[Canberra-pm] How to exit a hung pipe to a shell command [SEC=UNCLASSIFIED]

[Jepri]

Nearly forgot... there's a cpan module for z39.50.  In fact, more than one:

http://search.cpan.org/search?query=z39.50&mode=all

HTH

John.Hockaday at ga.gov.au wrote:
> Hi All,
> 
> I have a PERL pipe that calls a c++ binary called
> "/public/data/asddgate/isite/current/bin/zping".  It tries to ping an
> external zserver using the hostname and port parameters.  If the ping works
> it returns something like:
> 
> Z39.50 server at www.ga.gov.au on port 6668 is alive.
> 
>  and then exits the pipe.
> 
> Sometimes it can't zping because the zserver is down or the zping command is
> not allowed through a firewall so the pipe hangs for 224 seconds.  
> 
> There is an option of -t NN which sets how long to wait for a response from
> the zserver and I set this to 60 seconds (zping -t 60) but this doesn't seem
> to work when the pipe hangs.
> 
> I have tried to overcome this by using a combination of PERL while and sleep
> but I just can't seem to get it to work.  Here is a snippet of my code:
> 
> #################################################################
> #!/opt/csw/bin/perl
> ###################
> # sleep for 60 seconds or zping
> ###################
>   $hostname = shift;
>   $port = shift;
> 
>   $zping_cmd = '/public/data/asddgate/isite/current/bin/zping';
>   my ($alive);
> 
>   open (ZPING, "$zping_cmd -t 60 $hostname $port 2>&1 |")
>     or die "Cannot open zping: $!";
>   while (($results = <ZPING>) || (sleep(60) != 60) ) {
>     print "$results\n";
>     if ($results =~ m/is alive/) {
>       $alive = 1;
>       print "$results\n";
>       last;
>     }
>   }
>   print "closing ZPING and alive = $alive\n";
>   close ZPING;
> #################################################################
> 
> Am I doing this correctly or is there some other way to break this pipe after
> waiting for a set time and still continue with the code?  I tried alarm but
> it exits the script and I want to keep on processing.
> 
> Thanks.
> 
> 
>  John Hockaday
>  Geoscience Australia
>  GPO Box 378
>  Canberra ACT 2601
>  (02) 6249 9735
>  http://www.ga.gov.au/ 
>  john.hockaday\@ga.gov.au
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