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%% The contents of this file are subject to the Mozilla Public License
%% Version 1.1 (the "License"); you may not use this file except in
%% compliance with the License. You may obtain a copy of the License at
%% https://www.mozilla.org/MPL/
%%
%% Software distributed under the License is distributed on an "AS IS"
%% basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
%% License for the specific language governing rights and limitations
%% under the License.
%%
%% The Original Code is RabbitMQ.
%%
%% The Initial Developer of the Original Code is GoPivotal, Inc.
%% Copyright (c) 2007-2020 VMware, Inc. or its affiliates. All rights reserved.
%%
-module(rabbit_peer_discovery_dns).
-behaviour(rabbit_peer_discovery_backend).
-include("rabbit.hrl").
-export([list_nodes/0, supports_registration/0, register/0, unregister/0,
post_registration/0, lock/1, unlock/1]).
%% for tests
-export([discover_nodes/2, discover_hostnames/2]).
%%
%% API
%%
-spec list_nodes() ->
{ok, {Nodes :: [node()], rabbit_types:node_type()}}.
list_nodes() ->
case application:get_env(rabbit, cluster_formation) of
undefined ->
{ok, {[], disc}};
{ok, ClusterFormation} ->
case proplists:get_value(peer_discovery_dns, ClusterFormation) of
undefined ->
rabbit_log:warning("Peer discovery backend is set to ~s "
"but final config does not contain rabbit.cluster_formation.peer_discovery_dns. "
"Cannot discover any nodes because seed hostname is not configured!",
[?MODULE]),
{ok, {[], disc}};
Proplist ->
Hostname = rabbit_data_coercion:to_list(proplists:get_value(hostname, Proplist)),
{ok, {discover_nodes(Hostname, net_kernel:longnames()), rabbit_peer_discovery:node_type()}}
end
end.
-spec supports_registration() -> boolean().
supports_registration() ->
false.
-spec register() -> ok.
register() ->
ok.
-spec unregister() -> ok.
unregister() ->
ok.
-spec post_registration() -> ok.
post_registration() ->
ok.
-spec lock(Node :: atom()) -> not_supported.
lock(_Node) ->
not_supported.
-spec unlock(Data :: term()) -> ok.
unlock(_Data) ->
ok.
%%
%% Implementation
%%
discover_nodes(SeedHostname, LongNamesUsed) ->
[list_to_atom(rabbit_peer_discovery:append_node_prefix(H)) ||
H <- discover_hostnames(SeedHostname, LongNamesUsed)].
discover_hostnames(SeedHostname, LongNamesUsed) ->
lookup(SeedHostname, LongNamesUsed, ipv4) ++
lookup(SeedHostname, LongNamesUsed, ipv6).
decode_record(ipv4) ->
a;
decode_record(ipv6) ->
aaaa.
lookup(SeedHostname, LongNamesUsed, IPv) ->
IPs = inet_res:lookup(SeedHostname, in, decode_record(IPv)),
rabbit_log:info("Addresses discovered via ~s records of ~s: ~s",
[string:to_upper(atom_to_list(decode_record(IPv))),
SeedHostname,
string:join([inet_parse:ntoa(IP) || IP <- IPs], ", ")]),
Hosts = [extract_host(inet:gethostbyaddr(A), LongNamesUsed, A) ||
A <- IPs],
lists:filter(fun(E) -> E =/= error end, Hosts).
%% long node names are used
extract_host({ok, {hostent, FQDN, _, _, _, _}}, true, _Address) ->
FQDN;
%% short node names are used
extract_host({ok, {hostent, FQDN, _, _, _, _}}, false, _Address) ->
lists:nth(1, string:tokens(FQDN, "."));
extract_host({error, Error}, _, Address) ->
rabbit_log:error("Reverse DNS lookup for address ~s failed: ~p",
[inet_parse:ntoa(Address), Error]),
error.
|
