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From: Pavlos Parissis <pavlos.parissis@gmail.com>
Newsgroups: comp.lang.python
Subject: Re: intermittent ValueErrors from subprocess
Date: Mon, 16 May 2016 01:17:41 +0200
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From: Pavlos Parissis <pavlos.parissis@gmail.com>
To: python-list@python.org
Message-ID: <57390395.8070005@gmail.com>
Subject: Re: intermittent ValueErrors from subprocess
References: <57389A9D.1010205@gmail.com>
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On 16/05/2016 12:59 =CF=80=CE=BC, Chris Angelico wrote:
> On Mon, May 16, 2016 at 8:32 AM, Pavlos Parissis
> <pavlos.parissis@gmail.com> wrote:
>>> Searching the CPython sources for that exception shows one hit:
>>> selectors.py, where it converts a file object to an integer file
>>> descriptor. (You could have helped out by showing us the full
>>> traceback.)
>>
>> I did, https://gist.github.com/unixsurfer/67db620d87f667423f6f6e3a04e0=
bff5
>=20
> Ah. I didn't click that link in your original post - didn't know it
> was the traceback. Better would have been to at least say so; best
> would have been to include it inline.
>=20

I don't usually include traces as they have long lines and several
e-mail clients mess with them in a way that makes the trace unreadable.

>>> Is it possible you were running out of file descriptors,
>>> or in some other way unable to create the pipe?
>>
>> I don't think as I see right now only 8 FDs:
>>
>> sudo ls -1 /proc/22706/fd|wc
>>       8       8      16
>>
>=20
> If you can recreate the problem consistently,

I can't. This is my main problem. This code has been executed ~100K and
that exception has occurred only ~5 times.

> it would be worth
> messing around with slightly lower level APIs - using subprocess.Popen
> rather than check_output, for instance - and see what you can do
> without the pipes.

What do you mean by that?

> Somewhere, something's failing, and it's not easy
> to see what.
>=20
> ChrisA
>=20

Thanks once again,
Pavlos




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