From: Cyrill Gorcunov <gorcunov@gmail.com>
To: Konstantin Osipov <kostja.osipov@gmail.com>
Cc: tml <tarantool-patches@dev.tarantool.org>
Subject: Re: [Tarantool-patches] [PATCH 1/5] popen: Introduce a backend engine
Date: Sat, 30 Nov 2019 13:47:34 +0300 [thread overview]
Message-ID: <20191130104734.GR19879@uranus> (raw)
In-Reply-To: <20191130100445.GA16163@atlas>
On Sat, Nov 30, 2019 at 01:04:45PM +0300, Konstantin Osipov wrote:
>
> Could you provide a Lua example usage of popen() which would lead
> to the situation you describe here?
>
> Seems like in order for that to happen the Lua script has to
> provide both input and output streams to the called program, and
> in this case the script should not expect that there is any
> ordering in which the input is consumed and the output is
> produced.
>
> In any case discussing this problem would be easier if there is an
> example.
An example is in one of my patch, here is it (result file)
---
--
-- Test for stdin/out stream
--
script="prompt=''; read -n 5 prompt; echo -n $prompt"
| ---
| ...
popen = fio.popen(script, "rw")
| ---
| ...
popen:write("input")
| ---
| - 5
| ...
popen:read()
| ---
| - input
| ...
popen:close()
| ---
| - true
| - null
| ...
The main thing is that as far as I remember "real" stdin/out/err are
the unix pty terminals, and they are in blocking mode. IOW if you
run
$ sh -c "prompt=''; read -n 5 prompt; echo -n $prompt"
inside real shell the read will be blocked until you enter data
to stdin. And I think users of popen will expect the same behaviour.
Anyway, Kostya, I'll investigate python behaviour more on the weekend
to get in with more details.
next prev parent reply other threads:[~2019-11-30 10:47 UTC|newest]
Thread overview: 34+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-28 20:45 [Tarantool-patches] [PATCH 0/5] popen: Add ability to run external process Cyrill Gorcunov
2019-11-28 20:45 ` [Tarantool-patches] [PATCH 1/5] popen: Introduce a backend engine Cyrill Gorcunov
2019-11-29 5:52 ` Konstantin Osipov
2019-11-29 9:57 ` Cyrill Gorcunov
2019-11-29 5:59 ` Konstantin Osipov
2019-11-29 9:40 ` Cyrill Gorcunov
2019-11-29 11:19 ` Konstantin Osipov
2019-11-29 11:36 ` Cyrill Gorcunov
2019-11-29 14:50 ` Konstantin Osipov
2019-11-29 15:14 ` Cyrill Gorcunov
2019-11-29 15:17 ` Cyrill Gorcunov
2019-11-29 18:31 ` Konstantin Osipov
2019-11-29 19:17 ` Cyrill Gorcunov
2019-11-29 22:36 ` Cyrill Gorcunov
2019-11-30 4:21 ` Konstantin Osipov
2019-11-30 7:48 ` Cyrill Gorcunov
2019-11-30 4:14 ` Konstantin Osipov
2019-11-30 7:36 ` Cyrill Gorcunov
2019-11-30 10:04 ` Konstantin Osipov
2019-11-30 10:47 ` Cyrill Gorcunov [this message]
2019-11-30 10:54 ` Cyrill Gorcunov
2019-11-30 12:16 ` Cyrill Gorcunov
2019-11-30 20:30 ` Konstantin Osipov
2019-11-30 20:36 ` Cyrill Gorcunov
2019-12-13 2:50 ` Alexander Turenko
2019-11-28 20:45 ` [Tarantool-patches] [PATCH 2/5] lua/fio: Add lbox_fio_push_error as a separate helper Cyrill Gorcunov
2019-11-29 6:02 ` Konstantin Osipov
2019-11-29 9:47 ` Cyrill Gorcunov
2019-11-29 11:22 ` Konstantin Osipov
2019-11-29 11:42 ` Cyrill Gorcunov
2019-11-29 14:51 ` Konstantin Osipov
2019-11-28 20:45 ` [Tarantool-patches] [PATCH 3/5] popen/fio: Merge popen engine into fio internal module Cyrill Gorcunov
2019-11-28 20:45 ` [Tarantool-patches] [PATCH 4/5] popen/fio: Implement lua interface for a popen object Cyrill Gorcunov
2019-11-28 20:45 ` [Tarantool-patches] [PATCH 5/5] test: Add app/popen test Cyrill Gorcunov
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