Separate generating the replication response...

from doing the http request parsing to make it easier
to write unit tests for replication.

synapse/replication/resource.py

@@ -145,32 +145,43 @@ class ReplicationResource(Resource):
         timeout = parse_integer(request, "timeout", 10 * 1000)
 
         request.setHeader(b"Content-Type", b"application/json")
-        writer = _Writer(request)
 
-        @defer.inlineCallbacks
-        def replicate():
-            current_token = yield self.current_replication_token()
-            logger.info("Replicating up to %r", current_token)
-
-            yield self.account_data(writer, current_token, limit)
-            yield self.events(writer, current_token, limit)
-            yield self.presence(writer, current_token)  # TODO: implement limit
-            yield self.typing(writer, current_token)  # TODO: implement limit
-            yield self.receipts(writer, current_token, limit)
-            yield self.push_rules(writer, current_token, limit)
-            yield self.pushers(writer, current_token, limit)
-            yield self.state(writer, current_token, limit)
-            self.streams(writer, current_token)
+        request_streams = {
+            name: parse_integer(request, name)
+            for names in STREAM_NAMES for name in names
+        }
+        request_streams["streams"] = parse_string(request, "streams")
 
-            logger.info("Replicated %d rows", writer.total)
-            defer.returnValue(writer.total)
+        def replicate():
+            return self.replicate(request_streams, limit)
 
-        yield self.notifier.wait_for_replication(replicate, timeout)
+        result = yield self.notifier.wait_for_replication(replicate, timeout)
 
-        writer.finish()
+        request.write(json.dumps(result, ensure_ascii=False))
+        finish_request(request)
 
-    def streams(self, writer, current_token):
-        request_token = parse_string(writer.request, "streams")
+    @defer.inlineCallbacks
+    def replicate(self, request_streams, limit):
+        writer = _Writer()
+        current_token = yield self.current_replication_token()
+        logger.info("Replicating up to %r", current_token)
+
+        yield self.account_data(writer, current_token, limit, request_streams)
+        yield self.events(writer, current_token, limit, request_streams)
+        # TODO: implement limit
+        yield self.presence(writer, current_token, request_streams)
+        yield self.typing(writer, current_token, request_streams)
+        yield self.receipts(writer, current_token, limit, request_streams)
+        yield self.push_rules(writer, current_token, limit, request_streams)
+        yield self.pushers(writer, current_token, limit, request_streams)
+        yield self.state(writer, current_token, limit, request_streams)
+        self.streams(writer, current_token, request_streams)
+
+        logger.info("Replicated %d rows", writer.total)
+        defer.returnValue(writer.finish())
+
+    def streams(self, writer, current_token, request_streams):
+        request_token = request_streams.get("streams")
 
         streams = []
 
@@ -195,9 +206,9 @@ class ReplicationResource(Resource):
                 )
 
     @defer.inlineCallbacks
-    def events(self, writer, current_token, limit):
-        request_events = parse_integer(writer.request, "events")
-        request_backfill = parse_integer(writer.request, "backfill")
+    def events(self, writer, current_token, limit, request_streams):
+        request_events = request_streams.get("events")
+        request_backfill = request_streams.get("backfill")
 
         if request_events is not None or request_backfill is not None:
             if request_events is None:
@@ -228,10 +239,10 @@ class ReplicationResource(Resource):
             )
 
     @defer.inlineCallbacks
-    def presence(self, writer, current_token):
+    def presence(self, writer, current_token, request_streams):
         current_position = current_token.presence
 
-        request_presence = parse_integer(writer.request, "presence")
+        request_presence = request_streams.get("presence")
 
         if request_presence is not None:
             presence_rows = yield self.presence_handler.get_all_presence_updates(
@@ -244,10 +255,10 @@ class ReplicationResource(Resource):
             ))
 
     @defer.inlineCallbacks
-    def typing(self, writer, current_token):
+    def typing(self, writer, current_token, request_streams):
         current_position = current_token.presence
 
-        request_typing = parse_integer(writer.request, "typing")
+        request_typing = request_streams.get("typing")
 
         if request_typing is not None:
             typing_rows = yield self.typing_handler.get_all_typing_updates(
@@ -258,10 +269,10 @@ class ReplicationResource(Resource):
             ))
 
     @defer.inlineCallbacks
-    def receipts(self, writer, current_token, limit):
+    def receipts(self, writer, current_token, limit, request_streams):
         current_position = current_token.receipts
 
-        request_receipts = parse_integer(writer.request, "receipts")
+        request_receipts = request_streams.get("receipts")
 
         if request_receipts is not None:
             receipts_rows = yield self.store.get_all_updated_receipts(
@@ -272,12 +283,12 @@ class ReplicationResource(Resource):
             ))
 
     @defer.inlineCallbacks
-    def account_data(self, writer, current_token, limit):
+    def account_data(self, writer, current_token, limit, request_streams):
         current_position = current_token.account_data
 
-        user_account_data = parse_integer(writer.request, "user_account_data")
-        room_account_data = parse_integer(writer.request, "room_account_data")
-        tag_account_data = parse_integer(writer.request, "tag_account_data")
+        user_account_data = request_streams.get("user_account_data")
+        room_account_data = request_streams.get("room_account_data")
+        tag_account_data = request_streams.get("tag_account_data")
 
         if user_account_data is not None or room_account_data is not None:
             if user_account_data is None:
@@ -303,10 +314,10 @@ class ReplicationResource(Resource):
             ))
 
     @defer.inlineCallbacks
-    def push_rules(self, writer, current_token, limit):
+    def push_rules(self, writer, current_token, limit, request_streams):
         current_position = current_token.push_rules
 
-        push_rules = parse_integer(writer.request, "push_rules")
+        push_rules = request_streams.get("push_rules")
 
         if push_rules is not None:
             rows = yield self.store.get_all_push_rule_updates(
@@ -318,10 +329,11 @@ class ReplicationResource(Resource):
             ))
 
     @defer.inlineCallbacks
-    def pushers(self, writer, current_token, limit):
+    def pushers(self, writer, current_token, limit, request_streams):
         current_position = current_token.pushers
 
-        pushers = parse_integer(writer.request, "pushers")
+        pushers = request_streams.get("pushers")
+
         if pushers is not None:
             updated, deleted = yield self.store.get_all_updated_pushers(
                 pushers, current_position, limit
@@ -336,10 +348,11 @@ class ReplicationResource(Resource):
             ))
 
     @defer.inlineCallbacks
-    def state(self, writer, current_token, limit):
+    def state(self, writer, current_token, limit, request_streams):
         current_position = current_token.state
 
-        state = parse_integer(writer.request, "state")
+        state = request_streams.get("state")
+
         if state is not None:
             state_groups, state_group_state = (
                 yield self.store.get_all_new_state_groups(
@@ -356,9 +369,8 @@ class ReplicationResource(Resource):
 
 class _Writer(object):
     """Writes the streams as a JSON object as the response to the request"""
-    def __init__(self, request):
+    def __init__(self):
         self.streams = {}
-        self.request = request
         self.total = 0
 
     def write_header_and_rows(self, name, rows, fields, position=None):
@@ -377,8 +389,7 @@ class _Writer(object):
         self.total += len(rows)
 
     def finish(self):
-        self.request.write(json.dumps(self.streams, ensure_ascii=False))
-        finish_request(self.request)
+        return self.streams
 
 
 class _ReplicationToken(collections.namedtuple("_ReplicationToken", (