OGSA-WG workflow session minutes
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8 May 2007

Participants
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- as per session sign-in sheet

Minutes: Michel Drescher

Workflow
--------
- Steve McGough gives an introductory presentation
- Scope of OGSA workflow
  -- Error handling out
  -- Error detection in scope
  -- Graphical representation (visualisation) SHOULD be out of scope
  -- Cyclic declarations (i.e. dependencies) are out of scope
- AI-0504: Get in contact with Taverna
           Drill use cases for cyclic dependancy declarations
- How to do workflow
  -- Extend JSDL, BES etc. or
  -- use existing langauges on top of JSDL
- Extending JSDL
  -- Pre and post conditions to a JSDL job
- BPEL over JSDL
- Presentation about OMII-JSDL (for workflow over JSDL)
  -- Liang Chen, UCL
  -- Processes (in workflow terms) are defined in BPEL lenguage
  -- Those processes are executed on a BPEL engine
  -- Use graphical BPEL designer
  -- Submite to Active BPEL
  -- Active BPEL executes encoded processes
  -- Invokes GridSAM job submission middleware
  -- Started out with one big BPEL document
  -- Break up into several sub-workflows
  -- sub-workflows organised (and invoked) hierarchically
  -- Tools available:
     --- BPEL Designer
	     ---- Eclipse tool
		 ---- Supports WS-BPEL 2.0
		 ---- Uses several Eclipse plugins (WTP, EMF, GEF
		 ---- etc.
  -- ActiveBPEL
     --- Open SOurce BPEL engine
	 --- sits on Axis/Tomcat
	 --- Security: HTTPS, (OMII)WS-Security
	 --- Performance: Scalable, stable, Thread optimised
 -- Questions:
    --- Did you try using different BPEL engines?
	    --- The beauty is that BLEP workflow are exposed as web services
		--- But no, only one BPEL engine used
	--- Does BPEL support a binding to a more abstract workflow definition?
	    ---- No.
- Chris Kantarijev takes over, and hosts a discussion about workflows
  -- Chris explains the use case template available on the Twiki
  -- Which facilities do we have to provide?
     --- e.g. error detection and recovery
  -- How to drive the discussion and use cases?
- Do you have a survey on existing standards?
  -- This seem to be the goal
- WFXML (OASIS effort) has not been investigated yet
- The group discusses the possible future directions
  -- The group may pick a standard, or pick and profile it, rather than standards
- Users all do their individual things
- However workflow features might be extracted that are commonly used
- Put something together and have people bark at it?
- The workflow effort seem not to move forward
- But we might make it move forward
- How about constraining the workflow scope down to things like
  -- Support (JSDL) job execution with data staging support
  -- This led to the effort to compile use cases
- Does the group miss the stakeholders that would support the effort in OGSA?
- Tools for proprietary solutions are available, and active users won't likely switch
  -- Therefore can we embed our efforts in this?
- BPEL is out there and used as there semm nothing as good as defined as BPEL
- Question: OGSA endorses BPEL, who's going to complain?
  -- Question hasn't really been answered, the discussion turned away
- BPEL seem to follow a rather static model of job submission and resource location and discovery
- Chris closes the session with further pointers to upcoming sessions in this event