actions.py

   1 from time import time
   2 from pickle import loads, dumps
   3
   4 from bsddb3 import db
   5
   6 from const import reactor
   7 import const
   8
   9 from hash import intify
  10 from knode import KNode as Node
  11 from ktable import KTable, K
  12
  13 class ActionBase:
  14     """ base class for some long running asynchronous proccesses like finding nodes or values """
  15     def __init__(self, table, target, callback):
  16         self.table = table
  17         self.target = target
  18         self.int = intify(target)
  19         self.found = {}
  20         self.queried = {}
  21         self.answered = {}
  22         self.callback = callback
  23         self.outstanding = 0
  24         self.finished = 0
  25
  26         def sort(a, b, int=self.int):
  27             """ this function is for sorting nodes relative to the ID we are looking for """
  28             x, y = int ^ a.int, int ^ b.int
  29             if x > y:
  30                 return 1
  31             elif x < y:
  32                 return -1
  33             return 0
  34         self.sort = sort
  35
  36     def goWithNodes(self, t):
  37         pass
  38
  39
  40
  41 FIND_NODE_TIMEOUT = 15
  42
  43 class FindNode(ActionBase):
  44     """ find node action merits it's own class as it is a long running stateful process """
  45     def handleGotNodes(self, args):
  46         args, conn = args
  47         l, sender = args
  48         sender['host'] = conn['host']
  49         sender = Node().initWithDict(sender)
  50         self.table.table.insertNode(sender)
  51         if self.finished or self.answered.has_key(sender.id):
  52             # a day late and a dollar short
  53             return
  54         self.outstanding = self.outstanding - 1
  55         self.answered[sender.id] = 1
  56         for node in l:
  57             n = Node().initWithDict(node)
  58             if not self.found.has_key(n.id):
  59                 self.found[n.id] = n
  60         self.schedule()
  61
  62     def schedule(self):
  63         """
  64             send messages to new peers, if necessary
  65         """
  66         if self.finished:
  67             return
  68         l = self.found.values()
  69         l.sort(self.sort)
  70
  71         for node in l:
  72             if node.id == self.target:
  73                 self.finished=1
  74                 return self.callback([node])
  75             if not self.queried.has_key(node.id) and node.id != self.table.node.id:
  76                 #xxxx t.timeout = time.time() + FIND_NODE_TIMEOUT
  77                 df = node.findNode(self.target, self.table.node.senderDict())
  78                 df.addCallbacks(self.handleGotNodes, self.makeMsgFailed(node))
  79                 self.outstanding = self.outstanding + 1
  80                 self.queried[node.id] = 1
  81             if self.outstanding >= const.CONCURRENT_REQS:
  82                 break
  83         assert(self.outstanding) >=0
  84         if self.outstanding == 0:
  85             ## all done!!
  86             self.finished=1
  87             reactor.callFromThread(self.callback, l[:K])
  88
  89     def makeMsgFailed(self, node):
  90         def defaultGotNodes(err, self=self, node=node):
  91             self.table.table.nodeFailed(node)
  92             if self.finished:
  93                 return
  94             self.outstanding = self.outstanding - 1
  95             self.schedule()
  96         return defaultGotNodes
  97
  98     def goWithNodes(self, nodes):
  99         """
 100             this starts the process, our argument is a transaction with t.extras being our list of nodes
 101             it's a transaction since we got called from the dispatcher
 102         """
 103         for node in nodes:
 104             if node.id == self.table.node.id:
 105                 continue
 106             else:
 107                 self.found[node.id] = node
 108
 109         self.schedule()
 110
 111
 112 GET_VALUE_TIMEOUT = 15
 113 class GetValue(FindNode):
 114     """ get value task """
 115     def handleGotNodes(self, args):
 116         args, conn = args
 117         l, sender = args
 118         sender['host'] = conn['host']
 119         sender = Node().initWithDict(sender)
 120         self.table.table.insertNode(sender)
 121         if self.finished or self.answered.has_key(sender.id):
 122             # a day late and a dollar short
 123             return
 124         self.outstanding = self.outstanding - 1
 125         self.answered[sender.id] = 1
 126         # go through nodes
 127         # if we have any closer than what we already got, query them
 128         if l.has_key('nodes'):
 129             for node in l['nodes']:
 130                 n = Node().initWithDict(node)
 131                 if not self.found.has_key(n.id):
 132                     self.found[n.id] = n
 133         elif l.has_key('values'):
 134             def x(y, z=self.results):
 135                 y = y.data
 136                 if not z.has_key(y):
 137                     z[y] = 1
 138                     return y
 139                 else:
 140                     return None
 141             v = filter(None, map(x, l['values']))
 142             if(len(v)):
 143                 reactor.callFromThread(self.callback, v)
 144         self.schedule()
 145
 146     ## get value
 147     def schedule(self):
 148         if self.finished:
 149             return
 150         l = self.found.values()
 151         l.sort(self.sort)
 152
 153         for node in l:
 154             if not self.queried.has_key(node.id) and node.id != self.table.node.id:
 155                 #xxx t.timeout = time.time() + GET_VALUE_TIMEOUT
 156                 df = node.findValue(self.target, self.table.node.senderDict())
 157                 df.addCallback(self.handleGotNodes)
 158                 df.addErrback(self.makeMsgFailed(node))
 159                 self.outstanding = self.outstanding + 1
 160                 self.queried[node.id] = 1
 161             if self.outstanding >= const.CONCURRENT_REQS:
 162                 break
 163         assert(self.outstanding) >=0
 164         if self.outstanding == 0:
 165             ## all done, didn't find it!!
 166             self.finished=1
 167             reactor.callFromThread(self.callback,[])
 168
 169     ## get value
 170     def goWithNodes(self, nodes, found=None):
 171         self.results = {}
 172         if found:
 173             for n in found:
 174                 self.results[n] = 1
 175         for node in nodes:
 176             if node.id == self.table.node.id:
 177                 continue
 178             else:
 179                 self.found[node.id] = node
 180
 181         self.schedule()
 182
 183
 184
 185 class KeyExpirer:
 186     def __init__(self, store, itime, kw):
 187         self.store = store
 188         self.itime = itime
 189         self.kw = kw
 190         reactor.callLater(const.KEINITIAL_DELAY, self.doExpire)
 191
 192     def doExpire(self):
 193         self.cut = `time() - const.KE_AGE`
 194         self._expire()
 195
 196     def _expire(self):
 197         ic = self.itime.cursor()
 198         sc = self.store.cursor()
 199         kc = self.kw.cursor()
 200         irec = None
 201         try:
 202             irec = ic.set_range(self.cut)
 203         except db.DBNotFoundError:
 204             # everything is expired
 205             f = ic.prev
 206             irec = f()
 207         else:
 208             f = ic.next
 209         i = 0
 210         while irec:
 211             it, h = irec
 212             try:
 213                 k, v, lt = loads(self.store[h])
 214             except KeyError:
 215                 ic.delete()
 216             else:
 217                 if lt < self.cut:
 218                     try:
 219                         kc.set_both(k, h)
 220                     except db.DBNotFoundError:
 221                         print "Database inconsistency!  No key->value entry when a store entry was found!"
 222                     else:
 223                         kc.delete()
 224                     self.store.delete(h)
 225                     ic.delete()
 226                     i = i + 1
 227                 else:
 228                     break
 229             irec = f()
 230
 231         reactor.callLater(const.KE_DELAY, self.doExpire)
 232         if(i > 0):
 233             print ">>>KE: done expiring %d" % i
 234