+# XXX - replace with "with" statements once we switch to 2.5
+def synchronized(fn):
+ def sync_fn(*args, **kw_args):
+ db_lock.acquire()
+ try: return fn(*args, **kw_args)
+ finally: db_lock.release()
+ sync_fn.__doc__ = fn.__doc__
+ sync_fn.__name__ = fn.__name__
+ return sync_fn
+
+
+class Database(dict):
+ def __init__(self):
+ self._min_timestamp = 0
+
+ def _compute_effective_rspecs(self):
+ """Calculate the effects of loans and store the result in field _rspec. At the moment, we allow slivers to loan only those resources that they have received directly from PLC. In order to do the accounting, we store three different rspecs: field 'rspec', which is the resources given by PLC; field '_rspec', which is the actual amount of resources the sliver has after all loans; and variable resid_rspec, which is the amount of resources the sliver has after giving out loans but not receiving any."""
+ slivers = {}
+ for name, rec in self.iteritems():
+ if 'rspec' in rec:
+ rec['_rspec'] = rec['rspec'].copy()
+ slivers[name] = rec
+ for rec in slivers.itervalues():
+ eff_rspec = rec['_rspec']
+ resid_rspec = rec['rspec'].copy()
+ for target, resname, amt in rec.get('_loans', []):
+ if target in slivers and amt <= resid_rspec[resname] - MINIMUM_ALLOCATION[resname]:
+ eff_rspec[resname] -= amt
+ resid_rspec[resname] -= amt
+ slivers[target]['_rspec'][resname] += amt
+
+ def deliver_record(self, rec):
+ """A record is simply a dictionary with 'name' and 'timestamp' keys. We keep some persistent private data in the records under keys that start with '_'; thus record updates should not displace such keys."""
+ if rec['timestamp'] < self._min_timestamp: return
+ name = rec['name']
+ old_rec = self.get(name)
+ if old_rec == None: self[name] = rec
+ elif rec['timestamp'] > old_rec['timestamp']:
+ for key in old_rec.keys():
+ if not key.startswith('_'): del old_rec[key]
+ old_rec.update(rec)
+
+ def set_min_timestamp(self, ts):
+ """The ._min_timestamp member is the timestamp on the last comprehensive update. We use it to determine if a record is stale. This method should be called whenever new GetSlivers() data comes in."""
+ self._min_timestamp = ts
+ for name, rec in self.items():
+ if rec['timestamp'] < ts: del self[name]
+
+ def sync(self):
+ """Synchronize reality with the database contents. This method does a lot of things, and it's currently called after every single batch of database changes (a GetSlivers(), a loan, a record). It may be necessary in the future to do something smarter."""
+
+ # delete expired records
+ now = time.time()
+ for name, rec in self.items():
+ if rec.get('expires', now) < now: del self[name]
+
+ self._compute_effective_rspecs()
+
+ # create and destroy accounts as needed
+ logger.verbose("database:sync : fetching accounts")
+ existing_acct_names = accounts.all()
+ for name in existing_acct_names:
+ logger.verbose("database:sync : loop on %s"%name)
+ if name not in self: accounts.get(name).ensure_destroyed()
+ for name, rec in self.iteritems():
+ slivr = accounts.get(name)
+ logger.verbose("database:sync : %s is %s" %(name,slivr._get_class()))
+ # Make sure we refresh accounts that are running
+ if rec['instantiation'] == 'plc-instantiated': slivr.ensure_created(rec)
+ elif rec['instantiation'] == 'nm-controller': slivr.ensure_created(rec)
+ # Back door to ensure PLC overrides Ticket in delegation.
+ elif rec['instantiation'] == 'delegated' and slivr._get_class() != None:
+ # if the ticket has been delivered and the nm-contoroller started the slice
+ # update rspecs and keep them up to date.
+ if slivr.is_running(): slivr.ensure_created(rec)
+
+ # Wake up bwmom to update limits.
+ bwmon.lock.set()
+ global dump_requested
+ dump_requested = True
+ db_cond.notify()
+