Allow external processes to mark a user as syncing. (#812)

* Add infrastructure to the presence handler to track sync requests in external processes

* Expire stale entries for dead external processes

* Add an http endpoint for making users as syncing

Add some docstrings and comments.

* Fixes

2 files changed, 61 insertions, 0 deletions

diff --git a/synapse/replication/presence_resource.py b/synapse/replication/presence_resource.py
new file mode 100644
index 0000000000..fc18130ab4
--- /dev/null
+++ b/synapse/replication/presence_resource.py
@@ -0,0 +1,59 @@
+# Copyright 2016 OpenMarket 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 synapse.http.server import respond_with_json_bytes, request_handler
+from synapse.http.servlet import parse_json_object_from_request
+
+from twisted.web.resource import Resource
+from twisted.web.server import NOT_DONE_YET
+from twisted.internet import defer
+
+
+class PresenceResource(Resource):
+    """
+    HTTP endpoint for marking users as syncing.
+
+    POST /_synapse/replication/presence HTTP/1.1
+    Content-Type: application/json
+
+    {
+        "process_id": "<process_id>",
+        "syncing_users": ["<user_id>"]
+    }
+    """
+
+    def __init__(self, hs):
+        Resource.__init__(self)  # Resource is old-style, so no super()
+
+        self.version_string = hs.version_string
+        self.clock = hs.get_clock()
+        self.presence_handler = hs.get_presence_handler()
+
+    def render_POST(self, request):
+        self._async_render_POST(request)
+        return NOT_DONE_YET
+
+    @request_handler()
+    @defer.inlineCallbacks
+    def _async_render_POST(self, request):
+        content = parse_json_object_from_request(request)
+
+        process_id = content["process_id"]
+        syncing_user_ids = content["syncing_users"]
+
+        yield self.presence_handler.update_external_syncs(
+            process_id, set(syncing_user_ids)
+        )
+
+        respond_with_json_bytes(request, 200, "{}")
diff --git a/synapse/replication/resource.py b/synapse/replication/resource.py
index 847f212a3d..8c2d487ff4 100644
--- a/synapse/replication/resource.py
+++ b/synapse/replication/resource.py
@@ -16,6 +16,7 @@
 from synapse.http.servlet import parse_integer, parse_string
 from synapse.http.server import request_handler, finish_request
 from synapse.replication.pusher_resource import PusherResource
+from synapse.replication.presence_resource import PresenceResource
 
 from twisted.web.resource import Resource
 from twisted.web.server import NOT_DONE_YET
@@ -115,6 +116,7 @@ class ReplicationResource(Resource):
         self.clock = hs.get_clock()
 
         self.putChild("remove_pushers", PusherResource(hs))
+        self.putChild("syncing_users", PresenceResource(hs))
 
     def render_GET(self, request):
         self._async_render_GET(request)