This page will be used to track the issues related to supporting Dirac 3 with ganga. At the time of writing these are the current Dirac 3 API docs. A branch has been made off the HEAD with the name GangaLHCb-4-DIRAC3. There is a Dirac 3 discussion page here.

CDC Effort

The CDC test jobs will use the Dirac backend with some Gaudi jobs. Having the DiracSpitter working would be nice but is not a requirement. The major changes to take account of are:

  • Dirac now requires its own special build of python. Currently this lives in $DIRAC3ROOT/Linux_i686_glibc-2.3.3, where $DIRAC3ROOT is currently /afs/ This internalises all of the dependencies on the lcg ui and the security modules needed.
  • All of the imports have changed. These need to be checked in the api docs. Examples include from DIRAC.Interfaces.API.Dirac import Dirac. Job is now a generic class, so we need to use LHCbJob.
  • The return code structure has been made consistent so that all commands return a dictionary. There needs to be some sort of switch made on OK eg:
result = dirac.callAPI()
if result['OK']
   result = result['Value']
   logger.warning('Somthing went wrong with Dirac (%s)'  % result['Message'])
   result = None
This will need lots of little changes to support, but it seems like a positive change.
  • The logger has changed, and we can now make dirac silent. The levels are ALWAYS, INFO, VERBOSE, DEBUG. ALWAYS is silent and should be the default.

I (Will) have made a start on this by writing a little wrapper around the Dirac python. See here.

Longer Term Issues

  • Proper support for python subprocesses.
  • Server slide job splitting
  • Dirac local running (does this need an internet connection?)

-- WillReece - 20 May 2008

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Topic revision: r2 - 2008-05-30 - WillReece
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