Add oslo_cache to default_subnet driver

This patch adds oslo_cache to the default subnet driver to
avoid unneed calls to neutron when creating pods (or when
getting subnet information)

Change-Id: I93b6bed424757e4138ba656251ae5da46b857da1

kuryr_kubernetes/config.py

@@ -148,6 +148,15 @@ octavia_defaults = [
                default='L3'),
 ]
 
+cache_defaults = [
+    cfg.BoolOpt('enabled',
+                help=_("Enable caching."),
+                default=True),
+    cfg.StrOpt('backend',
+               help=_("Select backend cache option."),
+               default="dogpile.cache.memory"),
+]
+
 
 CONF = cfg.CONF
 CONF.register_opts(kuryr_k8s_opts)
@@ -155,6 +164,7 @@ CONF.register_opts(daemon_opts, group='cni_daemon')
 CONF.register_opts(k8s_opts, group='kubernetes')
 CONF.register_opts(neutron_defaults, group='neutron_defaults')
 CONF.register_opts(octavia_defaults, group='octavia_defaults')
+CONF.register_opts(cache_defaults, group='cache_defaults')
 
 CONF.register_opts(lib_config.core_opts)
 CONF.register_opts(lib_config.binding_opts, 'binding')

kuryr_kubernetes/controller/drivers/default_subnet.py

@@ -13,6 +13,7 @@
 #    License for the specific language governing permissions and limitations
 #    under the License.
 
+from oslo_cache import core as cache
 from oslo_config import cfg
 
 from kuryr_kubernetes import clients
@@ -21,8 +22,25 @@ from kuryr_kubernetes.controller.drivers import base
 from kuryr_kubernetes import os_vif_util
 
 
+CONF = cfg.CONF
+
+subnet_caching_opts = [
+    cfg.BoolOpt('caching', default=True),
+    cfg.IntOpt('cache_time', default=3600),
+]
+
+CONF.register_opts(subnet_caching_opts, "subnet_caching")
+
+cache.configure(CONF)
+subnet_cache_region = cache.create_region()
+MEMOIZE = cache.get_memoization_decorator(
+    CONF, subnet_cache_region, "subnet_caching")
+
+cache.configure_cache_region(CONF, subnet_cache_region)
+
+
+@MEMOIZE
 def _get_subnet(subnet_id):
-    # TODO(ivc): add caching (e.g. oslo.cache with dict backend)
     neutron = clients.get_neutron_client()
 
     n_subnet = neutron.show_subnet(subnet_id).get('subnet')

kuryr_kubernetes/opts.py

@@ -15,6 +15,7 @@ from oslo_log import _options
 
 from kuryr.lib import opts as lib_opts
 from kuryr_kubernetes import config
+from kuryr_kubernetes.controller.drivers import default_subnet
 from kuryr_kubernetes.controller.drivers import nested_vif
 from kuryr_kubernetes.controller.drivers import vif_pool
 from kuryr_kubernetes.controller.managers import pool
@@ -26,6 +27,8 @@ _kuryr_k8s_opts = [
     ('pod_vif_nested', nested_vif.nested_vif_driver_opts),
     ('vif_pool', vif_pool.vif_pool_driver_opts),
     ('octavia_defaults', config.octavia_defaults),
+    ('cache_defaults', config.cache_defaults),
+    ('subnet_caching', default_subnet.subnet_caching_opts),
     ('pool_manager', pool.pool_manager_opts),
     ('cni_daemon', config.daemon_opts),
 ]

releasenotes/notes/oslo-caching-b11881cfb9dc306c.yaml

@@ -0,0 +1,22 @@
+---
+features:
+  - |
+    oslo.cache support has been added to the default_subnet driver. This
+    allows to skip unnecessary calls to neutron to retrieve network and
+    subnet information that can be cached and retrieved faster. It includes
+    the generic oslo caching options to enable/disable it as well as to
+    specify the backend to use (dogpile.cache.memory by default). In addition
+    it includes the specific options ofr the subnet driver, to enable/disable
+    it just for this driver, as well as to specify the cache time. To change
+    default configurations, the next can be modified at kuryr.conf
+
+    .. code-block:: ini
+
+      [cache]
+      enable=True
+      backend=dogpile.cache.memory
+
+      [subnet_caching]
+      caching=True
+      cache_time=3600
+

requirements.txt

@@ -8,6 +8,7 @@ kuryr-lib>=0.5.0 # Apache-2.0
 pbr!=2.1.0,>=2.0.0 # Apache-2.0
 requests>=2.14.2 # Apache-2.0
 eventlet!=0.18.3,!=0.20.1,<0.21.0,>=0.18.2 # MIT
+oslo.cache>=1.26.0 # Apache-2.0
 oslo.config>=4.6.0 # Apache-2.0
 oslo.log>=3.30.0 # Apache-2.0
 oslo.reports>=1.18.0 # Apache-2.0