in reply to Re^15: Net::OpenSSH loosing lines ins reply
in thread Net::OpenSSH loosing lines ins reply

Don't call master_exited. Though that would probably not solve anything.

What is print returning? 

for (@cmdout) {
  my $bytes = print $_;
  print STDERR "bytes: $bytes, err: $!\n";
}

[download]

Also, use strace in order to see what is going on at the OS level.

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Re^17: Net::OpenSSH loosing lines ins reply
by Andy16 (Acolyte) on Jun 04, 2014 at 19:23 UTC
    Hi Salva,

    good ideas, will follow up tomorrow,
    but hard to do - as I have to read the full output line by line every time to find, if there is one missing...
    If I only count the lines - I miss the info.

    grrr...
[reply]
      Good morning Salva,


      I think you lead us to the correct track... :-)


      open OUT, ">", "./trace.out";
my $line =0;
foreach (@cmdout) {
    $line++;
    my $bytes = print  $line.": ".$_;
    print OUT "$line: bytes: $bytes, err: $! \n";
}
close(OUT);

      [download]


      IF everything is fine trace looks like this for all lines:
      ...
1880: bytes: 1, err: Inappropriate ioctl for device 
1881: bytes: 1, err: Inappropriate ioctl for device 
1882: bytes: 1, err: Inappropriate ioctl for device 
1883: bytes: 1, err: Inappropriate ioctl for device 
1884: bytes: 1, err: Inappropriate ioctl for device 
...

      [download]
      IF it starts to fail:
      ...
1891: bytes: 1, err: Inappropriate ioctl for device 
1892: bytes: 1, err: Inappropriate ioctl for device 
1893: bytes: , err: Resource temporarily unavailable 
1894: bytes: , err: Resource temporarily unavailable 
1895: bytes: , err: Resource temporarily unavailable 
1896: bytes: , err: Resource temporarily unavailable 
1897: bytes: , err: Resource temporarily unavailable 
...

      [download]


      Does this ring a bell?
      update caught it in strace:
      write(1, "07651738\n1313:   switchport acce"..., 4096) = 4096
write(1, ": interface Ethernet2/36\n1426:  "..., 4096) = 4096
write(1, "ntrusted\n1539:   service-policy "..., 4096) = 4096
write(1, "torm-control broadcast level 10."..., 4096) = 4096
write(1, "rol broadcast level 10.00\n1782: "..., 4096) = -1 EAGAIN (Re
+source temporarily unavailable)
write(1, "t level 10.00\n1894:   service-po"..., 4096) = -1 EAGAIN (Re
+source temporarily unavailable)
write(1, "e-policy type queuing input N7K-"..., 4096) = -1 EAGAIN (Res
+ource temporarily unavailable)
write(1, "141:   channel-group 1305 mode a"..., 4096) = -1 EAGAIN (Res
+ource temporarily unavailable)
write(1, "storm-control broadcast level 10"..., 4096) = -1 EAGAIN (Res
+ource temporarily unavailable)

      [download]
[reply]
[d/l]
[select]
        write(1, "torm-control broadcast level 10."..., 4096) = 4096
write(1, "rol broadcast level 10.00\n1782: "..., 4096) = -1 EAGAIN (Re
+source temporarily unavailable)

        [download]

        The only plausible explanation I can think of is OpenSSH ssh setting STDOUT into non-blocking mode. BTW, how are you capturing STDOUT?

        Add a dump of /proc/$$/fdinfo: 

        open OUT, ">", "./trace.out";

for (0, 1, 2) {
    local $/;
    open my $fdinfo, '<', "/proc/$$/fdinfo/$_";
    my $info = <$fdinfo>;
    print OUT "fdinfo $_:\n$info\n\n";
}

my $line =0;
foreach (@cmdout) {
    $line++;
    my $bytes = print  $line.": ".$_;
    print OUT "$line: bytes: $bytes, err: $! \n";
}
close(OUT);

        [download]

        The non-blocking flag is 0x4000. You may also like to generate dumps of fdinfo before the constructor call and before and after calling capture.

[reply]
[d/l]
[select]

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