zilencer: Only accept SYNCED_BILLING_EVENTS.

I expect we would ignore extra events anyway, but this just makes it
easier to reason about how the system works.

zerver/tests/test_push_notifications.py

@@ -1434,6 +1434,27 @@ class AnalyticsBouncerTest(BouncerTestCase):
             RealmCount.objects.all(), InstallationCount.objects.all(), RealmAuditLog.objects.all()
         )
 
+        # This first post should fail because of excessive audit log event types.
+        result = self.uuid_post(
+            self.server_uuid,
+            "/api/v1/remotes/server/analytics",
+            {
+                "realm_counts": orjson.dumps(realm_count_data).decode(),
+                "installation_counts": orjson.dumps(installation_count_data).decode(),
+                "realmauditlog_rows": orjson.dumps(realmauditlog_data).decode(),
+                "realms": orjson.dumps([]).decode(),
+            },
+            subdomain="",
+        )
+        self.assert_json_error(result, "Invalid event type.")
+
+        # Start again only using synced billing events.
+        realm_count_data, installation_count_data, realmauditlog_data = build_analytics_data(
+            RealmCount.objects.all(),
+            InstallationCount.objects.all(),
+            RealmAuditLog.objects.filter(event_type__in=RemoteRealmAuditLog.SYNCED_BILLING_EVENTS),
+        )
+
         # Send the data to the bouncer without any realms data. This should lead
         # to successful saving of the data, but with the remote_realm foreign key
         # set to NULL.

zilencer/views.py

@@ -523,7 +523,11 @@ def remote_server_notify_push(
 
 
 def validate_incoming_table_data(
-    server: RemoteZulipServer, model: Any, rows: List[Dict[str, Any]], is_count_stat: bool = False
+    server: RemoteZulipServer,
+    model: Any,
+    rows: List[Dict[str, Any]],
+    *,
+    is_count_stat: bool,
 ) -> None:
     last_id = get_last_id_from_server(server, model)
     for row in rows:
@@ -532,6 +536,10 @@ def validate_incoming_table_data(
             or row["property"] in BOUNCER_ONLY_REMOTE_COUNT_STAT_PROPERTIES
         ):
             raise JsonableError(_("Invalid property {property}").format(property=row["property"]))
+
+        if not is_count_stat and row["event_type"] not in RemoteRealmAuditLog.SYNCED_BILLING_EVENTS:
+            raise JsonableError(_("Invalid event type."))
+
         if row.get("id") is None:
             # This shouldn't be possible, as submitting data like this should be
             # prevented by our param validators.
@@ -702,15 +710,24 @@ def remote_server_post_analytics(
         remote_server_version_updated = True
 
     validate_incoming_table_data(
-        server, RemoteRealmCount, [dict(count) for count in realm_counts], True
+        server,
+        RemoteRealmCount,
+        [dict(count) for count in realm_counts],
+        is_count_stat=True,
     )
     validate_incoming_table_data(
-        server, RemoteInstallationCount, [dict(count) for count in installation_counts], True
+        server,
+        RemoteInstallationCount,
+        [dict(count) for count in installation_counts],
+        is_count_stat=True,
     )
 
     if realmauditlog_rows is not None:
         validate_incoming_table_data(
-            server, RemoteRealmAuditLog, [dict(row) for row in realmauditlog_rows]
+            server,
+            RemoteRealmAuditLog,
+            [dict(row) for row in realmauditlog_rows],
+            is_count_stat=False,
         )
 
     if realms is not None: