CICAgent

From Igridrm

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Current revision as of 19:11, 2 May 2006

CICAgent is yellow pages agent storing grid resources represented by WorkerAgents. Resource adevertisements are stored in jena ontology model. For performance reasons jena's database persistence is used (currently MySQL database).

Contents

Services

Resource Query Service

Service type Resource Query Service
Description Service allows querying of resources previously registered by WorkerAgents. Queries can be expressed in SPARQL or RDQL syntax. Querying mechanism can be easily extended to support other querying languages offered by jena ARQ module.

Depending on the query clause results are returned in different format:

  • SELECT query returns ResultSet serialized in RDF/XML-ABBREV format
  • CONSTRUCT and DESCRIBE query returns RDF graph serialized in RDF/XML-ABBREV format
  • ASK query returns boolean answer
Protocols FIPA Request Protocol
ACL FIPA-ACL
Content Languages FIPA-SL0
Ontologies Messaging
Example
(REQUEST
 :sender (agent-identifier 
     :name tester@kameleon:1099/JADE  
     :addresses (sequence http://kameleon:7778/acc ) 
     :X-JADE-agent-classname gridrm.test.cic.CICTesterAgent)
 :receiver 
   (set ( agent-identifier :name cic-agent@kameleon:1099/JADE  :addresses (sequence http://kameleon:7778/acc )) )
 :content 
   "((action (agent-identifier :name cic-agent@kameleon:1099/JADE :addresses (sequence http://kameleon:7778/acc)) 
      (CICQueryResource :resourceQuery
        (OntoQuery
          :ontoQuerySyntax http://jena.hpl.hp.com/2003/07/query/SPARQL 
          :ontoQueryStr \\"PREFIX grid: <http://gridagents.sourceforge.net/Grid#> 
                          DESCRIBE ?res WHERE { ?res grid:cpuClockSpeedMhz ?cpu .
                          FILTER (?cpu >= 1000)}\\"))))" 
 :language  fipa-sl0
 :ontology  Messaging  
 :reply-by  20060501T145408274Z
 :protocol  fipa-request
 :conversation-id  C26811873_1146495245282)

(INFORM
 :sender (agent-identifier 
   :name cic-agent@kameleon:1099/JADE  
   :addresses (sequence http://kameleon:7778/acc ) 
   :X-JADE-agent-classname gridrm.agents.cic.CICAgent )
 :receiver  (set ( agent-identifier 
    :name tester@kameleon:1099/JADE  
    :addresses (sequence http://kameleon:7778/acc ) 
    :X-JADE-agent-classname gridrm.test.cic.CICTesterAgent ) )
 :content  "((result 
   (action (agent-identifier :name cic-agent@kameleon:1099/JADE :addresses (sequence http://kameleon:7778/acc)) 
      (CICQueryResource :resourceQuery
        (OntoQuery 
          :ontoQuerySyntax http://jena.hpl.hp.com/2003/07/query/SPARQL 
          :ontoQueryStr \\"PREFIX grid: <http://gridagents.sourceforge.net/Grid#> 
                          DESCRIBE ?res WHERE {  ?res grid:cpuClockSpeedMhz ?cpu .  
                          FILTER (?cpu >= 1000)}\\"))) 
   (RdfGraphResult :rdfGraph 
     (OntoData 
       :ontoDataLang RDF/XML-ABBREV 
       :ontoDataStr \\"<rdf:RDF
                          xmlns:grid="http://gridagents.sourceforge.net/Grid#"
                          xmlns:rdf="http://www.w3.org/1999/02/22-rdf-syntax-ns#">
                      <grid:UnitaryComputer rdf:about="jade://myLaptop@kameleon:1099/JADE">
                        <grid:cpuClockSpeedMhz rdf:datatype="http://www.w3.org/2001/XMLSchema#int">
                          1500
                        </grid:cpuClockSpeedMhz>
                        <rdf:type rdf:resource="http://gridagents.sourceforge.net/Grid#ComputerSystem"/>
                      </grid:UnitaryComputer>
                      </rdf:RDF>\\"))))" 
 :reply-with  tester@kameleon:1099/JADE1146495245939  
 :language  fipa-sl0  
 :ontology  Messaging  
 :protocol  fipa-request
 :conversation-id  C26811873_1146495245282 )
FIPA DF Registration
(service-description   
 :name "igrid-rm-cic-service"
 :type "igrid-rm-cic-service-query-resource"
 :protocol (set "FIPA-Request")   
 :ontology (set "Messaging")   
 :language (set "FIPA-SL0")

Resource Registration Service

to be written

Request handling

Each request to CICAgent involves operation on jena model which is stored in database. For performance reasons CICAgent does not perform those operations by itself. It delegates incoming requests to CICDbAgents. A CICDbAgent can perform one operation at a time. Hence CICAgent remembers which database agents are busy and marks them as locked. Once the result is returned from CICDbAgent again it is marked as unoccupied.

Simple request

Example of simple CIC request.

Multiple concurrent requests

This example shows how CICAgent handles larger traffic. There are 5 requests sent to cic-service. CICAgent has three database agents, thus it handles three requests. Once the requests are accomplished the other two are handled.

The CICAgent does not queues requests by itself. Requests are messages and are queued by jade platform in message datastore. CICAgent simply runs cyclic ActionRequestResponder behaviours. The number of these behaviours is equal to the number of CICAgents and hence it can only handle concurrenlty three requests.

The exact number of CICAgents is going to be precised by appropriate performance simulations.

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