#! /usr/bin/python import sha as shamodule import os, random from pkg_resources import require require('PyRRD') from pyrrd import graph from pyrrd.rrd import DataSource, RRD, RRA def sha(s): return shamodule.new(s).digest() def randomid(): return os.urandom(20) class Node: def __init__(self, nid, queen, simulator): self.nid = nid self.queen = queen self.simulator = simulator self.shares = {} self.capacity = random.randrange(1000) self.utilization = 0 self.files = [] def permute_peers(self, fileid): permuted = [(sha(fileid+n.nid),n) for n in self.queen.get_all_nodes()] permuted.sort() return permuted def publish_file(self, fileid, size, numshares=100): sharesize = 4 * size / numshares permuted = self.permute_peers(fileid) last_givento = None tried = 0 givento = [] while numshares and permuted: pid,node = permuted.pop(0) tried += 1 last_givento = pid if node.accept_share(fileid, sharesize): givento.append((pid,node)) numshares -= 1 if numshares: # couldn't push, should delete for pid,node in givento: node.delete_share(fileid) return False self.files.append((fileid, numshares)) self.queen.please_preserve(fileid, size, tried, last_givento) return (True, tried) def accept_share(self, fileid, sharesize): accept = False if self.utilization < self.capacity: # we have room! yay! self.shares[fileid] = sharesize self.utilization += sharesize return True if self.decide(sharesize): # we don't, but we'll make room self.make_space(sharesize) self.shares[fileid] = sharesize self.utilization += sharesize return True else: # we're full, try elsewhere return False def decide(self, sharesize): if sharesize > self.capacity: return False return False return random.random() > 0.5 def make_space(self, sharesize): assert sharesize <= self.capacity while self.capacity - self.utilization < sharesize: victim = random.choice(self.shares.keys()) self.simulator.lost_data(self.shares[victim]) self.delete_share(victim) def delete_share(self, fileid): if fileid in self.shares: self.utilization -= self.shares[fileid] del self.shares[fileid] return True return False def retrieve_file(self): if not self.files: return fileid,numshares = random.choice(self.files) needed = numshares / 4 peers = [] for pid,node in self.permute_peers(fileid): if random.random() > self.simulator.P_NODEAVAIL: continue # node isn't available right now if node.has_share(fileid): peers.append(node) if len(peers) >= needed: return True return False def delete_file(self): if not self.files: return False which = random.choice(self.files) self.files.remove(which) fileid,numshares = which self.queen.delete(fileid) return True class Queen: def __init__(self, simulator): self.living_files = {} self.utilization = 0 # total size of all active files self.simulator = simulator self.simulator.stamp_utilization(self.utilization) def get_all_nodes(self): return self.all_nodes def please_preserve(self, fileid, size, tried, last_givento): self.living_files[fileid] = (size, tried, last_givento) self.utilization += size self.simulator.stamp_utilization(self.utilization) def please_delete(self, fileid): self.delete(fileid) def permute_peers(self, fileid): permuted = [(sha(fileid+n.nid),n) for n in self.get_all_nodes()] permuted.sort() return permuted def delete(self, fileid): permuted = self.permute_peers(fileid) size, tried, last_givento = self.living_files[fileid] pid = "" while tried and pid < last_givento: pid,node = permuted.pop(0) had_it = node.delete_share(fileid) if had_it: tried -= 1 self.utilization -= size self.simulator.stamp_utilization(self.utilization) del self.living_files[fileid] class Simulator: NUM_NODES = 1000 EVENTS = ["ADDFILE", "DELFILE", "ADDNODE", "DELNODE"] RATE_ADDFILE = 1.0 / 10 RATE_DELFILE = 1.0 / 20 RATE_ADDNODE = 1.0 / 3000 RATE_DELNODE = 1.0 / 4000 P_NODEAVAIL = 1.0 def __init__(self): self.time = 1164783600 # small numbers of seconds since the epoch confuse rrdtool self.prevstamptime = int(self.time) ds = DataSource(ds_name='utilizationds', ds_type='GAUGE', heartbeat=1) rra = RRA(cf='AVERAGE', xff=0.1, steps=1, rows=1200) self.rrd = RRD("/tmp/utilization.rrd", ds=[ds], rra=[rra], start=self.time) self.rrd.create() self.queen = q = Queen(self) self.all_nodes = [Node(randomid(), q, self) for i in range(self.NUM_NODES)] q.all_nodes = self.all_nodes self.next = [] self.schedule_events() self.verbose = False self.added_files = 0 self.added_data = 0 self.deleted_files = 0 self.published_files = [] self.failed_files = 0 self.lost_data_bytes = 0 # bytes deleted to make room for new shares def stamp_utilization(self, utilization): if int(self.time) > (self.prevstamptime+1): self.rrd.bufferValue(self.time, utilization) self.prevstamptime = int(self.time) def write_graph(self): self.rrd.update() self.rrd = None import gc gc.collect() def1 = graph.DataDefinition(vname="a", rrdfile='/tmp/utilization.rrd', ds_name='utilizationds') area1 = graph.Area(value="a", color="#990033", legend='utilizationlegend') g = graph.Graph('/tmp/utilization.png', imgformat='PNG', width=540, height=100, vertical_label='utilizationverticallabel', title='utilizationtitle', lower_limit=0) g.data.append(def1) g.data.append(area1) g.write() def add_file(self): size = random.randrange(1000) n = random.choice(self.all_nodes) if self.verbose: print "add_file(size=%d, from node %s)" % (size, n) fileid = randomid() able = n.publish_file(fileid, size) if able: able, tried = able self.added_files += 1 self.added_data += size self.published_files.append(tried) else: self.failed_files += 1 def lost_data(self, size): self.lost_data_bytes += size def delete_file(self): all_nodes = self.all_nodes[:] random.shuffle(all_nodes) for n in all_nodes: if n.delete_file(): self.deleted_files += 1 return print "no files to delete" def _add_event(self, etype): rate = getattr(self, "RATE_" + etype) next = self.time + random.expovariate(rate) self.next.append((next, etype)) self.next.sort() def schedule_events(self): types = set([e[1] for e in self.next]) for etype in self.EVENTS: if not etype in types: self._add_event(etype) def do_event(self): time, etype = self.next.pop(0) assert time > self.time current_time = self.time self.time = time self._add_event(etype) if etype == "ADDFILE": self.add_file() elif etype == "DELFILE": self.delete_file() elif etype == "ADDNODE": pass #self.add_node() elif etype == "DELNODE": #self.del_node() pass # self.print_stats(current_time, etype) def print_stats_header(self): print "time: added failed lost avg_tried" def print_stats(self, time, etype): if not self.published_files: avg_tried = "NONE" else: avg_tried = sum(self.published_files) / len(self.published_files) print time, etype, self.added_data, self.failed_files, self.lost_data_bytes, avg_tried, len(self.queen.living_files), self.queen.utilization global s s = None def main(): # rrdtool.create("foo.rrd", # "--step 10", # "DS:files-added:DERIVE::0:1000", # "RRA:AVERAGE:1:1:1200", # ) global s s = Simulator() # s.print_stats_header() for i in range(1000): s.do_event() print "%d files added, %d files deleted" % (s.added_files, s.deleted_files) return s if __name__ == '__main__': main()