add additional deprecation warnings for KVS options

We had a single deprecation warning for KVS functionality being
removed in Pike, located at keystone/common/kvs/core.py [1]

This change adds deprecation warnings to the various config
options and backends that used core.py.

[1] https://github.com/openstack/keystone/blob/master/keystone/common/kvs/core.py#L98-L101

Related-Bug: 1077282

bp deprecated-as-of-ocata

Change-Id: Ia63f0ac8543cf1e938baa712e21f08f582dc26ed

keystone/common/kvs/backends/inmemdb.py

@@ -17,11 +17,16 @@
 import copy
 
 from dogpile.cache import api
+from oslo_log import versionutils
 
 
 NO_VALUE = api.NO_VALUE
 
 
+@versionutils.deprecated(
+    versionutils.deprecated.OCATA,
+    what='keystone.common.kvs.backends.MemoryBackend',
+    remove_in=+1)
 class MemoryBackend(api.CacheBackend):
     """A backend that uses a plain dictionary.
 

keystone/common/kvs/backends/memcached.py

@@ -20,6 +20,7 @@ import time
 from dogpile.cache import api
 from dogpile.cache.backends import memcached
 from oslo_cache.backends import memcache_pool
+from oslo_log import versionutils
 from six.moves import range
 
 import keystone.conf
@@ -72,6 +73,10 @@ class MemcachedLock(object):
         client.delete(self.key)
 
 
+@versionutils.deprecated(
+    versionutils.deprecated.OCATA,
+    what='keystone.common.kvs.backends.MemcachedBackend',
+    remove_in=+1)
 class MemcachedBackend(object):
     """Pivot point to leverage the various dogpile.cache memcached backends.
 

keystone/conf/kvs.py

@@ -11,13 +11,23 @@
 # under the License.
 
 from oslo_config import cfg
+from oslo_log import versionutils
 
 from keystone.conf import utils
 
 
+_DEPRECATE_KVS_MSG = utils.fmt("""
+This option has been deprecated in the O release and will be removed in the P
+release. Use SQL backends instead.
+""")
+
+
 backends = cfg.ListOpt(
     'backends',
     default=[],
+    deprecated_for_removal=True,
+    deprecated_reason=_DEPRECATE_KVS_MSG,
+    deprecated_since=versionutils.deprecated.OCATA,
     help=utils.fmt("""
 Extra `dogpile.cache` backend modules to register with the `dogpile.cache`
 library. It is not necessary to set this value unless you are providing a
@@ -27,6 +37,9 @@ custom KVS backend beyond what `dogpile.cache` already supports.
 config_prefix = cfg.StrOpt(
     'config_prefix',
     default='keystone.kvs',
+    deprecated_for_removal=True,
+    deprecated_reason=_DEPRECATE_KVS_MSG,
+    deprecated_since=versionutils.deprecated.OCATA,
     help=utils.fmt("""
 Prefix for building the configuration dictionary for the KVS region. This
 should not need to be changed unless there is another `dogpile.cache` region
@@ -36,6 +49,9 @@ with the same configuration name.
 enable_key_mangler = cfg.BoolOpt(
     'enable_key_mangler',
     default=True,
+    deprecated_for_removal=True,
+    deprecated_reason=_DEPRECATE_KVS_MSG,
+    deprecated_since=versionutils.deprecated.OCATA,
     help=utils.fmt("""
 Set to false to disable using a key-mangling function, which ensures
 fixed-length keys are used in the KVS store. This is configurable for debugging
@@ -47,6 +63,9 @@ default_lock_timeout = cfg.IntOpt(
     'default_lock_timeout',
     default=5,
     min=0,
+    deprecated_for_removal=True,
+    deprecated_reason=_DEPRECATE_KVS_MSG,
+    deprecated_since=versionutils.deprecated.OCATA,
     help=utils.fmt("""
 Number of seconds after acquiring a distributed lock that the backend should
 consider the lock to be expired. This option should be tuned relative to the

keystone/conf/memcache.py

@@ -11,13 +11,23 @@
 # under the License.
 
 from oslo_config import cfg
+from oslo_log import versionutils
 
 from keystone.conf import utils
 
 
+_DEPRECATE_KVS_MSG = utils.fmt("""
+This option has been deprecated in the O release and will be removed in the P
+release. Use oslo.cache instead.
+""")
+
+
 servers = cfg.ListOpt(
     'servers',
     default=['localhost:11211'],
+    deprecated_for_removal=True,
+    deprecated_reason=_DEPRECATE_KVS_MSG,
+    deprecated_since=versionutils.deprecated.OCATA,
     help=utils.fmt("""
 Comma-separated list of memcached servers in the format of
 `host:port,host:port` that keystone should use for the `memcache` token

keystone/token/persistence/backends/kvs.py

@@ -18,6 +18,7 @@ import copy
 import threading
 
 from oslo_log import log
+from oslo_log import versionutils
 from oslo_utils import timeutils
 import six
 
@@ -36,6 +37,10 @@ LOG = log.getLogger(__name__)
 STORE_CONF_LOCK = threading.Lock()
 
 
+@versionutils.deprecated(
+    versionutils.deprecated.OCATA,
+    what='keystone.token.persistence.backends.kvs.Token',
+    remove_in=+1)
 class Token(token.persistence.TokenDriverBase):
     """KeyValueStore backend for tokens.
 

releasenotes/notes/deprecated-as-of-ocata-a5b2f1e3e39f818e.yaml

@@ -7,3 +7,13 @@ deprecations:
     It's recommended to replace the ``endpoint_filter.sql`` catalog backend
     with the ``sql`` backend. The ``endpoint_filter.sql`` backend will be
     removed in the `Pike` release.
+  - >
+    [`blueprint deprecated-as-of-ocata <https://blueprints.launchpad.net/keystone/+spec/deprecated-as-of-ocata>`_]
+    Various KVS backends and config options have been deprecated and will be
+    removed in the `Pike` release. This includes:
+
+      * ``keystone.common.kvs.backends.inmemdb.MemoryBackend``
+      * ``keystone.common.kvs.backends.memcached.MemcachedBackend``
+      * ``keystone.token.persistence.backends.kvs.Token``
+      * all config options under ``[kvs]`` in `keystone.conf`
+      * the config option ``[memcached] servers`` in `keystone.conf`