Re: PoCo::Client::Ping intermittently fails to emit pings

The post($sender, $event, ....) call sends $event response back to  
your code if send() fails.  The response address, round-trip time, and  
TTL are undefined.  The response time is "now".

You've added logging in a good place, if you want to solve this by  
modifying the module.  It might be better to catch the $event in your  
application and log the problem there.

-- 
Rocco Caputo - [email protected]


On Apr 21, 2009, at 16:31, Stuart Kendrick wrote:

> i'm walking through .../perl5/site_perl/5.10.0/POE/Component/Client/ 
> Ping.pm
>
> where do we emit an error if we are unable to send an ICMP packet?
>
>
>
> seems to me that we decide to send the ping in the very last line of  
> 'sub poco_ping_ping':
>
> [...]
> # Request a ping.  This code borrows heavily from Net::Ping.
>
> sub poco_ping_ping {
> [...]
>  _send_packet($kernel, $heap);
> }
>
>
> and we actually send the ping on line 362, within the '_send_packet'  
> routine, specifically, from the 'send' phrase within the 'unless'   
> clause:
>
>
> sub _send_packet {
>  my ($kernel, $heap) = @_;
>  return unless (scalar @{$heap->{queue}});
> [...]
>  # Send the packet.  If send() fails, then we bail with an error.
>  my @user_args = ();
>  ($event, @user_args) = @$event if ref($event) eq "ARRAY";
>
>  DEBUG and warn "sending packet sequence number $seq\n";
>  unless (send($heap->{socket_handle}, $msg, ICMP_FLAGS,  
> $socket_address)) {
>    $kernel->post(
>      $sender, $event,
>      [ $address,    # REQ_ADDRESS
>        $timeout,    # REQ_TIMEOUT
>        time(),      # REQ_TIME
>        @user_args,  # REQ_USER_ARGS
>      ],
>      [ undef,   # RES_ADDRESS
>        undef,   # RES_ROUNDTRIP
>        time(),  # RES_TIME
>        undef,   # RES_TTL
>      ],
>    );
>    _check_for_close($kernel, $heap);
>    return;
>  }
> [...]
>
>
> now, i see the comment "If send() fails, then we bail with an  
> error".  but i don't see where we actually spit out an error  
> message.  seems to me that _send_packet returns with a value of 0  
> (that 'return' statement just after the call to  
> _check_for_close) ... but i don't see us checking the return value  
> of _send_packet, back in "sub poco_ping_ping"
>
>
> or ... does the "$kernel-post( ..." event trigger an error message,  
> through some mechanism i don't understand?
>
> would it be reasonable for me to add the following, in order to  
> track the success/failure of the call to send()  ?
>
> [...]
>  unless (send($heap->{socket_handle}, $msg, ICMP_FLAGS,  
> $socket_address)) {
>    warn "Unable to send() ICMP packet";
>    $kernel->post(
> [...]
>
> or would i be duplicating effort performed elsewhere?
>
> actually, what i really want to do is to log such events to syslog,  
> so am i headed in a fruitful direction by adding the following?
>
> [...]
>  unless (send($heap->{socket_handle}, $msg, ICMP_FLAGS,  
> $socket_address)) {
>    use Sys::Syslog;
>    openlog('PoCo-Ping', 'nofatal,ndelay,pid', 'local0');
>    syslog('error', 'Unable to send() ICMP packet');
>    closelog();
>    $kernel->post(
> [...]
>
>
> --sk