File 3421-Reconnect-to-epmd.patch of Package erlang
From 180d8555d8b364b367cd3e43a4cb03e7be9642b6 Mon Sep 17 00:00:00 2001
From: Simon Cornish <zl9d97p02@sneakemail.com>
Date: Mon, 25 Jan 2021 09:43:28 -0800
Subject: [PATCH] Reconnect to epmd
When the connection to epmd is lost, try to reconnect every 2s
---
erts/doc/src/erl_dist_protocol.xml | 3 -
lib/kernel/doc/src/erl_epmd.xml | 6 +-
lib/kernel/src/erl_epmd.erl | 17 ++++-
lib/kernel/test/erl_distribution_SUITE.erl | 88 ++++++++++++++++++++++
4 files changed, 107 insertions(+), 7 deletions(-)
diff --git a/erts/doc/src/erl_dist_protocol.xml b/erts/doc/src/erl_dist_protocol.xml
index 8cb8e09615..a8ec5bbaeb 100644
--- a/erts/doc/src/erl_dist_protocol.xml
+++ b/erts/doc/src/erl_dist_protocol.xml
@@ -430,9 +430,6 @@ io:format("old/unused name ~ts at port ~p, fd = ~p ~n",
<p>where n = <c>Length</c> - 1.</p>
- <p>The current implementation of Erlang does not care if the connection
- to the EPMD is broken.</p>
-
<p>The response for a <c>STOP_REQ</c> is as follows:</p>
<table align="left">
diff --git a/lib/kernel/src/erl_epmd.erl b/lib/kernel/src/erl_epmd.erl
index 7cc84b2475..96806ae3e7 100644
--- a/lib/kernel/src/erl_epmd.erl
+++ b/lib/kernel/src/erl_epmd.erl
@@ -53,13 +53,14 @@
-import(lists, [reverse/1]).
--record(state, {socket, port_no = -1, name = ""}).
+-record(state, {socket, port_no = -1, name = "", family}).
-type state() :: #state{}.
-include("inet_int.hrl").
-include("erl_epmd.hrl").
+-define(RECONNECT_TIME, 2000).
%%%----------------------------------------------------------------------
%%% API
%%%----------------------------------------------------------------------
@@ -228,7 +230,8 @@ handle_call({register, Name, PortNo, Family}, _From, State) ->
{alive, Socket, Creation} ->
S = State#state{socket = Socket,
port_no = PortNo,
- name = Name},
+ name = Name,
+ family = Family},
{reply, {ok, Creation}, S};
Error ->
{reply, Error, State}
@@ -263,7 +266,17 @@ handle_cast(_, State) ->
-spec handle_info(term(), state()) -> {'noreply', state()}.
handle_info({tcp_closed, Socket}, State) when State#state.socket =:= Socket ->
+ erlang:send_after(?RECONNECT_TIME, self(), reconnect),
{noreply, State#state{socket = -1}};
+handle_info(reconnect, State) when State#state.socket =:= -1 ->
+ case do_register_node(State#state.name, State#state.port_no, State#state.family) of
+ {alive, Socket, _Creation} ->
+ %% ignore the received creation
+ {noreply, State#state{socket = Socket}};
+ _Error ->
+ erlang:send_after(?RECONNECT_TIME, self(), reconnect),
+ {noreply, State}
+ end;
handle_info(_, State) ->
{noreply, State}.
diff --git a/lib/kernel/test/erl_distribution_SUITE.erl b/lib/kernel/test/erl_distribution_SUITE.erl
index 67faa4911c..1c7b067375 100644
--- a/lib/kernel/test/erl_distribution_SUITE.erl
+++ b/lib/kernel/test/erl_distribution_SUITE.erl
@@ -30,6 +30,7 @@
-export([tick/1, tick_change/1,
nodenames/1, hostnames/1,
illegal_nodenames/1, hidden_node/1,
+ epmd_reconnect/1,
setopts/1,
table_waste/1, net_setuptime/1,
inet_dist_options_options/1,
@@ -54,6 +55,7 @@
tick_cli_test/1, tick_cli_test1/1,
tick_serv_test/2, tick_serv_test1/1,
run_remote_test/1,
+ epmd_reconnect_do/2,
setopts_do/2,
setopts_deadlock_test/2,
keep_conn/1, time_ping/1]).
@@ -64,6 +66,8 @@
-export([pinger/1]).
-define(DUMMY_NODE,dummy@test01).
+-define(ALT_EPMD_PORT, "12321").
+-define(ALT_EPMD_CMD, "epmd -port "++?ALT_EPMD_PORT).
%%-----------------------------------------------------------------
%% The distribution is mainly tested in the big old test_suite.
@@ -82,6 +86,7 @@ all() ->
all() ->
[tick, tick_change, nodenames, hostnames, illegal_nodenames,
+ epmd_reconnect,
hidden_node, setopts,
table_waste, net_setuptime, inet_dist_options_options,
{group, monitor_nodes}].
@@ -117,9 +122,15 @@ init_per_testcase(TC, Config) when TC == hostnames;
file:make_dir("hostnames_nodedir"),
file:write_file("hostnames_nodedir/ignore_core_files",""),
Config;
+init_per_testcase(epmd_reconnect, Config) ->
+ [] = os:cmd(?ALT_EPMD_CMD++" -relaxed_command_check -daemon"),
+ Config;
init_per_testcase(Func, Config) when is_atom(Func), is_list(Config) ->
Config.
+end_per_testcase(epmd_reconnect, _Config) ->
+ os:cmd(?ALT_EPMD_CMD++" -kill"),
+ ok;
end_per_testcase(_Func, _Config) ->
ok.
@@ -427,6 +438,83 @@ tick_cli_test1(Node) ->
end
end.
+epmd_reconnect(Config) when is_list(Config) ->
+ NodeNames = [N1,N2,N3] = get_nodenames(3, ?FUNCTION_NAME),
+ Nodes = [atom_to_list(full_node_name(NN)) || NN <- NodeNames],
+
+ DCfg = "-epmd_port "++?ALT_EPMD_PORT,
+
+ {_N1F,Port1} = start_node_unconnected(DCfg, N1, ?MODULE, run_remote_test,
+ ["epmd_reconnect_do", atom_to_list(node()), "1" | Nodes]),
+ {_N2F,Port2} = start_node_unconnected(DCfg, N2, ?MODULE, run_remote_test,
+ ["epmd_reconnect_do", atom_to_list(node()), "2" | Nodes]),
+ {_N3F,Port3} = start_node_unconnected(DCfg, N3, ?MODULE, run_remote_test,
+ ["epmd_reconnect_do", atom_to_list(node()), "3" | Nodes]),
+ Ports = [Port1, Port2, Port3],
+
+ ok = reap_ports(Ports),
+
+ ok.
+
+reap_ports([]) ->
+ ok;
+reap_ports(Ports) ->
+ case (receive M -> M end) of
+ {Port, Message} ->
+ case lists:member(Port, Ports) andalso Message of
+ {data,String} ->
+ io:format("~p: ~s\n", [Port, String]),
+ reap_ports(Ports);
+ {exit_status,0} ->
+ reap_ports(Ports -- [Port])
+ end
+ end.
+
+epmd_reconnect_do(_Node, ["1", Node1, Node2, Node3]) ->
+ Names = [Name || Name <- [hd(string:tokens(Node, "@")) || Node <- [Node1, Node2, Node3]]],
+ %% wait until all nodes are registered
+ ok = wait_for_names(Names),
+ "Killed" ++_ = os:cmd(?ALT_EPMD_CMD++" -kill"),
+ open_port({spawn, ?ALT_EPMD_CMD}, []),
+ %% check that all nodes reregister with epmd
+ ok = wait_for_names(Names),
+ lists:foreach(fun(Node) ->
+ ANode = list_to_atom(Node),
+ pong = net_adm:ping(ANode),
+ {epmd_reconnect_do, ANode} ! {stop, Node1, Node}
+ end, [Node2, Node3]),
+ ok;
+epmd_reconnect_do(_Node, ["2", Node1, Node2, _Node3]) ->
+ register(epmd_reconnect_do, self()),
+ receive {stop, Node1, Node2} ->
+ ok
+ after 7000 ->
+ exit(timeout)
+ end;
+epmd_reconnect_do(_Node, ["3", Node1, _Node2, Node3]) ->
+ register(epmd_reconnect_do, self()),
+ receive {stop, Node1, Node3} ->
+ ok
+ after 7000 ->
+ exit(timeout)
+ end.
+
+wait_for_names(Names) ->
+ %% wait for up to 3 seconds (the current retry timer in erl_epmd is 2s)
+ wait_for_names(lists:sort(Names), 30, 100).
+
+wait_for_names(Names, N, Wait) when N > 0 ->
+ try
+ {ok, Info} = erl_epmd:names(),
+ Names = lists:sort([Name || {Name, _Port} <- Info]),
+ ok
+ catch
+ error:{badmatch, _} ->
+ timer:sleep(Wait),
+ wait_for_names(Names, N-1, Wait)
+ end.
+
+
setopts(Config) when is_list(Config) ->
register(setopts_regname, self()),
[N1,N2,N3,N4,N5] = get_nodenames(5, setopts),
--
2.26.2
