#!/usr/bin/env python

import sys
import pickle
from optparse import OptionParser

from string import join

class Parser(OptionParser):
    def __init__(self):
	OptionParser.__init__(self, 
		usage='%prog [options] state_file [allocid]')
	self.add_option('--field', dest='field', default='manifest',
		help='field to extract: deafult %default')


parser = Parser()
opts, args = parser.parse_args()

if len(args) == 1:
    fn = args[0]
    a = None
elif len(args) == 2:
    fn, a = args
else:
    parser.print_help()
    sys.exit(1)

try:
    f = open(fn, 'r')
    d = pickle.load(f)
    f.close()
except EnvironmentError, e:
    sys.exit("Can't read %s: %s" % (e.filename or '!?', e.strerror))
except pickle.PickleError, e:
    f.close()
    sys.exit("Unpickling error: %s" %e)

if 'allocation' in d:
    alloc = d['allocation']

    if a:
	if a in alloc:
	    if opts.field in alloc[a]:
		print alloc[a][opts.field]
	    else:
		sys.exit('No %s in %s' % (opts.field, a))
	else:
	    sys.exit('Allocation %s not in state' % a)
    else:
	for k in alloc.keys():
	    if opts.field in alloc[k]:
		print k
else:
    sys.exit('No allocation in state')