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<!-- Module User's Guide -->

<chapter>
    
    <title>&adminguide;</title>
    
    <section>
	<title>Overview</title>
	<para>
		This module provides an interactive config file debugger. It can print
		a trace of config script execution for a SIP message to log and set
		breakpoints on every script action, allowing step-by-step execution of 
		the routing and response scripts.
	</para>
	<para>
		Debugging can be done from local or remote host via RPC interface (e.g.,
		XMLRPC, &sercmd;, siremis).
	</para>
	<para>
		The framework to set breakpoints on specific actions and config lines
		is not exported to RPC. Each action can be accompanied by an
		breakpoint or you can use dbg_breakpoint() function to set a breakpoint
		at certain line. Global breakpoints can be enabled/disabled at runtime.
		The script running trace can also be enabled/disabled at runtime.
	</para>
	<para>
		When the SIP router process is stopped at a breakpoint, you can
		investigate the values of any pseudo-variables. Note that some of
		pseudo-variables may produce memory leaks; a fix is planned in the
		future (here fall pseudo-variables with dynamic name such as htable,
		sqlops). References to SIP message, avps, headers, script and shared
		variables are safe.
	</para>
    </section>
    <section>
	<title>Dependencies</title>
	<section>
	    <title>&kamailio; Modules</title>
	    <para>
		The following modules must be loaded before this module:
	    	<itemizedlist>
		    <listitem>
			<para>
			    <emphasis>none</emphasis>.
			</para>
		    </listitem>
	    	</itemizedlist>
	    </para>
	</section>
	<section>
	    <title>External Libraries or Applications</title>
	    <para>
		The following libraries or applications must be installed before running
		&kamailio; with this module loaded:
	    	<itemizedlist>
		    <listitem>
			<para>
			    <emphasis>None</emphasis>.
			</para>
		    </listitem>
	    	</itemizedlist>
	    </para>
	</section>
    </section>
    <section>
	<title>Parameters</title>
	<section>
	    <title><varname>cfgtrace</varname> (int)</title>
	    <para>
			Control whether the config script trace is enabled or disabled
			at startup. You can change the value at runtime without
			restart, globally or per process.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>0</quote> (disabled).
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>cfgtrace</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "cfgtrace", 1)
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>breakpoint</varname> (int)</title>
	    <para>
			Control whether every line (global) breakpoint is enabled
			or disabled at startup.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>0</quote> (disabled).
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>breakpoint</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "breakpoint", 1)
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>log_level</varname> (int)</title>
	    <para>
			What log level is to be used to print module-specific messages.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>-1</quote> (L_ERR).
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>log_level</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "log_level", 1)
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>log_facility</varname> (str)</title>
	    <para>
			Which log facility is to be used to print module-specific messages.
			By using this setting, you can configure syslog to send debug
			messages to a separate log channel, like a specific kamailio-debug log file.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>NULL</quote> (default from core).
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>log_facility</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "log_facility", "LOG_DAEMON")
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>log_prefix</varname> (str)</title>
	    <para>
			String to print before any module-specific messages.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>*** cfgtrace:</quote>.
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>log_prefix</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "log_prefix", "from-debugger-with-love:")
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>step_usleep</varname> (int)</title>
	    <para>
			Microseconds to sleep before checking for new commands when
			waiting at a breakpoint.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>100000</quote> (that is 0.1 sec).
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>step_usleep</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "step_usleep", 500000)
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>step_loops</varname> (int)</title>
	    <para>
			How many sleeps of 'step_usleep' the RPC process performs when
			waiting for a reply from a worker process before responding to RPC.
			This avoids blocking RPC process forever in case the worker
			process 'forgets' to write back a reply.
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>200</quote>.
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>step_loops</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "step_loops", 100)
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>mod_hash_size</varname> (int)</title>
	    <para>
		Used to compute power of two as size of internal hash table to store levels
		per module (e.g., if its set to 4, internal hash table has 16 slots).
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>0</quote> - feature disabled.
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>mod_hash_size</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "mod_hash_size", 5)
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>mod_level_mode</varname> (int)</title>
	    <para>
        Enable or disable per module log level (0 - disabled, 1 - enabled).
	    </para>
	    <para>
		<emphasis>
		    Default value is <quote>0</quote>.
		</emphasis>
	    </para>
	    <example>
		<title>Set <varname>mod_level_mode</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "mod_level_mode", 1)
...
</programlisting>
	    </example>
	</section>

	<section>
	    <title><varname>mod_level</varname> (str)</title>
	    <para>
		Specify module log level - the value must be in the format:
		modulename=level. The parameter can be set many times. For core
		log level, use module name 'core'.
	    </para>
	    <example>
		<title>Set <varname>mod_level</varname> parameter</title>
		<programlisting format="linespecific">
...
modparam("debugger", "mod_level", "core=3")
modparam("debugger", "mod_level", "tm=3")
...
</programlisting>
	    </example>
	</section>
	</section>
	
    <section>
	<title>Functions</title>
 	<section>
	    <title>
		<function moreinfo="none">dbg_breakpoint(mode)</function>
	    </title>
	    <para>
			Anchor a breakpoint at the current line of the config (the one
			on which this function is called). The 'mode' specifies whether 
			the breakpoint is enabled (1) or disabled (0) at startup.
	    </para>
		<para>
			Note that this version of the module does not export this anchors to RPC for
			interactive debugging (temporarily disabled).
	    </para>
		<example>
		<title><function>dbg_breakpoint</function> usage</title>
		<programlisting format="linespecific">
...
if($si=="10.0.0.10")
	dbg_breakpoint("1");
...
</programlisting>
	    </example>
	</section>
	
    </section>
	
	<section>
		<title>Exported RPC Functions</title>

	<section>
		<title>
		<function moreinfo="none">dbg.ls</function>
		</title>
		<para>
			List &kamailio; processes with info related to interactive
			debugging.
		</para>
		<para>
		Name: <emphasis>dbg.list</emphasis>
		</para>
		<para>Parameters:</para>
		<itemizedlist>
			<listitem><para>_pid_ : pid for which to list the details.  If 'pid' is
			omitted then will print for all processes.</para></listitem>	  
		</itemizedlist>
		<para>
		Examples of use with &sercmd;:
		</para>
        <programlisting  format="linespecific">
		dbg.ls
		dbg.ls 1234
		</programlisting>
    </section>

	<section>
		<title>
		<function moreinfo="none">dbg.trace</function>
		</title>
		<para>
			Control config script running trace.
		</para>
		<para>
		Name: <emphasis>dbg.trace</emphasis>
		</para>
		<para>Parameters:</para>
		<itemizedlist>
			<listitem><para>_cmd_ : command can be 'on' or 'off' to
				enable or disable tracing for one or all processes.</para>
		</listitem>
			<listitem><para>_pid_ : pid for which to list the details. If 'pid' is
				omitted, then details for all processes will be printed.</para>
		</listitem>
		</itemizedlist>
		<para>
		Examples for using with &sercmd;:
		</para>
        <programlisting  format="linespecific">
		dbg.trace on
		dbg.trace off
		dbg.trace on 1234
		</programlisting>
    </section>

	<section>
		<title>
		<function moreinfo="none">dbg.bp</function>
		</title>
		<para>
			Control breakpoints and config execution.
		</para>
		<para>
		Name: <emphasis>dbg.bp</emphasis>
		</para>
		<para>Parameters:</para>
		<itemizedlist>
			<listitem><para>_cmd_ : command, see next section for
			the list of available values.</para>
		</listitem>
		<listitem><para>_pid_ : process id for which to apply the command.
				If 'pid' is omitted, then the inner command will be applied 
				to all processes.</para>
		</listitem>
		<listitem><para>_params_ : extra params specific for each command.</para>
		</listitem>
		</itemizedlist>
		<para>Commands:</para>
		<itemizedlist>
		<listitem>
			<para>on - turn on breakpoints. Pid parameter is optional.
			</para>
		</listitem>
		<listitem>
			<para>off - turn off breakpoints. Pid parameter is optional.
			</para>
		</listitem>
		<listitem>
			<para>keep - keep breakpoints only for pid given as parameter
			</para>
		</listitem>
		<listitem>
			<para>release - disable breakpoints for processes that are
			not waiting at a breakpoint. Pid parameter is optional.</para>
		</listitem>
		<listitem>
			<para>next - run the action under breakpoint and stop at next one
			(step by step execution). Pid parameter is mandatory.
			</para>
		</listitem>
		<listitem>
			<para>move - run the action under breakpoint and remove the rest
			of breakpoints (continue execution without stopping again at next
			actions). Pid parameter is mandatory.</para>
		</listitem>
		<listitem>
			<para>show - print details about the current breakpoint for pid.
			Pid parameter is mandatory.</para>
		</listitem>
		<listitem>
			<para>eval - evaluate a pseudo-variable and print the result in RPC
			Pid parameter is mandatory.</para>
		</listitem>
		<listitem>
			<para>log - evaluate a pseudo-variable and print the result in SIP
			router logs. Pid parameter is mandatory.</para>
		</listitem>
		</itemizedlist>
		<para>
		Examples for using with &sercmd;:
		</para>
        <programlisting  format="linespecific">
		dbg.bp off
		dbg.bp on
		dbg.bp release
		dbg.bp on 1234
		dbg.bp eval 1234 $fu
		dbg.bp move 1234
		</programlisting>
    </section>

    </section>
	<section>
		<title>Usage</title>
		<para>
		A common usage is to investigate the execution path for a specific
		SIP message. Just enable cfg running trace, send the message and
		watch the logs.
		</para>
		<para>
		Another typical usage is to do interactive debugging and run
		each line of the route blocks of the configuration file step-by-step for a
		particular SIP message.
		</para>
		<para>
		You need to connect using &sercmd; (or other RPC client) to &kamailio;.
		Then you can enable cfg breakpoints and send the SIP message. One
		process will be in waiting state ('state' field different than 0 when
		you do dbg.ls). Calling dbg.release will set the other &kamailio;
		processes in no-breakpoint mode so they can process other SIP messages
		without need to interact with them.
		</para>
		<para>
		A process blocked at a breakpoint is waiting for a command. Use
		'dbg.bp next pid' to execute the current action and stop at the next
		one. 'dbg.bp eval pid PV' can be used to retrieve the value of PV. Once
		you are done and want to continue the execution of the config wihtout
		interaction use 'dbg.bp move pid'.
		</para>
		<para>
		Example of a session:
		</para>
<programlisting  format="linespecific">
...
&sercmd;> dbg.ls
{
	entry: 0
	pid: 6393
	set: 3
	state: 0
	in.pid: 0
	in.cmd: 0
}
{
	entry: 1
	pid: 6394
	set: 3
	state: 0
	in.pid: 0
	in.cmd: 0
}
...
{
	entry: 9
	pid: 6402
	set: 3
	state: 1
	in.pid: 0
	in.cmd: 0
}

&sercmd;> dbg.bp show 6402
at bkp [/etc/kamailio/debugger.cfg:369] a=6 n=route

&sercmd;> dbg.bp next 6402
exec [/etc/kamailio/debugger.cfg:369] a=6 n=route

&sercmd;> dbg.bp next 6402
exec [/etc/kamailio/debugger.cfg:462] a=17 n=if

&sercmd;> dbg.bp eval 6402 $fu
$fu : t=str v=sip:test@kamailio.org

&sercmd;> dbg.bp move 6402
200 ok
...
</programlisting>
		<para>
		Running the config trace looks like:
		</para>
<programlisting  format="linespecific">
...
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=368 a=6 n=route
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=461 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=456 a=26 n=mf_process_maxfwd_header
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=466 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=461 a=27 n=sanity_check
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=371 a=6 n=route
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=659 a=3 n=return
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=374 a=6 n=route
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=501 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=470 a=25 n=has_totag
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=386 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=379 a=26 n=is_method
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=386 a=25 n=t_check_trans
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=389 a=6 n=route
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=643 a=3 n=return
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=393 a=26 n=remove_hf
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=398 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=394 a=26 n=is_method
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=404 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=398 a=26 n=is_method
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=404 a=6 n=route
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=682 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=409 a=6 n=route
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=575 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=550 a=26 n=is_method
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=551 a=3 n=return
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=412 a=6 n=route
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=518 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=505 a=26 n=is_method
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=513 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=507 a=42 n=isflagset
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=516 a=17 n=if
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=513 a=26 n=save
 9(6285) ERROR: *** cfgtrace: c=[/etc/kamailio/debugger.cfg] l=516 a=3 n=exit
...
</programlisting>
		<para>
			The above example is for a registration with default config for
			version 3.1.0, without authentication. Listed fields are:
			'c' - config file; 'l' - line; 'a' - internal action id;
			'n' - name of executed action. 'ERROR' prefix is printed
			because these messages were sent to the L_ERR log level.
		</para>
    </section>

</chapter>