Groups | Search | Server Info | Keyboard shortcuts | Login | Register [http] [https] [nntp] [nntps]

Groups > comp.lang.python > #90272

Re: calling base class method fetches no results

Show key headers only | View raw

[Multipart message — attachments visible in raw view] - view raw

I am really sorry for any inconvenience caused, I was trying to fix this
bug from last 2 days so I had to post it here. It now has been resolved.
Thanks a lot for your time. I'll be careful again. Have a great weekend!

On Sat, May 9, 2015 at 4:36 PM, Dave Angel <davea@davea.name> wrote:

> On 05/09/2015 03:59 AM, david jhon wrote:
>
>> Hi, I am sorry for sending in five attachments, I cloned the code from
>> here
>> <https://bitbucket.org/msharif/hedera/src>: Let me explain it here:
>>
>>
> Please don't top-post.  Your earlier problem description, which I could
> make no sense of, is now located after your later "clarification".
>
> Thanks for eliminating the attachments.  Many cannot see them.  And for
> extracting only part of the code into the message.  It's still too much for
> me, but others may manage it okay.  To me, it seems likely that most of
> that code will not have any part in the problem you're describing. And in
> some places you have code that's missing its context.
>
> Now, eliminate the pieces of code that are irrelevant to your question,
> and state the problem in terms that make sense.  Somebody is instantiating
> an object.  Exactly which class is being used for that? Somebody else is
> calling a particular method (be specific, rather than just saying "some
> method"), and it's giving the wrong results.  And apparently, those wrong
> results depend on which source file something happens in.
>
>
>
>  Routing Base class defined in DCRouting.py:
>>
>> import logging
>> from copy import copy
>>
>> class Routing(object):
>>      '''Base class for data center network routing.
>>
>>      Routing engines must implement the get_route() method.
>>      '''
>>
>>      def __init__(self, topo):
>>          '''Create Routing object.
>>
>>          @param topo Topo object from Net parent
>>          '''
>>          self.topo = topo
>>
>>      def get_route(self, src, dst, hash_):
>>          '''Return flow path.
>>
>>          @param src source host
>>          @param dst destination host
>>          @param hash_ hash value
>>
>>          @return flow_path list of DPIDs to traverse (including hosts)
>>          '''
>>          raise NotImplementedError
>>
>>      def routes(self, src, dst):
>>          ''' Return list of paths
>>
>>          Only works for Fat-Tree topology
>>
>>          @ param src source host
>>          @ param dst destination host
>>
>>          @ return list of DPIDs (including inputs)
>>          '''
>>
>>          complete_paths = [] # List of complete dpid routes
>>
>>          src_paths = { src : [[src]] }
>>          dst_paths = { dst : [[dst]] }
>>
>>          dst_layer = self.topo.layer(dst)
>>          src_layer = self.topo.layer(src)
>>
>>          lower_layer = src_layer
>>          if dst_layer > src_layer:
>>              lower_layer = dst_layer
>>
>>
>>          for front_layer in range(lower_layer-1, -1, -1):
>>              if src_layer > front_layer:
>>              # expand src frontier
>>                  new_src_paths = {}
>>                  for node in sorted(src_paths):
>>                      path_list = src_paths[node]
>>                      for path in path_list:
>>                          last_node = path[-1]
>>                          for frontier_node in
>> self.topo.upper_nodes(last_node):
>>                              new_src_paths[frontier_node] = [path +
>> [frontier_node]]
>>
>>                              if frontier_node in dst_paths:
>>                                  dst_path_list = dst_paths[frontier_node]
>>                                  for dst_path in dst_path_list:
>>                                      dst_path_copy = copy ( dst_path )
>>                                      dst_path_copy.reverse()
>>                                      complete_paths.append( path +
>> dst_path_copy)
>>                  src_paths = new_src_paths
>>
>>              if dst_layer > front_layer:
>>              # expand dst frontier
>>                  new_dst_paths = {}
>>                  for node in sorted(dst_paths):
>>                      path_list = dst_paths[node]
>>                      for path in path_list:
>>                          last_node = path[-1]
>>                          for frontier_node in
>> self.topo.upper_nodes(last_node):
>>                              new_dst_paths[frontier_node] = [ path +
>> [frontier_node]]
>>
>>                              if frontier_node in src_paths:
>>                                  src_path_list = src_paths[frontier_node]
>>                                  dst_path_copy = copy( path )
>>                                  dst_path_copy.reverse()
>>                                  for src_path in src_path_list:
>>                                      complete_paths.append( src_path +
>> dst_path_copy)
>>
>>                  dst_paths = new_dst_paths
>>
>>              if complete_paths:
>>                  return complete_paths
>> class HashedRouting(Routing):
>>      ''' Hashed routing '''
>>
>>      def __init__(self, topo):
>>          self.topo = topo
>>
>>      def get_route(self, src, dst, hash_):
>>          ''' Return flow path. '''
>>
>>          if src == dst:
>>              return [src]
>>
>>          paths = self.routes(src,dst)
>>          if paths:
>>              #print 'hash_:', hash_
>>              choice = hash_ % len(paths)
>>              #print 'choice:', choice
>>              path = sorted(paths)[choice]
>>              #print 'path:', path
>>              return path
>>
>> ============>
>> Instantiated in util.py:
>>
>> from DCTopo import FatTreeTopo
>> from mininet.util import makeNumeric
>> from DCRouting import HashedRouting, Routing
>>
>> TOPOS = {'ft': FatTreeTopo}
>> ROUTING = {'ECMP' : HashedRouting}
>>
>>
>> def buildTopo(topo):
>>      topo_name, topo_param = topo.split( ',' )
>>      return TOPOS[topo_name](makeNumeric(topo_param))
>>
>>
>> def getRouting(routing, topo):
>>      return ROUTING[routing](topo)
>>
>
> A comment on that last line that says it instantiates the child class
> would have been very helpful.
>
> But even though I can now search for calls to that function, I still
> cannot make sense out of that context, either.
>
>
>
>> ============================> utilized in HController. py:
>> A Piece of code which works with self.r.routes() method:
>> Following list of methods are defined in HController.py
>>
>>      def _ecmp_hash(self, packet):
>>          ''' Return an ECMP-style 5-tuple hash for TCP/IP packets,
>> otherwise
>> 0.
>>          RFC2992 '''
>>          hash_input = [0] * 5
>>          if isinstance(packet.next, ipv4):
>>              ip = packet.next
>>              hash_input[0] = ip.srcip.toUnsigned()
>>              hash_input[1] = ip.dstip.toUnsigned()
>>              hash_input[2] = ip.protocol
>>              if isinstance(ip.next, tcp) or isinstance(ip.next, udp):
>>                  l4 = ip.next
>>                  hash_input[3] = l4.srcport
>>                  hash_input[4] = l4.dstport
>>                  return crc32(pack('LLHHH', *hash_input))
>>          return 0
>>
>>      def _install_reactive_path(self, event, out_dpid, final_out_port,
>> packet):
>>          ''' Install entries on route between two switches. '''
>>          in_name = self.t.node_gen(dpid = event.dpid).name_str()
>>          out_name = self.t.node_gen(dpid = out_dpid).name_str()
>>          hash_ = self._ecmp_hash(packet)
>>          paths = self.r.routes(src_name, dst_name)
>>          if paths == None:
>>               print "PATH is None :("
>>               return
>>          route = self.r.get_route(in_name, out_name, hash_)
>>          print "Route:",route
>>          print '-'*80
>>          if route == None:
>>              print None, "route between", in_name, "and", out_name
>>              return
>>
>>          match = of.ofp_match.from_packet(packet)
>>
>>          for i, node in enumerate(route):
>>              node_dpid = self.t.node_gen(name = node).dpid
>>              if i < len(route) - 1:
>>                  next_node = route[i + 1]
>>                  out_port, next_in_port = self.t.port(node, next_node)
>>              else:
>>                  out_port = final_out_port
>>              self.switches[node_dpid].install(out_port, match,
>> idle_timeout
>> = 10)
>>
>>          if isinstance(packet.next, of.ipv4) and
>> isinstance(packet.next.next, of.tcp):
>>              self.matchDict[(packet.next.srcip, packet.next.dstip,
>> packet.next.next.srcport, packet.next.next.dstport)] = (route, match)
>>
>>      def _handle_PacketIn(self, event):
>>          if not self.all_switches_up:
>>              #log.info("Saw PacketIn before all switches were up -
>> ignoring." )
>>              return
>>
>>          packet = event.parsed
>>          dpid = event.dpid
>>          in_port = event.port
>>
>>          # Learn MAC address of the sender on every packet-in.
>>          self.macTable[packet.src] = (dpid, in_port)
>>          sw_name = self.t.node_gen(dpid = dpid).name_str()
>>          #print "Sw:", sw_name, packet.src, packet.dst,"port", in_port,
>> packet.dst.isMulticast(),"macTable", packet.dst in self.macTable
>>          #print '-'*80
>>
>>          # Insert flow, deliver packet directly to destination.
>>
>>          if packet.dst in self.macTable:
>>              out_dpid, out_port = self.macTable[packet.dst]
>>              self._install_reactive_path(event, out_dpid, out_port,
>> packet)
>>
>>              self.switches[out_dpid].send_packet_data(out_port,
>> event.data)
>>
>>          else:
>>              self._flood(event)
>>
>> ===================> code snippet which returns 'None' number of paths.
>>      def _GlobalFirstFit(self,flow):
>>          '''do the Hedera global first fit here'''
>>          src_name = self.t.node_gen(dpid = flow['src']).name_str()
>>          dst_name = self.t.node_gen(dpid = flow['dst']).name_str()
>>          print 'Global Fisrt Fit for the elephant flow from
>> ',src_name,'to',
>> dst_name
>>          paths = self.r.routes(src_name,dst_name)
>>          print 'all routes found for the big flow:\n',paths
>>          GFF_route = None
>>          if paths == None:
>>             return
>>          else:
>>            for path in paths:
>>              fitCheck = True
>>
>>              for i in range(1,len(path)):
>>                  fitCheck = False
>>                  if self.bwReservation.has_key(path[i-1]) and
>> self.bwReservation[path[i-1]].has_key(path[i]):
>>                      if
>> self.bwReservation[path[i-1]][path[i]]['reserveDemand'] + flow['demand'] >
>> 1 :
>>                          break
>>                      else:
>>
>> #self.bwReservation[path[i-1]][path[i]]['reserveDemand'] += flow['demand']
>>                          fitCheck = True
>>                  else:
>>                      self.bwReservation[path[i-1]]={}
>>
>> self.bwReservation[path[i-1]][path[i]]={'reserveDemand':0}
>>                      fitCheck = True
>>              if fitCheck == True:
>>                  for i in range(1,len(path)):
>>
>>  self.bwReservation[path[i-1]][path[i]]['reserveDemand']
>> += flow['demand']
>>                  GFF_route = path
>>                  print "GFF route found:", path
>>                  break
>>          if GFF_route != None:
>>              """install new GFF_path between source and destintaion"""
>>              self. _install_GFF_path(GFF_route,flow['match'])
>>
>> def launch(topo = None, routing = None, bw = None ):
>>      #print topo
>>      if not topo:
>>          raise Exception ("Please specify the topology")
>>      else:
>>          t = buildTopo(topo)
>>
>>      r = getRouting(routing, t)
>>      if bw == None:
>>          bw = 10.0 #Mb/s
>>          bw = float(bw/1000) #Gb/s
>>      else:
>>          bw = float(bw)/1000
>>      core.registerNew(HController, t, r, bw)
>>      log.info("** HController is running
>>
>> I am really sorry for any inconvenience caused. I, ve tried to make it a
>> bit clear here. I am not even able to debug the code by setting a python
>> debugging point pdb. I need help from you guys. Thanks a lot again for
>> your
>> time and help.
>>
>> Best Regards,
>> David
>>
>>
>> On Sat, May 9, 2015 at 12:07 PM, Mark Lawrence <breamoreboy@yahoo.co.uk>
>> wrote:
>>
>>  On 09/05/2015 07:41, david jhon wrote:
>>>
>>>  Hello everyone,
>>>>
>>>> I am new to python and trying to run an example code from mininet tests.
>>>> Basically, I am trying to call a method in Hcontroller.py from base
>>>> class
>>>> Routing defined in DCRouting.py which runs and fetches all the required
>>>> results in install_reactive_path() method, but it returns None when it
>>>> is
>>>> called from _GlobalFirstFit. I hope someone here could help me fix this
>>>> bug..
>>>>
>>>> I am attaching all the three files(DCRouting.py, HController.py,
>>>> util.py)
>>>> to have a look into. Thanks in advance for your time, help or
>>>> suggestion.
>>>> Thanks a lot!
>>>>
>>>> kind regards,
>>>> David
>>>>
>>>>
>>>>  I'm sorry but I'm not wading through nearly 30kb of code in five
>>> attachments.  Please see http://sscce.org/ for how to put your question
>>> so you're more likely to get answers.
>>>
>>> --
>>> My fellow Pythonistas, ask not what our language can do for you, ask
>>> what you can do for our language.
>>>
>>> Mark Lawrence
>>>
>>> --
>>> https://mail.python.org/mailman/listinfo/python-list
>>>
>>>
>>
>>
>>
>
> --
> DaveA
> --
> https://mail.python.org/mailman/listinfo/python-list
>

Back to comp.lang.python | Previous | Next | Find similar | Unroll thread

Thread

Re: calling base class method fetches no results david jhon <djhon9813@gmail.com> - 2015-05-09 17:08 +0500

csiph-web