4.3: Implement AMQP-1.0 delivery-count for CQs

deps/rabbit/src/rabbit_amqqueue_process.erl

@@ -905,16 +905,32 @@ ack(AckTags, ChPid, State) ->
                           State1#q{backing_queue_state = BQS1}
                   end).
 
-requeue(AckTags, ChPid, State) ->
+requeue(AckTags, DelFailed, ChPid, State) ->
     subtract_acks(ChPid, AckTags, State,
-                  fun (State1) -> requeue_and_run(AckTags, false, State1) end).
+                  fun (State1) -> requeue_and_run(AckTags, DelFailed, false, State1) end).
+
+discard(AckTags, DelFailed, ChPid, State) ->
+    with_dlx(
+      State#q.dlx,
+      fun (X) -> subtract_acks(ChPid, AckTags, State,
+                               fun (State1) ->
+                                       dead_letter_rejected_msgs(
+                                         AckTags, DelFailed, X, State1)
+                               end) end,
+      fun () -> rabbit_global_counters:messages_dead_lettered(rejected, rabbit_classic_queue,
+                                                              disabled, length(AckTags)),
+                ack(AckTags, ChPid, State) end).
+
+requeue_and_run(AckTags, ActiveConsumersChanged, State) ->
+    requeue_and_run(AckTags, true, ActiveConsumersChanged, State).
 
 requeue_and_run(AckTags,
+                DelFailed,
                 ActiveConsumersChanged,
                 #q{backing_queue = BQ,
                    backing_queue_state = BQS0} = State0) ->
     WasEmpty = BQ:is_empty(BQS0),
-    {_MsgIds, BQS} = BQ:requeue(AckTags, BQS0),
+    {_MsgIds, BQS} = BQ:requeue(AckTags, DelFailed, BQS0),
     State1 = State0#q{backing_queue_state = BQS},
     {_Dropped, State2} = maybe_drop_head(State1),
     State3 = drop_expired_msgs(State2),
@@ -1079,11 +1095,11 @@ dead_letter_expired_msgs(ExpirePred, X, State = #q{backing_queue = BQ}) ->
                              BQ:fetchwhile(ExpirePred, DLFun, Acc, BQS1)
                      end, expired, X, State).
 
-dead_letter_rejected_msgs(AckTags, X,  State = #q{backing_queue = BQ}) ->
+dead_letter_rejected_msgs(AckTags, DelFailed, X,  State = #q{backing_queue = BQ}) ->
     {ok, State1} =
         dead_letter_msgs(
           fun (DLFun, Acc, BQS) ->
-                  {Acc1, BQS1} = BQ:ackfold(DLFun, Acc, BQS, AckTags),
+                  {Acc1, BQS1} = BQ:ackfold(DLFun, Acc, BQS, AckTags, DelFailed),
                   {ok, Acc1, BQS1}
           end, rejected, X, State),
     State1.
@@ -1258,7 +1274,8 @@ prioritise_cast(Msg, _Len, State) ->
         delete_immediately                   -> 8;
         {delete_exclusive, _Pid}             -> 8;
         {run_backing_queue, _Mod, _Fun}      -> 6;
-        {ack, _AckTags, _ChPid}              -> 4; %% [1]
+        {ack, _AckTags, _ChPid}              -> 4; %% [1] %% @todo Remove when 'rabbitmq_4.3.0' FF is required.
+        {complete, _AckTags, _ChPid}         -> 4; %% [1]
         {resume, _ChPid}                     -> 3;
         {notify_sent, _ChPid, _Credit}       -> consumer_bias(State, 0, 2);
         _                                    -> 0
@@ -1527,23 +1544,28 @@ handle_cast({deliver,
     State1 = State#q{senders = Senders1},
     noreply(maybe_deliver_or_enqueue(Delivery, Delivered, State1));
 
+%% Compat for RabbitMQ 4.2. @todo Remove when 'rabbitmq_4.3.0' FF is required.
 handle_cast({ack, AckTags, ChPid}, State) ->
+    handle_cast({complete, AckTags, ChPid}, State);
+handle_cast({reject, true, AckTags, ChPid}, State) ->
+    handle_cast({requeue, AckTags, ChPid}, State);
+handle_cast({reject, false, AckTags, ChPid}, State) ->
+    handle_cast({discard, AckTags, ChPid}, State);
+
+handle_cast({complete, AckTags, ChPid}, State) ->
     noreply(ack(AckTags, ChPid, State));
 
-handle_cast({reject, true,  AckTags, ChPid}, State) ->
-    noreply(requeue(AckTags, ChPid, State));
+handle_cast({requeue, AckTags, ChPid}, State) ->
+    noreply(requeue(AckTags, false, ChPid, State));
 
-handle_cast({reject, false, AckTags, ChPid}, State) ->
-    noreply(with_dlx(
-              State#q.dlx,
-              fun (X) -> subtract_acks(ChPid, AckTags, State,
-                                       fun (State1) ->
-                                               dead_letter_rejected_msgs(
-                                                 AckTags, X, State1)
-                                       end) end,
-              fun () -> rabbit_global_counters:messages_dead_lettered(rejected, rabbit_classic_queue,
-                                                                      disabled, length(AckTags)),
-                        ack(AckTags, ChPid, State) end));
+handle_cast({discard, AckTags, ChPid}, State) ->
+    noreply(discard(AckTags, true, ChPid, State));
+
+handle_cast({modify, AckTags, DelFailed, false, _Anns, ChPid}, State) ->
+    noreply(requeue(AckTags, DelFailed, ChPid, State));
+
+handle_cast({modify, AckTags, DelFailed, true, _Anns, ChPid}, State) ->
+    noreply(discard(AckTags, DelFailed, ChPid, State));
 
 handle_cast({delete_exclusive, ConnPid}, State) ->
     log_delete_exclusive(ConnPid, State),

deps/rabbit/src/rabbit_backing_queue.erl

@@ -163,11 +163,11 @@
 
 %% Reinsert messages into the queue which have already been delivered
 %% and were pending acknowledgement.
--callback requeue([ack()], state()) -> {msg_ids(), state()}.
+-callback requeue([ack()], boolean(), state()) -> {msg_ids(), state()}.
 
 %% Fold over messages by ack tag. The supplied function is called with
 %% each message, its ack tag, and an accumulator.
--callback ackfold(msg_fun(A), A, state(), [ack()]) -> {A, state()}.
+-callback ackfold(msg_fun(A), A, state(), [ack()], boolean()) -> {A, state()}.
 
 %% How long is my queue?
 -callback len(state()) -> non_neg_integer().

deps/rabbit/src/rabbit_classic_queue.erl

@@ -333,16 +333,31 @@ cancel(Q, Spec, State) ->
 -spec settle(rabbit_amqqueue:name(), rabbit_queue_type:settle_op(),
              rabbit_types:ctag(), [non_neg_integer()], state()) ->
     {state(), rabbit_queue_type:actions()}.
-settle(QName, {modify, _DelFailed, Undel, _Anns}, CTag, MsgIds, State) ->
+settle(QName, Op, CTag, MsgIds, State) ->
+    case rabbit_feature_flags:is_enabled('rabbitmq_4.3.0') of
+        true -> settle_43(QName, Op, CTag, MsgIds, State);
+        false -> settle_compat(QName, Op, CTag, MsgIds, State)
+    end.
+
+settle_43(_QName, {modify, DelFailed, Undel, Anns}, _CTag, MsgIds, State = #?STATE{pid = Pid}) ->
+    Arg = {modify, MsgIds, DelFailed, Undel, Anns, self()},
+    delegate:invoke_no_result(Pid, {gen_server2, cast, [Arg]}),
+    {State, []};
+settle_43(_QName, Op, _CTag, MsgIds, State = #?STATE{pid = Pid}) ->
+    Arg = {Op, MsgIds, self()},
+    delegate:invoke_no_result(Pid, {gen_server2, cast, [Arg]}),
+    {State, []}.
+
+settle_compat(QName, {modify, _DelFailed, Undel, _Anns}, CTag, MsgIds, State) ->
     %% translate modify into other op
     Op = case Undel of
              true ->
                  discard;
              false ->
                  requeue
          end,
-    settle(QName, Op, CTag, MsgIds, State);
-settle(_QName, Op, _CTag, MsgIds, State = #?STATE{pid = Pid}) ->
+    settle_compat(QName, Op, CTag, MsgIds, State);
+settle_compat(_QName, Op, _CTag, MsgIds, State = #?STATE{pid = Pid}) ->
     Arg = case Op of
               complete ->
                   {ack, MsgIds, self()};
@@ -430,6 +445,8 @@ supports_stateful_delivery() -> true.
 deliver(Qs0, Msg0, Options) ->
     %% add guid to content here instead of in rabbit_basic:message/3,
     %% as classic queues are the only ones that need it
+    %% @todo Do we need to regenerate it for every time it gets dead lettered?
+    %%       We can likely do better and avoid rewriting to the shared message store.
     Msg = mc:prepare(store, mc:set_annotation(id, rabbit_guid:gen(), Msg0)),
     Mandatory = maps:get(mandatory, Options, false),
     MsgSeqNo = maps:get(correlation, Options, undefined),

deps/rabbit/src/rabbit_core_ff.erl

@@ -218,3 +218,10 @@
       depends_on    => ['rabbitmq_4.1.0'],
       callbacks     => #{enable => {rabbit_khepri, enable_feature_flag}}
      }}).
+
+-rabbit_feature_flag(
+   {'rabbitmq_4.3.0',
+    #{desc          => "Allows rolling upgrades to 4.3.x",
+      stability     => stable,
+      depends_on    => ['rabbitmq_4.2.0']
+     }}).

deps/rabbit/src/rabbit_priority_queue.erl

@@ -28,8 +28,8 @@
 -export([init/3, terminate/2, delete_and_terminate/2, delete_crashed/1,
          purge/1, purge_acks/1,
          publish/5, publish_delivered/4, discard/3, drain_confirmed/1,
-         dropwhile/2, fetchwhile/4, fetch/2, drop/2, ack/2, requeue/2,
-         ackfold/4, len/1, is_empty/1, depth/1,
+         dropwhile/2, fetchwhile/4, fetch/2, drop/2, ack/2, requeue/3,
+         ackfold/5, len/1, is_empty/1, depth/1,
          update_rates/1, needs_timeout/1, timeout/1,
          handle_pre_hibernate/1, resume/1, msg_rates/1,
          info/2, invoke/3, is_duplicate/2,
@@ -279,27 +279,27 @@ ack(AckTags, State = #state{bq = BQ}) ->
 ack(AckTags, State = #passthrough{bq = BQ, bqs = BQS}) ->
     ?passthrough2(ack(AckTags, BQS)).
 
-requeue(AckTags, State = #state{bq = BQ}) ->
+requeue(AckTags, DelFailed, State = #state{bq = BQ}) ->
     fold_by_acktags2(fun (AckTagsN, BQSN) ->
-                             BQ:requeue(AckTagsN, BQSN)
+                             BQ:requeue(AckTagsN, DelFailed, BQSN)
                      end, AckTags, State);
-requeue(AckTags, State = #passthrough{bq = BQ, bqs = BQS}) ->
-    ?passthrough2(requeue(AckTags, BQS)).
+requeue(AckTags, DelFailed, State = #passthrough{bq = BQ, bqs = BQS}) ->
+    ?passthrough2(requeue(AckTags, DelFailed, BQS)).
 
 %% Similar problem to fetchwhile/4
-ackfold(MsgFun, Acc, State = #state{bq = BQ}, AckTags) ->
+ackfold(MsgFun, Acc, State = #state{bq = BQ}, AckTags, DelFailed) ->
     AckTagsByPriority = partition_acktags(AckTags),
     fold2(
       fun (P, BQSN, AccN) ->
               case maps:find(P, AckTagsByPriority) of
                   {ok, ATagsN} -> {AccN1, BQSN1} =
-                                      BQ:ackfold(MsgFun, AccN, BQSN, ATagsN),
+                                      BQ:ackfold(MsgFun, AccN, BQSN, ATagsN, DelFailed),
                                   {priority_on_acktags(P, AccN1), BQSN1};
                   error        -> {AccN, BQSN}
               end
       end, Acc, State);
-ackfold(MsgFun, Acc, State = #passthrough{bq = BQ, bqs = BQS}, AckTags) ->
-    ?passthrough2(ackfold(MsgFun, Acc, BQS, AckTags)).
+ackfold(MsgFun, Acc, State = #passthrough{bq = BQ, bqs = BQS}, AckTags, DelFailed) ->
+    ?passthrough2(ackfold(MsgFun, Acc, BQS, AckTags, DelFailed)).
 
 len(#state{bq = BQ, bqss = BQSs}) ->
     add0(fun (_P, BQSN) -> BQ:len(BQSN) end, BQSs);