STOMP: add support for consumer priorities

x-priority header allows to specify the consumer priority

Author: mkuratczyk

deps/rabbitmq_stomp/include/rabbit_stomp_headers.hrl

@@ -30,6 +30,7 @@
 -define(HEADER_X_STREAM_FILTER, "x-stream-filter").
 -define(HEADER_X_STREAM_MATCH_UNFILTERED, "x-stream-match-unfiltered").
 -define(HEADER_PRIORITY, "priority").
+-define(HEADER_X_PRIORITY, "x-priority").
 -define(HEADER_RECEIPT, "receipt").
 -define(HEADER_REDELIVERED, "redelivered").
 -define(HEADER_REPLY_TO, "reply-to").

deps/rabbitmq_stomp/src/rabbit_stomp_processor.erl

@@ -718,7 +718,8 @@ do_subscribe(Destination, DestHdr, Frame,
 subscribe_arguments(Frame) ->
     subscribe_arguments([?HEADER_X_STREAM_OFFSET,
                          ?HEADER_X_STREAM_FILTER,
-                         ?HEADER_X_STREAM_MATCH_UNFILTERED], Frame, []).
+                         ?HEADER_X_STREAM_MATCH_UNFILTERED,
+                         ?HEADER_X_PRIORITY], Frame, []).
 
 subscribe_arguments([], _Frame , Acc) ->
     Acc;
@@ -749,6 +750,14 @@ subscribe_argument(?HEADER_X_STREAM_MATCH_UNFILTERED, Frame, Acc) ->
             [{list_to_binary(?HEADER_X_STREAM_MATCH_UNFILTERED), bool, MU}] ++ Acc;
         not_found ->
             Acc
+    end;
+subscribe_argument(?HEADER_X_PRIORITY, Frame, Acc) ->
+    Priority = rabbit_stomp_frame:integer_header(Frame, ?HEADER_X_PRIORITY),
+    case Priority of
+        {ok, P} ->
+            [{list_to_binary(?HEADER_X_PRIORITY), byte, P}] ++ Acc;
+        not_found ->
+            Acc
     end.
 
 check_subscription_access(Destination = {topic, _Topic},

deps/rabbitmq_stomp/test/system_SUITE.erl

@@ -28,6 +28,7 @@ groups() ->
         publish_unauthorized_error,
         subscribe_error,
         subscribe,
+        subscribe_with_x_priority,
         unsubscribe_ack,
         subscribe_ack,
         send,
@@ -161,6 +162,42 @@ subscribe(Config) ->
     {ok, _Client2, _, [<<"hello">>]} = stomp_receive(Client1, "MESSAGE"),
     ok.
 
+subscribe_with_x_priority(Config) ->
+    Version = ?config(version, Config),
+    StompPort = rabbit_ct_broker_helpers:get_node_config(Config, 0, tcp_port_stomp),
+    Channel = ?config(amqp_channel, Config),
+    ClientA = ?config(stomp_client, Config),
+    #'queue.declare_ok'{} =
+    amqp_channel:call(Channel, #'queue.declare'{queue     = ?QUEUE,
+                                                durable   = true,
+                                                arguments = [{<<"x-queue-type">>, longstr, <<"quorum">>},
+                                                             {<<"x-single-active-consumer">>, bool, true}
+                                                            ]}),
+
+    %% subscribe and wait for receipt
+    rabbit_stomp_client:send(
+      ClientA, "SUBSCRIBE", [{"destination", ?DESTINATION}, {"receipt", "foo"}]),
+    {ok, _ClientA1, _, _} = stomp_receive(ClientA, "RECEIPT"),
+
+    %% subscribe with a higher priority and wait for receipt
+    {ok, ClientB} = rabbit_stomp_client:connect(Version, StompPort),
+    rabbit_stomp_client:send(
+      ClientB, "SUBSCRIBE", [{"destination", ?DESTINATION},
+                             {"receipt", "foo"},
+                             {"x-priority", 10}
+                            ]),
+    {ok, ClientB1, _, _} = stomp_receive(ClientB, "RECEIPT"),
+
+    %% send from amqp
+    Method = #'basic.publish'{exchange = <<"">>, routing_key = ?QUEUE},
+
+    amqp_channel:call(Channel, Method, #amqp_msg{props = #'P_basic'{},
+                                                 payload = <<"hello">>}),
+
+    %% ClientB should receive the message since it has a higher priority
+    {ok, _ClientB2, _, [<<"hello">>]} = stomp_receive(ClientB1, "MESSAGE"),
+    ok.
+
 unsubscribe_ack(Config) ->
     Channel = ?config(amqp_channel, Config),
     Client = ?config(stomp_client, Config),