sfa/plc/api.py

   1 #
   2 # SFA XML-RPC and SOAP interfaces
   3 #
   4
   5 import sys
   6 import os
   7 import traceback
   8 import string
   9 import datetime
  10 import xmlrpclib
  11
  12 from sfa.util.faults import *
  13 from sfa.util.api import *
  14 from sfa.util.config import *
  15 from sfa.util.sfalogging import logger
  16 import sfa.util.xmlrpcprotocol as xmlrpcprotocol
  17 from sfa.trust.auth import Auth
  18 from sfa.trust.rights import Right, Rights, determine_rights
  19 from sfa.trust.credential import Credential,Keypair
  20 from sfa.trust.certificate import Certificate
  21 from sfa.util.xrn import get_authority, hrn_to_urn
  22 from sfa.util.plxrn import hostname_to_hrn, hrn_to_pl_slicename, hrn_to_pl_slicename, slicename_to_hrn
  23 from sfa.util.nodemanager import NodeManager
  24 try:
  25     from collections import defaultdict
  26 except:
  27     class defaultdict(dict):
  28         def __init__(self, default_factory=None, *a, **kw):
  29             if (default_factory is not None and
  30                 not hasattr(default_factory, '__call__')):
  31                 raise TypeError('first argument must be callable')
  32             dict.__init__(self, *a, **kw)
  33             self.default_factory = default_factory
  34         def __getitem__(self, key):
  35             try:
  36                 return dict.__getitem__(self, key)
  37             except KeyError:
  38                 return self.__missing__(key)
  39         def __missing__(self, key):
  40             if self.default_factory is None:
  41                 raise KeyError(key)
  42             self[key] = value = self.default_factory()
  43             return value
  44         def __reduce__(self):
  45             if self.default_factory is None:
  46                 args = tuple()
  47             else:
  48                 args = self.default_factory,
  49             return type(self), args, None, None, self.items()
  50         def copy(self):
  51             return self.__copy__()
  52         def __copy__(self):
  53             return type(self)(self.default_factory, self)
  54         def __deepcopy__(self, memo):
  55             import copy
  56             return type(self)(self.default_factory,
  57                               copy.deepcopy(self.items()))
  58         def __repr__(self):
  59             return 'defaultdict(%s, %s)' % (self.default_factory,
  60                                             dict.__repr__(self))
  61 ## end of http://code.activestate.com/recipes/523034/ }}}
  62
  63 def list_to_dict(recs, key):
  64     """
  65     convert a list of dictionaries into a dictionary keyed on the
  66     specified dictionary key
  67     """
  68     keys = [rec[key] for rec in recs]
  69     return dict(zip(keys, recs))
  70
  71 class SfaAPI(BaseAPI):
  72
  73     # flat list of method names
  74     import sfa.methods
  75     methods = sfa.methods.all
  76
  77     def __init__(self, config = "/etc/sfa/sfa_config.py", encoding = "utf-8",
  78                  methods='sfa.methods', peer_cert = None, interface = None,
  79                 key_file = None, cert_file = None, cache = None):
  80         BaseAPI.__init__(self, config=config, encoding=encoding, methods=methods, \
  81                          peer_cert=peer_cert, interface=interface, key_file=key_file, \
  82                          cert_file=cert_file, cache=cache)
  83
  84         self.encoding = encoding
  85         from sfa.util.table import SfaTable
  86         self.SfaTable = SfaTable
  87         # Better just be documenting the API
  88         if config is None:
  89             return
  90
  91         # Load configuration
  92         self.config = Config(config)
  93         self.auth = Auth(peer_cert)
  94         self.interface = interface
  95         self.key_file = key_file
  96         self.key = Keypair(filename=self.key_file)
  97         self.cert_file = cert_file
  98         self.cert = Certificate(filename=self.cert_file)
  99         self.credential = None
 100         # Initialize the PLC shell only if SFA wraps a myPLC
 101         rspec_type = self.config.get_aggregate_type()
 102         if (rspec_type == 'pl' or rspec_type == 'vini' or \
 103             rspec_type == 'eucalyptus' or rspec_type == 'max'):
 104             self.plshell = self.getPLCShell()
 105             self.plshell_version = "4.3"
 106
 107         self.hrn = self.config.SFA_INTERFACE_HRN
 108         self.time_format = "%Y-%m-%d %H:%M:%S"
 109
 110     def getPLCShell(self):
 111         self.plauth = {'Username': self.config.SFA_PLC_USER,
 112                        'AuthMethod': 'password',
 113                        'AuthString': self.config.SFA_PLC_PASSWORD}
 114         try:
 115             sys.path.append(os.path.dirname(os.path.realpath("/usr/bin/plcsh")))
 116             self.plshell_type = 'direct'
 117             import PLC.Shell
 118             shell = PLC.Shell.Shell(globals = globals())
 119         except:
 120             self.plshell_type = 'xmlrpc'
 121             url = self.config.SFA_PLC_URL
 122             shell = xmlrpclib.Server(url, verbose = 0, allow_none = True)
 123
 124         return shell
 125
 126     def getCredential(self):
 127         """
 128         Return a valid credential for this interface.
 129         """
 130         type = 'authority'
 131         path = self.config.SFA_DATA_DIR
 132         filename = ".".join([self.interface, self.hrn, type, "cred"])
 133         cred_filename = path + os.sep + filename
 134         cred = None
 135         if os.path.isfile(cred_filename):
 136             cred = Credential(filename = cred_filename)
 137             # make sure cred isnt expired
 138             if not cred.get_expiration or \
 139                datetime.datetime.today() < cred.get_expiration():
 140                 return cred.save_to_string(save_parents=True)
 141
 142         # get a new credential
 143         if self.interface in ['registry']:
 144             cred =  self.__getCredentialRaw()
 145         else:
 146             cred =  self.__getCredential()
 147         cred.save_to_file(cred_filename, save_parents=True)
 148
 149         return cred.save_to_string(save_parents=True)
 150
 151
 152     def getDelegatedCredential(self, creds):
 153         """
 154         Attempt to find a credential delegated to us in
 155         the specified list of creds.
 156         """
 157         if creds and not isinstance(creds, list):
 158             creds = [creds]
 159         delegated_creds = filter_creds_by_caller(creds,self.hrn)
 160         if not delegated_creds:
 161             return None
 162         return delegated_creds[0]
 163
 164     def __getCredential(self):
 165         """
 166         Get our credential from a remote registry
 167         """
 168         from sfa.server.registry import Registries
 169         registries = Registries(self)
 170         registry = registries[self.hrn]
 171         cert_string=self.cert.save_to_string(save_parents=True)
 172         # get self credential
 173         self_cred = registry.GetSelfCredential(cert_string, self.hrn, 'authority')
 174         # get credential
 175         cred = registry.GetCredential(self_cred, self.hrn, 'authority')
 176         return Credential(string=cred)
 177
 178     def __getCredentialRaw(self):
 179         """
 180         Get our current credential directly from the local registry.
 181         """
 182
 183         hrn = self.hrn
 184         auth_hrn = self.auth.get_authority(hrn)
 185
 186         # is this a root or sub authority
 187         if not auth_hrn or hrn == self.config.SFA_INTERFACE_HRN:
 188             auth_hrn = hrn
 189         auth_info = self.auth.get_auth_info(auth_hrn)
 190         table = self.SfaTable()
 191         records = table.findObjects(hrn)
 192         if not records:
 193             raise RecordNotFound
 194         record = records[0]
 195         type = record['type']
 196         object_gid = record.get_gid_object()
 197         new_cred = Credential(subject = object_gid.get_subject())
 198         new_cred.set_gid_caller(object_gid)
 199         new_cred.set_gid_object(object_gid)
 200         new_cred.set_issuer_keys(auth_info.get_privkey_filename(), auth_info.get_gid_filename())
 201
 202         r1 = determine_rights(type, hrn)
 203         new_cred.set_privileges(r1)
 204         new_cred.encode()
 205         new_cred.sign()
 206
 207         return new_cred
 208
 209
 210     def loadCredential (self):
 211         """
 212         Attempt to load credential from file if it exists. If it doesnt get
 213         credential from registry.
 214         """
 215
 216         # see if this file exists
 217         # XX This is really the aggregate's credential. Using this is easier than getting
 218         # the registry's credential from iteslf (ssl errors).
 219         ma_cred_filename = self.config.SFA_DATA_DIR + os.sep + self.interface + self.hrn + ".ma.cred"
 220         try:
 221             self.credential = Credential(filename = ma_cred_filename)
 222         except IOError:
 223             self.credential = self.getCredentialFromRegistry()
 224
 225     ##
 226     # Convert SFA fields to PLC fields for use when registering up updating
 227     # registry record in the PLC database
 228     #
 229     # @param type type of record (user, slice, ...)
 230     # @param hrn human readable name
 231     # @param sfa_fields dictionary of SFA fields
 232     # @param pl_fields dictionary of PLC fields (output)
 233
 234     def sfa_fields_to_pl_fields(self, type, hrn, record):
 235
 236         def convert_ints(tmpdict, int_fields):
 237             for field in int_fields:
 238                 if field in tmpdict:
 239                     tmpdict[field] = int(tmpdict[field])
 240
 241         pl_record = {}
 242         #for field in record:
 243         #    pl_record[field] = record[field]
 244
 245         if type == "slice":
 246             if not "instantiation" in pl_record:
 247                 pl_record["instantiation"] = "plc-instantiated"
 248             pl_record["name"] = hrn_to_pl_slicename(hrn)
 249             if "url" in record:
 250                pl_record["url"] = record["url"]
 251             if "description" in record:
 252                 pl_record["description"] = record["description"]
 253             if "expires" in record:
 254                 pl_record["expires"] = int(record["expires"])
 255
 256         elif type == "node":
 257             if not "hostname" in pl_record:
 258                 if not "hostname" in record:
 259                     raise MissingSfaInfo("hostname")
 260                 pl_record["hostname"] = record["hostname"]
 261             if not "model" in pl_record:
 262                 pl_record["model"] = "geni"
 263
 264         elif type == "authority":
 265             pl_record["login_base"] = hrn_to_pl_login_base(hrn)
 266
 267             if not "name" in pl_record:
 268                 pl_record["name"] = hrn
 269
 270             if not "abbreviated_name" in pl_record:
 271                 pl_record["abbreviated_name"] = hrn
 272
 273             if not "enabled" in pl_record:
 274                 pl_record["enabled"] = True
 275
 276             if not "is_public" in pl_record:
 277                 pl_record["is_public"] = True
 278
 279         return pl_record
 280
 281     def fill_record_pl_info(self, records):
 282         """
 283         Fill in the planetlab specific fields of a SFA record. This
 284         involves calling the appropriate PLC method to retrieve the
 285         database record for the object.
 286
 287         PLC data is filled into the pl_info field of the record.
 288
 289         @param record: record to fill in field (in/out param)
 290         """
 291         # get ids by type
 292         node_ids, site_ids, slice_ids = [], [], []
 293         person_ids, key_ids = [], []
 294         type_map = {'node': node_ids, 'authority': site_ids,
 295                     'slice': slice_ids, 'user': person_ids}
 296
 297         for record in records:
 298             for type in type_map:
 299                 if type == record['type']:
 300                     type_map[type].append(record['pointer'])
 301
 302         # get pl records
 303         nodes, sites, slices, persons, keys = {}, {}, {}, {}, {}
 304         if node_ids:
 305             node_list = self.plshell.GetNodes(self.plauth, node_ids)
 306             nodes = list_to_dict(node_list, 'node_id')
 307         if site_ids:
 308             site_list = self.plshell.GetSites(self.plauth, site_ids)
 309             sites = list_to_dict(site_list, 'site_id')
 310         if slice_ids:
 311             slice_list = self.plshell.GetSlices(self.plauth, slice_ids)
 312             slices = list_to_dict(slice_list, 'slice_id')
 313         if person_ids:
 314             person_list = self.plshell.GetPersons(self.plauth, person_ids)
 315             persons = list_to_dict(person_list, 'person_id')
 316             for person in persons:
 317                 key_ids.extend(persons[person]['key_ids'])
 318
 319         pl_records = {'node': nodes, 'authority': sites,
 320                       'slice': slices, 'user': persons}
 321
 322         if key_ids:
 323             key_list = self.plshell.GetKeys(self.plauth, key_ids)
 324             keys = list_to_dict(key_list, 'key_id')
 325
 326         # fill record info
 327         for record in records:
 328             # records with pointer==-1 do not have plc info.
 329             # for example, the top level authority records which are
 330             # authorities, but not PL "sites"
 331             if record['pointer'] == -1:
 332                 continue
 333
 334             for type in pl_records:
 335                 if record['type'] == type:
 336                     if record['pointer'] in pl_records[type]:
 337                         record.update(pl_records[type][record['pointer']])
 338                         break
 339             # fill in key info
 340             if record['type'] == 'user':
 341                 if 'key_ids' not in record:
 342                     logger.info("user record has no 'key_ids' - need to import from myplc ?")
 343                 else:
 344                     pubkeys = [keys[key_id]['key'] for key_id in record['key_ids'] if key_id in keys]
 345                     record['keys'] = pubkeys
 346
 347         # fill in record hrns
 348         records = self.fill_record_hrns(records)
 349
 350         return records
 351
 352     def fill_record_hrns(self, records):
 353         """
 354         convert pl ids to hrns
 355         """
 356
 357         # get ids
 358         slice_ids, person_ids, site_ids, node_ids = [], [], [], []
 359         for record in records:
 360             if 'site_id' in record:
 361                 site_ids.append(record['site_id'])
 362             if 'site_ids' in records:
 363                 site_ids.extend(record['site_ids'])
 364             if 'person_ids' in record:
 365                 person_ids.extend(record['person_ids'])
 366             if 'slice_ids' in record:
 367                 slice_ids.extend(record['slice_ids'])
 368             if 'node_ids' in record:
 369                 node_ids.extend(record['node_ids'])
 370
 371         # get pl records
 372         slices, persons, sites, nodes = {}, {}, {}, {}
 373         if site_ids:
 374             site_list = self.plshell.GetSites(self.plauth, site_ids, ['site_id', 'login_base'])
 375             sites = list_to_dict(site_list, 'site_id')
 376         if person_ids:
 377             person_list = self.plshell.GetPersons(self.plauth, person_ids, ['person_id', 'email'])
 378             persons = list_to_dict(person_list, 'person_id')
 379         if slice_ids:
 380             slice_list = self.plshell.GetSlices(self.plauth, slice_ids, ['slice_id', 'name'])
 381             slices = list_to_dict(slice_list, 'slice_id')
 382         if node_ids:
 383             node_list = self.plshell.GetNodes(self.plauth, node_ids, ['node_id', 'hostname'])
 384             nodes = list_to_dict(node_list, 'node_id')
 385
 386         # convert ids to hrns
 387         for record in records:
 388             # get all relevant data
 389             type = record['type']
 390             pointer = record['pointer']
 391             auth_hrn = self.hrn
 392             login_base = ''
 393             if pointer == -1:
 394                 continue
 395
 396             if 'site_id' in record:
 397                 site = sites[record['site_id']]
 398                 login_base = site['login_base']
 399                 record['site'] = ".".join([auth_hrn, login_base])
 400             if 'person_ids' in record:
 401                 emails = [persons[person_id]['email'] for person_id in record['person_ids'] \
 402                           if person_id in  persons]
 403                 usernames = [email.split('@')[0] for email in emails]
 404                 person_hrns = [".".join([auth_hrn, login_base, username]) for username in usernames]
 405                 record['persons'] = person_hrns
 406             if 'slice_ids' in record:
 407                 slicenames = [slices[slice_id]['name'] for slice_id in record['slice_ids'] \
 408                               if slice_id in slices]
 409                 slice_hrns = [slicename_to_hrn(auth_hrn, slicename) for slicename in slicenames]
 410                 record['slices'] = slice_hrns
 411             if 'node_ids' in record:
 412                 hostnames = [nodes[node_id]['hostname'] for node_id in record['node_ids'] \
 413                              if node_id in nodes]
 414                 node_hrns = [hostname_to_hrn(auth_hrn, login_base, hostname) for hostname in hostnames]
 415                 record['nodes'] = node_hrns
 416             if 'site_ids' in record:
 417                 login_bases = [sites[site_id]['login_base'] for site_id in record['site_ids'] \
 418                                if site_id in sites]
 419                 site_hrns = [".".join([auth_hrn, lbase]) for lbase in login_bases]
 420                 record['sites'] = site_hrns
 421
 422         return records
 423
 424     def fill_record_sfa_info(self, records):
 425
 426         def startswith(prefix, values):
 427             return [value for value in values if value.startswith(prefix)]
 428
 429         # get person ids
 430         person_ids = []
 431         site_ids = []
 432         for record in records:
 433             person_ids.extend(record.get("person_ids", []))
 434             site_ids.extend(record.get("site_ids", []))
 435             if 'site_id' in record:
 436                 site_ids.append(record['site_id'])
 437
 438         # get all pis from the sites we've encountered
 439         # and store them in a dictionary keyed on site_id
 440         site_pis = {}
 441         if site_ids:
 442             pi_filter = {'|roles': ['pi'], '|site_ids': site_ids}
 443             pi_list = self.plshell.GetPersons(self.plauth, pi_filter, ['person_id', 'site_ids'])
 444             for pi in pi_list:
 445                 # we will need the pi's hrns also
 446                 person_ids.append(pi['person_id'])
 447
 448                 # we also need to keep track of the sites these pis
 449                 # belong to
 450                 for site_id in pi['site_ids']:
 451                     if site_id in site_pis:
 452                         site_pis[site_id].append(pi)
 453                     else:
 454                         site_pis[site_id] = [pi]
 455
 456         # get sfa records for all records associated with these records.
 457         # we'll replace pl ids (person_ids) with hrns from the sfa records
 458         # we obtain
 459
 460         # get the sfa records
 461         table = self.SfaTable()
 462         person_list, persons = [], {}
 463         person_list = table.find({'type': 'user', 'pointer': person_ids})
 464         # create a hrns keyed on the sfa record's pointer.
 465         # Its possible for  multiple records to have the same pointer so
 466         # the dict's value will be a list of hrns.
 467         persons = defaultdict(list)
 468         for person in person_list:
 469             persons[person['pointer']].append(person)
 470
 471         # get the pl records
 472         pl_person_list, pl_persons = [], {}
 473         pl_person_list = self.plshell.GetPersons(self.plauth, person_ids, ['person_id', 'roles'])
 474         pl_persons = list_to_dict(pl_person_list, 'person_id')
 475
 476         # fill sfa info
 477         for record in records:
 478             # skip records with no pl info (top level authorities)
 479             #if record['pointer'] == -1:
 480             #    continue
 481             sfa_info = {}
 482             type = record['type']
 483             if (type == "slice"):
 484                 # all slice users are researchers
 485                 record['geni_urn'] = hrn_to_urn(record['hrn'], 'slice')
 486                 record['PI'] = []
 487                 record['researcher'] = []
 488                 for person_id in record.get('person_ids', []):
 489                     hrns = [person['hrn'] for person in persons[person_id]]
 490                     record['researcher'].extend(hrns)
 491
 492                 # pis at the slice's site
 493                 if 'site_id' in record and record['site_id'] in site_pis:
 494                     pl_pis = site_pis[record['site_id']]
 495                     pi_ids = [pi['person_id'] for pi in pl_pis]
 496                     for person_id in pi_ids:
 497                         hrns = [person['hrn'] for person in persons[person_id]]
 498                         record['PI'].extend(hrns)
 499                         record['geni_creator'] = record['PI']
 500
 501             elif (type.startswith("authority")):
 502                 record['url'] = None
 503                 if record['hrn'] in self.aggregates:
 504                     record['url'] = self.aggregates[record['hrn']].url
 505
 506                 if record['pointer'] != -1:
 507                     record['PI'] = []
 508                     record['operator'] = []
 509                     record['owner'] = []
 510                     for pointer in record.get('person_ids', []):
 511                         if pointer not in persons or pointer not in pl_persons:
 512                             # this means there is not sfa or pl record for this user
 513                             continue
 514                         hrns = [person['hrn'] for person in persons[pointer]]
 515                         roles = pl_persons[pointer]['roles']
 516                         if 'pi' in roles:
 517                             record['PI'].extend(hrns)
 518                         if 'tech' in roles:
 519                             record['operator'].extend(hrns)
 520                         if 'admin' in roles:
 521                             record['owner'].extend(hrns)
 522                         # xxx TODO: OrganizationName
 523             elif (type == "node"):
 524                 sfa_info['dns'] = record.get("hostname", "")
 525                 # xxx TODO: URI, LatLong, IP, DNS
 526
 527             elif (type == "user"):
 528                 sfa_info['email'] = record.get("email", "")
 529                 sfa_info['geni_urn'] = hrn_to_urn(record['hrn'], 'user')
 530                 sfa_info['geni_certificate'] = record['gid']
 531                 # xxx TODO: PostalAddress, Phone
 532             record.update(sfa_info)
 533
 534     def fill_record_info(self, records):
 535         """
 536         Given a SFA record, fill in the PLC specific and SFA specific
 537         fields in the record.
 538         """
 539         if not isinstance(records, list):
 540             records = [records]
 541
 542         self.fill_record_pl_info(records)
 543         self.fill_record_sfa_info(records)
 544
 545     def update_membership_list(self, oldRecord, record, listName, addFunc, delFunc):
 546         # get a list of the HRNs tht are members of the old and new records
 547         if oldRecord:
 548             oldList = oldRecord.get(listName, [])
 549         else:
 550             oldList = []
 551         newList = record.get(listName, [])
 552
 553         # if the lists are the same, then we don't have to update anything
 554         if (oldList == newList):
 555             return
 556
 557         # build a list of the new person ids, by looking up each person to get
 558         # their pointer
 559         newIdList = []
 560         table = self.SfaTable()
 561         records = table.find({'type': 'user', 'hrn': newList})
 562         for rec in records:
 563             newIdList.append(rec['pointer'])
 564
 565         # build a list of the old person ids from the person_ids field
 566         if oldRecord:
 567             oldIdList = oldRecord.get("person_ids", [])
 568             containerId = oldRecord.get_pointer()
 569         else:
 570             # if oldRecord==None, then we are doing a Register, instead of an
 571             # update.
 572             oldIdList = []
 573             containerId = record.get_pointer()
 574
 575     # add people who are in the new list, but not the oldList
 576         for personId in newIdList:
 577             if not (personId in oldIdList):
 578                 addFunc(self.plauth, personId, containerId)
 579
 580         # remove people who are in the old list, but not the new list
 581         for personId in oldIdList:
 582             if not (personId in newIdList):
 583                 delFunc(self.plauth, personId, containerId)
 584
 585     def update_membership(self, oldRecord, record):
 586         if record.type == "slice":
 587             self.update_membership_list(oldRecord, record, 'researcher',
 588                                         self.plshell.AddPersonToSlice,
 589                                         self.plshell.DeletePersonFromSlice)
 590         elif record.type == "authority":
 591             # xxx TODO
 592             pass
 593
 594
 595
 596 class ComponentAPI(BaseAPI):
 597
 598     def __init__(self, config = "/etc/sfa/sfa_config.py", encoding = "utf-8", methods='sfa.methods',
 599                  peer_cert = None, interface = None, key_file = None, cert_file = None):
 600
 601         BaseAPI.__init__(self, config=config, encoding=encoding, methods=methods, peer_cert=peer_cert,
 602                          interface=interface, key_file=key_file, cert_file=cert_file)
 603         self.encoding = encoding
 604
 605         # Better just be documenting the API
 606         if config is None:
 607             return
 608
 609         self.nodemanager = NodeManager(self.config)
 610
 611     def sliver_exists(self):
 612         sliver_dict = self.nodemanager.GetXIDs()
 613         if slicename in sliver_dict.keys():
 614             return True
 615         else:
 616             return False
 617
 618     def get_registry(self):
 619         addr, port = self.config.SFA_REGISTRY_HOST, self.config.SFA_REGISTRY_PORT
 620         url = "http://%(addr)s:%(port)s" % locals()
 621         server = xmlrpcprotocol.get_server(url, self.key_file, self.cert_file)
 622         return server
 623
 624     def get_node_key(self):
 625         # this call requires no authentication,
 626         # so we can generate a random keypair here
 627         subject="component"
 628         (kfd, keyfile) = tempfile.mkstemp()
 629         (cfd, certfile) = tempfile.mkstemp()
 630         key = Keypair(create=True)
 631         key.save_to_file(keyfile)
 632         cert = Certificate(subject=subject)
 633         cert.set_issuer(key=key, subject=subject)
 634         cert.set_pubkey(key)
 635         cert.sign()
 636         cert.save_to_file(certfile)
 637         registry = self.get_registry()
 638         # the registry will scp the key onto the node
 639         registry.get_key()
 640
 641     def getCredential(self):
 642         """
 643         Get our credential from a remote registry
 644         """
 645         path = self.config.SFA_DATA_DIR
 646         config_dir = self.config.config_path
 647         cred_filename = path + os.sep + 'node.cred'
 648         try:
 649             credential = Credential(filename = cred_filename)
 650             return credential.save_to_string(save_parents=True)
 651         except IOError:
 652             node_pkey_file = config_dir + os.sep + "node.key"
 653             node_gid_file = config_dir + os.sep + "node.gid"
 654             cert_filename = path + os.sep + 'server.cert'
 655             if not os.path.exists(node_pkey_file) or \
 656                not os.path.exists(node_gid_file):
 657                 self.get_node_key()
 658
 659             # get node's hrn
 660             gid = GID(filename=node_gid_file)
 661             hrn = gid.get_hrn()
 662             # get credential from registry
 663             cert_str = Certificate(filename=cert_filename).save_to_string(save_parents=True)
 664             registry = self.get_registry()
 665             cred = registry.GetSelfCredential(cert_str, hrn, 'node')
 666             Credential(string=cred).save_to_file(credfile, save_parents=True)
 667
 668             return cred
 669
 670     def clean_key_cred(self):
 671         """
 672         remove the existing keypair and cred  and generate new ones
 673         """
 674         files = ["server.key", "server.cert", "node.cred"]
 675         for f in files:
 676             filepath = KEYDIR + os.sep + f
 677             if os.path.isfile(filepath):
 678                 os.unlink(f)
 679
 680         # install the new key pair
 681         # GetCredential will take care of generating the new keypair
 682         # and credential
 683         self.get_node_key()
 684         self.getCredential()
 685
 686