1. Portals, Portlets, and Clients to Grid Services Marlon Pierce Community Grids Lab Indiana University mpierce@cs.indiana.edu

2. Useful Links These slides are available from here: These slides are available from here: http://www.servogrid.org/slide/iSERVO/ IRIS_WebServices_2005/http://www.servogrid.org/slide/iSERVO/ IRIS_WebServices_2005/ General portlet tutorial information is available from here: General portlet tutorial information is available from here: http://www.servogrid.org/slide/iSERVO/ NMI/OGCE2TutorialMaterial/http://www.servogrid.org/slide/iSERVO/ NMI/OGCE2TutorialMaterial/ Grid portlets are available from here: Grid portlets are available from here: http://www.collab-ogce.orghttp://www.collab-ogce.org

3. Outline Globus toolkit review Globus toolkit review Computational Portals and Portlets Computational Portals and Portlets Building Grid Portlets with the Java CoG Kit Building Grid Portlets with the Java CoG Kit

4. Purpose of Talk I am not affiliated with Globus and do not develop Globus Web Services. I am not affiliated with Globus and do not develop Globus Web Services. I just use Globus services as-is.I just use Globus services as-is. My slides are from this point of view.My slides are from this point of view. My emphasis is on building Web Portals from portlets as clients to Grid services using the Java COG kit. My emphasis is on building Web Portals from portlets as clients to Grid services using the Java COG kit. The Java CoG kit project is lead by Gregor von Laszewski at Argonne National Labs The Java CoG kit project is lead by Gregor von Laszewski at Argonne National Labs I work with Gregor through the Open Grid Computing Environments project. I work with Gregor through the Open Grid Computing Environments project. We build portlets using the Java CoGWe build portlets using the Java CoG I also lead portlet and Web Service development for the NASA SERVOGrid project. I also lead portlet and Web Service development for the NASA SERVOGrid project. Grid services, GIS servicesGrid services, GIS services

5. SERVOGrid Summary Portlet-based portal Portlet-based portal With portal extensions to support secure remote portlets.With portal extensions to support secure remote portlets. “Execution Grid” Web Services “Execution Grid” Web Services Run remote tasks using Ant job managers.Run remote tasks using Ant job managers. Move files around (upload, download, crossload).Move files around (upload, download, crossload). Maintain persistent user session stateMaintain persistent user session state “Context” “Context” Application metadata to describe applications.Application metadata to describe applications. Provide data portal applications. Provide data portal applications. Monitor jobsMonitor jobs Data Grid Web Services Data Grid Web Services Use Geographical Information System standards. Web Feature Service Encodes GPS, Seismic, and Fault data archives as GML. Working on high performance web services. Web Map Service Generates interactive web maps using features and other map servers. Streaming video version in development. Sensor Grid Services Real time streaming GPS Data mining on streams Information Grid Services Information Grid Services Extended UDDI WS-Context for session metadata. www.crisisgrid.orgquakesim.jpl.nasa.org

6. Globus Toolkit Overview The Globus Toolkit provides foundations for building “Virtual Organizations.” The Globus Toolkit provides foundations for building “Virtual Organizations.” Single Sign-On Authentication Single Sign-On Authentication Log in once, access all machines on your Grid.Log in once, access all machines on your Grid. Grid Security Infrastructure Grid Security Infrastructure Public Key InfrastructurePublic Key Infrastructure Generic Security Service programming interfacesGeneric Security Service programming interfaces Secure Remote Resource Access Secure Remote Resource Access Remotely execute tasks.Remotely execute tasks. Interact with both shells and queuing systems.Interact with both shells and queuing systems. Secure, high performance file transfer Secure, high performance file transfer Information services for your grid resources. Information services for your grid resources.

7. Globus Toolkit 2.x GT 2 services implemented as Unix services. GT 2 services implemented as Unix services. You quite commonly manage them through /etc/xinetd.d or similar.You quite commonly manage them through /etc/xinetd.d or similar. Standard services in xinetd.d: Standard services in xinetd.d: GRAM gatekeeper for running remote tasks.GRAM gatekeeper for running remote tasks. GridFTP for file transfersGridFTP for file transfers Upload, download, and third party. Upload, download, and third party. MDS information servicesMDS information services MyProxy: a remote credential repository so that you don’t need to keep lots of copies of your private key.MyProxy: a remote credential repository so that you don’t need to keep lots of copies of your private key. Jim Basney at NCSA is the MyProxy guy. Jim Basney at NCSA is the MyProxy guy. Support for both remote shell operations and queuing systems. Support for both remote shell operations and queuing systems. PBS and LSF tend to be best supported.PBS and LSF tend to be best supported. You may be able to find others.You may be able to find others. Many other Globus-related tools have come and gone. Many other Globus-related tools have come and gone.

8. Globus Toolkit and Web Services Globus and others in the Global Grid Forum realized that they needed to provide more than just a bag of services Globus and others in the Global Grid Forum realized that they needed to provide more than just a bag of services Needed a framework for building new services.Needed a framework for building new services. Needed standard languages for writing service APIsNeeded standard languages for writing service APIs Standard messaging envelopes.Standard messaging envelopes. Web Services were the natural fit.Web Services were the natural fit. The Open Grid Services Architecture (OGSA) outlines the basic premise of the Globus approach to Web Services. The Open Grid Services Architecture (OGSA) outlines the basic premise of the Globus approach to Web Services. Globus Toolkit 3.x was the initial implementation of these ideas. Globus Toolkit 3.x was the initial implementation of these ideas. But it was found to be unsustainable. But it was found to be unsustainable. Initial spec (“OGSI”) was too monolithic, took to long to approve, made custom extensions to WSDL, had portions that were superseded by the main stream Web Service community, and was disconnected from the general community (OASIS, W3C).Initial spec (“OGSI”) was too monolithic, took to long to approve, made custom extensions to WSDL, had portions that were superseded by the main stream Web Service community, and was disconnected from the general community (OASIS, W3C). See http://www-128.ibm.com/developerworks/library/ws- resource/ogsi_to_wsrf_1.0.pdf for some discussion.See http://www-128.ibm.com/developerworks/library/ws- resource/ogsi_to_wsrf_1.0.pdf for some discussion.http://www-128.ibm.com/developerworks/library/ws- resource/ogsi_to_wsrf_1.0.pdfhttp://www-128.ibm.com/developerworks/library/ws- resource/ogsi_to_wsrf_1.0.pdf GT 4 release (April 2005) attempts to correct these problems. GT 4 release (April 2005) attempts to correct these problems.

9. Some Globus 2 Services v. Globus 4 Web Services PKI X.509 certificates used for mutual authentication PKI X.509 certificates used for mutual authentication GSI Security GSI Security GSSAPI-based socket connectionsGSSAPI-based socket connections GRAM GRAM Uses Resource Specification Language (RSL)Uses Resource Specification Language (RSL) Binds to PBS, LSF, and possibly other schedulers with third party plugins (support may vary).Binds to PBS, LSF, and possibly other schedulers with third party plugins (support may vary). GridFTP GridFTP Note GT 4 includes GridFTP 2.0, which is a different codebase from GridFTP 1.17 bundled in previous Globus releases.Note GT 4 includes GridFTP 2.0, which is a different codebase from GridFTP 1.17 bundled in previous Globus releases. We have reported some incompatibilities, which I think have been addressed in GT 4.0.1.We have reported some incompatibilities, which I think have been addressed in GT 4.0.1. Still PKI X.509 based mutual authentication… Still PKI X.509 based mutual authentication… But used now with Web Service Security: SSL and WS-Security But used now with Web Service Security: SSL and WS-Security Your certificates work in both GT versions. WS-GRAM WS-GRAM Replaces RSL with XML Job Descriptors. Uses Reliable File Transfer and GridFTP to support file staging and multiple jobs (which is a pain to install). Binds to PBS, LSF Reliable File Transfer (RFT) Reliable File Transfer (RFT) Web Service-based Uses “scheduling” techniques to do batch file transfers that don’t require persistent client connections. Builds on GridFTP.

10. Grid (and Web Service) Clients Web and Grid Services run in service hosting environments. Web and Grid Services run in service hosting environments. Apache Axis, Globus WS container, etc.Apache Axis, Globus WS container, etc. Clients likewise need to run in client hosting environments. Clients likewise need to run in client hosting environments. Graphical Use Interfaces, Desktops, Web Browser PortalsGraphical Use Interfaces, Desktops, Web Browser Portals But also grid and web service shells.But also grid and web service shells. Gridshell, HPSearch Gridshell, HPSearch We will focus on portals, since these are the most common and have standards. We will focus on portals, since these are the most common and have standards.

11. Building Grid Portals

12. A Famous Web Portal

13. A Famous Portal, After Login

14. What to Notice After logging in, my colors, layouts, and content all changed. After logging in, my colors, layouts, and content all changed. I get my stock list, my Bloomington weather, my news stories, etc.I get my stock list, my Bloomington weather, my news stories, etc. I got rid of “Garfield”I got rid of “Garfield” As we will see later, each of these content fragments (encircled) is managed by a thing called a portlet… As we will see later, each of these content fragments (encircled) is managed by a thing called a portlet… … I don’t guarantee that this is true for Yahoo’s web site but it is true for a large class of enterprise Java portal systems.… I don’t guarantee that this is true for Yahoo’s web site but it is true for a large class of enterprise Java portal systems. Portlets are the key to portal software reuse. Portlets are the key to portal software reuse.

15. Let 10,000 Flowers Bloom Many portal projects have been launched since late ’90s. Many portal projects have been launched since late ’90s. HotPage from SDSC, NCSA efforts, DOD, DOE Portals, NASA IPGHotPage from SDSC, NCSA efforts, DOD, DOE Portals, NASA IPG 2002 Special Issue of Concurrency and Computation: Practice and Experience.2002 Special Issue of Concurrency and Computation: Practice and Experience. The field continues to be active The field continues to be active An upcoming issue of Concurrency will survey the current field.An upcoming issue of Concurrency will survey the current field. Based on Global Grid Forum 14 Science Gateway workshop in June 2005.Based on Global Grid Forum 14 Science Gateway workshop in June 2005. GCE2005 workshop at Supercomputing 05.GCE2005 workshop at Supercomputing 05. http://www.ggf.org/ggf_events_lodging_ggf15.htm http://www.ggf.org/ggf_events_lodging_ggf15.htm Global Grid Forum’s Grid Computing Environments (GCE) Research Group Global Grid Forum’s Grid Computing Environments (GCE) Research Group Community forumCommunity forum How do we share and reuse all of this work? How do we share and reuse all of this work?

16. Portal User Interface Grid Resource Broker Service Grid and Web Protocols Information and Data Services Database Service Database HPC or Compute Cluster Grid Information Services, SRB Portal Client Stub Portal Client Stub Portal Client Stub JDBC, Local, or Remote Connection Three-Tiered Architecture Three-tiered architecture is accepted standard for accessing Grid and other services

17. What Is a Portlet? A portlet is a piece of Java code that manages the content of one section of a web portal’s HTML. A portlet is a piece of Java code that manages the content of one section of a web portal’s HTML. It can do anything else that a Java web application can do. It can do anything else that a Java web application can do. You can connect a portlet to a database, invoke a web service, download an RSS feed, etc.You can connect a portlet to a database, invoke a web service, download an RSS feed, etc. It lives in a portlet container, which creates, manages, and destroys all the portlets of the portal. It lives in a portlet container, which creates, manages, and destroys all the portlets of the portal. Portlet containers are part of portals. Portlet containers are part of portals. Portals must do other things like manage login, users, groups, layouts, etc.Portals must do other things like manage login, users, groups, layouts, etc. JSR 168 standardizes two main things: JSR 168 standardizes two main things: How the portlet container manages portlet lifecyclesHow the portlet container manages portlet lifecycles How the portlets are programmed.How the portlets are programmed.

18. JSR 168 Overview A General Review of JSR 168

19. What is JSR 168? From the portlet development point of view, it is really very simple: From the portlet development point of view, it is really very simple: You write a java class that extends GenericPortlet.You write a java class that extends GenericPortlet. You override/implement several methods inherited from GenericPortlet.You override/implement several methods inherited from GenericPortlet. You use some supporting classes/interfacesYou use some supporting classes/interfaces Many are analogous to their servlet equivalents Many are analogous to their servlet equivalents Some (portletsession) actually seem to be trivial wrappers around servlet equivalents in Pluto. Some (portletsession) actually seem to be trivial wrappers around servlet equivalents in Pluto. I have a complete example in the extended slides. I have a complete example in the extended slides. See also tutorial slides.See also tutorial slides.

20. Some GenericPortlet.java Methods MethodDescription Init Called when the portlet is created. Override if you need to set initial params. doView Controls what happens immediately before the portlet is displayed in view mode. Normally you override this. doHelp, doEdit Other portlet display modes processAction Place for handling any actions before turning over to the display mode method (like doView). You should override this for web forms.

21. Some Supporting Classes/Interfaces ClassDescription PortletContext Similar to servlet context; get context info and the RequestDispatcher from here. PortletSession Stores attribute information for a single portlet application across multiple requests. RenderRequest, RenderResponse The request and response objects available to the doView() method. Similar to the normal servlet request ActionRequest,Actio nResponse The request and response objects available to the processAction() method. Similar to the servlet request and response objects. PortletURL Use this to create URLs that reference the portal. PortletRequestDispa tcher Use this to include/forward to a JSP or servlet in the same portlet app. WindowState See if you are in minimized, maximized, normal state.

22. The Big Picture As a portlet developer, the previous set of classes are all you normally touch. As a portlet developer, the previous set of classes are all you normally touch. The portlet container (Pluto) is responsible for running your portlets. The portlet container (Pluto) is responsible for running your portlets. Init, invoke methods, destroy.Init, invoke methods, destroy. Portlets have a very limited way of interacting with the container. Portlets have a very limited way of interacting with the container. It is a black box->black hole.It is a black box->black hole. The API is basically one-way.The API is basically one-way.

23. A Comment on Portlet Coding The extended example makes some important and dubious assumptions The extended example makes some important and dubious assumptions Developers would want to write a GenericPortlet extension for every single portlet they develop.Developers would want to write a GenericPortlet extension for every single portlet they develop. And write really complicated processAction() and doView() methods. And write really complicated processAction() and doView() methods. Developers will like the specific JSR 168 portlet-style Model-View-Controller that it forces on them.Developers will like the specific JSR 168 portlet-style Model-View-Controller that it forces on them. Developers will gladly ignore other development methodologies/frameworks like Velocity, Struts, and Java Server Faces.Developers will gladly ignore other development methodologies/frameworks like Velocity, Struts, and Java Server Faces. Fortunately, these other development environments can be mapped to portlet actions. Fortunately, these other development environments can be mapped to portlet actions. In the OGCE project, we have developed support for Velocity portlets.In the OGCE project, we have developed support for Velocity portlets. We are transitioning to Java Server FacesWe are transitioning to Java Server Faces

24. Some Free JSR 168 Containers ContainerComments GridSphere Supports JSF. I recommend. Popular container in scientific portal community. uPortal Supports WSRP; JSF support planned. I have used extensively, but prefer GridSphere. LifeRay Depends heavily on EJB. Interesting set of portlets but too non-portable. ExoPortal I found this difficult to use, had some incompatibilities with CoG jars. StringBeans Supports WSRP, JSF. I have not yet evaluated.

25. The Java CoG Kit Gregor von Laszewski Argonne National Laboratory University of Chicago gregor@mcs.anl.govhttp://www.cogkit.org

26. The Story So Far… Globus has several interesting services that can be used out of the box. Globus has several interesting services that can be used out of the box. Portlets can be used to build portals out of reusable parts. Portlets can be used to build portals out of reusable parts. Portlets (as Java code) can also be used to invoke remote services. Portlets (as Java code) can also be used to invoke remote services. Now we will look at how to do this for Grid applications. Now we will look at how to do this for Grid applications.

27. CoG Kits CoG Kits make Grid programming simple and new technologies are easy to integrate CoG Kits make Grid programming simple and new technologies are easy to integrate We focus on a CoG Kit for Java We focus on a CoG Kit for Java Python also available (K. Jackson, LBNL)Python also available (K. Jackson, LBNL) Availability: Java CoG Kit since 1997Availability: Java CoG Kit since 1997 The CoG provides two important things The CoG provides two important things A higher level programming client programming environment than stubs.A higher level programming client programming environment than stubs. A shield against different versions of the Globus toolkitA shield against different versions of the Globus toolkit Same high level API works with GT 2.4, GT 3.0.2, GT 3.2.0, GT 3.2.1, GT 4.0.0 Same high level API works with GT 2.4, GT 3.0.2, GT 3.2.0, GT 3.2.1, GT 4.0.0

28. CoG Abstraction Layer CoG CoG Data and Task Management Layer CoG Gridfaces Layer CoG CoG GridIDE GT2 GT3 OGSI classic GT4 WS-RF CondorUnicore Applications SSH Others Avaki SETI Nano materials Bio- Informatics Disaster Management Portals CoG Abstraction Layer CoG CoG Data and Task Management Layer CoG Gridfaces Layer CoG CoG GridIDE Development Support CoG Abstraction Layers

29. Grid Portlet Overview In the tutorial examples, we look at writing JSR 168 portlets using JSP and Velocity. In the tutorial examples, we look at writing JSR 168 portlets using JSP and Velocity. Grid Portlets are just portlets, and portlets are just Java applications. Grid Portlets are just portlets, and portlets are just Java applications. Use the Java CoG to make calls from the portlet code to the desired Grid service.Use the Java CoG to make calls from the portlet code to the desired Grid service. Can also make non-COG calls, such as to GridPort API.Can also make non-COG calls, such as to GridPort API. These APIs are not be portlet-specific, since you should be able to reuse the Grid APIs from other Java clients. These APIs are not be portlet-specific, since you should be able to reuse the Grid APIs from other Java clients. You can also build Web Services out of them.You can also build Web Services out of them. NCSA’s OGRE (general), Trebuchet (application specific) are examplesNCSA’s OGRE (general), Trebuchet (application specific) are examples NCSA Tupelo also makes use of COG in its metadata management services.NCSA Tupelo also makes use of COG in its metadata management services.

30. COG and Portlets We use the COG to illustrate some basic portlet programming features. We use the COG to illustrate some basic portlet programming features. We use the COG4 APIs in our ProxyManager, Job Submission, and GridFTP portlets We use the COG4 APIs in our ProxyManager, Job Submission, and GridFTP portlets Hides differences between Globus Toolkit versions.Hides differences between Globus Toolkit versions. Is also structured to handle task-based workflow and job composition.Is also structured to handle task-based workflow and job composition. For more detailed examples, see the extended version of these slides. For more detailed examples, see the extended version of these slides.

31. Task Handler Service Task Specification Security Context Service Contact The class diagram is the same for all grid tasks (running jobs, modifying files, moving data). Classes also abstract toolkit provider differences. You set these as parameters: GT2, GT4, etd.

32. Setting Up Task and Specification Task task=new TaskImpl(“mytask”, Task.JOB_SUBMISSION);task.setProvider(“GT2”); JobSpecification spec= new JobSpecificationImpl(); spec.setExecutable(“rm”);spec.setBatchJob(true);spec.setArguments(“-r”);…task.setSpecification(spec);

33. Setting Up the Service and Security Context Service service=new ServiceImpl(Service.JOB_SUBMISSION); service.setProvider(“GT2”); SecurityContext securityContext= CoreFactory.newSecurityContext(“GT2”); //Use cred object from ProxyManager securityContext.setCredentials(cred);service.setSecurityContext((SecurityContext)securityContext);

34. Set Up Service Contact and Finish ServiceContact serviceContact= new ServiceContact(“myhost.myorg.org”); service.setServiceContact(serviceContact);task.setService(Service.JOB_SUBMISSION_SERVICE,service); TaskHandler handler=new GenericTaskHandler(); handler.submit(task);

35. Summary and Future Directions Portlets provide a way to build reusable Web components. Portlets provide a way to build reusable Web components. The Java COG kit provides a nice abstraction layer for building Grid portlets. The Java COG kit provides a nice abstraction layer for building Grid portlets. Portlets can be written using JSP, Velocity, and JSF. Portlets can be written using JSP, Velocity, and JSF. In our OGCE project, we previously concentrated on Velocity but are now moving to Java Server Faces. In our OGCE project, we previously concentrated on Velocity but are now moving to Java Server Faces. Provides a clear way to build reusable widgets, not just portlets.Provides a clear way to build reusable widgets, not just portlets. AJAX techniques (such as Google Maps) provide a very way to build interactive Web Service clients. AJAX techniques (such as Google Maps) provide a very way to build interactive Web Service clients. There is a larger problem: can we define a general user interface component? There is a larger problem: can we define a general user interface component? Portlets would be a subclassPortlets would be a subclass But also include shells and desktop clients.But also include shells and desktop clients. These components would also require standard supporting services: These components would also require standard supporting services: Login, access control, layout management, ….Login, access control, layout management, ….

36. Basic Portlet Programming Guide

37. In Action: Get started. public class JunkPortlet extends GenericPortlet { public void init(){ //Do any initialization. } //Rest of the methods on following slides go here. …}

38. Override doView() protected void doView( RenderRequest req, RenderResponse res) protected void doView( RenderRequest req, RenderResponse res) throws PortletException, IOException { //Include the desired JSP or HTML page. //We could also use out to write directly to the response. WindowState state=req.getWindowState(); if(!state.equals(WindowState.MINIMIZED)) { res.setContentType("text/html"); res.setContentType("text/html"); PortletRequestDispatcher rd= PortletRequestDispatcher rd= getPortletContext().getRequestDispatcher(“MyJ SP.jsp”); rd.include(req,res); rd.include(req,res);} }

39. The JSP Page <% PortletSession portletSession=renderRequest.getPortletSession(); portletSession.setAttribute("localattname","localattval"); PortletURL url=renderResponse.createActionURL(); String theActionString=url.toString(); %> HTML Content is here. A form is below. "> "> </form>

40. Some Notes Include the tag, which will instantiate renderRequest, renderResponse, and portletConfig objects. Include the tag, which will instantiate renderRequest, renderResponse, and portletConfig objects. You can then just use them, as with request, response, and other JSP implicit objects.You can then just use them, as with request, response, and other JSP implicit objects. The renderRequest gives you access to the PortletSession, if you want to store session variables. The renderRequest gives you access to the PortletSession, if you want to store session variables. One of the trouble points.One of the trouble points. The renderResponse gives you access to the PortletURL object. The renderResponse gives you access to the PortletURL object. Use the PortletURL to generate a URL for the Use the PortletURL to generate a URL for the So that it points to portlet container and gets handled by the processAction() method, rather than going of into space.So that it points to portlet container and gets handled by the processAction() method, rather than going of into space. Handle href URLs similarly.Handle href URLs similarly. This is one of the sticking points.This is one of the sticking points.

41. Lastly, Override processAction() When you invoke the form on the previous JSP, the portlet container will pass the action handling to the processAction method. When you invoke the form on the previous JSP, the portlet container will pass the action handling to the processAction method. The ActionRequest can be used to get any of the parameters in a way similar to the usual HttpServletRequest. The ActionRequest can be used to get any of the parameters in a way similar to the usual HttpServletRequest. When the processAction method returns, the container then invokes the appropriate do method (usually doView). When the processAction method returns, the container then invokes the appropriate do method (usually doView). If you need to pass parameters on to doView, add them to the ActionResponse. If you need to pass parameters on to doView, add them to the ActionResponse. This will give them to the RenderRequest.This will give them to the RenderRequest. The example shows how to add ALL parameters.The example shows how to add ALL parameters. public void processAction (ActionRequest request, ActionResponse actionResponse) throws PortletException, java.io.IOException { public void processAction (ActionRequest request, ActionResponse actionResponse) throws PortletException, java.io.IOException { //Process request parameters … //Add any other request params // to the renderRequest actionResponse.setRenderPar ameters(request.getParamete rMap()); }

42. Deploying Portlet Applications The portlet container (i.e. uPortal) runs as a distinct web application. The portlet container (i.e. uPortal) runs as a distinct web application. That is, it has its own directory in tomcat.That is, it has its own directory in tomcat. Moreover, it runs as a separate context, with its own classloader, session management, etc.Moreover, it runs as a separate context, with its own classloader, session management, etc. Portlet applications are deployed as distinct war files/web applications. Portlet applications are deployed as distinct war files/web applications. You go through the container webapp to get to the portlet webapp.You go through the container webapp to get to the portlet webapp. Portlets in the same application share jars, classes, and runtime stuff like request and session variables.Portlets in the same application share jars, classes, and runtime stuff like request and session variables. Portlets in different portlet apps do not share anything.Portlets in different portlet apps do not share anything. JSR 168 containers vary in the specifics of their deployment procedures. JSR 168 containers vary in the specifics of their deployment procedures.

43. Writing Grid Portlets Extended Example

44. Grid Portlet Overview Previously we looked at writing JSR 168 portlets using JSP and Velocity. Previously we looked at writing JSR 168 portlets using JSP and Velocity. Grid Portlets are just portlets Grid Portlets are just portlets Use the Java CoG to make calls from the portlet code to the desired Grid service.Use the Java CoG to make calls from the portlet code to the desired Grid service. Can also make non-COG calls, such as to GridPort API.Can also make non-COG calls, such as to GridPort API. These APIs should not be portlet-specific, since you should be able to reuse the Grid APIs from other Java clients. These APIs should not be portlet-specific, since you should be able to reuse the Grid APIs from other Java clients. NCSA’s OGRE (general), Trebuchet (application specific) are examplesNCSA’s OGRE (general), Trebuchet (application specific) are examples NCSA Tupelo also makes use of COG in its metadata management services.NCSA Tupelo also makes use of COG in its metadata management services.

45. COG and Portlets We will use the COG to illustrate some basic portlet programming features. We will use the COG to illustrate some basic portlet programming features. We use the COG4 APIs in our ProxyManager, Job Submission, and GridFTP portlets We use the COG4 APIs in our ProxyManager, Job Submission, and GridFTP portlets Hides differences between Globus Toolkit versions.Hides differences between Globus Toolkit versions. Is also structured to handle task-based workflow and job composition.Is also structured to handle task-based workflow and job composition. But for in-depth COG questions, we defer to Gregor’s group. But for in-depth COG questions, we defer to Gregor’s group. Available through AG session today.Available through AG session today. Or docs available through www.cogkit.orgOr docs available through www.cogkit.orgwww.cogkit.org OGCE is an open consortium, and there are other alternatives. OGCE is an open consortium, and there are other alternatives. OGRE job management builds on COG for WorkflowOGRE job management builds on COG for Workflow GridPort uses the GGF Community Scheduling Framework and higher level tools (job sequencers, for instance).GridPort uses the GGF Community Scheduling Framework and higher level tools (job sequencers, for instance). Use what you likeUse what you like

46. Getting Proxy Credentials The key ingredient is getting proxy credentials into the portal and sharing between different portlets. The key ingredient is getting proxy credentials into the portal and sharing between different portlets. We use MyProxy for this We use MyProxy for this Advantage: you don’t have to store users’ long term keys on the web server.Advantage: you don’t have to store users’ long term keys on the web server. Disadvantage: you have to run a separate MyProxy server; users have to put keys there outside the portal.Disadvantage: you have to run a separate MyProxy server; users have to put keys there outside the portal. You must include the OGCE2 MyProxy portlet (or a variation of it) in your Grid portal to do any other Grid stuff. You must include the OGCE2 MyProxy portlet (or a variation of it) in your Grid portal to do any other Grid stuff. OGCE1 also had support for grid-proxy-init. OGCE1 also had support for grid-proxy-init. Would be able to add this, but you would need to manage your users’ long term keys.Would be able to add this, but you would need to manage your users’ long term keys.

48. Proxy Manager Under the Hood See ogce2/indiana/extreme/ProxyManager/mod ules/portlet/src for templates and code. See ogce2/indiana/extreme/ProxyManager/mod ules/portlet/src for templates and code. Templates illustrate several Velocity scripting concepts. Templates illustrate several Velocity scripting concepts. Control structures, variablesControl structures, variables But the action code is more interesting. But the action code is more interesting. This is where you do your Grid coding.This is where you do your Grid coding. Use Velocity’s Context object to communicate strings back to your templates.Use Velocity’s Context object to communicate strings back to your templates.

49. Proxy Manager Code Key part here is the doGet_proxy() method. Key part here is the doGet_proxy() method. Abbreviated code on the right. Abbreviated code on the right. MyProxy class: import from CoG kit. MyProxy class: import from CoG kit. GSSCredential class: standard Java security class. GSSCredential class: standard Java security class. ProxyManager class: used by us to pass credentials between portlets. ProxyManager class: used by us to pass credentials between portlets. public void doGet_proxy() { MyProxy myproxy= new MyProxy(…); new MyProxy(…); GSSCredential proxy= myproxy.get(…); myproxy.get(…); ProxyManager.addPr oxy(…); }

50. Writing Simple Job Submission Portlets For portlets, you have to deal with two main Grid issues: For portlets, you have to deal with two main Grid issues: Getting the credential from the proxy store.Getting the credential from the proxy store. And then using it.And then using it. The CoG APIs provide an additional nice layer of Grid abstraction for Grid tasks. The CoG APIs provide an additional nice layer of Grid abstraction for Grid tasks. We will look at this for wrapping GRAM calls.We will look at this for wrapping GRAM calls. We will assume the following: We will assume the following: You have your project set up to be warred with maven.You have your project set up to be warred with maven. You have chosen a development technology (like JSP + portlets or Velocity portlets).You have chosen a development technology (like JSP + portlets or Velocity portlets). You will be collecting the necessary input information from an HTML.You will be collecting the necessary input information from an HTML. You will be putting the action code in either the portlet (perhaps as a JavaBean) or Velocity action handler.You will be putting the action code in either the portlet (perhaps as a JavaBean) or Velocity action handler. All code snippets below go in this portlet/action code.All code snippets below go in this portlet/action code.

51. Write the Method Skeleton In your action code, write a method to do job submission. In your action code, write a method to do job submission. For Velocity, this maps to the “eventSubmit_” form parameter in your template.For Velocity, this maps to the “eventSubmit_” form parameter in your template. In portlets, this code is called by your processAction method.In portlets, this code is called by your processAction method. You will need to pass it, minimally, the ActionRequest and ActionResponse objects. You will need to pass it, minimally, the ActionRequest and ActionResponse objects. public void doSubmitJob( ActionRequest req, ActionResponse resp,…) { //Next, get proxy //Then, run command. }

52. Get the Proxy Now get the proxy from the local store. Now get the proxy from the local store. The ProxyManager class calls the static method getDefaultProxy to look up your credential using your portlet session. The ProxyManager class calls the static method getDefaultProxy to look up your credential using your portlet session. You need these imports You need these imports org.ietf.jgss.GSSCredentialorg.ietf.jgss.GSSCredential xportlets.proxymanager.Pro xyManager.xportlets.proxymanager.Pro xyManager. javax.portlet.* for everything else.javax.portlet.* for everything else. This assumes that you have retrieved a credential from the MyProxy server. This assumes that you have retrieved a credential from the MyProxy server. public doSubmitJob( ActionRequest req, ActionResponse res) { //Get the proxy PortletSession sess= req.getPortletSession() req.getPortletSession() GSSCredential cred= ProxyManager.getDefaultPr oxy(sess); //Next, run command }

53. Run the Command The CoG4 interfaces now come into play. You should first understand the general CoG approach. The CoG4 interfaces now come into play. You should first understand the general CoG approach. The COG4 interfaces attempt to abstract things at several layers The COG4 interfaces attempt to abstract things at several layers Tasks: a generic Grid functionTasks: a generic Grid function Remote command execution, file operation, or information inquiry. Remote command execution, file operation, or information inquiry. Has a specification and service Has a specification and service Is run by a handler Is run by a handler Specification: set the type of task (job submit, etc.) and its specific parameters.Specification: set the type of task (job submit, etc.) and its specific parameters. Service: sets the Globus Toolkit (or other) provider, security context, and service contact information.Service: sets the Globus Toolkit (or other) provider, security context, and service contact information. TaskHandler: runs the task.TaskHandler: runs the task. Note this scheme is intended to shield you from programming differences of different Globus toolkits. Note this scheme is intended to shield you from programming differences of different Globus toolkits.

54. Making Contact with the Portal The remaining issue is getting information from the HTML forms to the appropriate CoG calls. The remaining issue is getting information from the HTML forms to the appropriate CoG calls. This is done through the PortletRequest object. This is done through the PortletRequest object. Typically, it is actually the ActionRequest subclass.Typically, it is actually the ActionRequest subclass. In your doSubmitJob() command, just use In your doSubmitJob() command, just use String param=request.getParameter(“Param-Name”);String param=request.getParameter(“Param-Name”); “Param-Name” is replaced with the input parameter name in your HTML form.“Param-Name” is replaced with the input parameter name in your HTML form. In following code snippets, “quoted strings” are usually what you would pass in from the Web form. In following code snippets, “quoted strings” are usually what you would pass in from the Web form.

55. An Extended Code Example: Setting Up Task and Specification Task task=new TaskImpl(“mytask”, Task.JOB_SUBMISSION);task.setProvider(“GT2”); JobSpecification spec= new JobSpecificationImpl(); spec.setExecutable(“rm”);spec.setBatchJob(true);spec.setArguments(“-r”);…task.setSpecification(spec);

56. Extended Code Example: Setting Up the Service and Security Context Service service=new ServiceImpl(Service.JOB_SUBMISSION); service.setProvider(“GT2”); SecurityContext securityContext= CoreFactory.newSecurityContext(“GT2”); //Use cred object from ProxyManager securityContext.setCredentials(cred);service.setSecurityContext((SecurityContext)securityContext);

57. Extended Example: Set Up Service Contact and Finish ServiceContact serviceContact= new ServiceContact(“myhost.myorg.org”); service.setServiceContact(serviceContact);task.setService(Service.JOB_SUBMISSION_SERVICE,service); TaskHandler handler=new GenericTaskHandler(); handler.submit(task);

58. Monitoring Tasks Monitoring running tasks submitted by the COG is done through a status listener. Monitoring running tasks submitted by the COG is done through a status listener. Write a class that implements StatusListener interfaceWrite a class that implements StatusListener interface Create an instance of your listener and add it to the task:Create an instance of your listener and add it to the task: task.addStatusListener(myListener); task.addStatusListener(myListener); There is a small problem with doing this in a portal application There is a small problem with doing this in a portal application The listener must be instantiated in the action code, along with the rest of the COG classes.The listener must be instantiated in the action code, along with the rest of the COG classes. But these are lost after the action completes.But these are lost after the action completes. Simple solution: store it in the PortletSession Simple solution: store it in the PortletSession This will keep the listener object alive after the action completesThis will keep the listener object alive after the action completes Get the session from the PortletRequest (more typically, its subclass, ActionRequest)Get the session from the PortletRequest (more typically, its subclass, ActionRequest) Sample codeSample code PortletSession session=request.getPortletSession(); PortletSession session=request.getPortletSession(); session.setAttribute(“mytask”,myListener); session.setAttribute(“mytask”,myListener); When you are curious about your task’s status, fetch it out of the session by name.When you are curious about your task’s status, fetch it out of the session by name.