From 58b8c9da483ccdcef2d64b8781bf014e93964934 Mon Sep 17 00:00:00 2001
From: alexnk <alexnk@amazon.com>
Date: Mon, 29 Jul 2024 09:53:17 +0300
Subject: [PATCH] Try alternative process name if cluster could not be formed

---
 deps/rabbit/src/rabbit_quorum_queue.erl | 41 +++++++++++++++++++------
 deps/rabbit/test/quorum_queue_SUITE.erl | 33 ++++++++++++++++++++
 2 files changed, 65 insertions(+), 9 deletions(-)

diff --git a/deps/rabbit/src/rabbit_quorum_queue.erl b/deps/rabbit/src/rabbit_quorum_queue.erl
index 61b7c40d5d87..d575df35f863 100644
--- a/deps/rabbit/src/rabbit_quorum_queue.erl
+++ b/deps/rabbit/src/rabbit_quorum_queue.erl
@@ -224,27 +224,48 @@ declare(Q, _Node) when ?amqqueue_is_quorum(Q) ->
 
 start_cluster(Q) ->
     QName = amqqueue:get_name(Q),
-    Durable = amqqueue:is_durable(Q),
-    AutoDelete = amqqueue:is_auto_delete(Q),
-    Arguments = amqqueue:get_arguments(Q),
     Opts = amqqueue:get_options(Q),
+    Arguments = amqqueue:get_arguments(Q),
     ActingUser = maps:get(user, Opts, ?UNKNOWN_USER),
     QuorumSize = get_default_quorum_initial_group_size(Arguments),
+    {LeaderNode, FollowerNodes} =
+        rabbit_queue_location:select_leader_and_followers(Q, QuorumSize),
     RaName = case qname_to_internal_name(QName) of
                  {ok, A} ->
                      A;
                  {error, {too_long, N}} ->
                      rabbit_data_coercion:to_atom(ra:new_uid(N))
              end,
-    {LeaderNode, FollowerNodes} =
-        rabbit_queue_location:select_leader_and_followers(Q, QuorumSize),
+    rabbit_log:debug("Will start up to ~w replicas for quorum ~ts with leader on node '~ts'",
+                     [QuorumSize, rabbit_misc:rs(QName), LeaderNode]),
+    case internal_declare(Q, RaName, LeaderNode, FollowerNodes) of
+        {error, cluster_not_formed, Queue} ->
+            _ = rabbit_amqqueue:internal_delete(Queue, ActingUser),
+            AlternativeRaName = rabbit_data_coercion:to_atom(ra:new_uid(rabbit_queue_type_util:name_concat(QName))),
+            rabbit_log:debug("Could not form cluster ~ts, trying alternative name ~ts",
+                     [RaName, AlternativeRaName]),
+            case internal_declare(Q, AlternativeRaName, LeaderNode, FollowerNodes) of
+                {ok, NewQ} -> 
+                    {new, NewQ};
+                {error, cluster_not_formed, NewQ} -> declare_queue_error(cluster_not_formed, NewQ, LeaderNode, ActingUser)
+            end;
+        {ok, NewQ} -> 
+            {new, NewQ}
+    end.
+
+internal_declare(Q, RaName, LeaderNode, FollowerNodes) ->
+    QName = amqqueue:get_name(Q),
+    Durable = amqqueue:is_durable(Q),
+    AutoDelete = amqqueue:is_auto_delete(Q),
+    Arguments = amqqueue:get_arguments(Q),
+    Opts = amqqueue:get_options(Q),
+    ActingUser = maps:get(user, Opts, ?UNKNOWN_USER),
+
     LeaderId = {RaName, LeaderNode},
     NewQ0 = amqqueue:set_pid(Q, LeaderId),
     NewQ1 = amqqueue:set_type_state(NewQ0,
                                     #{nodes => [LeaderNode | FollowerNodes]}),
 
-    rabbit_log:debug("Will start up to ~w replicas for quorum ~ts with leader on node '~ts'",
-                     [QuorumSize, rabbit_misc:rs(QName), LeaderNode]),
     case rabbit_amqqueue:internal_declare(NewQ1, false) of
         {created, NewQ} ->
             RaConfs = [make_ra_conf(NewQ, ServerId)
@@ -275,7 +296,9 @@ start_cluster(Q) ->
                                          {arguments, Arguments},
                                          {user_who_performed_action,
                                           ActingUser}]),
-                    {new, NewQ};
+                    {ok, NewQ};
+                {error, cluster_not_formed} -> 
+                    {error, cluster_not_formed, NewQ};
                 {error, Error} ->
                     declare_queue_error(Error, NewQ, LeaderNode, ActingUser)
             catch
@@ -285,7 +308,7 @@ start_cluster(Q) ->
         {existing, _} = Ex ->
             Ex
     end.
-
+ 
 declare_queue_error(Error, Queue, Leader, ActingUser) ->
     _ = rabbit_amqqueue:internal_delete(Queue, ActingUser),
     {protocol_error, internal_error,
diff --git a/deps/rabbit/test/quorum_queue_SUITE.erl b/deps/rabbit/test/quorum_queue_SUITE.erl
index 15b75fac4a69..375869c7a047 100644
--- a/deps/rabbit/test/quorum_queue_SUITE.erl
+++ b/deps/rabbit/test/quorum_queue_SUITE.erl
@@ -123,6 +123,7 @@ all_tests() ->
      consume_invalid_arg_2,
      start_queue,
      long_name,
+     conflicting_name,
      stop_queue,
      restart_queue,
      restart_all_types,
@@ -564,6 +565,38 @@ long_name(Config) ->
                          [{<<"x-queue-type">>, longstr, <<"quorum">>}])),
     ok.
 
+conflicting_name(Config) ->
+    Node = rabbit_ct_broker_helpers:get_node_config(Config, 0, nodename),
+    User = ?config(rmq_username, Config),
+    VHost1 = <<"foo">>,
+    VHost2 = <<"foo_bar">>,
+    QName1 = <<"bar_baz">>,
+    QName2 = <<"baz">>,
+    
+    ok = rabbit_ct_broker_helpers:add_vhost(Config, Node, VHost1, User),
+    ok = rabbit_ct_broker_helpers:set_full_permissions(Config, User, VHost1),
+
+    ok = rabbit_ct_broker_helpers:add_vhost(Config, Node, VHost2, User),
+     ok = rabbit_ct_broker_helpers:set_full_permissions(Config, User, VHost2),
+
+    Conn1 = rabbit_ct_client_helpers:open_unmanaged_connection(Config, Node,
+                                                              VHost1),
+    {ok, Ch1} = amqp_connection:open_channel(Conn1),
+
+    ?assertEqual({'queue.declare_ok', QName1, 0, 0},
+                 declare(Ch1, QName1,
+                         [{<<"x-queue-type">>, longstr, <<"quorum">>}])),
+
+    Conn2 = rabbit_ct_client_helpers:open_unmanaged_connection(Config, Node,
+                                                              VHost2),
+    {ok, Ch2} = amqp_connection:open_channel(Conn2),
+
+    ?assertEqual({'queue.declare_ok', QName2, 0, 0},
+                 declare(Ch2, QName2,
+                         [{<<"x-queue-type">>, longstr, <<"quorum">>}])),
+
+    ok.
+
 start_queue_concurrent(Config) ->
     Servers = rabbit_ct_broker_helpers:get_node_configs(Config, nodename),
     LQ = ?config(queue_name, Config),