我正在创建一个节点集群,我想每次连接一个节点时都得到通知吗?
答案 0 :(得分:5)
创建一个gen_server
并在net_kernel:monitor_nodes(true)
方法中调用init
。现在,gen_server
将在节点加入或离开群集时收到{node_up, Node}
和{node_down, Node}
消息。
-module(node_monitor).
-behaviour(gen_server).
%% export API
-export([start_link/0,
stop/0
]).
%% export gen_server callbacks
-export([init/1,
handle_call/3,
handle_cast/2,
handle_info/2,
terminate/2,
code_change/3]).
-record(state, {}).
-define(SERVER_NAME, ?MODULE).
%%====================================
%% API
%%====================================
start_link() ->
gen_server:start_link({local, ?SERVER_NAME}, ?MODULE, [], []).
stop() ->
gen_server:cast(?SERVER_NAME, stop).
%%====================================
%% callbacks
%%====================================
init([]) ->
net_kernel:monitor_nodes(true),
{ok, #state{}}.
terminate(_Reason, _State) ->
ok.
code_change(_OldVsn, State, _Extra) ->
{ok, State}.
handle_info({nodeup, _Node} = Event, State) ->
%%TODO: do something here
{noreply, State};
handle_info({nodedown, _Node} = Event, State) ->
%%TODO: do something here
{noreply, State};
handle_info(_Msg, State) ->
{noreply, State}.
handle_cast(stop, State) ->
{stop, normal, State};
handle_cast(_Msg, State) ->
{noreply, State}.
handle_call(_Msg, _From, State) ->
Reply = ok,
{reply, Reply, State}.
不过请注意,所有节点都将收到这些通知。因此,如果每个群集仅一个节点应处理node_up
和node_down
通知,则该逻辑需要在gen_server的顶部实现。