create support user (#4141)

Allow for the creation of a support user.

A support user can access the server, join rooms, interact with other users, but does not appear in the user directory nor does it contribute to monthly active user limits.

synapse/storage/monthly_active_users.py

@@ -55,9 +55,12 @@ class MonthlyActiveUsersStore(SQLBaseStore):
                 txn,
                 tp["medium"], tp["address"]
             )
+
             if user_id:
-                self.upsert_monthly_active_user_txn(txn, user_id)
-                reserved_user_list.append(user_id)
+                is_support = self.is_support_user_txn(txn, user_id)
+                if not is_support:
+                    self.upsert_monthly_active_user_txn(txn, user_id)
+                    reserved_user_list.append(user_id)
             else:
                 logger.warning(
                     "mau limit reserved threepid %s not found in db" % tp
@@ -182,6 +185,18 @@ class MonthlyActiveUsersStore(SQLBaseStore):
         Args:
             user_id (str): user to add/update
         """
+        # Support user never to be included in MAU stats. Note I can't easily call this
+        # from upsert_monthly_active_user_txn because then I need a _txn form of
+        # is_support_user which is complicated because I want to cache the result.
+        # Therefore I call it here and ignore the case where
+        # upsert_monthly_active_user_txn is called directly from
+        # _initialise_reserved_users reasoning that it would be very strange to
+        #  include a support user in this context.
+
+        is_support = yield self.is_support_user(user_id)
+        if is_support:
+            return
+
         is_insert = yield self.runInteraction(
             "upsert_monthly_active_user", self.upsert_monthly_active_user_txn,
             user_id
@@ -200,6 +215,16 @@ class MonthlyActiveUsersStore(SQLBaseStore):
         in a database thread rather than the main thread, and we can't call
         txn.call_after because txn may not be a LoggingTransaction.
 
+        We consciously do not call is_support_txn from this method because it
+        is not possible to cache the response. is_support_txn will be false in
+        almost all cases, so it seems reasonable to call it only for
+        upsert_monthly_active_user and to call is_support_txn manually
+        for cases where upsert_monthly_active_user_txn is called directly,
+        like _initialise_reserved_users
+
+        In short, don't call this method with support users. (Support users
+        should not appear in the MAU stats).
+
         Args:
             txn (cursor):
             user_id (str): user to add/update
@@ -208,6 +233,7 @@ class MonthlyActiveUsersStore(SQLBaseStore):
             bool: True if a new entry was created, False if an
             existing one was updated.
         """
+
         # Am consciously deciding to lock the table on the basis that is ought
         # never be a big table and alternative approaches (batching multiple
         # upserts into a single txn) introduced a lot of extra complexity.

synapse/storage/registration.py

@@ -19,6 +19,7 @@ from six.moves import range
 
 from twisted.internet import defer
 
+from synapse.api.constants import UserTypes
 from synapse.api.errors import Codes, StoreError
 from synapse.storage import background_updates
 from synapse.storage._base import SQLBaseStore
@@ -168,7 +169,7 @@ class RegistrationStore(RegistrationWorkerStore,
 
     def register(self, user_id, token=None, password_hash=None,
                  was_guest=False, make_guest=False, appservice_id=None,
-                 create_profile_with_displayname=None, admin=False):
+                 create_profile_with_displayname=None, admin=False, user_type=None):
         """Attempts to register an account.
 
         Args:
@@ -184,6 +185,10 @@ class RegistrationStore(RegistrationWorkerStore,
             appservice_id (str): The ID of the appservice registering the user.
             create_profile_with_displayname (unicode): Optionally create a profile for
                 the user, setting their displayname to the given value
+            admin (boolean): is an admin user?
+            user_type (str|None): type of user. One of the values from
+                api.constants.UserTypes, or None for a normal user.
+
         Raises:
             StoreError if the user_id could not be registered.
         """
@@ -197,7 +202,8 @@ class RegistrationStore(RegistrationWorkerStore,
             make_guest,
             appservice_id,
             create_profile_with_displayname,
-            admin
+            admin,
+            user_type
         )
 
     def _register(
@@ -211,6 +217,7 @@ class RegistrationStore(RegistrationWorkerStore,
         appservice_id,
         create_profile_with_displayname,
         admin,
+        user_type,
     ):
         user_id_obj = UserID.from_string(user_id)
 
@@ -247,6 +254,7 @@ class RegistrationStore(RegistrationWorkerStore,
                         "is_guest": 1 if make_guest else 0,
                         "appservice_id": appservice_id,
                         "admin": 1 if admin else 0,
+                        "user_type": user_type,
                     }
                 )
             else:
@@ -260,6 +268,7 @@ class RegistrationStore(RegistrationWorkerStore,
                         "is_guest": 1 if make_guest else 0,
                         "appservice_id": appservice_id,
                         "admin": 1 if admin else 0,
+                        "user_type": user_type,
                     }
                 )
         except self.database_engine.module.IntegrityError:
@@ -456,6 +465,31 @@ class RegistrationStore(RegistrationWorkerStore,
 
         defer.returnValue(res if res else False)
 
+    @cachedInlineCallbacks()
+    def is_support_user(self, user_id):
+        """Determines if the user is of type UserTypes.SUPPORT
+
+        Args:
+            user_id (str): user id to test
+
+        Returns:
+            Deferred[bool]: True if user is of type UserTypes.SUPPORT
+        """
+        res = yield self.runInteraction(
+            "is_support_user", self.is_support_user_txn, user_id
+        )
+        defer.returnValue(res)
+
+    def is_support_user_txn(self, txn, user_id):
+        res = self._simple_select_one_onecol_txn(
+            txn=txn,
+            table="users",
+            keyvalues={"name": user_id},
+            retcol="user_type",
+            allow_none=True,
+        )
+        return True if res == UserTypes.SUPPORT else False
+
     @defer.inlineCallbacks
     def user_add_threepid(self, user_id, medium, address, validated_at, added_at):
         yield self._simple_upsert("user_threepids", {

synapse/storage/schema/delta/53/add_user_type_to_users.sql

@@ -0,0 +1,19 @@
+/* Copyright 2018 New Vector Ltd
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *    http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+/* The type of the user: NULL for a regular user, or one of the constants in 
+ * synapse.api.constants.UserTypes
+ */
+ALTER TABLE users ADD COLUMN user_type TEXT DEFAULT NULL;