See #7593. Use connection_max to stop connections in rabbitmq

deps/rabbit/BUILD.bazel

@@ -39,7 +39,7 @@ _APP_ENV = """[
 	    {frame_max, 131072},
 	    %% see rabbitmq-server#1593
 	    {channel_max, 2047},
-	    {connection_max, infinity},
+	    {ranch_connection_max, infinity},
 	    {heartbeat, 60},
 	    {msg_store_file_size_limit, 16777216},
 	    {msg_store_shutdown_timeout, 600000},
@@ -507,6 +507,11 @@ rabbitmq_integration_suite(
     size = "medium",
 )
 
+rabbitmq_integration_suite(
+    name = "per_node_limit_SUITE",
+    size = "medium",
+)
+
 rabbitmq_integration_suite(
     name = "metrics_SUITE",
     size = "medium",

deps/rabbit/Makefile

@@ -26,7 +26,7 @@ define PROJECT_ENV
 	    {frame_max, 131072},
 	    %% see rabbitmq-server#1593
 	    {channel_max, 2047},
-	    {connection_max, infinity},
+	    {ranch_connection_max, infinity},
 	    {heartbeat, 60},
 	    {msg_store_file_size_limit, 16777216},
 	    {msg_store_shutdown_timeout, 600000},

deps/rabbit/priv/schema/rabbit.schema

@@ -883,6 +883,20 @@ end}.
  end
 }.
 
+{mapping, "ranch_connection_max", "rabbit.ranch_connection_max",
+  [{datatype, [{atom, infinity}, integer]}]}.
+
+{translation, "rabbit.ranch_connection_max",
+ fun(Conf) ->
+  case cuttlefish:conf_get("ranch_connection_max", Conf, undefined) of
+      undefined -> cuttlefish:unset();
+      infinity  -> infinity;
+      Val when is_integer(Val) -> Val;
+      _         -> cuttlefish:invalid("should be a non-negative integer")
+  end
+ end
+}.
+
 
 {mapping, "max_message_size", "rabbit.max_message_size",
     [{datatype, integer}, {validators, ["max_message_size"]}]}.

deps/rabbit/src/rabbit_reader.erl

@@ -1212,12 +1212,13 @@ handle_method0(#'connection.open'{virtual_host = VHost},
                State = #v1{connection_state = opening,
                            connection       = Connection = #connection{
                                                 log_name = ConnName,
+                                                port = Port,
                                                 user = User = #user{username = Username},
                                                 protocol = Protocol},
                            helper_sup       = SupPid,
                            sock             = Sock,
                            throttle         = Throttle}) ->
-
+    ok = is_over_node_connection_limit(Port),
     ok = is_over_vhost_connection_limit(VHost, User),
     ok = is_over_user_connection_limit(User),
     ok = rabbit_access_control:check_vhost_access(User, VHost, {socket, Sock}, #{}),
@@ -1318,6 +1319,20 @@ is_vhost_alive(VHostPath, User) ->
                             [VHostPath, User#user.username, VHostPath])
     end.
 
+is_over_node_connection_limit(Port) ->
+    {Addr, _, _} = hd(rabbit_networking:tcp_listener_addresses(Port)),
+    Ref = rabbit_networking:ranch_ref(Addr, Port),
+    #{active_connections := ActiveConns} = ranch:info(Ref),
+    Limit = rabbit_misc:get_env(rabbit, connection_max, infinity),
+    case ActiveConns > Limit of
+        false -> ok;
+        true ->
+            rabbit_misc:protocol_error(not_allowed,
+                                       "connection refused: "
+                                       "node connection limit (~tp) is reached",
+                                       [Limit])
+    end.
+
 is_over_vhost_connection_limit(VHostPath, User) ->
     try rabbit_vhost_limit:is_over_connection_limit(VHostPath) of
         false         -> ok;

deps/rabbit/src/tcp_listener_sup.erl

@@ -35,7 +35,7 @@ start_link(IPAddress, Port, Transport, SocketOpts, ProtoSup, ProtoOpts, OnStartu
 init({IPAddress, Port, Transport, SocketOpts, ProtoSup, ProtoOpts, OnStartup, OnShutdown,
       ConcurrentAcceptorCount, ConcurrentConnsSups, ConnectionType, Label}) ->
     {ok, AckTimeout} = application:get_env(rabbit, ssl_handshake_timeout),
-    MaxConnections = max_conn(rabbit_misc:get_env(rabbit, connection_max, infinity),
+    MaxConnections = max_conn(rabbit_misc:get_env(rabbit, ranch_connection_max, infinity),
                               ConcurrentConnsSups),
     RanchListenerOpts = #{
       num_acceptors => ConcurrentAcceptorCount,

deps/rabbit/test/config_schema_SUITE_data/rabbit.snippets

@@ -287,13 +287,13 @@ tcp_listen_options.exit_on_close = false",
   "total_memory_available_override_value = 1024MB",
   [{rabbit,[{total_memory_available_override_value, "1024MB"}]}],
   []},
- {connection_max,
+ {ranch_connection_max,
-  "connection_max = 999",
+  "ranch_connection_max = 999",
-  [{rabbit,[{connection_max, 999}]}],
+  [{rabbit,[{ranch_connection_max, 999}]}],
   []},
- {connection_max,
+ {ranch_connection_max,
-  "connection_max = infinity",
+  "ranch_connection_max = infinity",
-  [{rabbit,[{connection_max, infinity}]}],
+  [{rabbit,[{ranch_connection_max, infinity}]}],
   []},
  {channel_max,
   "channel_max = 16",

deps/rabbit/test/per_node_limit_SUITE.erl

@@ -0,0 +1,99 @@
+%% This Source Code Form is subject to the terms of the Mozilla Public
+%% License, v. 2.0. If a copy of the MPL was not distributed with this
+%% file, You can obtain one at https://mozilla.org/MPL/2.0/.
+%%
+%% Copyright (c) 2011-2023 VMware, Inc. or its affiliates.  All rights reserved.
+%%
+
+-module(per_node_limit_SUITE).
+
+-include_lib("common_test/include/ct.hrl").
+-include_lib("amqp_client/include/amqp_client.hrl").
+-include_lib("eunit/include/eunit.hrl").
+
+-compile(export_all).
+
+all() ->
+    [
+     {group, parallel_tests}
+    ].
+
+groups() ->
+    [
+     {parallel_tests, [parallel], [
+                                   node_connection_limit
+                                  ]}
+    ].
+
+suite() ->
+    [
+      {timetrap, {minutes, 3}}
+    ].
+
+%% -------------------------------------------------------------------
+%% Testsuite setup/teardown.
+%% -------------------------------------------------------------------
+
+init_per_suite(Config) ->
+    rabbit_ct_helpers:log_environment(),
+    rabbit_ct_helpers:run_setup_steps(Config).
+
+end_per_suite(Config) ->
+    rabbit_ct_helpers:run_teardown_steps(Config).
+
+init_per_group(Group, Config) ->
+    Config1 = rabbit_ct_helpers:set_config(Config, [
+                {rmq_nodename_suffix, Group},
+                {rmq_nodes_count, 1}
+              ]),
+    rabbit_ct_helpers:run_steps(Config1,
+      rabbit_ct_broker_helpers:setup_steps() ++
+      rabbit_ct_client_helpers:setup_steps()).
+
+end_per_group(_Group, Config) ->
+    rabbit_ct_helpers:run_steps(Config,
+              rabbit_ct_client_helpers:teardown_steps() ++
+              rabbit_ct_broker_helpers:teardown_steps()).
+
+init_per_testcase(Testcase, Config) ->
+    rabbit_ct_helpers:testcase_started(Config, Testcase).
+
+end_per_testcase(Testcase, Config) ->
+    rabbit_ct_helpers:testcase_finished(Config, Testcase).
+
+%% -------------------------------------------------------------------
+%% Test cases
+%% -------------------------------------------------------------------
+
+node_connection_limit(Config) ->
+    %% Set limit to 0, don't accept any connections
+    set_node_limit(Config, 0),
+    {error, not_allowed} = rabbit_ct_client_helpers:open_unmanaged_connection(Config, 0),
+
+    %% Set limit to 5, accept 5 connections
+    Connections = open_connections_to_limit(Config, 5),
+    %% But no more than 5
+    {error, not_allowed} = rabbit_ct_client_helpers:open_unmanaged_connection(Config, 0),
+    close_all_connections(Connections),
+
+    set_node_limit(Config, infinity),
+    C = rabbit_ct_client_helpers:open_unmanaged_connection(Config, 0),
+    true = is_pid(C).
+
+%% -------------------------------------------------------------------
+%% Implementation
+%% -------------------------------------------------------------------
+
+open_connections_to_limit(Config, Limit) ->
+    set_node_limit(Config, Limit),
+    Connections = [rabbit_ct_client_helpers:open_unmanaged_connection(Config, 0) || _ <- lists:seq(1,Limit)],
+    true = lists:all(fun(E) -> is_pid(E) end, Connections),
+    Connections.
+
+close_all_connections(Connections) ->
+    [rabbit_ct_client_helpers:close_connection(C) || C <- Connections].
+
+set_node_limit(Config, Limit) ->
+    rabbit_ct_broker_helpers:rpc(Config, 0,
+                                 application,
+                                 set_env, [rabbit, connection_max, Limit]).