#!/usr/bin/python
# Copyright 2009-2010 Mike Perry. See LICENSE file.

"""

Support classes for statisics gathering in SQL Databases

DOCDOC

"""

import socket
import sys
import time
import datetime
import math

import PathSupport, TorCtl
from TorUtil import *
from PathSupport import *
from TorUtil import meta_port, meta_host, control_port, control_host, control_pass
from TorCtl import EVENT_TYPE, EVENT_STATE, TorCtlError

import sqlalchemy
import sqlalchemy.pool
import sqlalchemy.orm.exc
from sqlalchemy.orm import scoped_session, sessionmaker, eagerload, lazyload, eagerload_all
from sqlalchemy.orm.exc import NoResultFound
from sqlalchemy import create_engine, and_, or_, not_, func
from sqlalchemy.sql import func,select,alias,case
from sqlalchemy.schema import ThreadLocalMetaData,MetaData
from elixir import *
from elixir import options
# migrate from elixir 06 to 07
options.MIGRATION_TO_07_AID = True


# Nodes with a ratio below this value will be removed from consideration
# for higher-valued nodes
MIN_RATIO=0.5

NO_FPE=2**-50

#################### Session Usage ###############
# What is all this l_session madness? See:                                                                
# http://www.sqlalchemy.org/docs/orm/session.html#lifespan-of-a-contextual-session                        
#   "This has the effect such that each web request starts fresh with                                     
#   a brand new session, and is the most definitive approach to closing                                   
#   out a request." 

#################### Model #######################

# In elixir, the session (DB connection) is a property of the model..
# There can only be one for all of the listeners below that use it
# See http://elixir.ematia.de/trac/wiki/Recipes/MultipleDatabases
OP=None
tc_metadata = MetaData()
tc_metadata.echo=True
tc_session = scoped_session(sessionmaker(autoflush=True))

def setup_db(db_uri, echo=False, drop=False):
  # Memory-only sqlite requires some magic options...
  if db_uri == "sqlite://":
    tc_engine = create_engine(db_uri, echo=echo,
                              connect_args={'check_same_thread':False},
                              poolclass=sqlalchemy.pool.StaticPool)
  else:
    tc_engine = create_engine(db_uri, echo=echo)
  tc_metadata.bind = tc_engine
  tc_metadata.echo = echo

  setup_all()
  if drop: drop_all()
  create_all()

  if sqlalchemy.__version__ < "0.5.0":
    # DIAF SQLAlchemy. A token gesture at backwards compatibility
    # wouldn't kill you, you know.
    tc_session.add = tc_session.save_or_update

  if sqlalchemy.__version__ < "0.6.0":
    # clear() replaced with expunge_all
    tc_session.clear = tc_session.expunge_all

class Router(Entity):
  using_options(shortnames=True, order_by='-published', session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  idhex = Field(CHAR(40), primary_key=True, index=True)
  orhash = Field(CHAR(27))
  published = Field(DateTime)
  nickname = Field(Text)

  os = Field(Text)
  rate_limited = Field(Boolean)
  guard = Field(Boolean)
  exit = Field(Boolean)
  stable = Field(Boolean)
  v2dir = Field(Boolean)
  v3dir = Field(Boolean)
  hsdir = Field(Boolean)

  bw = Field(Integer)
  version = Field(Integer)
  # FIXME: is mutable=False what we want? Do we care?
  #router = Field(PickleType(mutable=False)) 
  circuits = ManyToMany('Circuit')
  streams = ManyToMany('Stream')
  detached_streams = ManyToMany('Stream')
  bw_history = OneToMany('BwHistory')
  stats = OneToOne('RouterStats', inverse="router")

  def from_router(self, router):
    self.published = router.published
    self.bw = router.bw
    self.idhex = router.idhex
    self.orhash = router.orhash
    self.nickname = router.nickname
    # XXX: Temporary hack. router.os can contain unicode, which makes
    # us barf. Apparently 'Text' types can't have unicode chars?
    # self.os = router.os
    self.rate_limited = router.rate_limited
    self.guard = "Guard" in router.flags
    self.exit = "Exit" in router.flags
    self.stable = "Stable" in router.flags
    self.v2dir = "V2Dir" in router.flags
    self.v3dir = "V3Dir" in router.flags
    self.hsdir = "HSDir" in router.flags
    self.version = router.version.version
    #self.router = router
    return self

class BwHistory(Entity):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  router = ManyToOne('Router')
  bw = Field(Integer)
  desc_bw = Field(Integer)
  rank = Field(Integer)
  pub_time = Field(DateTime)

class Circuit(Entity):
  using_options(shortnames=True, order_by='-launch_time', session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  routers = ManyToMany('Router')
  streams = OneToMany('Stream', inverse='circuit')
  detached_streams = ManyToMany('Stream', inverse='detached_circuits')
  extensions = OneToMany('Extension', inverse='circ')
  circ_id = Field(Integer, index=True)
  launch_time = Field(Float)
  last_extend = Field(Float)

class FailedCircuit(Circuit):
  using_mapper_options(save_on_init=False)
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  #failed_extend = ManyToOne('Extension', inverse='circ')
  fail_reason = Field(Text)
  fail_time = Field(Float)

class BuiltCircuit(Circuit):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  built_time = Field(Float)
  tot_delta = Field(Float)

class DestroyedCircuit(Circuit):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  destroy_reason = Field(Text)
  destroy_time = Field(Float)

class ClosedCircuit(BuiltCircuit):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  closed_time = Field(Float)

class Extension(Entity):
  using_mapper_options(save_on_init=False)
  using_options(shortnames=True, order_by='-time', session=tc_session, metadata=tc_metadata)
  circ = ManyToOne('Circuit', inverse='extensions')
  from_node = ManyToOne('Router')
  to_node = ManyToOne('Router')
  hop = Field(Integer)
  time = Field(Float)
  delta = Field(Float)

class FailedExtension(Extension):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  #failed_circ = ManyToOne('FailedCircuit', inverse='failed_extend')
  using_mapper_options(save_on_init=False)
  reason = Field(Text)

class Stream(Entity):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  using_options(shortnames=True, order_by='-start_time')
  using_mapper_options(save_on_init=False)
  tgt_host = Field(Text)
  tgt_port = Field(Integer)
  circuit = ManyToOne('Circuit', inverse='streams')
  detached_circuits = ManyToMany('Circuit', inverse='detatched_streams')
  ignored = Field(Boolean) # Directory streams
  strm_id = Field(Integer, index=True)
  start_time = Field(Float)
  tot_read_bytes = Field(Integer)
  tot_write_bytes = Field(Integer)
  init_status = Field(Text)
  close_reason = Field(Text) # Shared by Failed and Closed. Unused here.

class FailedStream(Stream):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  fail_reason = Field(Text)
  fail_time = Field(Float)

class ClosedStream(Stream):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  end_time = Field(Float)
  read_bandwidth = Field(Float)
  write_bandwidth = Field(Float)

  def tot_bytes(self):
    return self.tot_read_bytes
    #return self.tot_read_bytes+self.tot_write_bytes

  def bandwidth(self):
    return self.tot_bandwidth()

  def tot_bandwidth(self):
    #return self.read_bandwidth+self.write_bandwidth 
    return self.read_bandwidth

class RouterStats(Entity):
  using_options(shortnames=True, session=tc_session, metadata=tc_metadata)
  using_mapper_options(save_on_init=False)
  router = ManyToOne('Router', inverse="stats")
   
  # Easily derived from BwHistory
  min_rank = Field(Integer)
  avg_rank = Field(Float)
  max_rank = Field(Integer)
  avg_bw = Field(Float)
  avg_desc_bw = Field(Float)

  percentile = Field(Float)

  # These can be derived with a single query over 
  # FailedExtension and Extension
  circ_fail_to = Field(Float) 
  circ_fail_from = Field(Float)
  circ_try_to = Field(Float)
  circ_try_from = Field(Float)

  circ_from_rate = Field(Float)
  circ_to_rate = Field(Float)
  circ_bi_rate = Field(Float)

  circ_to_ratio = Field(Float)
  circ_from_ratio = Field(Float)
  circ_bi_ratio = Field(Float)

  avg_first_ext = Field(Float)
  ext_ratio = Field(Float)
 
  strm_try = Field(Integer)
  strm_closed = Field(Integer)

  sbw = Field(Float)
  sbw_dev = Field(Float)
  sbw_ratio = Field(Float)
  filt_sbw = Field(Float)
  filt_sbw_ratio = Field(Float)

  def _compute_stats_relation(stats_clause):
    l_session = tc_session()
    for rs in RouterStats.query.\
                   filter(stats_clause).\
                   options(eagerload_all('router.circuits.extensions')).\
                   all():
      rs.circ_fail_to = 0
      rs.circ_try_to = 0
      rs.circ_fail_from = 0
      rs.circ_try_from = 0
      tot_extend_time = 0
      tot_extends = 0
      for c in rs.router.circuits: 
        for e in c.extensions: 
          if e.to_node == r:
            rs.circ_try_to += 1
            if isinstance(e, FailedExtension):
              rs.circ_fail_to += 1
            elif e.hop == 0:
              tot_extend_time += e.delta
              tot_extends += 1
          elif e.from_node == r:
            rs.circ_try_from += 1
            if isinstance(e, FailedExtension):
              rs.circ_fail_from += 1
            
        if isinstance(c, FailedCircuit):
          pass # TODO: Also count timeouts against earlier nodes?
        elif isinstance(c, DestroyedCircuit):
          pass # TODO: Count these somehow..

      if tot_extends > 0: rs.avg_first_ext = (1.0*tot_extend_time)/tot_extends
      else: rs.avg_first_ext = 0
      if rs.circ_try_from > 0:
        rs.circ_from_rate = (1.0*rs.circ_fail_from/rs.circ_try_from)
      if rs.circ_try_to > 0:
        rs.circ_to_rate = (1.0*rs.circ_fail_to/rs.circ_try_to)
      if rs.circ_try_to+rs.circ_try_from > 0:
        rs.circ_bi_rate = (1.0*rs.circ_fail_to+rs.circ_fail_from)/(rs.circ_try_to+rs.circ_try_from)

      l_session.add(rs)
    l_session.commit()
    tc_session.remove()
  _compute_stats_relation = Callable(_compute_stats_relation)


  def _compute_stats_query(stats_clause):
    tc_session.expunge_all()
    l_session = tc_session()
    # http://www.sqlalchemy.org/docs/04/sqlexpression.html#sql_update
    to_s = select([func.count(Extension.id)], 
        and_(stats_clause, Extension.table.c.to_node_idhex
             == RouterStats.table.c.router_idhex)).as_scalar()
    from_s = select([func.count(Extension.id)], 
        and_(stats_clause, Extension.table.c.from_node_idhex
             == RouterStats.table.c.router_idhex)).as_scalar()
    f_to_s = select([func.count(FailedExtension.id)], 
        and_(stats_clause, FailedExtension.table.c.to_node_idhex
             == RouterStats.table.c.router_idhex,
             FailedExtension.table.c.row_type=='failedextension')).as_scalar()
    f_from_s = select([func.count(FailedExtension.id)], 
        and_(stats_clause, FailedExtension.table.c.from_node_idhex
                       == RouterStats.table.c.router_idhex,
             FailedExtension.table.c.row_type=='failedextension')).as_scalar()
    avg_ext = select([func.avg(Extension.delta)], 
        and_(stats_clause,
             Extension.table.c.to_node_idhex==RouterStats.table.c.router_idhex,
             Extension.table.c.hop==0, 
             Extension.table.c.row_type=='extension')).as_scalar()

    RouterStats.table.update(stats_clause, values=
      {RouterStats.table.c.circ_try_to:to_s,
       RouterStats.table.c.circ_try_from:from_s,
       RouterStats.table.c.circ_fail_to:f_to_s,
       RouterStats.table.c.circ_fail_from:f_from_s,
       RouterStats.table.c.avg_first_ext:avg_ext}).execute()

      # added case() to set NULL and avoid divide-by-zeros (Postgres)
    RouterStats.table.update(stats_clause, values=
      {RouterStats.table.c.circ_from_rate:
          case([(RouterStats.table.c.circ_try_from == 0, None)],
              else_=(RouterStats.table.c.circ_fail_from/RouterStats.table.c.circ_try_from)),
       RouterStats.table.c.circ_to_rate:
          case([(RouterStats.table.c.circ_try_to == 0, None)],
              else_=(RouterStats.table.c.circ_fail_to/RouterStats.table.c.circ_try_to)),
       RouterStats.table.c.circ_bi_rate:
          case([(RouterStats.table.c.circ_try_to+RouterStats.table.c.circ_try_from == 0, None)],
           else_=((RouterStats.table.c.circ_fail_to+RouterStats.table.c.circ_fail_from)
                          /
                 (RouterStats.table.c.circ_try_to+RouterStats.table.c.circ_try_from))),
      }).execute()


    # TODO: Give the streams relation table a sane name and reduce this too
    for rs in RouterStats.query.filter(stats_clause).\
                        options(eagerload('router'),
                                eagerload('router.detached_streams'),
                                eagerload('router.streams')).all():
      tot_bw = 0.0
      s_cnt = 0
      tot_bytes = 0.0
      tot_duration = 0.0
      for s in rs.router.streams:
        if isinstance(s, ClosedStream):
          tot_bytes += s.tot_bytes()
          tot_duration += s.end_time - s.start_time
          tot_bw += s.bandwidth()
          s_cnt += 1
      # FIXME: Hrmm.. do we want to do weighted avg or pure avg here?
      # If files are all the same size, it shouldn't matter..
      if s_cnt > 0:
        rs.sbw = tot_bw/s_cnt
      else: rs.sbw = None
      rs.strm_closed = s_cnt
      rs.strm_try = len(rs.router.streams)+len(rs.router.detached_streams)
      if rs.sbw:
        tot_var = 0.0
        for s in rs.router.streams:
          if isinstance(s, ClosedStream):
            tot_var += (s.bandwidth()-rs.sbw)*(s.bandwidth()-rs.sbw)
        tot_var /= s_cnt
        rs.sbw_dev = math.sqrt(tot_var)
      l_session.add(rs)
    l_session.commit()
    tc_session.remove()
  _compute_stats_query = Callable(_compute_stats_query)


  def _compute_stats(stats_clause):
    RouterStats._compute_stats_query(stats_clause)
    #RouterStats._compute_stats_relation(stats_clause)
  _compute_stats = Callable(_compute_stats)

  def _compute_ranks():
    tc_session.expunge_all()
    l_session = tc_session()
    min_r = select([func.min(BwHistory.rank)],
        BwHistory.table.c.router_idhex
            == RouterStats.table.c.router_idhex).as_scalar()
    avg_r = select([func.avg(BwHistory.rank)],
        BwHistory.table.c.router_idhex
            == RouterStats.table.c.router_idhex).as_scalar()
    max_r = select([func.max(BwHistory.rank)],
        BwHistory.table.c.router_idhex
            == RouterStats.table.c.router_idhex).as_scalar()
    avg_bw = select([func.avg(BwHistory.bw)],
        BwHistory.table.c.router_idhex
            == RouterStats.table.c.router_idhex).as_scalar()
    avg_desc_bw = select([func.avg(BwHistory.desc_bw)],
        BwHistory.table.c.router_idhex
            == RouterStats.table.c.router_idhex).as_scalar()

    RouterStats.table.update(values=
       {RouterStats.table.c.min_rank:min_r,
        RouterStats.table.c.avg_rank:avg_r,
        RouterStats.table.c.max_rank:max_r,
        RouterStats.table.c.avg_bw:avg_bw,
        RouterStats.table.c.avg_desc_bw:avg_desc_bw}).execute()

    #min_avg_rank = select([func.min(RouterStats.avg_rank)]).as_scalar()

    # the commented query breaks mysql because UPDATE cannot reference
    # target table in the FROM clause. So we throw in an anonymous alias and wrap
    # another select around it in order to get the nested SELECT stored into a 
    # temporary table.
    # FIXME: performance? no idea 
    #max_avg_rank = select([func.max(RouterStats.avg_rank)]).as_scalar()
    max_avg_rank = select([alias(select([func.max(RouterStats.avg_rank)]))]).as_scalar()

    RouterStats.table.update(values=
       {RouterStats.table.c.percentile:
            (100.0*RouterStats.table.c.avg_rank)/max_avg_rank}).execute()

    l_session.commit()
    tc_session.remove()
  _compute_ranks = Callable(_compute_ranks)

  def _compute_ratios(stats_clause):
    tc_session.expunge_all()
    l_session = tc_session()
    avg_from_rate = select([alias(
        select([func.avg(RouterStats.circ_from_rate)],
                           stats_clause)
        )]).as_scalar()
    avg_to_rate = select([alias(
        select([func.avg(RouterStats.circ_to_rate)],
                           stats_clause)
        )]).as_scalar()
    avg_bi_rate = select([alias(
        select([func.avg(RouterStats.circ_bi_rate)],
                           stats_clause)
        )]).as_scalar()
    avg_ext = select([alias(
        select([func.avg(RouterStats.avg_first_ext)],
                           stats_clause)
        )]).as_scalar()
    avg_sbw = select([alias(
        select([func.avg(RouterStats.sbw)],
                           stats_clause)
        )]).as_scalar()

    RouterStats.table.update(stats_clause, values=
       {RouterStats.table.c.circ_from_ratio:
         (1-RouterStats.table.c.circ_from_rate)/(1-avg_from_rate),
        RouterStats.table.c.circ_to_ratio:
         (1-RouterStats.table.c.circ_to_rate)/(1-avg_to_rate),
        RouterStats.table.c.circ_bi_ratio:
         (1-RouterStats.table.c.circ_bi_rate)/(1-avg_bi_rate),
        RouterStats.table.c.ext_ratio:
         avg_ext/RouterStats.table.c.avg_first_ext,
        RouterStats.table.c.sbw_ratio:
         RouterStats.table.c.sbw/avg_sbw}).execute()
    l_session.commit()
    tc_session.remove()
  _compute_ratios = Callable(_compute_ratios)

  def _compute_filtered_relational(min_ratio, stats_clause, filter_clause):
    l_session = tc_session()
    badrouters = RouterStats.query.filter(stats_clause).filter(filter_clause).\
                   filter(RouterStats.sbw_ratio < min_ratio).all()

    # TODO: Turn this into a single query....
    for rs in RouterStats.query.filter(stats_clause).\
          options(eagerload_all('router.streams.circuit.routers')).all():
      tot_sbw = 0
      sbw_cnt = 0
      for s in rs.router.streams:
        if isinstance(s, ClosedStream):
          skip = False
          #for br in badrouters:
          #  if br != rs:
          #    if br.router in s.circuit.routers:
          #      skip = True
          if not skip:
            # Throw out outliers < mean 
            # (too much variance for stddev to filter much)
            if rs.strm_closed == 1 or s.bandwidth() >= rs.sbw:
              tot_sbw += s.bandwidth()
              sbw_cnt += 1

      if sbw_cnt: rs.filt_sbw = tot_sbw/sbw_cnt
      else: rs.filt_sbw = None
      l_session.add(rs)
    if sqlalchemy.__version__ < "0.5.0":
      avg_sbw = RouterStats.query.filter(stats_clause).avg(RouterStats.filt_sbw)
    else:
      avg_sbw = l_session.query(func.avg(RouterStats.filt_sbw)).filter(stats_clause).scalar()
    for rs in RouterStats.query.filter(stats_clause).all():
      if type(rs.filt_sbw) == float and avg_sbw:
        rs.filt_sbw_ratio = rs.filt_sbw/avg_sbw
      else:
        rs.filt_sbw_ratio = None
      l_session.add(rs)
    l_session.commit()
    tc_session.remove()
  _compute_filtered_relational = Callable(_compute_filtered_relational)

  def _compute_filtered_ratios(min_ratio, stats_clause, filter_clause):
    RouterStats._compute_filtered_relational(min_ratio, stats_clause, 
                                             filter_clause)
    #RouterStats._compute_filtered_query(filter,min_ratio)
  _compute_filtered_ratios = Callable(_compute_filtered_ratios)

  def reset():
    tc_session.expunge_all()
    l_session = tc_session()
    RouterStats.table.drop()
    RouterStats.table.create()
    for r in Router.query.all():
      rs = RouterStats()
      rs.router = r
      r.stats = rs
      l_session.add(r)
    l_session.commit()
    tc_session.remove()
  reset = Callable(reset)

  def compute(pct_low=0, pct_high=100, stat_clause=None, filter_clause=None):
    l_session = tc_session()
    pct_clause = and_(RouterStats.percentile >= pct_low, 
                         RouterStats.percentile < pct_high)
    if stat_clause:
      stat_clause = and_(pct_clause, stat_clause)
    else:
      stat_clause = pct_clause
     
    RouterStats.reset()
    RouterStats._compute_ranks() # No filters. Ranks are independent
    RouterStats._compute_stats(stat_clause)
    RouterStats._compute_ratios(stat_clause)
    RouterStats._compute_filtered_ratios(MIN_RATIO, stat_clause, filter_clause)
    l_session.commit()
    tc_session.remove()
  compute = Callable(compute)  

  def write_stats(f, pct_low=0, pct_high=100, order_by=None, recompute=False, stat_clause=None, filter_clause=None, disp_clause=None, ignore_by_idhex=[]):
    l_session = tc_session()

    if not order_by:
      order_by=RouterStats.avg_first_ext

    if recompute:
      RouterStats.compute(pct_low, pct_high, stat_clause, filter_clause)

    pct_clause = and_(RouterStats.percentile >= pct_low, 
                         RouterStats.percentile < pct_high)

    # This is Fail City and sqlalchemy is running for mayor.
    if sqlalchemy.__version__ < "0.5.0":
      circ_from_rate = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.circ_from_rate)
      circ_to_rate = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.circ_to_rate)
      circ_bi_rate = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.circ_bi_rate)

      avg_first_ext = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.avg_first_ext)
      sbw = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.sbw)
      filt_sbw = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.filt_sbw)
      percentile = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.percentile)
    else:
      circ_from_rate = l_session.query(func.avg(RouterStats.circ_from_rate)).filter(pct_clause).filter(stat_clause).scalar()
      circ_to_rate = l_session.query(func.avg(RouterStats.circ_to_rate)).filter(pct_clause).filter(stat_clause).scalar()
      circ_bi_rate = l_session.query(func.avg(RouterStats.circ_bi_rate)).filter(pct_clause).filter(stat_clause).scalar()
      
      avg_first_ext = l_session.query(func.avg(RouterStats.avg_first_ext)).filter(pct_clause).filter(stat_clause).scalar()
      sbw = l_session.query(func.avg(RouterStats.sbw)).filter(pct_clause).filter(stat_clause).scalar()
      filt_sbw = l_session.query(func.avg(RouterStats.filt_sbw)).filter(pct_clause).filter(stat_clause).scalar()
      percentile = l_session.query(func.avg(RouterStats.percentile)).filter(pct_clause).filter(stat_clause).scalar()

    tc_session.remove()

    def cvt(a,b,c=1):
      if type(a) == float: return round(a/c,b)
      elif type(a) == int: return a
      elif type(a) == long: return a
      elif type(a) == type(None): return "None"
      else: return type(a)

    sql_key = """SQLSupport Statistics:
    CF=Circ From Rate          CT=Circ To Rate      CB=Circ To/From Rate
    CE=Avg 1st Ext time (s)    SB=Avg Stream BW     FB=Filtered stream bw
    SD=Strm BW stddev          CC=Circ To Attempts  ST=Strem attempts
    SC=Streams Closed OK       RF=Circ From Ratio   RT=Circ To Ratio     
    RB=Circ To/From Ratio      RE=1st Ext Ratio     RS=Stream BW Ratio   
    RF=Filt Stream Ratio       PR=Percentile Rank\n\n"""
 
    f.write(sql_key)
    f.write("Average Statistics:\n")
    f.write("   CF="+str(cvt(circ_from_rate,2)))
    f.write("  CT="+str(cvt(circ_to_rate,2)))
    f.write("  CB="+str(cvt(circ_bi_rate,2)))
    f.write("  CE="+str(cvt(avg_first_ext,2)))
    f.write("  SB="+str(cvt(sbw,2,1024)))
    f.write("  FB="+str(cvt(filt_sbw,2,1024)))
    f.write("  PR="+str(cvt(percentile,2))+"\n\n\n")

    for s in RouterStats.query.filter(pct_clause).filter(stat_clause).\
             filter(disp_clause).order_by(order_by).all():
      if s.router.idhex in ignore_by_idhex:
        plog("NOTICE", "Skipping stats on added exit "+s.router.idhex+" in "+f.name)
        continue
      f.write(s.router.idhex+" ("+s.router.nickname+")\n")
      f.write("   CF="+str(cvt(s.circ_from_rate,2)))
      f.write("  CT="+str(cvt(s.circ_to_rate,2)))
      f.write("  CB="+str(cvt(s.circ_bi_rate,2)))
      f.write("  CE="+str(cvt(s.avg_first_ext,2)))
      f.write("  SB="+str(cvt(s.sbw,2,1024)))
      f.write("  FB="+str(cvt(s.filt_sbw,2,1024)))
      f.write("  SD="+str(cvt(s.sbw_dev,2,1024))+"\n")
      f.write("   RF="+str(cvt(s.circ_from_ratio,2)))
      f.write("  RT="+str(cvt(s.circ_to_ratio,2)))
      f.write("  RB="+str(cvt(s.circ_bi_ratio,2)))
      f.write("  RE="+str(cvt(s.ext_ratio,2)))
      f.write("  RS="+str(cvt(s.sbw_ratio,2)))
      f.write("  RF="+str(cvt(s.filt_sbw_ratio,2)))
      f.write("  PR="+str(cvt(s.percentile,1))+"\n")
      f.write("   CC="+str(cvt(s.circ_try_to,1)))
      f.write("  ST="+str(cvt(s.strm_try, 1)))
      f.write("  SC="+str(cvt(s.strm_closed, 1))+"\n\n")

    f.flush()
  write_stats = Callable(write_stats)  
  

  def write_bws(f, pct_low=0, pct_high=100, order_by=None, recompute=False, stat_clause=None, filter_clause=None, disp_clause=None, ignore_by_idhex=[]):
    l_session = tc_session()
    if not order_by:
      order_by=RouterStats.avg_first_ext

    if recompute:
      RouterStats.compute(pct_low, pct_high, stat_clause, filter_clause)

    pct_clause = and_(RouterStats.percentile >= pct_low, 
                         RouterStats.percentile < pct_high)

    # This is Fail City and sqlalchemy is running for mayor.
    if sqlalchemy.__version__ < "0.5.0":
      sbw = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.sbw)
      filt_sbw = RouterStats.query.filter(pct_clause).filter(stat_clause).avg(RouterStats.filt_sbw)
    else:
      sbw = l_session.query(func.avg(RouterStats.sbw)).filter(pct_clause).filter(stat_clause).scalar()
      filt_sbw = l_session.query(func.avg(RouterStats.filt_sbw)).filter(pct_clause).filter(stat_clause).scalar()

    f.write(str(int(time.time()))+"\n")

    def cvt(a,b,c=1):
      if type(a) == float: return int(round(a/c,b))
      elif type(a) == int: return a
      elif type(a) == type(None): return "None"
      else: return type(a)

    for s in RouterStats.query.filter(pct_clause).filter(stat_clause).\
           filter(disp_clause).order_by(order_by).all():
      if s.router.idhex in ignore_by_idhex:
        plog("NOTICE", "Skipping stats on added exit "+s.router.idhex+" in "+f.name)
        continue
      f.write("node_id=$"+s.router.idhex+" nick="+s.router.nickname)
      f.write(" strm_bw="+str(cvt(s.sbw,0)))
      f.write(" filt_bw="+str(cvt(s.filt_sbw,0)))
      f.write(" circ_fail_rate="+str(s.circ_to_rate))
      f.write(" desc_bw="+str(int(cvt(s.avg_desc_bw,0))))
      f.write(" ns_bw="+str(int(cvt(s.avg_bw,0)))+"\n")

    f.flush()
    tc_session.remove()
  write_bws = Callable(write_bws)  
    

##################### End Model ####################

#################### Model Support ################
def reset_all():
  l_session = tc_session()
  plog("WARN", "SQLSupport.reset_all() called. See SQLSupport.py for details")
  # XXX: We still have a memory leak somewhere in here
  # Current suspects are sqlite, python-sqlite, or sqlalchemy misuse...
  # http://stackoverflow.com/questions/5552932/sqlalchemy-misuse-causing-memory-leak
  # The bandwidth scanners switched to a parent/child model because of this.

  # XXX: WARNING!
  # Must keep the routers around because circ_status_event may
  # reference old Routers that are no longer in consensus
  # and will raise an ObjectDeletedError. See function circ_status_event in
  # class CircuitListener in SQLSupport.py
  for r in Router.query.all():
    # This appears to be needed. the relation tables do not get dropped 
    # automatically.
    r.circuits = []
    r.streams = []
    r.detached_streams = []
    r.bw_history = [] 
    r.stats = None
    l_session.add(r)

  l_session.commit()
  tc_session.expunge_all()

  # XXX: WARNING!
  # May not clear relation all tables! (SQLAlchemy or Elixir bug)
  # Try: 
  # tc_session.execute('delete from router_streams__stream;')


  # XXX: WARNING!
  # This will cause Postgres databases to hang
  # on DROP TABLE. Possibly an issue with cascade.
  # Sqlite works though.

  BwHistory.table.drop() # Will drop subclasses
  Extension.table.drop()
  Stream.table.drop() 
  Circuit.table.drop()
  RouterStats.table.drop()

  RouterStats.table.create()
  BwHistory.table.create() 
  Extension.table.create()
  Stream.table.create() 
  Circuit.table.create()

  l_session.commit()

  #for r in Router.query.all():
  #  if len(r.bw_history) or len(r.circuits) or len(r.streams) or r.stats:
  #    plog("WARN", "Router still has dropped data!")

  plog("NOTICE", "Reset all SQL stats")
  tc_session.remove()

def refresh_all():
  # necessary to keep all sessions synchronized
  # This is probably a bug. See reset_all() above.
  # Call this after update_consensus(), _update_rank_history()
  # See: ScanSupport.reset_stats()
  # Could be a cascade problem too, see:
  # http://stackoverflow.com/questions/3481976/sqlalchemy-objectdeletederror-instance-class-at-has-been-deleted-help
  # Also see:
  # http://groups.google.com/group/sqlalchemy/browse_thread/thread/c9099eaaffd7c348
  [tc_session.refresh(r) for r in Router.query.all()]

##################### End Model Support ####################

class ConsensusTrackerListener(TorCtl.DualEventListener):
  def __init__(self):
    TorCtl.DualEventListener.__init__(self)
    self.last_desc_at = time.time()+60 # Give tor some time to start up
    self.consensus = None
    self.wait_for_signal = False

  CONSENSUS_DONE = 0x7fffffff

  # TODO: What about non-running routers and uptime information?
  def _update_rank_history(self, idlist):
    l_session = tc_session()
    plog("INFO", "Consensus change... Updating rank history")
    for idhex in idlist:
      if idhex not in self.consensus.routers: continue
      rc = self.consensus.routers[idhex]
      if rc.down: continue
      try:
        r = Router.query.options(eagerload('bw_history')).filter_by(
                                    idhex=idhex).with_labels().one()
        bwh = BwHistory(router=r, rank=rc.list_rank, bw=rc.bw,
                        desc_bw=rc.desc_bw, pub_time=r.published)
        r.bw_history.append(bwh)
        #l_session.add(bwh)
        l_session.add(r)
      except sqlalchemy.orm.exc.NoResultFound:
        plog("WARN", "No descriptor found for consenus router "+str(idhex))

    plog("INFO", "Consensus history updated.")
    l_session.commit()
    tc_session.remove()

  def _update_db(self, idlist):
    l_session = tc_session()
    # FIXME: It is tempting to delay this as well, but we need
    # this info to be present immediately for circuit construction...
    plog("INFO", "Consensus change... Updating db")
    for idhex in idlist:
      if idhex in self.consensus.routers:
        rc = self.consensus.routers[idhex]
        r = Router.query.filter_by(idhex=rc.idhex).first()
        if r and r.orhash == rc.orhash:
          # We already have it stored. (Possible spurious NEWDESC)
          continue
        if not r: r = Router()
        r.from_router(rc)
        l_session.add(r)
    plog("INFO", "Consensus db updated")
    l_session.commit()
    tc_session.remove()
    # testing
    #refresh_all() # Too many sessions, don't trust commit()

  def update_consensus(self):
    plog("INFO", "Updating DB with full consensus.")
    self.consensus = self.parent_handler.current_consensus()
    self._update_db(self.consensus.ns_map.iterkeys())

  def set_parent(self, parent_handler):
    if not isinstance(parent_handler, TorCtl.ConsensusTracker):
      raise TorCtlError("ConsensusTrackerListener can only be attached to ConsensusTracker instances")
    TorCtl.DualEventListener.set_parent(self, parent_handler)

  def heartbeat_event(self, e):
    l_session = tc_session()
    # This sketchiness is to ensure we have an accurate history
    # of each router's rank+bandwidth for the entire duration of the run..
    if e.state == EVENT_STATE.PRELISTEN:
      if not self.consensus: 
        global OP
        OP = Router.query.filter_by(
                 idhex="0000000000000000000000000000000000000000").first()
        if not OP:
          OP = Router(idhex="0000000000000000000000000000000000000000", 
                    orhash="000000000000000000000000000", 
                    nickname="!!TorClient", 
                    published=datetime.datetime.utcnow())
          l_session.add(OP)
          l_session.commit()
          tc_session.remove()
        self.update_consensus()
      # XXX: This hack exists because update_rank_history is expensive.
      # However, even if we delay it till the end of the consensus update, 
      # it still delays event processing for up to 30 seconds on a fast 
      # machine.
      # 
      # The correct way to do this is give SQL processing
      # to a dedicated worker thread that pulls events off of a secondary
      # queue, that way we don't block stream handling on this processing.
      # The problem is we are pretty heavily burdened with the need to 
      # stay in sync with our parent event handler. A queue will break this 
      # coupling (even if we could get all the locking right).
      #
      # A lighterweight hack might be to just make the scanners pause
      # on a condition used to signal we are doing this (and other) heavy 
      # lifting. We could have them possibly check self.last_desc_at..
      if not self.wait_for_signal and e.arrived_at - self.last_desc_at > 60.0:
        if self.consensus.consensus_count  < 0.95*(len(self.consensus.ns_map)):
          plog("INFO", "Not enough router descriptors: "
                       +str(self.consensus.consensus_count)+"/"
                       +str(len(self.consensus.ns_map)))
        elif not PathSupport.PathBuilder.is_urgent_event(e):
          plog("INFO", "Newdesc timer is up. Assuming we have full consensus")
          self._update_rank_history(self.consensus.ns_map.iterkeys())
          self.last_desc_at = ConsensusTrackerListener.CONSENSUS_DONE

  def new_consensus_event(self, n):
    if n.state == EVENT_STATE.POSTLISTEN:
      self.last_desc_at = n.arrived_at
      self.update_consensus()

  def new_desc_event(self, d): 
    if d.state == EVENT_STATE.POSTLISTEN:
      self.last_desc_at = d.arrived_at
      self.consensus = self.parent_handler.current_consensus()
      self._update_db(d.idlist)

class CircuitListener(TorCtl.PreEventListener):
  def set_parent(self, parent_handler):
    if not filter(lambda f: f.__class__ == ConsensusTrackerListener, 
                  parent_handler.post_listeners):
       raise TorCtlError("CircuitListener needs a ConsensusTrackerListener")
    TorCtl.PreEventListener.set_parent(self, parent_handler)
    # TODO: This is really lame. We only know the extendee of a circuit
    # if we have built the path ourselves. Otherwise, Tor keeps it a
    # secret from us. This prevents us from properly tracking failures
    # for normal Tor usage.
    if isinstance(parent_handler, PathSupport.PathBuilder):
      self.track_parent = True
    else:
      self.track_parent = False

  def circ_status_event(self, c):
    l_session = tc_session()
    if self.track_parent and c.circ_id not in self.parent_handler.circuits:
      tc_session.remove()
      return # Ignore circuits that aren't ours
    # TODO: Hrmm, consider making this sane in TorCtl.
    if c.reason: lreason = c.reason
    else: lreason = "NONE"
    if c.remote_reason: rreason = c.remote_reason
    else: rreason = "NONE"
    reason = c.event_name+":"+c.status+":"+lreason+":"+rreason

    output = [str(c.arrived_at), str(time.time()-c.arrived_at), c.event_name, str(c.circ_id), c.status]
    if c.path: output.append(",".join(c.path))
    if c.reason: output.append("REASON=" + c.reason)
    if c.remote_reason: output.append("REMOTE_REASON=" + c.remote_reason)
    plog("DEBUG", " ".join(output))
  
    if c.status == "LAUNCHED":
      circ = Circuit(circ_id=c.circ_id,launch_time=c.arrived_at,
                     last_extend=c.arrived_at)
      if self.track_parent:
        for r in self.parent_handler.circuits[c.circ_id].path:
          try:
            rq = Router.query.options(eagerload('circuits')).filter_by(
                                idhex=r.idhex).with_labels().one()
          except NoResultFound:
            plog("WARN", "Query for Router %s=%s in circ %s failed but was in parent_handler" %
                    (r.nickname, r.idhex, circ.circ_id))
            tc_session.remove()
            return
          circ.routers.append(rq) 
          #rq.circuits.append(circ) # done automagically?
          #l_session.add(rq)
      l_session.add(circ)
      l_session.commit()
    elif c.status == "EXTENDED":
      circ = Circuit.query.options(eagerload('extensions')).filter_by(
                       circ_id = c.circ_id).first()
      if not circ: 
        tc_session.remove()
        return # Skip circuits from before we came online

      e = Extension(circ=circ, hop=len(c.path)-1, time=c.arrived_at)

      if len(c.path) == 1:
        e.from_node = OP
      else:
        r_ext = c.path[-2]
        if r_ext[0] != '$': r_ext = self.parent_handler.name_to_key[r_ext]
        e.from_node = Router.query.filter_by(idhex=r_ext[1:]).one()

      r_ext = c.path[-1]
      if r_ext[0] != '$': r_ext = self.parent_handler.name_to_key[r_ext]

      e.to_node = Router.query.filter_by(idhex=r_ext[1:]).one()
      if not self.track_parent:
        # FIXME: Eager load here?
        circ.routers.append(e.to_node)
        e.to_node.circuits.append(circ)
        l_session.add(e.to_node)
 
      e.delta = c.arrived_at - circ.last_extend
      circ.last_extend = c.arrived_at
      circ.extensions.append(e)
      l_session.add(e)
      l_session.add(circ)
      l_session.commit()
    elif c.status == "FAILED":
      circ = Circuit.query.filter_by(circ_id = c.circ_id).first()
      if not circ: 
        tc_session.remove()
        return # Skip circuits from before we came online
        
      circ.expunge()
      if isinstance(circ, BuiltCircuit):
        # Convert to destroyed circuit
        Circuit.table.update(Circuit.id ==
                  circ.id).execute(row_type='destroyedcircuit')
        circ = DestroyedCircuit.query.filter_by(id=circ.id).one()
        circ.destroy_reason = reason
        circ.destroy_time = c.arrived_at
      else:
        # Convert to failed circuit
        Circuit.table.update(Circuit.id ==
                  circ.id).execute(row_type='failedcircuit')
        circ = FailedCircuit.query.options(
                  eagerload('extensions')).filter_by(id=circ.id).one()
        circ.fail_reason = reason
        circ.fail_time = c.arrived_at
        e = FailedExtension(circ=circ, hop=len(c.path), time=c.arrived_at)

        if len(c.path) == 0:
          e.from_node = OP
        else:
          r_ext = c.path[-1]
          if r_ext[0] != '$': r_ext = self.parent_handler.name_to_key[r_ext]
 
          e.from_node = Router.query.filter_by(idhex=r_ext[1:]).one()

        if self.track_parent:
          r=self.parent_handler.circuits[c.circ_id].path[len(c.path)]
          e.to_node = Router.query.filter_by(idhex=r.idhex).one()
        else:
          e.to_node = None # We have no idea..

        e.delta = c.arrived_at - circ.last_extend
        e.reason = reason
        circ.extensions.append(e)
        circ.fail_time = c.arrived_at
        l_session.add(e)

      l_session.add(circ)
      l_session.commit()
    elif c.status == "BUILT":
      circ = Circuit.query.filter_by(
                     circ_id = c.circ_id).first()
      if not circ:
        tc_session.remove()
        return # Skip circuits from before we came online

      circ.expunge()
      # Convert to built circuit
      Circuit.table.update(Circuit.id ==
                circ.id).execute(row_type='builtcircuit')
      circ = BuiltCircuit.query.filter_by(id=circ.id).one()
      
      circ.built_time = c.arrived_at
      circ.tot_delta = c.arrived_at - circ.launch_time
      l_session.add(circ)
      l_session.commit()
    elif c.status == "CLOSED":
      circ = BuiltCircuit.query.filter_by(circ_id = c.circ_id).first()
      if circ:
        circ.expunge()
        if lreason in ("REQUESTED", "FINISHED", "ORIGIN"):
          # Convert to closed circuit
          Circuit.table.update(Circuit.id ==
                    circ.id).execute(row_type='closedcircuit')
          circ = ClosedCircuit.query.filter_by(id=circ.id).one()
          circ.closed_time = c.arrived_at
        else:
          # Convert to destroyed circuit
          Circuit.table.update(Circuit.id ==
                    circ.id).execute(row_type='destroyedcircuit')
          circ = DestroyedCircuit.query.filter_by(id=circ.id).one()
          circ.destroy_reason = reason
          circ.destroy_time = c.arrived_at
        l_session.add(circ)
        l_session.commit()
    tc_session.remove()

class StreamListener(CircuitListener):
  def stream_bw_event(self, s):
    l_session = tc_session()
    strm = Stream.query.filter_by(strm_id = s.strm_id).first()
    if strm and strm.start_time and strm.start_time < s.arrived_at:
      plog("DEBUG", "Got stream bw: "+str(s.strm_id))
      strm.tot_read_bytes += s.bytes_read
      strm.tot_write_bytes += s.bytes_written
      l_session.add(strm)
      l_session.commit()
      tc_session.remove()
 
  def stream_status_event(self, s):
    l_session = tc_session()
    if s.reason: lreason = s.reason
    else: lreason = "NONE"
    if s.remote_reason: rreason = s.remote_reason
    else: rreason = "NONE"

    if s.status in ("NEW", "NEWRESOLVE"):
      strm = Stream(strm_id=s.strm_id, tgt_host=s.target_host, 
                    tgt_port=s.target_port, init_status=s.status,
                    tot_read_bytes=0, tot_write_bytes=0)
      l_session.add(strm)
      l_session.commit()
      tc_session.remove()
      return

    strm = Stream.query.filter_by(strm_id = s.strm_id).first()
    if self.track_parent and \
      (s.strm_id not in self.parent_handler.streams or \
           self.parent_handler.streams[s.strm_id].ignored):
      if strm:
        strm.delete()
        l_session.commit()
        tc_session.remove()
      return # Ignore streams that aren't ours

    if not strm: 
      plog("NOTICE", "Ignoring prior stream "+str(s.strm_id))
      return # Ignore prior streams

    reason = s.event_name+":"+s.status+":"+lreason+":"+rreason+":"+strm.init_status

    if s.status == "SENTCONNECT":
      # New circuit
      strm.circuit = Circuit.query.filter_by(circ_id=s.circ_id).first()
      if not strm.circuit:
        plog("NOTICE", "Ignoring prior stream "+str(strm.strm_id)+" with old circuit "+str(s.circ_id))
        strm.delete()
        l_session.commit()
        tc_session.remove()
        return
    else:
      circ = None
      if s.circ_id:
        circ = Circuit.query.filter_by(circ_id=s.circ_id).first()
      elif self.track_parent:
        circ = self.parent_handler.streams[s.strm_id].circ
        if not circ: circ = self.parent_handler.streams[s.strm_id].pending_circ
        if circ:
          circ = Circuit.query.filter_by(circ_id=circ.circ_id).first()

      if not circ:
        plog("WARN", "No circuit for "+str(s.strm_id)+" circ: "+str(s.circ_id))

      if not strm.circuit:
        plog("INFO", "No stream circuit for "+str(s.strm_id)+" circ: "+str(s.circ_id))
        strm.circuit = circ

      # XXX: Verify circ id matches stream.circ
    
    if s.status == "SUCCEEDED":
      strm.start_time = s.arrived_at
      for r in strm.circuit.routers: 
        plog("DEBUG", "Added router "+r.idhex+" to stream "+str(s.strm_id))
        r.streams.append(strm)
        l_session.add(r)
      l_session.add(strm)
      l_session.commit()
    elif s.status == "DETACHED":
      for r in strm.circuit.routers:
        r.detached_streams.append(strm)
        l_session.add(r)
      #strm.detached_circuits.append(strm.circuit)
      strm.circuit.detached_streams.append(strm)
      strm.circuit.streams.remove(strm)
      strm.circuit = None
      l_session.add(strm)
      l_session.commit()
    elif s.status == "FAILED":
      strm.expunge()
      # Convert to destroyed circuit
      Stream.table.update(Stream.id ==
                strm.id).execute(row_type='failedstream')
      strm = FailedStream.query.filter_by(id=strm.id).one()
      strm.fail_time = s.arrived_at
      strm.fail_reason = reason
      l_session.add(strm)
      l_session.commit()
    elif s.status == "CLOSED":
      if isinstance(strm, FailedStream):
        strm.close_reason = reason
      else:
        strm.expunge()
        if not (lreason == "DONE" or (lreason == "END" and rreason == "DONE")):
          # Convert to destroyed circuit
          Stream.table.update(Stream.id ==
                    strm.id).execute(row_type='failedstream')
          strm = FailedStream.query.filter_by(id=strm.id).one()
          strm.fail_time = s.arrived_at
        else: 
          # Convert to destroyed circuit
          Stream.table.update(Stream.id ==
                    strm.id).execute(row_type='closedstream')
          strm = ClosedStream.query.filter_by(id=strm.id).one()
          strm.read_bandwidth = strm.tot_read_bytes/(s.arrived_at-strm.start_time)
          strm.write_bandwidth = strm.tot_write_bytes/(s.arrived_at-strm.start_time)
          strm.end_time = s.arrived_at
          plog("DEBUG", "Stream "+str(strm.strm_id)+" xmitted "+str(strm.tot_bytes()))
        strm.close_reason = reason
      l_session.add(strm)
      l_session.commit()
    tc_session.remove()

def run_example(host, port):
  """ Example of basic TorCtl usage. See PathSupport for more advanced
      usage.
  """
  print "host is %s:%d"%(host,port)
  setup_db("sqlite:///torflow.sqlite", echo=False)

  #l_session = tc_session()
  #print l_session.query(((func.count(Extension.id)))).filter(and_(FailedExtension.table.c.row_type=='extension', FailedExtension.table.c.from_node_idhex == "7CAA2F5F998053EF5D2E622563DEB4A6175E49AC")).one()
  #return
  #for e in Extension.query.filter(FailedExtension.table.c.row_type=='extension').all():
  #  if e.from_node: print "From: "+e.from_node.idhex+" "+e.from_node.nickname
  #  if e.to_node: print "To: "+e.to_node.idhex+" "+e.to_node.nickname
  #tc_session.remove()
  #return

  s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
  s.connect((host,port))
  c = Connection(s)
  th = c.launch_thread()
  c.authenticate(control_pass)
  c.set_event_handler(TorCtl.ConsensusTracker(c))
  c.add_event_listener(ConsensusTrackerListener())
  c.add_event_listener(CircuitListener())

  print `c.extend_circuit(0,["moria1"])`
  try:
    print `c.extend_circuit(0,[""])`
  except TorCtl.ErrorReply: # wtf?
    print "got error. good."
  except:
    print "Strange error", sys.exc_info()[0]
   
  c.set_events([EVENT_TYPE.STREAM, EVENT_TYPE.CIRC,
          EVENT_TYPE.NEWCONSENSUS, EVENT_TYPE.NEWDESC,
          EVENT_TYPE.ORCONN, EVENT_TYPE.BW], True)

  th.join()
  return

  
if __name__ == '__main__':
  run_example(control_host,control_port)

