[asterisk-users] Re: FastAGI hangs up channel if server is not available

[Tony Mountifield]

In article <464C8977.4020501 at datatrakpos.com>,
Lee Jenkins <lee at datatrakpos.com> wrote:
> 
> Running 1.2.14
> 
> When I call a FastAGI script such as this script for an incoming call:
> 
> [calldirect]
> exten=>s,1,Answer()
> exten=>s,2,AGI(agi://192.168.1.175/calldirect?check&${CALLERID(num)})
> exten=>s,3,Goto(check_time,s,1)
> 
> and the FastAGI server is not running (Asterisk gets "connection 
> refused" TCP error), Asterisk just terminates the call like so:
> 
> May 17 12:58:00 WARNING[10154]: res_agi.c:210 launch_netscript: Connect 
> to 'agi://192.168.1.175/calldirect?check&NNNNNNNNNN' failed: Connection 
> refused
>    == Spawn extension (remove_caller, s, 2) exited non-zero on 
> 'SIP/datatrak-0978b670'
> 
> The text of the relevant wiki article 
> (http://www.voip-info.org/wiki-Asterisk+FastAGI) infers that execution 
> should roll through to the next executable line in the context where it 
> was called in the case of an error in executing the FastAGI:
> 
> "Asterisk 1.2
> Under Asterisk 1.2, if a request to a FastAGI service failed for any 
> reason, there was no way to determine this from the dialplan. The 
> recommended action is to set a channel variable before calling the 
> FastAGI, setting that variable to a known value within the FastAGI, and 
> then checking that variable once the AGI has returned..."
> 
> Is there a setting/var that I am missing?

No, the information is wrong. You need to make a small mod to res/res_agi.c
in order to trap this case. Look for the second occurrence of
LOCAL_USER_REMOVE, and add the lines just before it as show by this
patch extract (ignore the line numbers; I have other mods too):

@@ -2065,6 +2106,9 @@
                        close(fds[1]);
                if (efd > -1)
                        close(efd);
+       } else {
+               pbx_builtin_setvar_helper(chan, "AGISTATUS", "NOTFOUND");
+               res = 0;
        }
        LOCAL_USER_REMOVE(u);
        return res;

With this change, a refused connection will not hang up the channel, but
instead will set the AGISTATUS variable to "NOTFOUND".

Cheers
Tony
-- 
Tony Mountifield
Work: tony at softins.co.uk - http://www.softins.co.uk
Play: tony at mountifield.org - http://tony.mountifield.org