tahoe-lafs/misc/simulator.py
Zooko O'Whielacronx 59d6c3c822 decentralized directories: integration and testing
* use new decentralized directories everywhere instead of old centralized directories
 * provide UI to them through the web server
 * provide UI to them through the CLI
 * update unit tests to simulate decentralized mutable directories in order to test other components that rely on them
 * remove the notion of a "vdrive server" and a client thereof
 * remove the notion of a "public vdrive", which was a directory that was centrally published/subscribed automatically by the tahoe node (you can accomplish this manually by making a directory and posting the URL to it on your web site, for example)
 * add a notion of "wait_for_numpeers" when you need to publish data to peers, which is how many peers should be attached before you start.  The default is 1.
 * add __repr__ for filesystem nodes (note: these reprs contain a few bits of the secret key!)
 * fix a few bugs where we used to equate "mutable" with "not read-only".  Nowadays all directories are mutable, but some might be read-only (to you).
 * fix a few bugs where code wasn't aware of the new general-purpose metadata dict the comes with each filesystem edge
 * sundry fixes to unit tests to adjust to the new directories, e.g. don't assume that every share on disk belongs to a chk file.
2007-12-03 14:52:42 -07:00

293 lines
9.1 KiB
Python

#! /usr/bin/env 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, introducer, simulator):
self.nid = nid
self.introducer = introducer
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.introducer.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.introducer.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.introducer.delete(fileid)
return True
class IntroducerAndVdrive:
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.introducer = q = IntroducerAndVdrive(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.introducer.living_files), self.introducer.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()