[SOLVED] escaping from a function

[mbeals]

I'm writing a script that uses snmpwalk to pull in info off a server.  The gateway in front of the server has a failover such that if one network interface drops, the other comes alive.  So I effectively have two ips, one of which is active.  To do this I have a function that attempts to snmpwalk several OIDS for a given IP.  If the function succeeds, then it returns 1.  If the snmpwalk fails, I need to stop execution of the function so that it doesn't attempt to keep walking the same IP several more times.  Currently I use die() in the error handler, but that kills the entire script....I just need to stop execution of the function while allowing the script to move on to try the next IP address.  How do I construct an error handler to kill a function, but then allow the parent script to keep processing?

 

function walkProp($ip) {


function walkError($errno, $errstr)
	 { 
	die();
	 }

global $uptime, $MAC, $RX, $STAT, $SNR;

set_error_handler("walkError");
$uptime = snmpwalk($ip, "***, "1.3.6.1.2.1.1.9.1.4");
$MAC = snmpwalk($ip, "***", "1.3.6.1.2.1.10.127.1.3.3.1.2");
$RX = snmpwalk($ip, "***", "1.3.6.1.2.1.10.127.1.3.3.1.6");
$STAT = snmpwalk($ip, "***", "1.3.6.1.2.1.10.127.1.3.3.1.9");
$SNR = snmpwalk($ip, "***", "1.3.6.1.2.1.10.127.1.3.3.1.13");
restore_error_handler();

return '1';
}


if(walkProp($ip1)){
echo "IP 1 active";
}elseif(walkProp($ip2)){
echo "IP 2 active";
}else{
echo "connection down";
}

 

 

[GingerRobot]

You just need a return statement. A return statement literally returns control of the script back to where the function was called.

[mbeals]

i tried a return like this:

 

function walkProp($ip) {


function customError()
	 { 
	return false;
	 }

global $uptime, $MAC, $RX, $STAT, $SNR;

set_error_handler("customError");

$uptime = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.1.9.1.4");
$MAC = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.2");
$RX = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.6");
$STAT = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.9");
$SNR = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.13");
restore_error_handler();


return '1';
}

 

but it keeps marching through the function code as if an error handler wasn't even there.

[Ken2k7]

Can you explain your problem more accurately and more specifically? I don't understand

 

What do you mean 'kill a function'? Can you put up an example of what you want for success and fail attempts?

[mbeals]

The function is the one I just posted.  There are 5 consecutive SNMPwalk calls.

 

If the snmpwalk call is successful, then the data is recorded into the global variable and the function moves on to the next one.  If all 5 are successful then the function exits, returning 1.

 

If a snmpwalk fails, I want to halt execution of the function....preventing it from attempting to snmpwalk the same ip address again and again only to have it fail each time....and exit the function, returning 0 instead.

 

So when I run the function for IP1, if the IP is alive and host reachable, then the data retrieved by the snmpwalk is stored in a set of vars and my program can go on to finish processing that data.  If IP1 fails, then it moves on to IP2 and repeats

[Ken2k7]

So by snmpwalk fails, do you mean if one fails or if they all fail?

[mbeals]

if one fails.  As soon as snmpwalk returns an error, I want the function to give and just return 0.

[Ken2k7]

Oh, well I think you can just use a simple if statement for each statement. If any returns false, then you can return 0 right there and once a function hits the return line, the function stops.

 

So like:

if (!$uptime = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.1.9.1.4")) return 0;

else if (!$MAC = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.2")) return 0;

.

.

.

 

Get it?

[Daukan]

You can give an argument in snmpwalk() to limit it to one try manual snmpwalk()

[interpim]

will something like this work?

 

if(error){

exit();

}

[mbeals]

ken,

I'll try that.  Thanks for the idea.

 

Daukan, that's fine for a single call to snmpwalk, but I'm calling it 5 times in a row.  If the first call fails (to get one value), I don't want to try and call it again (to obtain the rest of the values).

[mbeals]

will something like this work?

 

if(error){

exit();

}

 

I tried that originally.  That (as well as using exit() or die() in the error handler) causes the entire script to exit.  So if I hit an error, it wouldn't try the second IP.

[trq]

<?php

function walkProp($ip) {

  global $uptime, $MAC, $RX, $STAT, $SNR;

  $uptime = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.1.9.1.4") || return false;
  $MAC = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.2") || return false;
  $RX = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.6") || return false;
  $STAT = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.9") || return false;
  $SNR = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.10.127.1.3.3.1.13") || return false;

  return true;
}

[mbeals]

it was honestly that easy?  thanks

[mbeals]

actually.....that didn't work.  gave a parse error,

but

 

if (!$uptime = snmpwalk($ip, "c9networks", "1.3.6.1.2.1.1.9.1.4")){ return 0;}

 

worked like a charm