Re^20: Net::OpenSSH loosing lines ins reply

Hi Salva,
on a normal run:

==============================
start
fdinfo 0:
pos:    0
flags:  0100002
fdinfo 1:
pos:    0
flags:  01
fdinfo 2:
pos:    0
flags:  01
==============================
after new
fdinfo 0:
pos:    0
flags:  0100002
fdinfo 1:
pos:    0
flags:  01
fdinfo 2:
pos:    0
flags:  01
==============================
after capture
fdinfo 0:
pos:    0
flags:  0100002
fdinfo 1:
pos:    0
flags:  04001
fdinfo 2:
pos:    0
flags:  04001
[download]

for a failed run:

==============================
start
fdinfo 0:
pos:    0
flags:  0100002
fdinfo 1:
pos:    0
flags:  01
fdinfo 2:
pos:    0
flags:  01
==============================
after new
fdinfo 0:
pos:    0
flags:  0100002
fdinfo 1:
pos:    0
flags:  01
fdinfo 2:
pos:    0
flags:  01
==============================
after capture
fdinfo 0:
pos:    0
flags:  0100002
fdinfo 1:
pos:    0
flags:  04001
fdinfo 2:
pos:    0
flags:  04001
[download]

so the same....

doesn't mean any thing to me... :-(

I capture output using "tee" or even simpler only using "wc -l".
For really using the script it would be called by another script and stdout would be read by caller.

Comment on Re^20: Net::OpenSSH loosing lines ins reply Select or Download Code

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Re^21: Net::OpenSSH loosing lines ins reply by salva (Canon) on Jun 05, 2014 at 09:57 UTC
As I had supposed, after the `capture` call, the `O_NONBLOCK` flag is set. The `ssh` command that is being run under the hood by `capture` is leaving `STDOUT` in non-blocking mode. The issue seems fixed in newer versions of OpenSSH, or at least I am unable to reproduce it with the latest one (6.6.1p1). In any case it is easy to workaround. Just using `capture2` instead of `capture` or setting `stderr_discard => 1` should make it go. BTW, there isn't any difference on the `fdinfo` dumps between the successfully and failed invocations because the problem is hidden behind a race condition. The perl process needs to be faster writing than `tee` reading for the intermediate pipe buffer to fill.	[reply] [d/l] [select]
Re^22: Net::OpenSSH loosing lines ins reply by Andy16 (Acolyte) on Jun 05, 2014 at 10:45 UTC
Hi Salva, GREAT changed to capture2 and problem did not reoccur up to now... Follwing your explanations - it shall be solved now! hero of my day! no chance for me digging that out....	[reply]

GREAT