Grid Computing, B. Wilkinson, 2005

1. Web Service Resource Framework Notes on “sticky note” assignment Grid Computing, B. Wilkinson, 2005

2. Environment • Uses the Java GT4 core, which can be installed directly on a PC. • Needs: • jdk, Java software development kit • ant, open source tool for building java code

3. Sticky Note Service • Represents a “sticky note as one might stick on the wall to give reminders. • Resource property: a string containing the sticky note text Assignment due tomorrow

4. Sticky Note Operations • Operations: • Write text into a note – “write-note” • Display the text of a note – “show-note” • Create a note (introduced in Exercise 2)

5. Exercise 1 • Build sticky note service • Deploy sticky note service. (Uses ant, not GT4 deploy command) • Start GT4 container • Execute a “show-note” client to use the show-note operation

6. Building/Deploying service • Uses command: ant deploy where deploy is an xml build file.

7. Starting container $ bin/globus-start-container -nosec No Security -- Do not use GT 4 security mechanisms

8. Starting SOAP server at: http://192.168.123.100:8080/wsrf/services/ With the following services:[1]: http://192.168.123.100:8080/wsrf/services/InMemoryServiceGroupEntry[2]: http://192.168.123.100:8080/wsrf/services/TriggerFactoryService[3]: http://192.168.123.100:8080/wsrf/services/IndexFactoryService[4]: http://192.168.123.100:8080/wsrf/services/Version[5]: http://192.168.123.100:8080/wsrf/services/IndexService[6]: http://192.168.123.100:8080/wsrf/services/NotificationConsumerService[7]: http://192.168.123.100:8080/wsrf/services/DefaultTriggerServiceEntry[8]: http://192.168.123.100:8080/wsrf/services/TriggerServiceEntry[9]: http://192.168.123.100:8080/wsrf/services/IndexServiceEntry[10]: http://192.168.123.100:8080/wsrf/services/StickyNoteService[11]: http://192.168.123.100:8080/wsrf/services/AdminService[12]: http://192.168.123.100:8080/wsrf/services/DefaultIndexService[13]: http://192.168.123.100:8080/wsrf/services/DefaultIndexServiceEntry[14]: http://192.168.123.100:8080/wsrf/services/DefaultTriggerService[15]: http://192.168.123.100:8080/wsrf/services/ShutdownService[16]: http://192.168.123.100:8080/wsrf/services/ContainerRegistryService[17]: http://192.168.123.100:8080/wsrf/services/TriggerService[18]: http://192.168.123.100:8080/wsrf/services/gsi/AuthenticationService[19]: http://192.168.123.100:8080/wsrf/services/InMemoryServiceGroupFactory[20]: http://192.168.123.100:8080/wsrf/services/InMemoryServiceGroup[21]: http://192.168.123.100:8080/wsrf/services/ContainerRegistryEntryService[22]: http://192.168.123.100:8080/wsrf/services/SubscriptionManagerService All https if security used The deployed StickyNote Servicce

9. Executing show-note client Command: $GLOBUS_LOCATION/bin/show-note -s http://localhost:8080/wsrf/services/StickyNoteService Get: <ns1:message xmlns:ns1=http://tutorial.globus.org/stickynote >hello.</ns1:message> This is the message on the sticky note

10. Executing write-note client $GLOBUS_LOCATION/bin/write-note -s http://localhost:8080/wsrf/services/StickyNoteServicecheeseMessage written. This is the text to be written in sticky note

11. Exercise 2Creating a Resource • In this exercise, you are asked to modify files to introduce the “create note” operation. • Files to modify: • sticky note service wsdl file, to include the create note operation • Sticky note service code, to include the create note operation • jndi deployment configuration file • Also create a “create-note” client

12. Resource Home • For managing resources. • Must modify Resource Home from Exercise 1 so as to handle multiple resources. • Done in deploy-jndi-conf.xml, by changing type of resource from “SingleNoteHome” to “ManyNoteHome” and associated details changed also.

13. Creating a new note $GLOBUS_LOCATION/bin/create-note -s http://localhost:8080/wsrf/services/StickyNoteServicenew note created...EPR written to file: note--1947556620.epr To see note: $GLOBUS_LOCATION/bin/show-note -e note--1947556620.epr<ns1:message xmlns:ns1=http://tutorial.globus.org/stickynote >hello.</ns1:message> Endpoint Reference

14. Sample file containing Endpoint Reference <StickyNoteEndpoint xsi:type="ns1:EndpointReferenceType" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:ns1="http://schemas.xmlsoap.org/ws/2004/03/addressing"> <ns1:Address xsi:type="ns1:AttributedURI">http://192.168.1.100:8080/wsrf/ services/ StickyNoteService </ns1:Address> <ns1:ReferenceProperties “xsi:type="ns1:ReferencePropertiesType"> <ns1:NoteKey xmlns:ns1="http://sticky.com">25781085 </ns1:NoteKey> </ns1:ReferenceProperties> <ns1:ReferenceParameters xsi:type="ns1:ReferenceParametersType"/> </StickyNoteEndpoint> Resource “key”

15. Sticky Note EPR Endpoint reference = EPR1 + resource “key” EPR1 (service URI) StickyNote service Resource Key Resource property “cheese” With multiple resources, each resource assigned a unique key identifying it

16. Exercise 3Destroying Resources • Add an operation “destroy” in service wsdl file • Add “DestroyProvider operation provider” in wsdd file • Test by creating Sticky note and using GT4 “wsrf-destroy” command.

17. Exercise 4Adding a resource property • A “lastModified” resource property is added which records the time that the sticky note message was last altered. • Requires 4 files to be modified: • wsdl file • Service code • A file containing constants • Client code to test it

18. Exercise 5Register with a Local Index Service • GT 4 provided with an index service that can maintain a list of available services. • Index service acts as local service registry. • In Exercise 5, the service is registered with the local GT 4 index service.

19. Container Index service Multiple Sticky notes (resources with resource properties) Note, the exercises asks each person to start their own container

20. Details to use index service • When resource created, “add” method of ResourceHome called. • Need to override this method to include registering Resource with local index service. • Need to modify ManyNoteHome.java

21. Querying Index Servicewsrf-query Browse index service with the GT4 wsrf-query command: $GLOBUS_LOCATION/bin/wsrf-query -s http://localhost:8080/wsrf/services/DefaultIndexService '/*' which will list the services in an XML format.

22. Exercise 6Register with a “Community” Index Service • A remote index service is used, which holds all the services of the “virtual organization.” • For our purposes, the community index service is at: http://beowulf.bear.uncw.edu:8080/wsrf/ services/DefaultIndexService

23. Community index service beowulf.bear.uncw.edu:8080/wsrf/services/ DefaultIndexService Local Index service Sticky note resources client StickyNote service

24. Implementation • Configure local index to register with community index service. • All local information, including service resource properties, copied to community index service.

25. Implementation Modify the file: $GLOBUS_LOCATION/etc/globus_wsrf_mds_ index/hierarchy.xml to include the URL of the community index service (<upstream> parameter)

26. Querying Community Index Service Have Community Index Service running. Use wsrf-query command: $GLOBUS_LOCATION/bin/wsrf-query -s http://beowulf.bear.uncw.edu:8080/wsrf/services/DefaultIndexService '/*' Should see contents of all local index services.

27. Community index service Student 1 Index entry Student 2 Index entry Student 1 container Local Index service Resources Local Index service Resources client Service client Service Student 2 container Only container and GT 4 core needed at each site to handle services.

28. Exercise 7Lease-based Lifetime • In lease-based model, resources must be kept alive by interested parties, otherwise resource dies. • Set a lifetime for a service after which the service is destroyed. • Clean up without having to use a destroy operation explicitly.

29. Termination Time Termination time exposed as a resource property. Can be set with GT4 wsrf-set-termination-time command. Example $GLOBUS_LOCATION/bin/wsrf-set-termination-time -e note--1234.epr 100 Termination time in seconds File containing EPR of resource (StickyNote)

30. Implementation • Add subscribe operation to wsdl file. • Add SubscribeProvider to wsdd file. • Modify StickyNote.java • Modify post-deploy.xml file See exercise write-up for more details

31. Exercise 8Notifications • Notifications, generally, are a means by which a client can be informed of changes that have occurred such as: • Changes to resource property values. • Methods added • Methods removed • Resources destroyed

32. In exercise 8, a second service, called watch-note, is used to display changes to the value of the StickyNote. watch-note Notification that note changed StickyNote resource property Different container Client Write note StickyNote Service

33. In Exercise 8, a second service, called watch-note, is used to inform the client of changes to the value of the StickyNote. • Need the client to “subscribe” to receive notifications. • Subscriptions are for a particular topic.

34. Exercise 9Resource Discovery • In this exercise, the local and community index services are searched for a particular StickyNote message. • Since Resources properties are XML, can use “XPath” queries for searching and retrieval. • Uses a “XPath” query (apparently embedded in a script called search-note in this exercise)

35. XML Path Language (XPath) • W3C recommendation, 1999 • A query language for search XML documents. • Queries formed by identifying a route to the desired data. • For details: http://www.w3.org/TR/xpath