On Using BPEL Extensibility to Implement OGSI and WSRF Grid WorkflowsSlide 2Slide 3Slide 4Slide 5Slide 6Slide 7Slide 8Slide 9Slide 10Slide 11Slide 12Slide 13BPEL And OGSI Integration*Issues in OGSI Integration *WSRF Support *Integration with Today Grid *Additional Issues *Slide 19On Using BPEL Extensibility to Implement OGSI and WSRF Grid WorkflowsAleksander SlomiskiPresented byOnyeka Ezenwoye CIS 6612 - Advanced Topics in Software Engineering2OutlineAgenda•Background•BPEL Overview•BPEL/OGSI•BPEL/WSRF•Other Issues•ConclusionAgendaBackgroundBPELBPEL / OGSIBPEL / WSRFOther IssuesConclusion3OutlineGrid: A dynamic multi-institutional network of computers that come together to share resources for the purpose of coordinated problem solving.AgendaBackgroundBPELBPEL / OGSIBPEL / WSRFresourceapplicationinstitutional boundaryAchieved through:1. Open general-purpose protocols2. Standard interfacesOther IssuesConclusion4OutlineAgendaBPEL / OGSIBPEL / WSRFWeb Services: A Web service is an application that is accessible over the internet.BackgroundBPELJava RMIApp 1 App N…FirewallFirewall FirewallFirewallEnterprise AEnterprise BEnterprise CEnterprise DInternet.NETApp 1 App N…CORBAApp 1 App N…etc.App 1 App N…Core Technologies:•XML (eXtensible Markup Language)•SOAP (Simple Object Access Protocol)•WSDL (Web Service Description Language)Other IssuesConclusion5OutlineWSDL<definition namespace = “http/… “> <message>+ defines data elements of operations <part>+ components of the message </message> <portType> defines the web service interface <operation>+ operations that can be performed <input> <output> <fault>* </portType> <binding> comms. protocols for operations </binding> <service> a list of binding and ports to the bindings </service></definition>AgendaBPEL / OGSIBPEL / WSRFBackgroundBPELSubscribePublishBindService ConsumerClientService ProviderServiceService BrokerWSDLLegendrequest flowreply flowprogram boundarymodule boundaryReplyService DescriptionOther IssuesConclusion6OutlineOpen Grid Service Infrastructure (OGSI) - 2001–Grid service interface standard•Methods allow access to Grid service•As well as Grid service state (SDE)–Optional factory interface–Naming and referencing of Grid services–Extends WSDL 1.1 (GWSDL)AgendaBPEL / OGSIBPEL / WSRFBackgroundBPELGrid Service Handle (GSH)Publish GSRBindService ConsumerClientService ProviderGrid ServiceOGSI RegistryGrid Service Reference(GSR)Legendrequest flowreply flowprogram boundarymodule boundaryReplyGrid Service ReferenceOGSI Grid service locator:•Multiple GHSs + GSRs + interface descriptionOther IssuesConclusion7OutlineWeb Service Resource Framework (WSRF) - 2004–Distinguish between service and stateful resource•Model stateful resource as a Web service–Modular (users decide which specification to use)AgendaBPEL / OGSIBPEL / WSRFBackgroundBPEL* www.globus.org/wsrfOGSI WSRFGrid Service Reference WS-Addressing Endpoint ReferenceGrid Service Handle WS-Addressing Endpoint ReferenceHandleResolver portType WS-RenewableReferencesService data defn & access WS-ResourcePropertiesGridService lifetime mgmt WS-ResourceLifeCycleNotification portTypes WS-NotificationFactory portType Treated as a patternServiceGroup portTypes WS-ServiceGroupBase fault type WS-BaseFaultsOGSI to WSRF*Other IssuesConclusion8OutlineWorkflow: A description of the sequence of interaction between a set of activities that are performed together to achieve a common goal.AgendaBPEL / OGSIBPEL / WSRFBackgroundBPELStep 1Step 3Step 2Step 4ActivityCondition / interactionOther IssuesConclusion•Rapid composition•Automation•Management9OutlineBPEL: An XML based workflow language for composing aggregate Web services.AgendaBackgroundBPEL / OGSIBPEL / WSRFBPELAmazon Store WSresultqueryGoogle Spell-checker WSresultphrase<portType name="GooglePortType"> <operation name="doSpellingSuggestion"> <input message="type:String"/> <output message="type:String"/> </operation> </portType><portType name=“AmazonPortType"> <operation name="ItemSearch"> <input message="type:ComplexType"/> <output message="type:Array"/> </operation> </portType>Other IssuesConclusion10OutlineGoogle-Amazon BPEL process•BPEL Engine interprets XML-grammar•Exposed as a Web service•Described by WSDL (version 1.1)AgendaBackgroundBPEL / OGSIBPEL / WSRFBPEL<portType name=“Google-AmazonPortType"> <operation name=“GoogleAmazonSearch"> <input message="type:String"/> <output message="type:Array"/> </operation> </portType>Amazon Store WSresultqueryGoogle Spell-checker WSresultphraseassignment activityOther IssuesConclusion11OutlinePartners<partnerLinks> <partnerLink myRole="googleAmazon" …partnerLinkType="lns:googleAmazonLinkType"/> <partnerLink partnerRole =“Google" …partnerLinkType="lns: GoogleLinkType "/> <partnerLink name=“Amazon“… partnerLinkType="lns:AmazonLinkType"/></partnerLinks>AgendaBackgroundBPEL / OGSIBPEL / WSRFBPELActivities<process>… <flow> <receive name="receive" partnerLink=“googleAmazon" …> … </receive> <invoke name="invokeGoogle" partnerLink =“google“ …> … </invoke> <invoke name="invokeAmazon" partnerLink="amazon" …> … </invoke> <reply name="reply" partnerLink=“googleAmazon" …> … </reply> </flow></process>receiveinvokeinvokereplyGoogleAmazonGoogle-AmazonPartnersOther IssuesConclusion12OutlineGoogle-Amazon BPEL processAgendaBackgroundBPEL / OGSIBPEL / WSRFBPELScreenshot from ActiveWebflowTM ProfessionalOther IssuesConclusion13OutlineFault Handling•Two constructs for handling faults; <catch> and <catchAll>.Event Handling•TimeoutAgendaBackgroundBPEL / OGSIBPEL / WSRFBPELBPEL Engineprocess135n51Message CorrelationOther IssuesConclusion<message name=“requestMessage"> <part name="firstName" type="xsd:string"/> <part name=“lastName" type="xsd:string"/> <part name=“custID" type="xsd:int"/></message>14OutlineAgendaBackgroundBPEL / OGSIBPEL / WSRFBPELBPEL And OGSI Integration*•Leveraging BPEL abstractions–BPEL Partner is known by interface (PortType)–Very powerful integration mechanism!•Understands natively GSH/Locator as service reference –Handle automatically GSH to GSR conversion•Supports Explicit and Implicit Lifecycle–GPEL workflow engine is also OGSI Factory* Aleksander SlomiskiOther IssuesConclusion15OutlineAgendaBackgroundBPEL / OGSIBPEL / WSRFBPELIssues in OGSI Integration *•GSH/GSR and WS-Addressing–Endpoint Reference (EPR) is