Fwd: Issue when using agent mobility in Cougaar

[daniel domingue]

Hello,

I tried the test you proposed with the ping demo and it works, the
agent's subscription works as described.

By rewriting another identical plugin from scratch ,
I was able to isolate the problem which is in the load() method of the plugin :

	public void load()
	{
		super.load();
		
		if(blackboard.didRehydrate())
		{
			
			blackboard.openTransaction();
			Collection c = blackboard.query(new LBAgentPredicate());
			blackboard.closeTransactionDontReset();
		}
	}

When I try to get a blackboard element from the load(), the problem
occurs. When the code concerning the blackboard transaction is
commented out, it works perfectly fine.
I don't know if using this type of calls to the blackboard in the
load() method has a direct impact on the other elements in it, and if
there is a good way of implementing this.

Best regards,

	
On Wed, Jun 25, 2008 at 8:17 PM, Todd Wright <twright at bbn.com> wrote:
> Daniel,
>
> I tested this in Cougaar 12.4 using the demo "ping" society and the "/move"
> servlet and it worked for me.
>
> Maybe there's something wrong with your MoveAgent request, 'though it looks
> okay to me.  It could be a bug that doesn't happen in the ping test, e.g. a
> race condition.
>
> Please run the following test:
>
> 1) Download and unzip Cougaar 12.4 from:
> http://cougaar.org/frs/?group_id=17&release_id=161
>
> 2) Unzip the required code:
> unzip -q cougaar.zip
> unzip -q cougaar-support.zip
> unzip -q demo-ping.zip
>
> 3) Set the required environment variables:
> export COUGAAR_INSTALL_PATH=/opt/Cougaar12_4
> export COUGAAR_SOCIETY_PATH=/opt/Cougaar12_4/ping
> export COUGAAR_RUNTIME_PATH=/opt/Cougaar12_4/ping/run
>
> 4) Modified the ping code to add debug output:
> cd ping
> modify src/org/cougaar/demo/ping/PingSender.java to add line 145:
>  log.shout("sub added="+sub.getAddedCollection()+"
> all="+sub.getCollection());
> ant jar
> mv tmp/ping.jar lib
> cd run
>
> 5) In one console run:
> cougaar ../configs/PingTwoNodesSociety.xml PingTwoNodesRuntime.xml Node1
> and then in a second console run:
> cougaar ../configs/PingTwoNodesSociety.xml PingTwoNodesRuntime.xml Node2
>
> 6) The first console prints:
>  SHOUT [PingSender] - A: sub added=[] all=[]
> This shows that the subscription starts out empty, as expected.
>
> 7) Let it run for a while then load:
> http://localhost:8800/$Node1/move?op=Move&mobileAgent=A&originNode=Node1&destNode=Node2&isForceRestart=false&action=Add
>
> 8) The first console prints:
>  SHOUT [DOTS] - P+-+....
> and the second console prints:
>  SHOUT [PingSender] - A: sub added=[] all=[(SimpleRelay uid=A/1214417255150
> source=A target=B query=10 reply=10)]
> This shows that the subscription "getAddedCollection()" is empty and the
> "iterator()" was repopulated with the prior state.
>
> Todd
>
> daniel domingue wrote:
>>
>> I'm trying a second attempt at the mailing list
>>
>>
>> ---------- Forwarded message ----------
>> From: daniel domingue <ddomingue at gmail.com>
>> Date: Fri, Jun 20, 2008 at 5:07 PM
>> Subject: Issue when using agent mobility in Cougaar
>> To: cougaar-developers at cougaar.org
>>
>>
>> Hello all,
>>
>> I have encountered a small problem when trying to use mobile agents.
>> The relocated agents have an IncrementalSubscription on message
>> elements in the blackboard which contain a specific object.
>> Mobility is triggered by a remote agent using the following code :
>>
>>               /* get a ticket identification from the mobility factory */
>>               Object ticketId = mobilityFactory.createTicketIdentifier();
>>
>>               /* get adresses of agent and host */
>>               MessageAddress agentAdd =
>> MessageAddress.getMessageAddress(agentName);
>>               MessageAddress origHostAdd =
>> MessageAddress.getMessageAddress(origHost);
>>
>>               /* create a transfer ticket with the needed information */
>>               Ticket mTicket = new
>> Ticket(ticketId,agentAdd,origHostAdd,this.nodeId,false);
>>
>>               /* create a move agent order with the created ticket */
>>               MoveAgent ac = mobilityFactory.createMoveAgent(mTicket);
>>
>>               /* post the ticket to the blackboard for proceeding */
>>               blackboard.publishAdd(ac);
>>
>>
>> Everything works fine except that the relocated agents receive old
>> messages through the getAddedCollection() performed in the execute()
>> method after the blackboard has been rehydrated.
>> Below is part of the code that filters the messages in the relocated
>> agents :
>>
>>       for (Iterator iter = aValMsgSubs.getAddedCollection().iterator();
>> iter.hasNext();)
>>               {
>>                       LS_Com_Target co = (LS_Com_Target) iter.next() ;
>>                       Object o = co.getData();
>>                       Msg_LBValidator m = ((Msg_LBValidator) o);
>>
>>                       /* placebo */
>>                       switch(m.getLoadType())
>>                       {
>>                       case(ScenarioEntry.MSG):
>>
>> loadinfo.setRemainingMSGLoadCycles(m.getElapsed());
>>                       loadinfo.setMsgTargets(m.getTargetAgents());
>>                       System.out.println(this.agentId.toString()+"
>> received MSG");
>>                       break;
>>
>>                       case(ScenarioEntry.PROC):
>>
>> loadinfo.setRemainingCPULoadCycles(m.getElapsed());
>>                       System.out.println(this.agentId.toString()+"
>> received PROC");
>>                       break;
>>
>>                       case(ScenarioEntry.SIZE):
>>
>> loadinfo.setRemainingMEMLoadCycles(m.getElapsed());
>>                       System.out.println(this.agentId.toString()+"
>> received SIZE");
>>                       break;
>>                       }
>>
>>                       modified=true;
>>
>>               }
>>
>> The problem I see is that when the blackboard is being rehydrated all
>> the old messages change state and are classified as new messages,
>> which are picked up at the first execute() call after the load().
>>
>> Any clue that could help would be appreciated!
>>
>>
>> Thanks in advance,
>>
>>
>> --
>> Daniel Domingue
>>
>>
>>
>



-- 
Daniel Domingue