通过port获取相应的节点名

今天看了霸爷的节点间通讯的通道微调和谁引起busy_dist_port之后，自己将两章的内容连起来，组合成一个小程序，通过节点名查到相应的port，然后通过port查到相应的节点名，代码如下：

-module(busyPort).

-compile([export_all]).

start(Node) ->
	Port = node_port(Node),
	annotate_port(busy_dist_port, Port, get_node_map()).

node_port(Node)->
    {_, Owner}=lists:keyfind(owner, 1, element(2, net_kernel:node_info(Node))),
    hd([P|| P<-erlang:ports(), erlang:port_info(P, connected) == {connected,Owner}]).

get_node_map() ->
    %% We're already peeking inside of the priave #net_address record
    %% in kernel/src/net_address.hrl, but it's exposed via
    %% net_kernel:nodes_info/0.  Alas, net_kernel:nodes_info/0 has
    %% a but in R14B* and R15B, so we can't use ... so we'll cheat.
    %% e.g.
    %% (foo@sbb)11> ets:tab2list(sys_dist).
    %% [{connection,bar@sbb,up,<0.56.0>,undefined,
    %%              {net_address,{{10,1,1,34},57368},"sbb",tcp,inet},
    %%              [],normal}]
    try
        [begin
             %% element(6, T) should be a #net_address record
             %% element(2, #net_address) is an {IpAddr, Port} tuple.
             if element(1, T) == connection,
                size(element(2, element(6, T))) == 2 ->
                     {element(2, element(6, T)), element(2, T)};
                true ->
                     {bummer, bummer}
         end
         end || T <- ets:tab2list(sys_dist)]
    catch _X:_Y ->
            %%error_logger:error_msg("~s:get_node_map: ~p ~p @ ~p\n",
            %%                       [?MODULE, _X, _Y, erlang:get_stacktrace()]),
            []
    end.
 
annotate_port(PortType, Port, NodeMap) ->
    try
        %% Need 'try': may race with disconnecting TCP peer
        {ok, Peer} = inet:peername(Port),
    case PortType of
        busy_port ->
        {busy_port, Peer};
        busy_dist_port ->
        {busy_dist_port, proplists:get_value(Peer, NodeMap, unknown)}
    end
    catch
        _X:_Y ->
        Port
    end.

查看效果的时候，先启动两个erlang shell，

$ erl -sname liufan
$ erl -sname yansha

然后通过net_adm:ping(yansha).将两个节点联通起来。
之后再起一个节点$erl -sname yueping

[liufan@liufan busy_dist_port]$ erl -sname yueping
Erlang R16B01 (erts-5.10.2) [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false]

Eshell V5.10.2  (abort with ^G)
(yueping@liufan)1> net_kernel:connect(liufan@liufan).
true
(yueping@liufan)2> busyPort:start(liufan@liufan).
{busy_dist_port,liufan@liufan}
(yueping@liufan)3> net_kernel:nodes_info().
{ok,[{liufan@liufan,[{owner,<0.40.0>},
                     {state,up},
                     {address,{net_address,{{127,0,0,1},45314},
                                           "liufan",tcp,inet}},
                     {type,normal},
                     {in,11},
                     {out,13}]},
     {yansha@liufan,[{owner,<0.47.0>},
                     {state,up},
                     {address,{net_address,{{127,0,0,1},39923},
                                           "liufan",tcp,inet}},
                     {type,normal},
                     {in,5},
                     {out,4}]}]}
(yueping@liufan)4> 

这样就实现了一个查询和反查询。相关代码见附件