Add ping method to auth engines to determine if they are reachable

data/users/externalldap.py

@@ -193,6 +193,18 @@ class LDAPUsers(FederatedUsers):
     email = response.get(self._email_attr, [None])[0]
     return (UserInformation(username=username, email=email, id=username), None)
 
+  def ping(self):
+    try:
+      with self._ldap.get_connection():
+        pass
+    except ldap.INVALID_CREDENTIALS:
+      return (False, 'LDAP Admin dn or password is invalid')
+    except ldap.LDAPError as lde:
+      logger.exception('Exception when trying to health check LDAP')
+      return (False, lde.message)
+
+    return (True, None)
+
   def get_user(self, username_or_email):
     """ Looks up a username or email in LDAP. """
     logger.debug('Looking up LDAP username or email %s', username_or_email)