Revert to REUSABLE client strategy as default for ldap3 connection

Revert to using ldap3.REUSABLE as the default client strategy and fix
configuration to allow setting the client strategy.

Author: skoranda

example/plugins/microservices/ldap_attribute_store.yaml.example

@@ -9,11 +9,14 @@ config:
       read_only : true
       version : 3
 
-      # See ldap3 client_strategies.
+      # See ldap3 client_strategies. The default
+      # is REUSABLE.
       client_strategy : RESTARTABLE
       auto_bind : true
-      pool_size : 10
-      pool_keepalive : 10
+      # Specify pool size and keepalive when using
+      # REUSABLE client strategy. Defaults are 10 and 10.
+      #pool_size : 10
+      #pool_keepalive : 10
 
       # Attributes to return from LDAP query.
       query_return_attributes:

src/satosa/micro_services/ldap_attribute_store.py

@@ -54,7 +54,7 @@ class LdapAttributeStore(ResponseMicroService):
         'read_only':                     True,
         'version':                       3,
         'auto_bind':                     False,
-        'client_strategy':               ldap3.RESTARTABLE,
+        'client_strategy':               'REUSABLE',
         'pool_size':                     10,
         'pool_keepalive':                10,
         }
@@ -287,18 +287,26 @@ def _ldap_connection_factory(self, config):
         msg = "Using bind DN {}".format(bind_dn)
         satosa_logging(logger, logging.DEBUG, msg, None)
 
-        pool_size = config['pool_size']
-        pool_keepalive = config['pool_keepalive']
-        msg = "Using pool size {}".format(pool_size)
-        satosa_logging(logger, logging.DEBUG, msg, None)
-        msg = "Using pool keep alive {}".format(pool_keepalive)
-        satosa_logging(logger, logging.DEBUG, msg, None)
-
         auto_bind = config['auto_bind']
-        client_strategy = config['client_strategy']
         read_only = config['read_only']
         version = config['version']
 
+        client_strategy_string = config['client_strategy']
+        client_strategy_map = {'SYNC':        ldap3.SYNC,
+                               'ASYNC':       ldap3.ASYNC,
+                               'LDIF':        ldap3.LDIF,
+                               'RESTARTABLE': ldap3.RESTARTABLE,
+                               'REUSABLE':    ldap3.REUSABLE}
+        client_strategy = client_strategy_map[client_strategy_string]
+
+        pool_size = config['pool_size']
+        pool_keepalive = config['pool_keepalive']
+        if client_strategy == ldap3.REUSABLE:
+            msg = "Using pool size {}".format(pool_size)
+            satosa_logging(logger, logging.DEBUG, msg, None)
+            msg = "Using pool keep alive {}".format(pool_keepalive)
+            satosa_logging(logger, logging.DEBUG, msg, None)
+
         try:
             connection = ldap3.Connection(
                             server,