Merge pull request #3633 from matrix-org/neilj/mau_tracker

API for monthly_active_users table

18 files changed, 414 insertions, 163 deletions

diff --git a/changelog.d/3633.feature b/changelog.d/3633.feature
new file mode 100644
index 0000000000..8007a04840
--- /dev/null
+++ b/changelog.d/3633.feature
@@ -0,0 +1 @@
+Add ability to limit number of monthly active users on the server
diff --git a/synapse/api/auth.py b/synapse/api/auth.py
index 5bbbe8e2e7..91b23ff1d7 100644
--- a/synapse/api/auth.py
+++ b/synapse/api/auth.py
@@ -213,7 +213,7 @@ class Auth(object):
                 default=[b""]
             )[0]
             if user and access_token and ip_addr:
-                self.store.insert_client_ip(
+                yield self.store.insert_client_ip(
                     user_id=user.to_string(),
                     access_token=access_token,
                     ip=ip_addr,
@@ -773,3 +773,15 @@ class Auth(object):
             raise AuthError(
                 403, "Guest access not allowed", errcode=Codes.GUEST_ACCESS_FORBIDDEN
             )
+
+    @defer.inlineCallbacks
+    def check_auth_blocking(self):
+        """Checks if the user should be rejected for some external reason,
+        such as monthly active user limiting or global disable flag
+        """
+        if self.hs.config.limit_usage_by_mau is True:
+            current_mau = yield self.store.get_monthly_active_count()
+            if current_mau >= self.hs.config.max_mau_value:
+                raise AuthError(
+                    403, "MAU Limit Exceeded", errcode=Codes.MAU_LIMIT_EXCEEDED
+                )
diff --git a/synapse/app/homeserver.py b/synapse/app/homeserver.py
index fba51c26e8..3a67db8b30 100755
--- a/synapse/app/homeserver.py
+++ b/synapse/app/homeserver.py
@@ -518,12 +518,15 @@ def run(hs):
     # If you increase the loop period, the accuracy of user_daily_visits
     # table will decrease
     clock.looping_call(generate_user_daily_visit_stats, 5 * 60 * 1000)
+    clock.looping_call(
+        hs.get_datastore().reap_monthly_active_users, 1000 * 60 * 60
+    )
 
     @defer.inlineCallbacks
     def generate_monthly_active_users():
         count = 0
         if hs.config.limit_usage_by_mau:
-            count = yield hs.get_datastore().count_monthly_users()
+            count = yield hs.get_datastore().get_monthly_active_count()
         current_mau_gauge.set(float(count))
         max_mau_value_gauge.set(float(hs.config.max_mau_value))
 
diff --git a/synapse/config/server.py b/synapse/config/server.py
index 6a471a0a5e..8fd2319759 100644
--- a/synapse/config/server.py
+++ b/synapse/config/server.py
@@ -69,12 +69,12 @@ class ServerConfig(Config):
 
         # Options to control access by tracking MAU
         self.limit_usage_by_mau = config.get("limit_usage_by_mau", False)
+        self.max_mau_value = 0
         if self.limit_usage_by_mau:
             self.max_mau_value = config.get(
                 "max_mau_value", 0,
             )
-        else:
-            self.max_mau_value = 0
+
         # FIXME: federation_domain_whitelist needs sytests
         self.federation_domain_whitelist = None
         federation_domain_whitelist = config.get(
diff --git a/synapse/handlers/auth.py b/synapse/handlers/auth.py
index 184eef09d0..7ea8ce9f94 100644
--- a/synapse/handlers/auth.py
+++ b/synapse/handlers/auth.py
@@ -520,7 +520,7 @@ class AuthHandler(BaseHandler):
         """
         logger.info("Logging in user %s on device %s", user_id, device_id)
         access_token = yield self.issue_access_token(user_id, device_id)
-        yield self._check_mau_limits()
+        yield self.auth.check_auth_blocking()
 
         # the device *should* have been registered before we got here; however,
         # it's possible we raced against a DELETE operation. The thing we
@@ -734,7 +734,7 @@ class AuthHandler(BaseHandler):
 
     @defer.inlineCallbacks
     def validate_short_term_login_token_and_get_user_id(self, login_token):
-        yield self._check_mau_limits()
+        yield self.auth.check_auth_blocking()
         auth_api = self.hs.get_auth()
         user_id = None
         try:
@@ -907,19 +907,6 @@ class AuthHandler(BaseHandler):
         else:
             return defer.succeed(False)
 
-    @defer.inlineCallbacks
-    def _check_mau_limits(self):
-        """
-        Ensure that if mau blocking is enabled that invalid users cannot
-        log in.
-        """
-        if self.hs.config.limit_usage_by_mau is True:
-            current_mau = yield self.store.count_monthly_users()
-            if current_mau >= self.hs.config.max_mau_value:
-                raise AuthError(
-                    403, "MAU Limit Exceeded", errcode=Codes.MAU_LIMIT_EXCEEDED
-                )
-
 
 @attr.s
 class MacaroonGenerator(object):
diff --git a/synapse/handlers/register.py b/synapse/handlers/register.py
index 289704b241..0e16bbe0ee 100644
--- a/synapse/handlers/register.py
+++ b/synapse/handlers/register.py
@@ -540,9 +540,7 @@ class RegistrationHandler(BaseHandler):
         Do not accept registrations if monthly active user limits exceeded
          and limiting is enabled
         """
-        if self.hs.config.limit_usage_by_mau is True:
-            current_mau = yield self.store.count_monthly_users()
-            if current_mau >= self.hs.config.max_mau_value:
-                raise RegistrationError(
-                    403, "MAU Limit Exceeded", Codes.MAU_LIMIT_EXCEEDED
-                )
+        try:
+            yield self.auth.check_auth_blocking()
+        except AuthError as e:
+            raise RegistrationError(e.code, str(e), e.errcode)
diff --git a/synapse/storage/__init__.py b/synapse/storage/__init__.py
index 134e4a80f1..23b4a8d76d 100644
--- a/synapse/storage/__init__.py
+++ b/synapse/storage/__init__.py
@@ -39,6 +39,7 @@ from .filtering import FilteringStore
 from .group_server import GroupServerStore
 from .keys import KeyStore
 from .media_repository import MediaRepositoryStore
+from .monthly_active_users import MonthlyActiveUsersStore
 from .openid import OpenIdStore
 from .presence import PresenceStore, UserPresenceState
 from .profile import ProfileStore
@@ -87,6 +88,7 @@ class DataStore(RoomMemberStore, RoomStore,
                 UserDirectoryStore,
                 GroupServerStore,
                 UserErasureStore,
+                MonthlyActiveUsersStore,
                 ):
 
     def __init__(self, db_conn, hs):
@@ -94,7 +96,6 @@ class DataStore(RoomMemberStore, RoomStore,
         self._clock = hs.get_clock()
         self.database_engine = hs.database_engine
 
-        self.db_conn = db_conn
         self._stream_id_gen = StreamIdGenerator(
             db_conn, "events", "stream_ordering",
             extra_tables=[("local_invites", "stream_id")]
@@ -267,31 +268,6 @@ class DataStore(RoomMemberStore, RoomStore,
 
         return self.runInteraction("count_users", _count_users)
 
-    def count_monthly_users(self):
-        """Counts the number of users who used this homeserver in the last 30 days
-
-        This method should be refactored with count_daily_users - the only
-        reason not to is waiting on definition of mau
-
-        Returns:
-            Defered[int]
-        """
-        def _count_monthly_users(txn):
-            thirty_days_ago = int(self._clock.time_msec()) - (1000 * 60 * 60 * 24 * 30)
-            sql = """
-                SELECT COALESCE(count(*), 0) FROM (
-                    SELECT user_id FROM user_ips
-                    WHERE last_seen > ?
-                    GROUP BY user_id
-                ) u
-            """
-
-            txn.execute(sql, (thirty_days_ago,))
-            count, = txn.fetchone()
-            return count
-
-        return self.runInteraction("count_monthly_users", _count_monthly_users)
-
     def count_r30_users(self):
         """
         Counts the number of 30 day retained users, defined as:-
diff --git a/synapse/storage/client_ips.py b/synapse/storage/client_ips.py
index b8cefd43d6..2489527f2c 100644
--- a/synapse/storage/client_ips.py
+++ b/synapse/storage/client_ips.py
@@ -35,6 +35,7 @@ LAST_SEEN_GRANULARITY = 120 * 1000
 
 class ClientIpStore(background_updates.BackgroundUpdateStore):
     def __init__(self, db_conn, hs):
+
         self.client_ip_last_seen = Cache(
             name="client_ip_last_seen",
             keylen=4,
@@ -74,6 +75,7 @@ class ClientIpStore(background_updates.BackgroundUpdateStore):
             "before", "shutdown", self._update_client_ips_batch
         )
 
+    @defer.inlineCallbacks
     def insert_client_ip(self, user_id, access_token, ip, user_agent, device_id,
                          now=None):
         if not now:
@@ -84,7 +86,7 @@ class ClientIpStore(background_updates.BackgroundUpdateStore):
             last_seen = self.client_ip_last_seen.get(key)
         except KeyError:
             last_seen = None
-
+        yield self.populate_monthly_active_users(user_id)
         # Rate-limited inserts
         if last_seen is not None and (now - last_seen) < LAST_SEEN_GRANULARITY:
             return
diff --git a/synapse/storage/monthly_active_users.py b/synapse/storage/monthly_active_users.py
new file mode 100644
index 0000000000..8b3beaf26a
--- /dev/null
+++ b/synapse/storage/monthly_active_users.py
@@ -0,0 +1,162 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector
+#
+# 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.
+
+from twisted.internet import defer
+
+from synapse.util.caches.descriptors import cached
+
+from ._base import SQLBaseStore
+
+# Number of msec of granularity to store the monthly_active_user timestamp
+# This means it is not necessary to update the table on every request
+LAST_SEEN_GRANULARITY = 60 * 60 * 1000
+
+
+class MonthlyActiveUsersStore(SQLBaseStore):
+    def __init__(self, dbconn, hs):
+        super(MonthlyActiveUsersStore, self).__init__(None, hs)
+        self._clock = hs.get_clock()
+        self.hs = hs
+
+    def reap_monthly_active_users(self):
+        """
+        Cleans out monthly active user table to ensure that no stale
+        entries exist.
+
+        Returns:
+            Deferred[]
+        """
+        def _reap_users(txn):
+
+            thirty_days_ago = (
+                int(self._clock.time_msec()) - (1000 * 60 * 60 * 24 * 30)
+            )
+            # Purge stale users
+            sql = "DELETE FROM monthly_active_users WHERE timestamp < ?"
+            txn.execute(sql, (thirty_days_ago,))
+
+            # If MAU user count still exceeds the MAU threshold, then delete on
+            # a least recently active basis.
+            # Note it is not possible to write this query using OFFSET due to
+            # incompatibilities in how sqlite and postgres support the feature.
+            # sqlite requires 'LIMIT -1 OFFSET ?', the LIMIT must be present
+            # While Postgres does not require 'LIMIT', but also does not support
+            # negative LIMIT values. So there is no way to write it that both can
+            # support
+            sql = """
+                DELETE FROM monthly_active_users
+                WHERE user_id NOT IN (
+                    SELECT user_id FROM monthly_active_users
+                    ORDER BY timestamp DESC
+                    LIMIT ?
+                    )
+                """
+            txn.execute(sql, (self.hs.config.max_mau_value,))
+
+        yield self.runInteraction("reap_monthly_active_users", _reap_users)
+        # It seems poor to invalidate the whole cache, Postgres supports
+        # 'Returning' which would allow me to invalidate only the
+        # specific users, but sqlite has no way to do this and instead
+        # I would need to SELECT and the DELETE which without locking
+        # is racy.
+        # Have resolved to invalidate the whole cache for now and do
+        # something about it if and when the perf becomes significant
+        self._user_last_seen_monthly_active.invalidate_all()
+        self.get_monthly_active_count.invalidate_all()
+
+    @cached(num_args=0)
+    def get_monthly_active_count(self):
+        """Generates current count of monthly active users
+
+        Returns:
+            Defered[int]: Number of current monthly active users
+        """
+
+        def _count_users(txn):
+            sql = "SELECT COALESCE(count(*), 0) FROM monthly_active_users"
+
+            txn.execute(sql)
+            count, = txn.fetchone()
+            return count
+        return self.runInteraction("count_users", _count_users)
+
+    def upsert_monthly_active_user(self, user_id):
+        """
+            Updates or inserts monthly active user member
+            Arguments:
+                user_id (str): user to add/update
+            Deferred[bool]: True if a new entry was created, False if an
+                existing one was updated.
+        """
+        is_insert = self._simple_upsert(
+            desc="upsert_monthly_active_user",
+            table="monthly_active_users",
+            keyvalues={
+                "user_id": user_id,
+            },
+            values={
+                "timestamp": int(self._clock.time_msec()),
+            },
+            lock=False,
+        )
+        if is_insert:
+            self._user_last_seen_monthly_active.invalidate((user_id,))
+            self.get_monthly_active_count.invalidate(())
+
+    @cached(num_args=1)
+    def _user_last_seen_monthly_active(self, user_id):
+        """
+            Checks if a given user is part of the monthly active user group
+            Arguments:
+                user_id (str): user to add/update
+            Return:
+                int : timestamp since last seen, None if never seen
+
+        """
+
+        return(self._simple_select_one_onecol(
+            table="monthly_active_users",
+            keyvalues={
+                "user_id": user_id,
+            },
+            retcol="timestamp",
+            allow_none=True,
+            desc="_user_last_seen_monthly_active",
+        ))
+
+    @defer.inlineCallbacks
+    def populate_monthly_active_users(self, user_id):
+        """Checks on the state of monthly active user limits and optionally
+        add the user to the monthly active tables
+
+        Args:
+            user_id(str): the user_id to query
+        """
+
+        if self.hs.config.limit_usage_by_mau:
+            last_seen_timestamp = yield self._user_last_seen_monthly_active(user_id)
+            now = self.hs.get_clock().time_msec()
+
+            # We want to reduce to the total number of db writes, and are happy
+            # to trade accuracy of timestamp in order to lighten load. This means
+            # We always insert new users (where MAU threshold has not been reached),
+            # but only update if we have not previously seen the user for
+            # LAST_SEEN_GRANULARITY ms
+            if last_seen_timestamp is None:
+                count = yield self.get_monthly_active_count()
+                if count < self.hs.config.max_mau_value:
+                    yield self.upsert_monthly_active_user(user_id)
+            elif now - last_seen_timestamp > LAST_SEEN_GRANULARITY:
+                yield self.upsert_monthly_active_user(user_id)
diff --git a/synapse/storage/prepare_database.py b/synapse/storage/prepare_database.py
index b290f834b3..b364719312 100644
--- a/synapse/storage/prepare_database.py
+++ b/synapse/storage/prepare_database.py
@@ -25,7 +25,7 @@ logger = logging.getLogger(__name__)
 
 # Remember to update this number every time a change is made to database
 # schema files, so the users will be informed on server restarts.
-SCHEMA_VERSION = 50
+SCHEMA_VERSION = 51
 
 dir_path = os.path.abspath(os.path.dirname(__file__))
 
diff --git a/synapse/storage/schema/delta/51/monthly_active_users.sql b/synapse/storage/schema/delta/51/monthly_active_users.sql
new file mode 100644
index 0000000000..c9d537d5a3
--- /dev/null
+++ b/synapse/storage/schema/delta/51/monthly_active_users.sql
@@ -0,0 +1,27 @@
+/* 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.
+ */
+
+-- a table of monthly active users, for use where blocking based on mau limits
+CREATE TABLE monthly_active_users (
+    user_id TEXT NOT NULL,
+    -- Last time we saw the user. Not guaranteed to be accurate due to rate limiting
+    -- on updates, Granularity of updates governed by
+    -- synapse.storage.monthly_active_users.LAST_SEEN_GRANULARITY
+    -- Measured in ms since epoch.
+    timestamp BIGINT NOT NULL
+);
+
+CREATE UNIQUE INDEX monthly_active_users_users ON monthly_active_users(user_id);
+CREATE INDEX monthly_active_users_time_stamp ON monthly_active_users(timestamp);
diff --git a/tests/api/test_auth.py b/tests/api/test_auth.py
index a82d737e71..5dc3398300 100644
--- a/tests/api/test_auth.py
+++ b/tests/api/test_auth.py
@@ -444,3 +444,28 @@ class AuthTestCase(unittest.TestCase):
         self.assertEqual("Guest access token used for regular user", cm.exception.msg)
 
         self.store.get_user_by_id.assert_called_with(USER_ID)
+
+    @defer.inlineCallbacks
+    def test_blocking_mau(self):
+        self.hs.config.limit_usage_by_mau = False
+        self.hs.config.max_mau_value = 50
+        lots_of_users = 100
+        small_number_of_users = 1
+
+        # Ensure no error thrown
+        yield self.auth.check_auth_blocking()
+
+        self.hs.config.limit_usage_by_mau = True
+
+        self.store.get_monthly_active_count = Mock(
+            return_value=defer.succeed(lots_of_users)
+        )
+
+        with self.assertRaises(AuthError):
+            yield self.auth.check_auth_blocking()
+
+        # Ensure does not throw an error
+        self.store.get_monthly_active_count = Mock(
+            return_value=defer.succeed(small_number_of_users)
+        )
+        yield self.auth.check_auth_blocking()
diff --git a/tests/handlers/test_auth.py b/tests/handlers/test_auth.py
index 55eab9e9cf..8a9bf2d5fd 100644
--- a/tests/handlers/test_auth.py
+++ b/tests/handlers/test_auth.py
@@ -132,14 +132,14 @@ class AuthTestCase(unittest.TestCase):
     @defer.inlineCallbacks
     def test_mau_limits_exceeded(self):
         self.hs.config.limit_usage_by_mau = True
-        self.hs.get_datastore().count_monthly_users = Mock(
+        self.hs.get_datastore().get_monthly_active_count = Mock(
             return_value=defer.succeed(self.large_number_of_users)
         )
 
         with self.assertRaises(AuthError):
             yield self.auth_handler.get_access_token_for_user_id('user_a')
 
-        self.hs.get_datastore().count_monthly_users = Mock(
+        self.hs.get_datastore().get_monthly_active_count = Mock(
             return_value=defer.succeed(self.large_number_of_users)
         )
         with self.assertRaises(AuthError):
@@ -151,13 +151,13 @@ class AuthTestCase(unittest.TestCase):
     def test_mau_limits_not_exceeded(self):
         self.hs.config.limit_usage_by_mau = True
 
-        self.hs.get_datastore().count_monthly_users = Mock(
+        self.hs.get_datastore().get_monthly_active_count = Mock(
             return_value=defer.succeed(self.small_number_of_users)
         )
         # Ensure does not raise exception
         yield self.auth_handler.get_access_token_for_user_id('user_a')
 
-        self.hs.get_datastore().count_monthly_users = Mock(
+        self.hs.get_datastore().get_monthly_active_count = Mock(
             return_value=defer.succeed(self.small_number_of_users)
         )
         yield self.auth_handler.validate_short_term_login_token_and_get_user_id(
diff --git a/tests/handlers/test_register.py b/tests/handlers/test_register.py
index 0937d71cf6..4ea59a58de 100644
--- a/tests/handlers/test_register.py
+++ b/tests/handlers/test_register.py
@@ -50,6 +50,10 @@ class RegistrationTestCase(unittest.TestCase):
         self.hs.get_macaroon_generator = Mock(return_value=self.macaroon_generator)
         self.hs.handlers = RegistrationHandlers(self.hs)
         self.handler = self.hs.get_handlers().registration_handler
+        self.store = self.hs.get_datastore()
+        self.hs.config.max_mau_value = 50
+        self.lots_of_users = 100
+        self.small_number_of_users = 1
 
     @defer.inlineCallbacks
     def test_user_is_created_and_logged_in_if_doesnt_exist(self):
@@ -80,51 +84,43 @@ class RegistrationTestCase(unittest.TestCase):
         self.assertEquals(result_token, 'secret')
 
     @defer.inlineCallbacks
-    def test_cannot_register_when_mau_limits_exceeded(self):
-        local_part = "someone"
-        display_name = "someone"
-        requester = create_requester("@as:test")
-        store = self.hs.get_datastore()
+    def test_mau_limits_when_disabled(self):
         self.hs.config.limit_usage_by_mau = False
-        self.hs.config.max_mau_value = 50
-        lots_of_users = 100
-        small_number_users = 1
-
-        store.count_monthly_users = Mock(return_value=defer.succeed(lots_of_users))
-
         # Ensure does not throw exception
-        yield self.handler.get_or_create_user(requester, 'a', display_name)
+        yield self.handler.get_or_create_user("requester", 'a', "display_name")
 
+    @defer.inlineCallbacks
+    def test_get_or_create_user_mau_not_blocked(self):
         self.hs.config.limit_usage_by_mau = True
-
-        with self.assertRaises(RegistrationError):
-            yield self.handler.get_or_create_user(requester, 'b', display_name)
-
-        store.count_monthly_users = Mock(return_value=defer.succeed(small_number_users))
-
-        self._macaroon_mock_generator("another_secret")
-
+        self.store.count_monthly_users = Mock(
+            return_value=defer.succeed(self.small_number_of_users)
+        )
         # Ensure does not throw exception
-        yield self.handler.get_or_create_user("@neil:matrix.org", 'c', "Neil")
-
-        self._macaroon_mock_generator("another another secret")
-        store.count_monthly_users = Mock(return_value=defer.succeed(lots_of_users))
+        yield self.handler.get_or_create_user("@user:server", 'c', "User")
 
+    @defer.inlineCallbacks
+    def test_get_or_create_user_mau_blocked(self):
+        self.hs.config.limit_usage_by_mau = True
+        self.store.get_monthly_active_count = Mock(
+            return_value=defer.succeed(self.lots_of_users)
+        )
         with self.assertRaises(RegistrationError):
-            yield self.handler.register(localpart=local_part)
+            yield self.handler.get_or_create_user("requester", 'b', "display_name")
 
-        self._macaroon_mock_generator("another another secret")
-        store.count_monthly_users = Mock(return_value=defer.succeed(lots_of_users))
+    @defer.inlineCallbacks
+    def test_register_mau_blocked(self):
+        self.hs.config.limit_usage_by_mau = True
+        self.store.get_monthly_active_count = Mock(
+            return_value=defer.succeed(self.lots_of_users)
+        )
+        with self.assertRaises(RegistrationError):
+            yield self.handler.register(localpart="local_part")
 
+    @defer.inlineCallbacks
+    def test_register_saml2_mau_blocked(self):
+        self.hs.config.limit_usage_by_mau = True
+        self.store.get_monthly_active_count = Mock(
+            return_value=defer.succeed(self.lots_of_users)
+        )
         with self.assertRaises(RegistrationError):
-            yield self.handler.register_saml2(local_part)
-
-    def _macaroon_mock_generator(self, secret):
-        """
-        Reset macaroon generator in the case where the test creates multiple users
-        """
-        macaroon_generator = Mock(
-            generate_access_token=Mock(return_value=secret))
-        self.hs.get_macaroon_generator = Mock(return_value=macaroon_generator)
-        self.hs.handlers = RegistrationHandlers(self.hs)
-        self.handler = self.hs.get_handlers().registration_handler
+            yield self.handler.register_saml2(localpart="local_part")
diff --git a/tests/storage/test__init__.py b/tests/storage/test__init__.py
deleted file mode 100644
index f19cb1265c..0000000000
--- a/tests/storage/test__init__.py
+++ /dev/null
@@ -1,65 +0,0 @@
-# -*- coding: utf-8 -*-
-# 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.
-
-from twisted.internet import defer
-
-import tests.utils
-
-
-class InitTestCase(tests.unittest.TestCase):
-    def __init__(self, *args, **kwargs):
-        super(InitTestCase, self).__init__(*args, **kwargs)
-        self.store = None  # type: synapse.storage.DataStore
-
-    @defer.inlineCallbacks
-    def setUp(self):
-        hs = yield tests.utils.setup_test_homeserver()
-
-        hs.config.max_mau_value = 50
-        hs.config.limit_usage_by_mau = True
-        self.store = hs.get_datastore()
-        self.clock = hs.get_clock()
-
-    @defer.inlineCallbacks
-    def test_count_monthly_users(self):
-        count = yield self.store.count_monthly_users()
-        self.assertEqual(0, count)
-
-        yield self._insert_user_ips("@user:server1")
-        yield self._insert_user_ips("@user:server2")
-
-        count = yield self.store.count_monthly_users()
-        self.assertEqual(2, count)
-
-    @defer.inlineCallbacks
-    def _insert_user_ips(self, user):
-        """
-        Helper function to populate user_ips without using batch insertion infra
-        args:
-            user (str):  specify username i.e. @user:server.com
-        """
-        yield self.store._simple_upsert(
-            table="user_ips",
-            keyvalues={
-                "user_id": user,
-                "access_token": "access_token",
-                "ip": "ip",
-                "user_agent": "user_agent",
-                "device_id": "device_id",
-            },
-            values={
-                "last_seen": self.clock.time_msec(),
-            }
-        )
diff --git a/tests/storage/test_client_ips.py b/tests/storage/test_client_ips.py
index bd6fda6cb1..7a58c6eb24 100644
--- a/tests/storage/test_client_ips.py
+++ b/tests/storage/test_client_ips.py
@@ -12,6 +12,7 @@
 # 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.
+from mock import Mock
 
 from twisted.internet import defer
 
@@ -27,9 +28,9 @@ class ClientIpStoreTestCase(tests.unittest.TestCase):
 
     @defer.inlineCallbacks
     def setUp(self):
-        hs = yield tests.utils.setup_test_homeserver()
-        self.store = hs.get_datastore()
-        self.clock = hs.get_clock()
+        self.hs = yield tests.utils.setup_test_homeserver()
+        self.store = self.hs.get_datastore()
+        self.clock = self.hs.get_clock()
 
     @defer.inlineCallbacks
     def test_insert_new_client_ip(self):
@@ -54,3 +55,62 @@ class ClientIpStoreTestCase(tests.unittest.TestCase):
             },
             r
         )
+
+    @defer.inlineCallbacks
+    def test_disabled_monthly_active_user(self):
+        self.hs.config.limit_usage_by_mau = False
+        self.hs.config.max_mau_value = 50
+        user_id = "@user:server"
+        yield self.store.insert_client_ip(
+            user_id, "access_token", "ip", "user_agent", "device_id",
+        )
+        active = yield self.store._user_last_seen_monthly_active(user_id)
+        self.assertFalse(active)
+
+    @defer.inlineCallbacks
+    def test_adding_monthly_active_user_when_full(self):
+        self.hs.config.limit_usage_by_mau = True
+        self.hs.config.max_mau_value = 50
+        lots_of_users = 100
+        user_id = "@user:server"
+
+        self.store.get_monthly_active_count = Mock(
+            return_value=defer.succeed(lots_of_users)
+        )
+        yield self.store.insert_client_ip(
+            user_id, "access_token", "ip", "user_agent", "device_id",
+        )
+        active = yield self.store._user_last_seen_monthly_active(user_id)
+        self.assertFalse(active)
+
+    @defer.inlineCallbacks
+    def test_adding_monthly_active_user_when_space(self):
+        self.hs.config.limit_usage_by_mau = True
+        self.hs.config.max_mau_value = 50
+        user_id = "@user:server"
+        active = yield self.store._user_last_seen_monthly_active(user_id)
+        self.assertFalse(active)
+
+        yield self.store.insert_client_ip(
+            user_id, "access_token", "ip", "user_agent", "device_id",
+        )
+        active = yield self.store._user_last_seen_monthly_active(user_id)
+        self.assertTrue(active)
+
+    @defer.inlineCallbacks
+    def test_updating_monthly_active_user_when_space(self):
+        self.hs.config.limit_usage_by_mau = True
+        self.hs.config.max_mau_value = 50
+        user_id = "@user:server"
+
+        active = yield self.store._user_last_seen_monthly_active(user_id)
+        self.assertFalse(active)
+
+        yield self.store.insert_client_ip(
+            user_id, "access_token", "ip", "user_agent", "device_id",
+        )
+        yield self.store.insert_client_ip(
+            user_id, "access_token", "ip", "user_agent", "device_id",
+        )
+        active = yield self.store._user_last_seen_monthly_active(user_id)
+        self.assertTrue(active)
diff --git a/tests/storage/test_monthly_active_users.py b/tests/storage/test_monthly_active_users.py
new file mode 100644
index 0000000000..0bfd24a7fb
--- /dev/null
+++ b/tests/storage/test_monthly_active_users.py
@@ -0,0 +1,66 @@
+# -*- coding: utf-8 -*-
+# Copyright 2018 New Vector
+#
+# 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.
+
+from twisted.internet import defer
+
+import tests.unittest
+import tests.utils
+from tests.utils import setup_test_homeserver
+
+
+class MonthlyActiveUsersTestCase(tests.unittest.TestCase):
+    def __init__(self, *args, **kwargs):
+        super(MonthlyActiveUsersTestCase, self).__init__(*args, **kwargs)
+
+    @defer.inlineCallbacks
+    def setUp(self):
+        self.hs = yield setup_test_homeserver()
+        self.store = self.hs.get_datastore()
+
+    @defer.inlineCallbacks
+    def test_can_insert_and_count_mau(self):
+        count = yield self.store.get_monthly_active_count()
+        self.assertEqual(0, count)
+
+        yield self.store.upsert_monthly_active_user("@user:server")
+        count = yield self.store.get_monthly_active_count()
+
+        self.assertEqual(1, count)
+
+    @defer.inlineCallbacks
+    def test__user_last_seen_monthly_active(self):
+        user_id1 = "@user1:server"
+        user_id2 = "@user2:server"
+        user_id3 = "@user3:server"
+        result = yield self.store._user_last_seen_monthly_active(user_id1)
+        self.assertFalse(result == 0)
+        yield self.store.upsert_monthly_active_user(user_id1)
+        yield self.store.upsert_monthly_active_user(user_id2)
+        result = yield self.store._user_last_seen_monthly_active(user_id1)
+        self.assertTrue(result > 0)
+        result = yield self.store._user_last_seen_monthly_active(user_id3)
+        self.assertFalse(result == 0)
+
+    @defer.inlineCallbacks
+    def test_reap_monthly_active_users(self):
+        self.hs.config.max_mau_value = 5
+        initial_users = 10
+        for i in range(initial_users):
+            yield self.store.upsert_monthly_active_user("@user%d:server" % i)
+        count = yield self.store.get_monthly_active_count()
+        self.assertTrue(count, initial_users)
+        yield self.store.reap_monthly_active_users()
+        count = yield self.store.get_monthly_active_count()
+        self.assertTrue(count, initial_users - self.hs.config.max_mau_value)
diff --git a/tests/utils.py b/tests/utils.py
index 9bff3ff3b9..ec40428e74 100644
--- a/tests/utils.py
+++ b/tests/utils.py
@@ -73,6 +73,7 @@ def setup_test_homeserver(name="test", datastore=None, config=None, reactor=None
         config.block_events_without_consent_error = None
         config.media_storage_providers = []
         config.auto_join_rooms = []
+        config.limit_usage_by_mau = False
 
         # disable user directory updates, because they get done in the
         # background, which upsets the test runner.