Watchdog

Created by Tika Oberueng.

LSL WATCHDOG

These are some simple scripts that watch other scripts in the same prim and restarts them if they crash.

DESIGN PRINCIPLE

First and foremost, a watchdog needs to be very robust. Small and simple is better. Performance is not a high priority and a watchdog does not need to run at a high rate of speed. For these reasons, these code examples have been written with timed self-resets, to keep the heap space clean. No fancy tricks that could lead to potential problems (more parts to break) have been included in these examples.

USE

Simply place the desired watchdog script into the prim containing the script(s) to monitor.

IMPORTANT: Hopefully it is obvious, but, the watchdog script MUST be a separate script from the primary scripts that are being watched!

OPTIONAL: Indeed, for extra assurance, you may wish to place BOTH watchdog scripts into the prim, and have the basic single-script watchdog watch the multiple script watchdog. However, it is very unlikely that you will realistically need to do so. If either watchdog regularly crashes, you have bigger problems than a watchdog can solve. :)

Enjoy. These scripts are released to the community in the public domain as of 2012-01-17. You are free to use them for any purpose including in commercial products. If you break something, you get to keep all the pieces. I only ask that you do not sell these as standalone scripts (they're on the wiki, silly). If you have improvements that you wish to share, please add it as another script on this page. -- Tika Oberueng

BASIC LSL WATCHDOG FOR A SINGLE PRIMARY SCRIPT <lsl> // Basic LSL Watchdog Script to watch a single script // 2012-01-17 By Tika Oberueng // Released to the public domain. // You break it, you get to keep both pieces. // string watchee = "Test"; // Set this to the name of a script in prim inventory to watch float interval = 60.0; // Number of seconds between watchdog checks. Probably best to keep this above >= 10

default {

   state_entry() {
       llSetTimerEvent(interval);
   }
   on_rez(integer param) {
       llResetScript();
   }
   timer() {
       llSetTimerEvent(0);
       if (!llGetScriptState(watchee)) {
           llResetOtherScript(watchee);
           llSetScriptState(watchee, TRUE);
           llRegionSay(DEBUG_CHANNEL, "Watchdog Trip: The script ["+watchee+"] has crashed and has been restarted.");
       }
       llSleep(1);
       llResetScript(); // Reset this script to keep it clean
   }

} </lsl>

BASIC LSL WATCHDOG FOR MULTIPLE SCRIPTS <lsl> // Basic LSL Watchdog Script to watch multiple scripts // 2012-01-17 By Tika Oberueng // Released to the public domain. // You break it, you get to keep both pieces. // float interval = 60.0; // Number of seconds between watchdog checks. Probably best to keep this above >= 10

default {

   state_entry() {
       llSetTimerEvent(interval);
   }
   on_rez(integer param) {
       llResetScript();
   }
   timer() {
       integer loop;
       string watchee;
       llSetTimerEvent(0);
       for (loop = llGetInventoryNumber(INVENTORY_SCRIPT) -1; loop > -1; --loop) {
           watchee = llGetInventoryName(INVENTORY_SCRIPT,loop);
           if (!llGetScriptState(watchee)) {
               if (watchee != llGetScriptName()) {
                   llResetOtherScript(watchee);
                   llSetScriptState(watchee, TRUE);
                   llRegionSay(DEBUG_CHANNEL, "Multiple Watchdog Trip: The script ["+watchee+"] has crashed and has been restarted.");
               }
           }
       }
       llSleep(1);
       llResetScript(); // Reset this script to keep it clean
   }

} </lsl>