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%% Generates a unique ID on the node start. |
| 2 |
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%% Registers the ID on all other nodes. |
| 3 |
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%% Used in ejabberd_local to find to which node to route IQ responses. |
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-module(mongoose_start_node_id). |
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-behaviour(gen_server). |
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%% API |
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-export([start_link/0]). |
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-export([node_id/0, node_id_to_name/1]). |
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-export([register_on_remote_node_rpc/3]). |
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%% gen_server callbacks |
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-export([init/1, handle_call/3, handle_cast/2, handle_info/2, |
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terminate/2, code_change/3]). |
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-ignore_xref([start_link/0, register_on_remote_node_rpc/3]). |
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-include("mongoose.hrl"). |
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-include("mongoose_logger.hrl"). |
| 20 |
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-type id() :: binary(). |
| 22 |
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-record(state, {start_id :: id(), mon_ref_to_start_id :: map()}). |
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-define(KEY, ?MODULE). |
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-spec node_id() -> id(). |
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node_id() -> |
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:-( |
persistent_term:get(?KEY). |
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-spec node_id_to_name(id()) -> {ok, node()} | {error, unknown_id}. |
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node_id_to_name(ID) -> |
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:-( |
case persistent_term:get({?KEY, ID}, undefined) of |
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undefined -> |
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:-( |
{error, unknown_id}; |
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Name -> |
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:-( |
{ok, Name} |
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end. |
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-spec start_link() -> {ok, pid()}. |
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start_link() -> |
| 41 |
54 |
gen_server:start_link({local, ?MODULE}, ?MODULE, [], []). |
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init(_) -> |
| 44 |
54 |
net_kernel:monitor_nodes(true), |
| 45 |
54 |
StartId = mongoose_bin:gen_from_crypto(), |
| 46 |
54 |
persistent_term:put(mongoose_start_node_id, StartId), |
| 47 |
54 |
[register_on_remote_node(RemoteNode, StartId) |
| 48 |
54 |
|| RemoteNode <- [node()|nodes()]], |
| 49 |
54 |
{ok, #state{start_id = StartId, mon_ref_to_start_id = #{}}}. |
| 50 |
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handle_call(_Request, _From, State) -> |
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:-( |
{reply, ok, State}. |
| 53 |
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handle_cast({register_cleaning_task, StartId, RemotePid}, |
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State = #state{mon_ref_to_start_id = Mon2StartId}) -> |
| 56 |
106 |
MonRef = erlang:monitor(process, RemotePid), |
| 57 |
106 |
Mon2StartId2 = maps:put(MonRef, StartId, Mon2StartId), |
| 58 |
106 |
{noreply, State#state{mon_ref_to_start_id = Mon2StartId2}}; |
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handle_cast(_Msg, State) -> |
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:-( |
{noreply, State}. |
| 61 |
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handle_info({nodeup, RemoteNode}, State = #state{start_id = StartId}) -> |
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8 |
register_on_remote_node(RemoteNode, StartId), |
| 64 |
8 |
{noreply, State}; |
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handle_info({'DOWN', MonRef, process, RemotePid, Reason}, |
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State = #state{mon_ref_to_start_id = Mon2StartId}) -> |
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23 |
case maps:get(MonRef, Mon2StartId, undefined) of |
| 68 |
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undefined -> |
| 69 |
:-( |
?LOG_ERROR(#{what => node_id_unexpected_monitor, |
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reason => Reason, |
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monitor_ref => MonRef, |
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remote_pid => RemotePid, |
| 73 |
:-( |
remote_node => node(RemotePid)}); |
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StartId -> |
| 75 |
23 |
persistent_term:erase({?KEY, StartId}), |
| 76 |
23 |
?LOG_WARNING(#{what => node_id_node_down, |
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reason => Reason, |
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monitor_ref => MonRef, |
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remote_pid => RemotePid, |
| 80 |
:-( |
remote_node => node(RemotePid)}) |
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end, |
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%% We use pid monitors instead of node monitors to avoid cleaning |
| 83 |
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%% start id when a node is restarting and reappearing very quicky. |
| 84 |
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%% I.e. node name could be reused by a newly started node, while Refs - not. |
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%% Pids could be also reused, but collisions are rare. |
| 86 |
23 |
{noreply, State#state{mon_ref_to_start_id = maps:remove(MonRef, Mon2StartId)}}; |
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handle_info(_Info, State) -> |
| 88 |
6 |
{noreply, State}. |
| 89 |
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terminate(_Reason, _State) -> |
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:-( |
ok. |
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code_change(_OldVsn, State, _Extra) -> |
| 93 |
:-( |
{ok, State}. |
| 94 |
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| 95 |
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register_on_remote_node(RemoteNode, StartId) -> |
| 96 |
137 |
Res = rpc:call(RemoteNode, ?MODULE, register_on_remote_node_rpc, |
| 97 |
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[node(), StartId, self()]), |
| 98 |
137 |
case Res of |
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ok -> |
| 100 |
137 |
ok; |
| 101 |
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_ -> |
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:-( |
?LOG_ERROR(#{what => node_id_register_on_remote_node_failed, |
| 103 |
:-( |
remote_node => RemoteNode, reason => Res}) |
| 104 |
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end. |
| 105 |
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| 106 |
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register_on_remote_node_rpc(RemoteNode, StartId, RemotePid) -> |
| 107 |
106 |
persistent_term:put({?KEY, StartId}, RemoteNode), |
| 108 |
106 |
gen_server:cast(?MODULE, {register_cleaning_task, StartId, RemotePid}), |
| 109 |
106 |
ok. |