move consumer listing from channel to queue

The main motivation here is that queues, not channels, are the logical
home of subscriptions. And rabbit plug-ins and other extensions may
bypass channels when subscribing to queues.

The queues also know more about consumers than channels, namely
whether a consumer requires acks. So this additional info we can now
display too.

And with the switch to queues the listing is now scoped by vhost.

5 files changed, 48 insertions, 20 deletions

diff --git a/docs/rabbitmqctl.1.pod b/docs/rabbitmqctl.1.pod
index 3f1ec3b4..398ab613 100644
--- a/docs/rabbitmqctl.1.pod
+++ b/docs/rabbitmqctl.1.pod
@@ -430,15 +430,19 @@ QoS prefetch count limit in force, 0 if unlimited
 =item list_consumers
 
 List consumers, i.e. subscriptions to a queue's message stream. Each
-line printed shows, separated by tab characters, the id of the channel
-process via which the subscription was created and is managed, the
-consumer tag which uniquely identifies the subscription within a
-channel, and the name of the queue subscribed to.
-
-The list_queues, list_exchanges and list_bindings commands accept an
-optional virtual host parameter for which to display results,
-defaulting to I<"/">. The default can be overridden with the B<-p>
-flag.
+line printed shows, separated by tab characters, the name of the queue
+subscribed to, the id of the channel process via which the
+subscription was created and is managed, the consumer tag which
+uniquely identifies the subscription within a channel, and a boolean
+indicating whether acknowledgements are expected for messages
+delivered to this consumer.
+
+=back
+
+The list_queues, list_exchanges, list_bindings and list_consumers
+commands accept an optional virtual host parameter for which to
+display results, defaulting to I<"/">. The default can be overridden
+with the B<-p> flag.
 
 =head1 OUTPUT ESCAPING
 
diff --git a/src/rabbit_amqqueue.erl b/src/rabbit_amqqueue.erl
index db7461b0..ea0eadc3 100644
--- a/src/rabbit_amqqueue.erl
+++ b/src/rabbit_amqqueue.erl
@@ -37,6 +37,7 @@
 -export([lookup/1, with/2, with_or_die/2,
          stat/1, stat_all/0, deliver/2, redeliver/2, requeue/3, ack/4]).
 -export([list/1, info_keys/0, info/1, info/2, info_all/1, info_all/2]).
+-export([consumers/1, consumers_all/1]).
 -export([claim_queue/2]).
 -export([basic_get/3, basic_consume/8, basic_cancel/4]).
 -export([notify_sent/2, unblock/2]).
@@ -74,6 +75,9 @@
 -spec(info/2 :: (amqqueue(), [info_key()]) -> [info()]).
 -spec(info_all/1 :: (vhost()) -> [[info()]]).
 -spec(info_all/2 :: (vhost(), [info_key()]) -> [[info()]]).
+-spec(consumers/1 :: (amqqueue()) -> [{pid(), ctag(), boolean()}]).
+-spec(consumers_all/1 ::
+      (vhost()) -> [{queue_name(), pid(), ctag(), boolean()}]).
 -spec(stat/1 :: (amqqueue()) -> qstats()).
 -spec(stat_all/0 :: () -> [qstats()]).
 -spec(delete/3 ::
@@ -240,6 +244,16 @@ info_all(VHostPath) -> map(VHostPath, fun (Q) -> info(Q) end).
 
 info_all(VHostPath, Items) -> map(VHostPath, fun (Q) -> info(Q, Items) end).
 
+consumers(#amqqueue{ pid = QPid }) ->
+    gen_server2:pcall(QPid, 9, consumers, infinity).
+
+consumers_all(VHostPath) ->
+    lists:concat(
+      map(VHostPath,
+          fun (Q) -> [{Q#amqqueue.name, ChPid, ConsumerTag, AckRequired} ||
+                         {ChPid, ConsumerTag, AckRequired} <- consumers(Q)]
+          end)).
+
 stat(#amqqueue{pid = QPid}) -> gen_server2:call(QPid, stat, infinity).
 
 stat_all() ->
diff --git a/src/rabbit_amqqueue_process.erl b/src/rabbit_amqqueue_process.erl
index 06e68a1b..94b89cd5 100644
--- a/src/rabbit_amqqueue_process.erl
+++ b/src/rabbit_amqqueue_process.erl
@@ -547,6 +547,15 @@ handle_call({info, Items}, _From, State) ->
     catch Error -> reply({error, Error}, State)
     end;
 
+handle_call(consumers, _From,
+            State = #q{active_consumers = ActiveConsumers,
+                       blocked_consumers = BlockedConsumers}) ->
+    reply(rabbit_misc:queue_fold(
+            fun ({ChPid, #consumer{tag = ConsumerTag,
+                                   ack_required = AckRequired}}, Acc) ->
+                    [{ChPid, ConsumerTag, AckRequired} | Acc]
+            end, [], queue:join(ActiveConsumers, BlockedConsumers)), State);
+
 handle_call({deliver_immediately, Txn, Message, ChPid}, _From, State) ->
     %% Synchronous, "immediate" delivery mode
     %%
diff --git a/src/rabbit_control.erl b/src/rabbit_control.erl
index c8a8d599..208aec09 100644
--- a/src/rabbit_control.erl
+++ b/src/rabbit_control.erl
@@ -159,7 +159,7 @@ Available commands:
   list_bindings  [-p <VHostPath>]
   list_connections [<ConnectionInfoItem> ...]
   list_channels [<ChannelInfoItem> ...]
-  list_consumers
+  list_consumers [-p <VHostPath>]
 
 Quiet output mode is selected with the \"-q\" flag. Informational
 messages are suppressed when quiet mode is in effect.
@@ -198,8 +198,10 @@ number, user, vhost, transactional, consumer_count,
 messages_unacknowledged, prefetch_count]. The default is to display
 pid, user, transactional, consumer_count, messages_unacknowledged.
 
-The output format for \"list_consumers\" is a list of rows containing
-the channel process id, consumer tag and queue name, in that order.
+The output format for \"list_consumers\" is a list of rows containing,
+in order, the queue name, channel process id, consumer tag, and a
+boolean indicating whether acknowledgements are expected from the
+consumer.
 
 "),
     halt(1).
@@ -301,8 +303,7 @@ action(list_bindings, Node, Args, Inform) ->
     display_info_list(
       [lists:zip(InfoKeys, tuple_to_list(X)) ||
           X <- rpc_call(Node, rabbit_exchange, list_bindings, [VHostArg])],
-      InfoKeys),
-    ok;
+      InfoKeys);
 
 action(list_connections, Node, Args, Inform) ->
     Inform("Listing connections", []),
@@ -318,14 +319,14 @@ action(list_channels, Node, Args, Inform) ->
     display_info_list(rpc_call(Node, rabbit_channel, info_all, [ArgAtoms]),
                       ArgAtoms);
 
-action(list_consumers, Node, [], Inform) ->
+action(list_consumers, Node, Args, Inform) ->
     Inform("Listing consumers", []),
-    InfoKeys = [channel_pid, consumer_tag, queue_name],
+    {VHostArg, _} = parse_vhost_flag_bin(Args),
+    InfoKeys = [queue_name, channel_pid, consumer_tag, ack_required],
     display_info_list(
       [lists:zip(InfoKeys, tuple_to_list(X)) ||
-          X <- rpc_call(Node, rabbit_channel, consumers_all, [])],
-      InfoKeys),
-    ok;
+          X <- rpc_call(Node, rabbit_amqqueue, consumers_all, [VHostArg])],
+      InfoKeys);
 
 action(Command, Node, Args, Inform) ->
     {VHost, RemainingArgs} = parse_vhost_flag(Args),
diff --git a/src/rabbit_tests.erl b/src/rabbit_tests.erl
index 2a580b98..ad113687 100644
--- a/src/rabbit_tests.erl
+++ b/src/rabbit_tests.erl
@@ -31,7 +31,7 @@
 
 -module(rabbit_tests).
 
--export([all_tests/0, test_parsing/0]).
+-export([all_tests/0, test_parsing/0, test_server_status/0]).
 
 %% Exported so the hook mechanism can call back
 -export([handle_hook/3, bad_handle_hook/3, extra_arg_hook/5]).