
+            if self._settings.create_router:
+                LOG.debug('Attempting to create Router {0}'.
+                          format(router_name))
+                external_network = self._settings.external_network
+                kwargs = {'id': external_network} \
+                    if uuidutils.is_uuid_like(external_network) \
+                    else {'name': external_network}
+                networks = self._neutron.list_networks(**kwargs). \
+                    get('networks')
+                ext_nets = filter(lambda n: n['router:external'], networks)
+                if len(ext_nets) == 0:
+                    raise KeyError('Router %s could not be created, '
+                                   'no external network found' % router_name)
+                nid = ext_nets[0]['id']
+
+                body_data = {
+                    'router': {
+                        'name': router_name,
+                        'external_gateway_info': {
+                            'network_id': nid
+                        },
+                        'admin_state_up': True,
+                    }
+                }
+                router = self._neutron.create_router(body=body_data).\
+                    get('router')
+                LOG.debug('Created router: {0}'.format(router))
+                return router['id']
+            else:
+                raise KeyError('Router %s was not found' % router_name)
         else:
             if routers[0]['external_gateway_info'] is None:
                 raise Exception('Please set external gateway '