xt.erl

-module(xt).

-export([start/1,start/4]).
-export([connect/5]).

-define(RESPONSE_TIMEOUT, 20000).

-define(NUM_CLIENTS, 10).
-define(DELAY, 1000).
-define(NUM_REQUESTS, 100).

start(Port) ->
    start(Port, ?NUM_CLIENTS, ?DELAY, ?NUM_REQUESTS).
start(Port, NumClients, Delay, NumRequests) ->
    Packet = binary:copy(<<"x">>, 100),
    [ spawn_link(?MODULE, connect, [Port, Client, Packet, Delay, NumRequests]) || Client <- lists:seq(1, NumClients) ].

connect(Port, Client, Packet, Delay, N) ->
    timer:sleep(crypto:rand_uniform(1, 5 * 1000)), % stagger the requests (milliseconds)
    error_logger:info_report([{connecting, Client, N}]),
    {ok, Socket} = gen_tcp:connect({127,0,0,1}, Port, [binary]),
    request(Client, Socket, Packet, Delay, N).

request(Client,_,_,_,0) ->
    error_logger:info_report([{complete, {client,Client}}]),
    run_complete;
request(Client, Socket, Packet, Delay, N) ->
    Size = byte_size(Packet),
    ok = gen_tcp:send(Socket, <<Size:4/unsigned-integer-unit:8, Packet/binary>>),
    receive
        {tcp, Socket, _Data} ->
            timer:sleep(Delay),
            request(Client, Socket, Packet, Delay, N-1);
        Error ->
            Error
    end.