Sounds good!
On Thu, Sep 26, 2013 at 9:24 AM, Hasitha Aravinda <[email protected]> wrote: > 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 > -- ============================ Srinath Perera, Ph.D. http://people.apache.org/~hemapani/ http://srinathsview.blogspot.com/
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