Source Code for Module ganeti.config.temporary_reservations

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 29   
 30   
 31  """Reserve resources, so that jobs can't take them. 
 32   
 33  """ 
 34   
 35  from ganeti import errors 
 36   
 37   
 38 -class TemporaryReservationManager(object): 
 39    """A temporary resource reservation manager. 
 40   
 41    This is used to reserve resources in a job, before using them, making sure 
 42    other jobs cannot get them in the meantime. 
 43   
 44    """ 
 45 -  def __init__(self): 
 46      self._ec_reserved = {} 
 47   
 48 -  def Reserved(self, resource): 
 49      for holder_reserved in self._ec_reserved.values(): 
 50        if resource in holder_reserved: 
 51          return True 
 52      return False 
 53   
 54 -  def Reserve(self, ec_id, resource): 
 55      if self.Reserved(resource): 
 56        raise errors.ReservationError("Duplicate reservation for resource '%s'" 
 57                                      % str(resource)) 
 58      if ec_id not in self._ec_reserved: 
 59        self._ec_reserved[ec_id] = set([resource]) 
 60      else: 
 61        self._ec_reserved[ec_id].add(resource) 
 62   
 63 -  def DropECReservations(self, ec_id): 
 64      if ec_id in self._ec_reserved: 
 65        del self._ec_reserved[ec_id] 
 66   
 67 -  def GetReserved(self): 
 68      all_reserved = set() 
 69      for holder_reserved in self._ec_reserved.values(): 
 70        all_reserved.update(holder_reserved) 
 71      return all_reserved 
 72   
 73 -  def GetECReserved(self, ec_id): 
 74      """ Used when you want to retrieve all reservations for a specific 
 75          execution context. E.g when commiting reserved IPs for a specific 
 76          network. 
 77   
 78      """ 
 79      ec_reserved = set() 
 80      if ec_id in self._ec_reserved: 
 81        ec_reserved.update(self._ec_reserved[ec_id]) 
 82      return ec_reserved 
 83   
 84 -  def Generate(self, existing, generate_one_fn, ec_id): 
 85      """Generate a new resource of this type 
 86   
 87      """ 
 88      assert callable(generate_one_fn) 
 89   
 90      all_elems = self.GetReserved() 
 91      all_elems.update(existing) 
 92      retries = 64 
 93      while retries > 0: 
 94        new_resource = generate_one_fn() 
 95        if new_resource is not None and new_resource not in all_elems: 
 96          break 
 97      else: 
 98        raise errors.ConfigurationError("Not able generate new resource" 
 99                                        " (last tried: %s)" % new_resource) 
100      self.Reserve(ec_id, new_resource) 
101      return new_resource 
102