ilookup.py

Go to the documentation of this file.

"""
Perform multiple DBI lookups with a single DBI query...
Made possible by restrictions on the nature of the lookups. 

The canonical example is looking up entries in GDaqRunInfo based on the 
runNo field (RunNo attribute)

"""
import logging
log = logging.getLogger(__name__)

class IEntry(object):
    def __init__(self, row, vrec ):
         self.row = row
         self.vrec = vrec 
    def __repr__(self):
         return "IEntry : SEQNO %s TimeStart %s TimeEnd %s " % ( self.vrec.seqno, self.vrec.contextrange.timestart, self.vrec.contextrange.timeend )

class ILookup(dict):
    """
    Example of use::

       il = ILookup( 10,100,1000, kls='GDaqRunInfo', ifield="runNo", iattr="RunNo" )
          #  corresponds to datasql WHERE clause :   runNo in (10,100,1000)
       print il[10]


    The positional arguments are used in datasql **IN** list, the query must result in
    the same number of entries as positional arguments.
    The ``iattr`` is needed as DybDbi attribute names are often different from fieldnames, this
    is used after the query with in memory lookup to arrange the results of the query by the argument
    values.

    Effectively the positional arguments must behave like primary keys with each arg 
    corresponding to one row. 

    """
    def __init__(self, *args , **kwa ):
        dict.__init__(self) 

        import DybDbi
        kls = getattr( DybDbi, kwa['kls'] ) 
        rpt = kls.Rpt()

        if len(args) > 1: 
            datasql = "%s in %s" % ( kwa['ifield'], str(tuple(args)) )
        else:
            datasql = "%s = %s" % ( kwa['ifield'], args[0] ) 

        rpt.ctx( sqlcontext=kwa['sqlcontext'] , datasql=datasql , task=-1, subsite=-1 )
        if len(rpt) < len(args):
           log.warn("failed to lookup and entry for every argument ... trouble ahead " )

        for arg in args:
            row = rpt.FirstRowWithIntValueForKey( kwa['iattr'] , arg )
            assert row, "Failed to find %s entry with arg %s using iattr %s " % ( kwa['kls'] , arg, kwa['iattr'] )
            self[arg] = IEntry( row, rpt.GetValidityRec(row) )


class IRunLookup(ILookup):
    """
    Specialization of :py:class:`DybDbi.ILookup`, for looking for run numbers in GDaqRunInfo, usage::

        iargs = (10,100,1000)
        irl = IRunLookup( *iargs )
        for ia in iargs:
            print ia, irl[ia]

    """
    kls = 'GDaqRunInfo'
    ifield = "runNo"
    iattr = "RunNo"
    sqlcontext = "1=1"

    def __init__(self, *args, **kwa ): 
         ILookup.__init__(self, *args, kls=kwa.get('kls',self.kls), ifield=kwa.get('ifield',self.ifield), iattr=kwa.get('iattr',self.iattr), sqlcontext=kwa.get('sqlcontext',self.sqlcontext) )


def args_():
    import argparse

    cls = IRunLookup

    ap = argparse.ArgumentParser(description=__doc__)
    ap.add_argument( 'iargs', nargs="+" , type=int,                help='One or more integer arguments to lookup ')
    ap.add_argument( '-k', '--kls',        default=cls.kls,        help='Name of DybDbi class. Default %(default)s ')
    ap.add_argument( '-d', '--ifield',     default=cls.ifield,     help='Payload integer fieldname corresponding to positional argument values. Default %(default)s ')
    ap.add_argument( '-s', '--sqlcontext', default=cls.sqlcontext, help='Extended query SQL context. Default %(default)s ')
    ap.add_argument( '-i', '--iattr',      default=cls.iattr,      help='DybDbi integer attribute name, used for the in memory lookup to arrange entries by argument. Default %(default)s ') 

    ap.add_argument(       '--dbconf',     default=None   ,       help='Name of section of ~/.my.cnf with DB connection parameters. Default %(default)s ')
    args = ap.parse_args()
    return args

def main():
    import os
    args = args_()
    if args.dbconf:
        os.environ['DBCONF'] = args.dbconf 
    il = ILookup( *args.iargs , kls=args.kls , ifield=args.ifield , iattr=args.iattr, sqlcontext=args.sqlcontext )
    for iarg in args.iargs:
        print iarg, il[iarg]
    return il

def check_irunlookup():
    iargs = (10,100,1000)
    irl = IRunLookup( *iargs )
    for ia in iargs:
        print ia, irl[ia]


if __name__ == '__main__':
    il = main()