Support for -s. More comments. Removed out of date documentation and bwcap.

[nodemanager.git] / database.py

diff --git a/database.py b/database.py
index c762638..d7ddf04 100644 (file)
--- a/database.py
+++ b/database.py
@@ -1,19 +1,32 @@
+"""The database houses information on slivers.  This information
+reaches the sliver manager in two different ways: one, through the
+GetSlivers() call made periodically; two, by users delivering tickets.
+The sync() method of the Database class turns this data into reality.
+
+The database format is a dictionary that maps account names to records
+(also known as dictionaries).  Inside each record, data supplied or
+computed locally is stored under keys that begin with an underscore,
+and data from PLC is stored under keys that don't.
+
+In order to maintain service when the node reboots during a network
+partition, the database is constantly being dumped to disk.
+"""
+
 import cPickle
 import threading
 import time
 
-try: from bwlimit import bwmin, bwmax
-except ImportError: bwmin, bwmax = 8, 1000000000
 import accounts
 import logger
 import tools
 
 
-DB_FILE = '/root/node_mgr_db.pickle'
+# We enforce minimum allocations to keep the clueless from hosing their slivers.
+# Disallow disk loans because there's currently no way to punish slivers over quota.
+MINIMUM_ALLOCATION = {'cpu_min': 0, 'cpu_share': 16, 'net_min': 0, 'net_max': 8, 'net2_min': 0, 'net2_max': 8, 'net_share': 1}
+LOANABLE_RESOURCES = MINIMUM_ALLOCATION.keys()
 
-LOANABLE_RESOURCES = ['cpu_min', 'cpu_share', 'net_min', 'net_max', 'net2_min', 'net2_max', 'net_share', 'disk_max']
-
-DEFAULT_ALLOCATIONS = {'enabled': 1, 'cpu_min': 0, 'cpu_share': 32, 'net_min': bwmin, 'net_max': bwmax, 'net2_min': bwmin, 'net2_max': bwmax, 'net_share': 1, 'disk_max': 5000000}
+DB_FILE = '/root/sliver_mgr_db.pickle'
 
 
 # database object and associated lock
@@ -25,6 +38,7 @@ db_cond = threading.Condition(db_lock)
 dump_requested = False
 
 # decorator that acquires and releases the database lock before and after the decorated operation
+# XXX - replace with "with" statements once we switch to 2.5
 def synchronized(fn):
     def sync_fn(*args, **kw_args):
         db_lock.acquire()
@@ -50,7 +64,7 @@ class Database(dict):
             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]:
+                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
@@ -66,11 +80,14 @@ class Database(dict):
         elif rec['timestamp'] >= self._min_timestamp: self[name] = 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():
@@ -112,33 +129,3 @@ def start():
         logger.log_exc()
         db = Database()
     tools.as_daemon_thread(run)
-
-@synchronized
-def GetSlivers_callback(data):
-    for d in data:
-        for sliver in d['slivers']:
-            rec = sliver.copy()
-            rec.setdefault('timestamp', d['timestamp'])
-            rec.setdefault('type', 'sliver.VServer')
-
-            # convert attributes field to a proper dict
-            attr_dict = {}
-            for attr in rec.pop('attributes'): attr_dict[attr['name']] = attr['value']
-
-            # squash keys
-            keys = rec.pop('keys')
-            rec.setdefault('keys', '\n'.join([key_struct['key'] for key_struct in keys]))
-
-            rec.setdefault('initscript', attr_dict.get('initscript'))
-            rec.setdefault('delegations', [])  # XXX - delegation not yet supported
-
-            # extract the implied rspec
-            rspec = {}
-            rec['rspec'] = rspec
-            for resname, default_amt in DEFAULT_ALLOCATIONS.iteritems():
-                try: amt = int(attr_dict[resname])
-                except (KeyError, ValueError): amt = default_amt
-                rspec[resname] = amt
-            db.deliver_record(rec)
-        db.set_min_timestamp(d['timestamp'])
-    db.sync()