script_trace([log_level, pv_format_string[, info_string]])
This function start the script tracing - this helps to better understand the flow of execution in the OpenSIPS script, like what function is executed, what line it is, etc. Moreover, you can also trace the values of pseudo-variables, as script execution progresses.

The blocks of the script where script tracing is enabled will print a line for each individual action that is done (e.g. assignments, conditional tests, module functions, core functions, etc.). Multiple pseudo-variables can be monitored by specifying a pv_format_string (e.g. "$ru---$avp(var1)").

The logs produced by multiple/different traced regions of your script can be differentiated (tagged) by specifying an additional plain string - info_string - as the 3rd parameter.

To disable script tracing, just do script_trace(). Otherwise, the tracing will automatically stop at the end the end of the top route.

Example of usage:

    script_trace( 1, "$rm from $si, ruri=$ru", "me");
will produce:
[line 578][me][module consume_credentials] -> (INVITE from ,
[line 581][me][core setsflag] -> (INVITE from ,
[line 583][me][assign equal] -> (INVITE from ,
[line 592][me][core if] -> (INVITE from ,
[line 585][me][module is_avp_set] -> (INVITE from ,
[line 589][me][core if] -> (INVITE from ,
[line 586][me][module is_method] -> (INVITE from ,
[line 587][me][module trace_dialog] -> (INVITE ,
[line 590][me][core setflag] -> (INVITE from ,