Subprocess puzzle and two questions

wrw at mac.com wrw at mac.com
Wed Nov 14 15:37:12 CET 2012


On Nov 14, 2012, at 9:22 AM, Roy Smith <roy at panix.com> wrote:

> In article <mailman.3666.1352873042.27098.python-list at python.org>,
> William Ray Wing <wrw at mac.com> wrote:
> 
>> On Nov 13, 2012, at 11:41 PM, Roy Smith <roy at panix.com> wrote:
>> 
>>> In article <mailman.3664.1352867713.27098.python-list at python.org>,
>>> wrw at mac.com wrote:
>>> 
>>>> I need to time the operation of a command-line utility (specifically 
>>>> nslookup) from within a python program I'm writing.
>>> 
>>> Ugh.  Why are you doing this?  Shelling out to nslookup is an incredibly 
>>> slow and clumsy way of doing name translation.  What you really want to 
>>> be doing is calling getaddrinfo() directly.
>>> 
>>> See http://docs.python.org/2/library/socket.html#socket.getaddrinfo for 
>>> details.
>>> -- 
>> Because, unless I'm badly mistaken (very possible), getaddrinfo doesn't let 
>> me specify the server from which the name is returned. I'm really not after 
>> the name, what I'm REALLY after is the fact that a path exists to the name 
>> server I specify (and how long it takes to respond). In the "good old days" I 
>> would just have ping'd it, but these days more and more DNS boxes (and 
>> servers of all sorts) are shutting off their ping response.
>> 
>> Thanks, Bill
> 
> Oh, my.  You're using DNS as a replacement for ping?  Fair enough.  In 
> that case, all you really care about is that you can connect to port 53 
> on the server...
> 
> import socket
> import time
> s = socket.socket()
> t0 = time.time()
> s.connect(('8.8.8.8', 53))
> t1 = time.time()
> print "it took %f seconds to connect" % (t1 - t0)
> -- 
> http://mail.python.org/mailman/listinfo/python-list

Now THAT looks better.  Simpler, cleaner, (longer, taller, stronger, faster, cheaper…  :-)

Thanks,
Bill


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