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.

changelog.d/4141.feature

@@ -0,0 +1 @@
+Special-case a support user for use in verifying behaviour of a given server. The support user does not appear in user directory or monthly active user counts.

docs/admin_api/register_api.rst

@@ -39,13 +39,13 @@ As an example::
     }
 
 The MAC is the hex digest output of the HMAC-SHA1 algorithm, with the key being
-the shared secret and the content being the nonce, user, password, and either
-the string "admin" or "notadmin", each separated by NULs. For an example of
-generation in Python::
+the shared secret and the content being the nonce, user, password, either the
+string "admin" or "notadmin", and optionally the user_type
+each separated by NULs. For an example of generation in Python::
 
   import hmac, hashlib
 
-  def generate_mac(nonce, user, password, admin=False):
+  def generate_mac(nonce, user, password, admin=False, user_type=None):
 
       mac = hmac.new(
         key=shared_secret,
@@ -59,5 +59,8 @@ generation in Python::
       mac.update(password.encode('utf8'))
       mac.update(b"\x00")
       mac.update(b"admin" if admin else b"notadmin")
+      if user_type:
+          mac.update(b"\x00")
+          mac.update(user_type.encode('utf8'))
 
       return mac.hexdigest()

synapse/_scripts/register_new_matrix_user.py

@@ -35,6 +35,7 @@ def request_registration(
     server_location,
     shared_secret,
     admin=False,
+    user_type=None,
     requests=_requests,
     _print=print,
     exit=sys.exit,
@@ -65,6 +66,9 @@ def request_registration(
     mac.update(password.encode('utf8'))
     mac.update(b"\x00")
     mac.update(b"admin" if admin else b"notadmin")
+    if user_type:
+        mac.update(b"\x00")
+        mac.update(user_type.encode('utf8'))
 
     mac = mac.hexdigest()
 
@@ -74,6 +78,7 @@ def request_registration(
         "password": password,
         "mac": mac,
         "admin": admin,
+        "user_type": user_type,
     }
 
     _print("Sending registration request...")
@@ -91,7 +96,7 @@ def request_registration(
     _print("Success!")
 
 
-def register_new_user(user, password, server_location, shared_secret, admin):
+def register_new_user(user, password, server_location, shared_secret, admin, user_type):
     if not user:
         try:
             default_user = getpass.getuser()
@@ -129,7 +134,8 @@ def register_new_user(user, password, server_location, shared_secret, admin):
         else:
             admin = False
 
-    request_registration(user, password, server_location, shared_secret, bool(admin))
+    request_registration(user, password, server_location, shared_secret,
+                         bool(admin), user_type)
 
 
 def main():
@@ -154,6 +160,12 @@ def main():
         default=None,
         help="New password for user. Will prompt if omitted.",
     )
+    parser.add_argument(
+        "-t",
+        "--user_type",
+        default=None,
+        help="User type as specified in synapse.api.constants.UserTypes",
+    )
     admin_group = parser.add_mutually_exclusive_group()
     admin_group.add_argument(
         "-a",
@@ -208,7 +220,8 @@ def main():
     if args.admin or args.no_admin:
         admin = args.admin
 
-    register_new_user(args.user, args.password, args.server_url, secret, admin)
+    register_new_user(args.user, args.password, args.server_url, secret,
+                      admin, args.user_type)
 
 
 if __name__ == "__main__":

synapse/api/auth.py

@@ -802,9 +802,10 @@ def check_auth_blocking(self, user_id=None, threepid=None):
             threepid should never be set at the same time.
         """
 
-        # Never fail an auth check for the server notices users
+        # Never fail an auth check for the server notices users or support user
         # This can be a problem where event creation is prohibited due to blocking
-        if user_id == self.hs.config.server_notices_mxid:
+        is_support = yield self.store.is_support_user(user_id)
+        if user_id == self.hs.config.server_notices_mxid or is_support:
             return
 
         if self.hs.config.hs_disabled:

synapse/api/constants.py

@@ -119,3 +119,11 @@ class RoomVersions(object):
 
 ServerNoticeMsgType = "m.server_notice"
 ServerNoticeLimitReached = "m.server_notice.usage_limit_reached"
+
+
+class UserTypes(object):
+    """Allows for user type specific behaviour. With the benefit of hindsight
+    'admin' and 'guest' users should also be UserTypes. Normal users are type None
+    """
+    SUPPORT = "support"
+    ALL_USER_TYPES = (SUPPORT)

synapse/handlers/register.py

@@ -126,6 +126,7 @@ def register(
         make_guest=False,
         admin=False,
         threepid=None,
+        user_type=None,
         default_display_name=None,
     ):
         """Registers a new client on the server.
@@ -141,6 +142,8 @@ def register(
               since it offers no means of associating a device_id with the
               access_token. Instead you should call auth_handler.issue_access_token
               after registration.
+            user_type (str|None): type of user. One of the values from
+              api.constants.UserTypes, or None for a normal user.
             default_display_name (unicode|None): if set, the new user's displayname
               will be set to this. Defaults to 'localpart'.
         Returns:
@@ -190,6 +193,7 @@ def register(
                 make_guest=make_guest,
                 create_profile_with_displayname=default_display_name,
                 admin=admin,
+                user_type=user_type,
             )
 
             if self.hs.config.user_directory_search_all_users:
@@ -242,9 +246,16 @@ def _auto_join_rooms(self, user_id):
         # auto-join the user to any rooms we're supposed to dump them into
         fake_requester = create_requester(user_id)
 
-        # try to create the room if we're the first user on the server
+        # try to create the room if we're the first real user on the server. Note
+        # that an auto-generated support user is not a real user and will never be
+        # the user to create the room
         should_auto_create_rooms = False
-        if self.hs.config.autocreate_auto_join_rooms:
+        is_support = yield self.store.is_support_user(user_id)
+        # There is an edge case where the first user is the support user, then
+        # the room is never created, though this seems unlikely and
+        # recoverable from given the support user being involved in the first
+        # place.
+        if self.hs.config.autocreate_auto_join_rooms and not is_support:
             count = yield self.store.count_all_users()
             should_auto_create_rooms = count == 1
         for r in self.hs.config.auto_join_rooms:

synapse/handlers/room.py

@@ -433,7 +433,7 @@ def create_room(self, requester, config, ratelimit=True,
         """
         user_id = requester.user.to_string()
 
-        self.auth.check_auth_blocking(user_id)
+        yield self.auth.check_auth_blocking(user_id)
 
         if not self.spam_checker.user_may_create_room(user_id):
             raise SynapseError(403, "You are not permitted to create rooms")

synapse/handlers/user_directory.py

@@ -125,9 +125,12 @@ def handle_local_profile_change(self, user_id, profile):
         """
         # FIXME(#3714): We should probably do this in the same worker as all
         # the other changes.
-        yield self.store.update_profile_in_user_dir(
-            user_id, profile.display_name, profile.avatar_url, None,
-        )
+        is_support = yield self.store.is_support_user(user_id)
+        # Support users are for diagnostics and should not appear in the user directory.
+        if not is_support:
+            yield self.store.update_profile_in_user_dir(
+                user_id, profile.display_name, profile.avatar_url, None,
+            )
 
     @defer.inlineCallbacks
     def handle_user_deactivated(self, user_id):
@@ -329,14 +332,7 @@ def _handle_deltas(self, deltas):
                     public_value=Membership.JOIN,
                 )
 
-                if change is None:
-                    # Handle any profile changes
-                    yield self._handle_profile_change(
-                        state_key, room_id, prev_event_id, event_id,
-                    )
-                    continue
-
-                if not change:
+                if change is False:
                     # Need to check if the server left the room entirely, if so
                     # we might need to remove all the users in that room
                     is_in_room = yield self.store.is_host_joined(
@@ -354,16 +350,25 @@ def _handle_deltas(self, deltas):
                     else:
                         logger.debug("Server is still in room: %r", room_id)
 
-                if change:  # The user joined
-                    event = yield self.store.get_event(event_id, allow_none=True)
-                    profile = ProfileInfo(
-                        avatar_url=event.content.get("avatar_url"),
-                        display_name=event.content.get("displayname"),
-                    )
+                is_support = yield self.store.is_support_user(state_key)
+                if not is_support:
+                    if change is None:
+                        # Handle any profile changes
+                        yield self._handle_profile_change(
+                            state_key, room_id, prev_event_id, event_id,
+                        )
+                        continue
+
+                    if change:  # The user joined
+                        event = yield self.store.get_event(event_id, allow_none=True)
+                        profile = ProfileInfo(
+                            avatar_url=event.content.get("avatar_url"),
+                            display_name=event.content.get("displayname"),
+                        )
 
-                    yield self._handle_new_user(room_id, state_key, profile)
-                else:  # The user left
-                    yield self._handle_remove_user(room_id, state_key)
+                        yield self._handle_new_user(room_id, state_key, profile)
+                    else:  # The user left
+                        yield self._handle_remove_user(room_id, state_key)
             else:
                 logger.debug("Ignoring irrelevant type: %r", typ)
 

synapse/rest/client/v1/admin.py

@@ -23,7 +23,7 @@
 
 from twisted.internet import defer
 
-from synapse.api.constants import Membership
+from synapse.api.constants import Membership, UserTypes
 from synapse.api.errors import AuthError, Codes, NotFoundError, SynapseError
 from synapse.http.servlet import (
     assert_params_in_dict,
@@ -158,6 +158,11 @@ def on_POST(self, request):
                 raise SynapseError(400, "Invalid password")
 
         admin = body.get("admin", None)
+        user_type = body.get("user_type", None)
+
+        if user_type is not None and user_type not in UserTypes.ALL_USER_TYPES:
+            raise SynapseError(400, "Invalid user type")
+
         got_mac = body["mac"]
 
         want_mac = hmac.new(
@@ -171,6 +176,9 @@ def on_POST(self, request):
         want_mac.update(password)
         want_mac.update(b"\x00")
         want_mac.update(b"admin" if admin else b"notadmin")
+        if user_type:
+            want_mac.update(b"\x00")
+            want_mac.update(user_type.encode('utf8'))
         want_mac = want_mac.hexdigest()
 
         if not hmac.compare_digest(
@@ -189,6 +197,7 @@ def on_POST(self, request):
             password=body["password"],
             admin=bool(admin),
             generate_token=False,
+            user_type=user_type,
         )
 
         result = yield register._create_registration_details(user_id, body)

synapse/storage/monthly_active_users.py

@@ -55,9 +55,12 @@ def _initialise_reserved_users(self, txn, threepids):
                 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 @@ def upsert_monthly_active_user(self, user_id):
         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 @@ def upsert_monthly_active_user_txn(self, txn, user_id):
         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 @@ def upsert_monthly_active_user_txn(self, txn, user_id):
             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.