Tsung - Using Erlang expressions in variable substitution

Question

In Tsung you can substitute variables like this: %%_counter%%. But how do I do something like %%_counter * 2 + 1%%?

Answer 1

Here's an example of adding %%_tsung_userid%% and %%_counter%% into the variable %%_total%%.

<setdynvars sourcetype="eval" code="fun({Pid,DynVars})->
                   {ok,Tsung_userid} = ts_dynvars:lookup(tsung_userid,DynVars),
                   {ok,Counter} = ts_dynvars:lookup(counter,DynVars),
                   Tsung_userid + Counter end.">
        <var name="total" />
</setdynvars>

I don't know if there's a more concise way.