Hi Sheryl, Chris, Thank you both for providing detailed suggestions/use-cases of when to use PGEs. This certainly has helped me, and hopefully will help others as well.
Thanks! Rishi On Sep 27, 2011, at 7:51 PM, "Mattmann, Chris A (388J)" <[email protected]> wrote: > Hi Rishi, > > Thanks for your email. My thoughts below: > > On Sep 27, 2011, at 1:32 PM, Verma, Rishi (317I) wrote: > >> Hi All, >> >> This is something I have been wondering myself, and perhaps other >> CAS-Workflow users have been wondering as well so I thought I'd put this >> question out there. >> >> The question is: in which circumstances does it make sense to use PGEs for >> representing workflow tasks? In other words, which types of situations favor >> wrapping a workflow task as a PGETaskInstance versus using the generic >> WorkflowTaskInstance? >> >> Based on my own experience with CAS-PGE, I feel it makes sense to go for >> using PGEs for the following types of situations: >> [1] Extensive use of external programs is required for the execution of a >> workflow task >> [2] Gathering products from, or ingesting products to the CAS-FileManager is >> needed for the execution of a workflow task > > and to add Sheryl's (also a good one): > > [3] When a task requires workflow context metadata and/or it generates > metadata that it adds to the workflow context metadata to be used later down > in the pipeline. > > And here are some of mine: > > [4] When you need to generate an input configuration file (or set of > configuration files) that serve as input to the PGE and those configuration > files are based in some form on CAS metadata, environment variables, command > line parameters, etc. > [5] When you want to extract metadata for the output product files for a PGE. > > Basically CAS-PGE implements a specialized, optimized workflow of: > > [4], then [2] (gathering part, combined with the ability to get information > from CAS-Workflow and CAS-Resource as envisioned), then [3], then [1], then > [5], then [2] (ingestion part). > > Those are the types of tasks that CAS-PGE is good for. > > Other than that, a WorkflowTaskInstance might make more sense. The nice thing > about CAS-PGE is that the goal is to not have to write code, but to write XML > to be able to integrate underlying science algorithms. > > HTH! > > Cheers, > Chris > > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Chris Mattmann, Ph.D. > Senior Computer Scientist > NASA Jet Propulsion Laboratory Pasadena, CA 91109 USA > Office: 171-266B, Mailstop: 171-246 > Email: [email protected] > WWW: http://sunset.usc.edu/~mattmann/ > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ > Adjunct Assistant Professor, Computer Science Department > University of Southern California, Los Angeles, CA 90089 USA > ++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ >
