sfa/methods/resolve.py

   1 ### $Id$
   2 ### $URL$
   3 import traceback
   4 from sfa.util.faults import *
   5 from sfa.util.method import Method
   6 from sfa.util.parameter import Parameter, Mixed
   7 from sfa.trust.auth import Auth
   8 from sfa.util.record import GeniRecord
   9 from sfa.util.genitable import GeniTable
  10 from sfa.util.debug import log
  11 from sfa.server.registry import Registries
  12 from sfa.util.prefixTree import prefixTree
  13
  14 class resolve(Method):
  15     """
  16     Resolve a record.
  17
  18     @param cred credential string authorizing the caller
  19     @param hrn human readable name to resolve
  20     @return a list of record dictionaries or empty list
  21     """
  22
  23     interfaces = ['registry']
  24
  25     accepts = [
  26         Parameter(str, "Credential string"),
  27         Parameter(str, "Human readable name (hrn)")
  28         ]
  29
  30     returns = [GeniRecord]
  31
  32     def call(self, cred, hrn):
  33
  34         self.api.auth.check(cred, 'resolve')
  35         good_records = []
  36
  37         # load all know registry names into a prefix tree and attempt to find
  38         # the longest matching prefix
  39         registries = Registries(self.api)
  40         hrns = registries.keys()
  41         tree = prefixTree()
  42         tree.load(hrns)
  43         registry_hrn = tree.best_match(hrn)
  44
  45         #if there was no match then this record belongs to an unknow registry
  46         if not registry_hrn:
  47             raise MissingAuthority(hrn)
  48
  49         # if the best match (longest matching hrn) is not the local registry,
  50         # forward the request
  51         if registry_hrn != self.api.hrn:
  52             credential = self.api.getCredential()
  53             try:
  54                 records = registries[registry_hrn].resolve(credential, hrn)
  55                 good_records = [record.as_dict() for record in records]
  56                 if good_records:
  57                     return good_records
  58             except:
  59                 traceback.print_exc()
  60
  61         # if we still havnt found the record yet, try the local registry
  62         table = GeniTable()
  63         records = table.find(hrn)
  64         if not records:
  65             raise RecordNotFound(hrn)
  66         for record in records:
  67             try:
  68                 self.api.fill_record_info(record)
  69                 good_records.append(dict(record))
  70             except PlanetLabRecordDoesNotExist:
  71                 # silently drop the ones that are missing in PL
  72                 print >> log, "ignoring geni record ", record.get_name(), \
  73                               " because pl record does not exist"
  74                 table.remove(record)
  75
  76
  77         return good_records
  78