Allow to configure the default loadbalancer provider

By using a dummy loadbalancer driver it is possible to declare a default
provider for opencontrail.

In neutron.conf set:
    service_provider=LOADBALANCER:haproxy:neutron_plugin_contrail.plugins.opencontrail.loadbalancer.driver.OpencontrailLoadbalancerDummyDriver:default
Then the default provider will be haproxy.

If no service_provider is set the default provider will be opencontrail
(the default provider created by SVC monitor)

Closes-Bug: #1521625
Change-Id: I112700e04ba485f5f48855d553dc345bf4c5fe74

neutron_plugin_contrail/plugins/opencontrail/loadbalancer/driver.py

@@ -0,0 +1,61 @@
+try:
+    from neutron.services.loadbalancer.drivers import abstract_driver
+except ImportError:
+    from neutron_lbaas.services.loadbalancer.drivers import abstract_driver
+
+"""Dummy LBAAS driver for OpenContrail.
+
+This allows to specify a default provider in the neutron.conf.
+
+LBAAS drivers are now in contrail svc_monitor.
+"""
+
+
+class OpencontrailLoadbalancerDummyDriver(
+        abstract_driver.LoadBalancerAbstractDriver):
+
+    def __init__(self, plugin):
+        pass
+
+    def create_vip(self, context, vip):
+        pass
+
+    def update_vip(self, context, old_vip, vip):
+        pass
+
+    def delete_vip(self, context, vip):
+        pass
+
+    def create_pool(self, context, pool):
+        pass
+
+    def update_pool(self, context, old_pool, pool):
+        pass
+
+    def delete_pool(self, context, pool):
+        pass
+
+    def stats(self, context, pool_id):
+        pass
+
+    def create_member(self, context, member):
+        pass
+
+    def update_member(self, context, old_member, member):
+        pass
+
+    def delete_member(self, context, member):
+        pass
+
+    def update_pool_health_monitor(self, context,
+                                   health_monitor,
+                                   pool_id):
+        pass
+
+    def create_pool_health_monitor(self, context,
+                                   health_monitor,
+                                   pool_id):
+        pass
+
+    def delete_pool_health_monitor(self, context, health_monitor, pool_id):
+        pass

neutron_plugin_contrail/plugins/opencontrail/loadbalancer/loadbalancer_pool.py

@@ -143,13 +143,8 @@ def create(self, context, pool):
         Create a loadbalancer_pool object.
         """
         p = pool['pool']
-        try:
-            sas_fq_name = ["default-global-system-config"]
-            sas_fq_name.append(p['provider'])
-            sas_obj = self._api.service_appliance_set_read(fq_name=sas_fq_name)
-        except NoIdError:
-            raise pconf.ServiceProviderNotFound(
-                provider=p['provider'], service_type=constants.LOADBALANCER)
+
+        sas_obj = self.check_provider_exists(p['provider'])
 
         tenant_id = self._get_tenant_id_for_create(context, p)
         project = self._project_read(project_id=tenant_id)
@@ -176,7 +171,7 @@ def create(self, context, pool):
 
         pool.set_service_appliance_set(sas_obj)
 
-         # Custom attributes
+        # Custom attributes
         if p['custom_attributes'] != attr.ATTR_NOT_SPECIFIED:
             custom_attributes = KeyValuePairs()
             self.create_update_custom_attributes(p['custom_attributes'], custom_attributes)

neutron_plugin_contrail/plugins/opencontrail/loadbalancer/plugin.py

@@ -7,6 +7,9 @@
     from neutron.extensions import loadbalancer
 except ImportError:
     from neutron_lbaas.extensions import loadbalancer
+from neutron.db import servicetype_db as sdb
+from neutron.plugins.common import constants
+from neutron.services import provider_configuration as pconf
 
 
 class LoadBalancerPlugin(LoadBalancerPluginDb):
@@ -17,13 +20,26 @@ class LoadBalancerPlugin(LoadBalancerPluginDb):
 
     def __init__(self):
         super(LoadBalancerPlugin, self).__init__()
+        self._get_default_provider()
+
+    def _get_default_provider(self):
+        service_type_manager = sdb.ServiceTypeManager.get_instance()
+        try:
+            provider = (service_type_manager.
+                        get_default_service_provider(None,
+                                                     constants.LOADBALANCER))
+        except pconf.DefaultServiceProviderNotFound:
+            self.default_provider = "opencontrail"
+        else:
+            self._pool_manager.check_provider_exists(provider['name'])
+            self.default_provider = provider['name']
 
     def get_plugin_description(self):
         return "OpenContrail LoadBalancer Service Plugin"
 
     def _pool_update_provider(self, context, pool):
         if 'provider' not in pool or not pool['provider'] or pool['provider'].__class__ is object:
-            pool['provider'] = "opencontrail"
+            pool['provider'] = self.default_provider
 
     def create_pool(self, context, pool):
         self._pool_update_provider(context, pool['pool'])

neutron_plugin_contrail/plugins/opencontrail/loadbalancer/resource_manager.py

@@ -2,18 +2,20 @@
 # Copyright (c) 2014 Juniper Networks, Inc. All rights reserved.
 #
 
+import six
+import uuid
 from abc import ABCMeta, abstractmethod, abstractproperty
 from eventlet import greenthread
+
 from neutron.common import exceptions as n_exc
 try:
     from neutron.extensions import loadbalancer
 except ImportError:
     from neutron_lbaas.extensions import loadbalancer
-
 from neutron.plugins.common import constants
+from neutron.services import provider_configuration as pconf
+
 from vnc_api.vnc_api import NoIdError, RefsExistError
-import six
-import uuid
 
 
 class LoadbalancerMethodInvalid(n_exc.BadRequest):
@@ -111,6 +113,19 @@ def update_object(self, obj, id, resource):
         """
         return False
 
+    def check_provider_exists(self, provider_name):
+        """
+        Check if service-appliance-set for provider exists in the API
+        """
+        try:
+            sas_fq_name = ["default-global-system-config"]
+            sas_fq_name.append(provider_name)
+            sas_obj = self._api.service_appliance_set_read(fq_name=sas_fq_name)
+        except NoIdError:
+            raise pconf.ServiceProviderNotFound(
+                provider=provider_name, service_type=constants.LOADBALANCER)
+        return sas_obj
+
     def _get_tenant_id_for_create(self, context, resource):
         if context.is_admin and 'tenant_id' in resource:
             tenant_id = resource['tenant_id']