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當使用gen_tcp
行爲時,我發現了一個有趣的問題。我有一臺服務器和一個客戶端。服務器接受連接,客戶端創建許多進程,都嘗試連接到偵聽服務器。使用gen_tcp時接受套接字的速率
如果我嘗試啓動產生許多進程的客戶端,這些進程都嘗試同時連接到套接字,則很多進程都會失敗。但是,如果我把timer:sleep(x)
然後每個插座正在接受。
這是否意味着gen_tcp:accept()
有一個限制,它可以接受一些連接請求?
代碼爲服務器和客戶端如下:
accept(State = #state{lsocket = LSocket, num = Num}) ->
case gen_tcp:accept(LSocket) of
{ok, Socket} ->
io:format("Accepted ~p ~n", [Num]),
{sockets, List} = hd(ets:lookup(csockets, sockets)),
NewList = [Socket | List],
ets:insert(csockets, {sockets, NewList}),
Pid = spawn(fun() -> loop(Socket) end),
gen_tcp:controlling_process(Socket, Pid),
accept(State#state{num = Num + 1});
{error, closed} -> State
end.
loop(Socket) ->
case gen_tcp:recv(Socket, 0) of
{ok, Data} ->
gen_tcp:send(Socket, Data),
loop(Socket);
{error, closed} ->
io:format(" CLOSED ~n"),
ok
end.
客戶:
send(State = #state{low = Low, high = Low}) ->
State;
send(State = #state{low = Low}) ->
N = Low rem 10,
Dest = lists:nth(N + 1, State#state.dest),
spawn(?MODULE, loop, [Dest, Low]),
%%timer:sleep(1),
NewState = State#state{low = Low + 1},
send(NewState).
loop({IP, Port}, Low) ->
case gen_tcp:connect(IP, Port, [binary]) of
{ok, Socket} ->
io:format("~p Connected ~n", [Low]),
gen_tcp:send(Socket, "Hi"),
receive
{tcp, RecPort, Data} ->
io:format("I have received ~p on port ~p ~p ~n", [Data, RecPort, Low])
end;
_Else ->
io:format("The connection failed ~n"),
loop({IP, Port}, Low)
end.
您可以在客戶端中打印_Else結果以獲取無法連接到服務器的原因。我已經重新格式化了您的帖子,以便更輕鬆地閱讀它。 看來,當客戶端成功連接時,客戶端不會循環,並且進程立即終止,關閉套接字。 – Pascal
您需要檢查您的TCP偵聽積壓,默認值爲5.您可以通過'{backlog,B}'選項在您的監聽調用中進行設置,其中'B'是一個整數。哦,而且'gen_tcp'不是行爲,它只是一個模塊。 –