Re: [nox-dev] Event triggered subprocess call
So the confusing bit is that you're being lied to. The lambda function being
referred to is actually on line 132 of coreapps/pyrt/pyoxidereactor.py.
Inside subprocess.py, os.waitpid has been called and is blocking. This is
where the stack trace leads. However, while waitpid is blocking, the SIGCHLD
from the subprocess dying is causing the signal handler from
pyoxidereactor.py:132 to be invoked, which is causing an exception because the
handler (a lambda function) is taking no arguments by Python tries to call it
with two (I believe I am responsible for this bug -- oops!). The interpreter
then throws an exception in the context of the call that was interrupted
instead of at the actual site (kind of understandable, but confusing for
sure!).
So, to fix this, you can just fix the lambda function, by changing line 132 in
pyoxidereactor.py to:
signal.signal(signal.SIGCHLD, lambda n,f: self.callLater(0, reapAllProcesses))
However, since this code was originally written, I think Twisted has
confronted handling of child process reaping, which is what lines 132 and 138
in pyoxidereactor are trying to fix. So... I think you can probably just
comment out lines 132 and 138 and Twisted will take care of this. I'm no
Twisted expert, though. If you notice that removing these lines leads to
zombie processes, add them back in (and let me know, please!). :)
-- Murphy
On Thursday, June 09, 2011 02:37:47 AM Partti, Tapio (NSN - FI/Espoo) wrote:
Hi all.
When giving out a subprocess call (with subprocess.check_call) in any
event's callback function, nox gives out the following error.
3|reactor|ERR:Unhandled Error
Traceback (most recent call last):
--- exception caught here ---
File ./nox/coreapps/pyrt/pyoxidereactor.py, line 85, in
__call__
self.func(*self.args, **self.kw);
File ./nox/coreapps/examples/pyswitch.py, line 110, in
timer_callback
subprocess.check_call('uname', shell=True)
File /usr/lib/python2.6/subprocess.py, line 483, in
check_call
retcode = call(*popenargs, **kwargs)
File /usr/lib/python2.6/subprocess.py, line 470, in call
return Popen(*popenargs, **kwargs).wait()
File /usr/lib/python2.6/subprocess.py, line 1182, in wait
pid, sts = _eintr_retry_call(os.waitpid, self.pid, 0)
File /usr/lib/python2.6/subprocess.py, line 455, in
_eintr_retry_call
return func(*args)
exceptions.TypeError: lambda() takes no arguments (2 given)
In the sample case I put a line subprocess.check_call('uname',
shell=True) in pyswitches timer_callback function. If I do the same in
some simple python application using twisted reactor, there are no
errors. Could someone explain why the error occurs and what is the
reason for it? I mean, I can ignore this error with a try-catch sentence
and everything seems ok, but am I then doing something that should not
be done for some good reason.
Thanks,
Tapio Partti
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[nox-dev] how to use Authentication component
Hi all, I met difficulty in using /Authontication/ component,and i need your help. here is my problem: I want to know the location of each host,and i think there must be a function in Authentication component that i can ues,but i don't know which one. Any one knows? also,should i import the component in my codefile like /from nox.netapps.authenticator.pyauth import */ ? --- yan 6/10 ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev
Re: [nox-dev] Doubt about len parameter in packet in event
Hi Luciano I guess you're using the ofp_packet_in-total_len value? That is indeed the length of the packet that came into the port which generated the pkt_in. If you're looking to compute the overall traffic sent from a server, you can also use the flow_exp message and sum it for all the flows sent by that server. On Wed, May 25, 2011 at 11:05 PM, lignac...@inf.ufrgs.br wrote: Hello, I have developed a script to distribute flows among three servers using mininet + FlowVisor + Nox. I tested the scripts with Iperf and Wireshark and apparently it is working well. My only question is related to the len parameter in packet_in event. I am using this parameter to calculate the traffic sent for each server. Can I really use this parameter? Does it represent the length of the packet? PS. I just sum the len´s value when the switch receives a IP_TYPE packet. Thank you. My best regards. Luciano Ignaczak This message was sent using IMP, the Internet Messaging Program. ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev
Re: [nox-dev] how can nox controller get rtt time?
Hi Yi-Shou You could possibly use the following to approx for RTT time: timestamp(barrier_reply) - timestamp(fwd pkt_in), assuming the barrier_request is sent with the pkt_out of the reverse direction ICMP. On Wed, May 11, 2011 at 8:16 AM, false ladj...@yahoo.com.tw wrote: Hi, I have a problem about the nox controller get rtt time from NetFPGA based OpenFlow switch. Assuming there are two hosts connecting to a LAN network is established by NetFPGA based OF switch, and hosts can not communication with nox controller which control the NetFPGA based OF swtich because hosts do not connect to internet. Then, if hosts can not tell rtt time to nox controller, does the nox controller has any methods can know rtt time between hosts? Any suggest will be helpful! Thank you! Yi-Shou ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev
Re: [nox-dev] how to use Authentication component
You may be able to listen for Host_event (with filter Host_event.action == Action.ADD), and track the datapath_id and port of each host. In the python side, I think it is Host_bind_event. 2011/6/10 颜玮 yan...@bupt.edu.cn: Hi all, I met difficulty in using Authontication component,and i need your help. here is my problem: I want to know the location of each host,and i think there must be a function in Authentication component that i can ues,but i don't know which one. Any one knows? also,should i import the component in my codefile like from nox.netapps.authenticator.pyauth import * ? --- yan 6/10 ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev ___ nox-dev mailing list nox-dev@noxrepo.org http://noxrepo.org/mailman/listinfo/nox-dev
