Use BMemcacheClientPool if tls_enabled=true

This commit adds the tls_enabled parameter to the conf_dict, so to
eventually use it in the backend driver.
In addition, it switches from _memcache_pool.MemcacheClientPool to
_bmemcache_pool.BMemcacheClientPool when tls_enabled=true
(python-memcached does not support tls anyway).

Jira: https://issues.redhat.com/browse/OSPRH-16651
Change-Id: I1ceac2aa96c23227caf202b16f9a520083745537
(cherry picked from commit c3023dbc2e)
(cherry picked from commit 5d7c471509)

oslo_cache/backends/memcache_pool.py

@@ -56,7 +56,8 @@ class PooledMemcachedBackend(memcached_backend.MemcachedBackend):
     # Composed from GenericMemcachedBackend's and MemcacheArgs's __init__
     def __init__(self, arguments):
         super(PooledMemcachedBackend, self).__init__(arguments)
-        if arguments.get('sasl_enabled', False):
+        if (arguments.get('tls_enabled', False) or
+                arguments.get('sasl_enabled', False)):
             self.client_pool = _bmemcache_pool.BMemcacheClientPool(
                 self.url,
                 arguments,

oslo_cache/core.py

@@ -189,6 +189,9 @@ def _build_cache_config(conf):
 
         conf_dict['%s.arguments.tls_context' % prefix] = tls_context
 
+        # pass the value of tls_enabled to the backend
+        conf_dict['%s.arguments.tls_enabled' % prefix] = conf.cache.tls_enabled
+
     # NOTE(hberaud): Pymemcache support socket keepalive, If it is enable in
     # our config then configure it to enable this feature.
     # The socket keepalive feature means that pymemcache will be able to check

releasenotes/notes/use-bmemcache-for-memcache-pool-if-tls-enabled-733d98c265a3a9a1.yaml

@@ -0,0 +1,4 @@
+---
+fixes:
+  - |
+    If tls_enabled=true memcache_pool has been switched to use bmemcached.