Hi Srinath, We changed only the registration service implementation and others are unchanged. Initial decision was to have a one registration service (Jax-ws service) for whole BPS cluster. But we have found some difficulties to implement it. So in the current architecture, registration service is implemented as a carbon admin service and now it is per tenant. This approach has resolved security and tenant related problems we had.
Other change is we have introduced an option in configuration to skip the registration service during the task creation phase. This is not compliant with HT 1.1 specification. But this will prevent additional overhead of registration service invocation. This is an optimization configuration. Thanks, Hasitha. On Thu, Sep 26, 2013 at 7:15 AM, Srinath Perera <[email protected]> wrote: > Hi Hasitha, > > Do we have major changes from what we agree on the last review? do we need a > new review? > > --Srinath > > > On Thu, Sep 19, 2013 at 12:07 PM, Hasitha Aravinda <[email protected]> wrote: >> >> Hi all, >> >> I was working on $subject during past few weeks and have completed its >> implementation. This mail will brief its basic >> functionalities/configurations and changes have been done to the code base. >> >> Support for HumanTask Coordination. >> >> B4P module and Task Engine supports following functions, >> >> Support for Task Coordination : Exit, Skip, Fault protocol messages >> Support for Human Task Context : Using this function, process designer can >> make a task Skippable, override task priority at run time. >> >> >> >> This feature has introduced additional services (i.e Registration service, >> Task engine protocol handler) to both B4P module and Task engine. These >> service are implemented as admin services. Following diagram will explain >> its overall architecture. >> >> >> >> HTCoordinator is an axis2 module, which is engaged with Human Task >> Services. It does task registration with Task parent. Protocol Handler >> services handle coordination protocol messages ( exit, skip, and fault ). We >> reuse HumanTask's callback service as the task parent's protocol handler >> service. >> >> >> Message exchange scenarios in human task coordination. >> >> Task Registration with Task Parent. >> >> 1) People Activity sends a task creation request with both ws-coordination >> context and task context soap headers. ws-coordination context contains the >> EPR of the registration service and Task context has override attributes of >> the task. >> 2) The Task creation request is captured by HT coordinator ( the Axis2 >> module ) and send task registration request to the task parent's >> registration service. Task registration request contains EPR of the task >> engine's protocol handler service. >> 3) Registration service registers the task and persists coordination data >> in the database. Then it sends back registration response. >> 4) Now Task engine creates the task. >> 5) Task creation response is sent back to People Activity with task >> correlation details. >> >> On successful Task completion : Task output is sent to the callback >> service. >> If a task is Skipped by the Task owner: Task engine sends a skip protocol >> message to the Task parent's protocol handler. Then corresponding people >> activity is marked as completed. >> If task experience a fault: Task engine sends a fault protocol message to >> the Task parent's protocol handler. Then B4P module throw a >> nonRecoverableError in the scope enclosing the people activity. >> If Process Instance terminated or Completed with Fault: Sends a exit >> protocol message to task engine, to exit all human tasks, which are >> associated with a particular process instance. >> >> At the end of last four message exchange scenarios, relevant coordination >> data are removed from the database. >> >> >> Design Requirement >> >> Task Parent listens to Life cycle events of process instances, which are >> generated by ode engine and uses the instance termination event to send Exit >> protocol message to task processor for the termination of associated task >> instances. Therefore enabling instanceLifecycle events is required for a >> bpel process which uses b4p extension activity. >> >> >> Configuration and Backward compatibility >> >> This feature support backward compatibility and configurable using >> b4p-coordination-config.xml and humantask.xml. >> >> Enable HumanTask Coordination: In default configuration, humantask >> coordination is disabled. User can enable this feature by setting >> <TaskCoordinationEnabled > to true. >> >> Registration service : This service is compliant with HumanTask 1.1 >> Specification. However, Task Registration introduces overhead as additional >> web service invocation is required. So in default configuration Task >> Registration and Registration service are disabled. >> >> Protocol Handler/Registration service authentication: These services are >> implemented as wso2 carbon admin services. In order to access these >> services, a user needs to be authenticated to the system. In wso2 bps Task >> coordination, these service are authenticated using a user created in BPS >> and configured within the config files. These credentials can be secured >> (encrypted) using WSO2 secure vault tool. >> >> Clustered Task Engines: If task engines are clustered, user need to >> specify load balancer URL in the above configuration files. >> >> >> >> Previous Architecture Discussions: >> >> [1] Implementing HumanTask Coordination Protocol for BPS >> [2] Coordination Support for Human Tasks >> [3] Authenticating the Task parent in HumanTask coordination service >> >> >> Thanks, >> Hasitha >> >> -- >> Hasitha Aravinda, >> Software Engineer, >> WSO2 Inc. >> Email: [email protected] >> Mobile: +94 71 8 210 200 >> >> _______________________________________________ >> Architecture mailing list >> [email protected] >> https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture >> > > > > -- > ============================ > Srinath Perera, Ph.D. > http://people.apache.org/~hemapani/ > http://srinathsview.blogspot.com/ > > _______________________________________________ > Architecture mailing list > [email protected] > https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture > -- Hasitha Aravinda, Software Engineer, WSO2 Inc. Email: [email protected] Mobile: +94 71 8 210 200 _______________________________________________ Architecture mailing list [email protected] https://mail.wso2.org/cgi-bin/mailman/listinfo/architecture
