Erlang module for Tsung to extract data from large files

elasticsearch.erl

-module(elasticsearch).
-export([autocomplete/1, autocomplete/0,
         search/1, search/0,
         start/0,
         stop/0,
         loop/1]).
-on_load(start/0).

%% Return an autocomplete request
autocomplete() ->
    autocomplete(true).
autocomplete(_) ->
    elasticsearch_autocomplete ! {next, self()},
    receive
        {ok, Json} -> Json
    end.

%% Return a search request
search() ->
    search(true).
search(_) ->
    elasticsearch_search ! {next, self()},
    receive
        {ok, Json} -> Json
    end.

%% Start/stop file processes
start() ->
    true = start(elasticsearch_autocomplete, "/data/tsung/autocomplete4"),
    true = start(elasticsearch_search, "/data/tsung/top"),
    ok.
start(Process, Table) ->
    register(Process,
             spawn(?MODULE, loop, [Table])).
stop() ->
    true = stop(elasticsearch_autocomplete) and
        stop(elasticsearch_search),
    ok.
stop(Process) ->
    Process ! {kill, self()},
    receive
        ok -> true;
        _ -> false
    end.

%% Main loop for file processes
loop(Table) ->
    {ok, Ref} = file:open(Table, [read]),
    loop(Ref, Table).

loop(Ref, Table) ->
    receive
        {next, From} ->
            send_next_line(Ref, Table, From);
        {kill, From} ->
            From ! ok
    end.

send_next_line(Ref, Table, From) ->
    R = file:read_line(Ref),
    case R of
        {ok, Line} ->
            send_next_line(Ref, Table, From, Line);
        eof ->
            ok = file:close(Ref),
            {ok, NRef} = file:open(Table, [read]),
            send_next_line(NRef, Table, From)
    end.

send_next_line(Ref, Table, From, Line) ->
    NLine = string:strip(Line),
    case NLine of
        "" ->
            send_next_line(Ref, Table, From);
        _ ->
            From ! {ok, NLine},
            loop(Ref, Table)
    end.

elasticsearch.xml

<?xml version="1.0"?>
<!DOCTYPE tsung SYSTEM "/usr/share/tsung/tsung-1.0.dtd">
<tsung loglevel="notice" version="1.0">
  <clients>
    <client host="bench-02" maxusers="15000" cpu="4"/>
    <client host="bench-03" maxusers="15000" cpu="4"/>
    <client host="bench-04" maxusers="15000" cpu="4"/>
    <client host="bench-05" maxusers="15000" cpu="4"/>
    <client host="bench-06" maxusers="15000" cpu="4"/>
    <client host="bench-07" maxusers="15000" cpu="4"/>
    <client host="bench-08" maxusers="15000" cpu="4"/>
    <client host="bench-09" maxusers="15000" cpu="4"/>
  </clients>
  
  <servers>
    <server host="es-18" port="9200" type="tcp"></server>
    <server host="es-19" port="9200" type="tcp"></server>
    <server host="es-20" port="9200" type="tcp"></server>
    <server host="es-21" port="9200" type="tcp"></server>
    <server host="es-22" port="9200" type="tcp"></server>
    <server host="es-23" port="9200" type="tcp"></server>
    <server host="es-24" port="9200" type="tcp"></server>
    <server host="es-25" port="9200" type="tcp"></server>
    <server host="es-26" port="9200" type="tcp"></server>
    <server host="es-27" port="9200" type="tcp"></server>
    <server host="es-28" port="9200" type="tcp"></server>
    <server host="es-29" port="9200" type="tcp"></server>
    <server host="es-30" port="9200" type="tcp"></server>
  </servers>

  <monitoring>
    <monitor host="es-18" type="snmp"></monitor>
    <monitor host="es-19" type="snmp"></monitor>
    <monitor host="es-20" type="snmp"></monitor>
    <monitor host="es-21" type="snmp"></monitor>
    <monitor host="es-22" type="snmp"></monitor>
    <monitor host="es-23" type="snmp"></monitor>
    <monitor host="es-24" type="snmp"></monitor>
    <monitor host="es-25" type="snmp"></monitor>
    <monitor host="es-26" type="snmp"></monitor>
    <monitor host="es-27" type="snmp"></monitor>
    <monitor host="es-28" type="snmp"></monitor>
    <monitor host="es-29" type="snmp"></monitor>
    <monitor host="es-30" type="snmp"></monitor>
  </monitoring>
  
  <load>
   <arrivalphase phase="0" duration="30" unit="second">
     <users arrivalrate="1000" unit="second"></users>
   </arrivalphase>

   <arrivalphase phase="1" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="2" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="3" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="4" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="5" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="6" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="7" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="8" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="9" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
   <arrivalphase phase="10" duration="30" unit="second">
     <users maxnumber="5000" arrivalrate="500" unit="second"></users>
   </arrivalphase>
  </load>

  <options>
   <option type="ts_http" name="user_agent">
    <user_agent probability="100">Mozilla/5.0 (X11; Linux x86_64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/29.0.1547.57 Safari/537.36</user_agent>
   </option>
  </options>

 <sessions>
  <session name="elasticsearch" probability="100" type="ts_http">
    <for from="1" to="10000" incr="1" var="counter">
      <transaction name="autocomplete">
        <request subst="true">
          <http url="/autocomplete/suggest/_search" method="POST" version="1.1"
                contents="%%elasticsearch:autocomplete%%"
                content_type="application/json">
          </http>
        </request>
      </transaction>
      <thinktime min="1" max="2" random="true"/>
      <transaction name="search">
        <request subst="true">
          <http url="/video/video/_search" method="POST" version="1.1"
                contents="%%elasticsearch:search%%"
                content_type="application/json">
          </http>
        </request>
      </transaction>
      <thinktime min="1" max="4" random="true"/>
    </for>
  </session>
 </sessions>
</tsung>