You are viewing a plain text version of this content. The canonical link for it is here.
Posted to modperl@perl.apache.org by ubr <ul...@senstadt.verwalt-berlin.de> on 2000/06/28 16:35:29 UTC
mod_perl socket problem
Hello mailinglist, i have a problem...
I wrote a mod_perl-script running on an Apache-Server which has
to receive a GIF-File from a NT-Server via a IO::Socket. (see code below)
On the NT-side there is a JAVA-programm.
Here some information about the used software:
(A) my workstation:
Linux 2.2.13
Apache/1.3.9 (Unix) (SuSE/Linux) PHP/3.0.12 mod_perl/1.21
perl, version 5.005_03
(B) production server:
Linux 2.2.7
Apache/1.3.6 (Unix) (SuSE/Linux) PHP/3.0.7 mod_perl/1.19
perl, version 5.005_02
(C) test-server:
Linux 2.2.5
Apache/1.3.4 (Unix) (SuSE/Linux) PHP/3.0.7 mod_perl/1.18
perl, version 5.005_02
I developed and tested the script on my workstation (A) and it worked.
Moving to the production server (B) or another test-server (C) the
mod_perl-script seems to crash without a sigh (C) or doesn´t receive
the whole file (B).
I have concentrated on the more severe problem (crashing on test-server C).
The script cycles through the while-loop receiving a packet, sends
a newline to the JAVA-program and writes to the IMG-Handle.
And then after some packets it dies, just before the handshaking newline.
The debugging output "GetFile: ready" does´nt appear in the logfile (GISLOG)
and the function does´nt return to the main program (No further output
in GISLOG)
There is no message in the apache error_log and also
standalone Perl in debugmode (perl -d ) gave up without any comment,
leaves me alone on the commandline.
And more confusing is:
The httpd child process does not die, according to the server status report.
Why dies perl in debug-mode when mod_perl survives it. At least i think so,
because as far as my knowledge goes mod_perl is a part of the httpd-process.
I would appreciate hints for further reading and/or tips how to debug this
problem.
The apache and linux versions are different on the three servers,
suggesting me to update. But i hope there is another solution for this problem.
Can someone point me in the right direction?
Many thanks in advance
Uli
part of geoServ.pl -------------------------------------------------------------
1 sub GetFile {
2 my ($remote_host, $filename,$remote_port)=@_;
3 my $i;
4 $i=0;
5 open(IMG,"> $htmlroot/$filename");
6 print $GISLOG "GetFile: trying $remote_host:$remote_port :\n";
7 $socket = IO::Socket::INET->new(PeerAddr => $remote_host,
8 PeerPort => $remote_port,
9 Proto => "tcp",
10 Timeout => 5,
11 Type => SOCK_STREAM)
12 or die "Couldnt connect to $remote_host:$remote_port : $@\n";
13 print $GISLOG "GetFile: connected $remote_host:$remote_port :\n";
14 $socket->autoflush(1);
15 if ($socket){ print "Connected<br>\n";}
16 $fSize= <$socket>;
17 print "fSize: $fSize XXX<br>\n";
18 print $socket "\n";
19 print $GISLOG "GetFile: receiving ";
20 print "GetFile: receiving .... ";
21 $sizeRead=0;
22 while(<$socket>){
23 print $GISLOG $i++." ";
24 print $socket "\n"; # ok, there on the other side
25 print IMG $_;
26 }
27 print $GISLOG "GetFile: ready ";
28 close($socket);
29 close(IMG);
30 }
-----------------------------------------------------------------------------
PS: The problem appears while redeveloping parts of a project
for the Digital Environmental Atlas of Berlin.
If You are interested, an entrypoint to see the older, working solution is for example:
http://www.sensut.berlin.de/sensut/umwelt/uisonline/dua96/html/ek102.ht
Re: mod_perl socket problem
Posted by Rob Tanner <rt...@onlinemac.com>.
--On Wednesday, June 28, 2000 4:35 PM +0200 ubr
<ul...@senstadt.verwalt-berlin.de> wrote:
> Hello mailinglist, i have a problem...
>
> I wrote a mod_perl-script running on an Apache-Server which has
> to receive a GIF-File from a NT-Server via a IO::Socket. (see code below)
> On the NT-side there is a JAVA-programm.
>
> Here some information about the used software:
> (A) my workstation:
> Linux 2.2.13
> Apache/1.3.9 (Unix) (SuSE/Linux) PHP/3.0.12 mod_perl/1.21
> perl, version 5.005_03
> (B) production server:
> Linux 2.2.7
> Apache/1.3.6 (Unix) (SuSE/Linux) PHP/3.0.7 mod_perl/1.19
> perl, version 5.005_02
> (C) test-server:
> Linux 2.2.5
> Apache/1.3.4 (Unix) (SuSE/Linux) PHP/3.0.7 mod_perl/1.18
> perl, version 5.005_02
>
> I developed and tested the script on my workstation (A) and it worked.
> Moving to the production server (B) or another test-server (C) the
> mod_perl-script seems to crash without a sigh (C) or doesn´t receive
> the whole file (B).
>
I'm not all that familiar with the various issues surrounding the earlier
releases of mod_perl, but you do notice the above trend. Earlier versions
of mod_perl and Apache have the problem, the later do not. Mod_perl's
current release is 1.24 and apache is 1.3.12. Unless there's a
show-stopper bug in the most recent version of something, I like to keep up
to date so that I don't rediscover something that has already been fixed.
> I have concentrated on the more severe problem (crashing on test-server
> C).
>
> The script cycles through the while-loop receiving a packet, sends
> a newline to the JAVA-program and writes to the IMG-Handle.
> And then after some packets it dies, just before the handshaking newline.
>
> The debugging output "GetFile: ready" does´nt appear in the logfile
> (GISLOG) and the function does´nt return to the main program (No further
> output in GISLOG)
>
Looking at your code, one thing I think might be quite problematics is the
use of the "die" statement. According to the eagle book, except during
apache initialization and startup, die does not necessarily behave as
advertised. I suggest that instead you print to STDERR since apache
reopens that handle to point to error_log, and then simply return with an
SERVER_ERROR set. That way apache handles it as apache was designed to do,
and you won't suffer any of the possible negative consequences of "die".
That might get you a long way towards figuring out what all is going on.
And don't overlook the profuse use of "print STDERR" to write out debugging
information to the error_log. That one mechanism has helped me to find
more bugs than I'm even willing to admit to have had.
Hope that's helpful.
-- Rob
_ _ _ _ _ _ _ _ _ _
/\_\_\_\_\ /\_\ /\_\_\_\_\_\
/\/_/_/_/_/ /\/_/ \/_/_/_/_/_/ QUIDQUID LATINE DICTUM SIT,
/\/_/__\/_/ __ /\/_/ /\/_/ PROFUNDUM VIDITUR
/\/_/_/_/_/ /\_\ /\/_/ /\/_/
/\/_/ \/_/ /\/_/_/\/_/ /\/_/ (Whatever is said in Latin
\/_/ \/_/ \/_/_/_/_/ \/_/ appears profound)
Rob Tanner
McMinnville, Oregon
rtanner@onlinemac.com