Core & Internals: allow external cache for auth tokens. Closes rucio#…

…5297

Allow setting auth tokens in memcached, but make it configurable and
default this behavior to disabled.

lib/rucio/core/authentication.py

@@ -37,10 +37,12 @@
 from base64 import b64decode
 
 import paramiko
-from dogpile.cache import make_region
 from dogpile.cache.api import NO_VALUE
+from dogpile.cache import make_region
 from sqlalchemy import and_, or_, select, delete
 
+from rucio.common.cache import make_region_memcached
+from rucio.common.config import config_get_bool
 from rucio.common.exception import CannotAuthenticate, RucioException
 from rucio.common.utils import chunks, generate_uuid
 from rucio.core.account import account_exists
@@ -59,12 +61,10 @@ def generate_key(token, session=None):
     return generate_key
 
 
-TOKENREGION = make_region(
-    function_key_generator=token_key_generator
-).configure(
-    'dogpile.cache.memory',
-    expiration_time=3600
-)
+if config_get_bool('cache', 'use_external_cache_for_auth_tokens', default=False):
+    TOKENREGION = make_region_memcached(expiration_time=3600, function_key_generator=token_key_generator)
+else:
+    TOKENREGION = make_region(function_key_generator=token_key_generator).configure('dogpile.cache.memory', expiration_time=3600)
 
 
 @transactional_session