Modify ldap init to support multiple ldap hosts

Author: ktyogurt

README.md

@@ -24,7 +24,7 @@ sudo dnf install python2-devel python3-devel openldap-devel
 | base_ou                    | yes      |                | Base OU to search for user and group entries                                                                                   |
 | group_dns                  | yes      |                | Which groups user must be member of to be granted access (group names are considered case-insensitive)                         |
 | group_dns_check            | no       | `and`          | What kind of check to perform when validating user group membership (`and` / `or`). When `and` behavior is used, user needs to be part of all the specified groups and when `or` behavior is used, user needs to be part of at least one or more of the specified groups. |
-| host                       | yes      |                | Hostname of the LDAP server                                                                                                    |
+| host                       | yes      |                | Hostname of the LDAP server. Multiple comma-separated entries are allowed.                                                                                                     |
 | port                       | yes      |                | Port of the LDAP server                                                                                                        |
 | use_ssl                    | no       | `false`        | Use LDAPS to connect                                                                                                           |
 | use_tls                    | no       | `false`        | Start TLS on LDAP to connect                                                                                                   |

st2auth_ldap/ldap_backend.py

@@ -279,7 +279,11 @@ def _init_connection(self):
 
         # Setup connection and options.
         protocol = 'ldaps' if self._use_ssl else 'ldap'
-        endpoint = '%s://%s:%d' % (protocol, self._host, int(self._port))
+        hosts = self._host.split(',')
+        for i in range(len(hosts)):
+            hosts[i] = '%s://%s:%d' % (protocol, hosts[i], int(self._port))
+
+        endpoint = ','.join(hosts)
         connection = ldap.initialize(endpoint, trace_level=trace_level)
         connection.set_option(ldap.OPT_DEBUG_LEVEL, 255)
         connection.set_option(ldap.OPT_PROTOCOL_VERSION, ldap.VERSION3)

tests/unit/test_backend.py

@@ -25,6 +25,7 @@
 
 
 LDAP_HOST = '127.0.0.1'
+LDAP_MULTIPLE_HOSTS = '127.0.0.1,localhost'
 LDAPS_PORT = 636
 LDAP_BIND_DN = 'cn=Administrator,cn=users,dc=stackstorm,dc=net'
 LDAP_BIND_PASSWORD = uuid.uuid4().hex
@@ -114,6 +115,25 @@ def test_authenticate(self):
         authenticated = backend.authenticate(LDAP_USER_UID, LDAP_USER_PASSWD)
         self.assertTrue(authenticated)
 
+    @mock.patch.object(
+        ldap.ldapobject.SimpleLDAPObject, 'simple_bind_s',
+        mock.MagicMock(return_value=None))
+    @mock.patch.object(
+        ldap.ldapobject.SimpleLDAPObject, 'search_s',
+        mock.MagicMock(side_effect=[LDAP_USER_SEARCH_RESULT, LDAP_GROUP_SEARCH_RESULT]))
+    def test_authenticate_with_multiple_ldap_hosts(self):
+        backend = ldap_backend.LDAPAuthenticationBackend(
+            LDAP_BIND_DN,
+            LDAP_BIND_PASSWORD,
+            LDAP_BASE_OU,
+            LDAP_GROUP_DNS,
+            LDAP_MULTIPLE_HOSTS,
+            id_attr=LDAP_ID_ATTR
+        )
+
+        authenticated = backend.authenticate(LDAP_USER_UID, LDAP_USER_PASSWD)
+        self.assertTrue(authenticated)
+
     @mock.patch.object(
         ldap.ldapobject.SimpleLDAPObject, 'simple_bind_s',
         mock.MagicMock(return_value=None))