1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
|
%% 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) 2010-2021 VMware, Inc. or its affiliates. All rights reserved.
%%
-module(rabbit_mirror_queue_mode_nodes).
-include("rabbit.hrl").
-behaviour(rabbit_mirror_queue_mode).
-export([description/0, suggested_queue_nodes/5, validate_policy/1]).
-rabbit_boot_step({?MODULE,
[{description, "mirror mode nodes"},
{mfa, {rabbit_registry, register,
[ha_mode, <<"nodes">>, ?MODULE]}},
{requires, rabbit_registry},
{enables, kernel_ready}]}).
description() ->
[{description, <<"Mirror queue to specified nodes">>}].
suggested_queue_nodes(PolicyNodes0, CurrentMaster, _SNodes, SSNodes, NodesRunningRabbitMQ) ->
PolicyNodes1 = [list_to_atom(binary_to_list(Node)) || Node <- PolicyNodes0],
%% If the current master is not in the nodes specified, then what we want
%% to do depends on whether there are any synchronised mirrors. If there
%% are then we can just kill the current master - the admin has asked for
%% a migration and we should give it to them. If there are not however
%% then we must keep the master around so as not to lose messages.
PolicyNodes = case SSNodes of
[] -> lists:usort([CurrentMaster | PolicyNodes1]);
_ -> PolicyNodes1
end,
Unavailable = PolicyNodes -- NodesRunningRabbitMQ,
AvailablePolicyNodes = PolicyNodes -- Unavailable,
case AvailablePolicyNodes of
[] -> %% We have never heard of anything? Not much we can do but
%% keep the master alive.
{CurrentMaster, []};
_ -> case lists:member(CurrentMaster, AvailablePolicyNodes) of
true -> {CurrentMaster,
AvailablePolicyNodes -- [CurrentMaster]};
false -> %% Make sure the new master is synced! In order to
%% get here SSNodes must not be empty.
SyncPolicyNodes = [Node ||
Node <- AvailablePolicyNodes,
lists:member(Node, SSNodes)],
NewMaster = case SyncPolicyNodes of
[Node | _] -> Node;
[] -> erlang:hd(SSNodes)
end,
{NewMaster, AvailablePolicyNodes -- [NewMaster]}
end
end.
validate_policy([]) ->
{error, "ha-mode=\"nodes\" list must be non-empty", []};
validate_policy(Nodes) when is_list(Nodes) ->
case [I || I <- Nodes, not is_binary(I)] of
[] -> ok;
Invalid -> {error, "ha-mode=\"nodes\" takes a list of strings, "
"~p was not a string", [Invalid]}
end;
validate_policy(Params) ->
{error, "ha-mode=\"nodes\" takes a list, ~p given", [Params]}.
|
