[drmaa-wg] Added flow processor to DRMAA for Ruby samples

[Andreas Haas]

Hi,

I added yesterday a little flow processor to the DRMAA for Ruby
samples. A short description can be found in README below.

Regards,
Andreas

== Workflow interpreter and processor

    flow.rb is a utility for running job workflows in
    DRMAA-compliant DRM systems. Workflows are specified in
    flowfiles that allow expression of

      * concurrent and sequencial execution of sub-flows
      * multiple runs of sub-flows with varying parameter sets
      * acutal jobs are defined in terms of DRMAA attributes

    in addition any subflow or sets of subflows can be run
    as used with make(1) by specifying it as target.

=== Job defaults

    To minimize the extend attributes necessarily to be
    specified in flowfiles, flow.rb provides defaults for
    jobs command path, stdout/stdin path, current working
    directory and job name.

=== Workflow verification

    The -verify option can be used to print dependencies and
    job attributes for diagnosis purposes and to ensure each
    workflow job can be run, a number of verifications is
    performed before the first job gets submitted.

=== Job streaming

    Large workflows are automatically run in job streaming
    mode upon DRM saturation and a job maximum can be used
    to set in .flowrc.rb an upper limit of job concurrently
    be kept in the DRM for each workflow.

=== Pre-submission plug-in

    Enforcement of site-specific policies can easily be
    achieved through pre-submission procedures that allow
    any job attribute freely be modified.