Piping messages in a CustomLog

Hi,

I've been trying all day to get Apache to pipe log messages to a Perl
script. Shouldn't be too difficult, but it simply isn't working.
Here's my configuration entry:

CustomLog "|logs/custom_log.pl" combined

I've tried this both in VirtualHost directives and outside of them.
I've also tried prepending "perl" and an absolute path to the perl
executable, and using an absolute path to the script. Using a custom
log to a simple log file works fine.

And here's the logs/custom_log.pl file:

#!usr/bin/perl -w
open LOG_OUT, "> logs/custom.log" or die $!;
print LOG_OUT "this is a test\n";
while (<STDIN>) {
print LOG_OUT $_;
}

I've also tried using an absolute path to the custom.log file. The
script runs fine when I call it from the command line in the Apache
root.

This is on WinXP, Apache 2.0.44, Perl v5.8.6 (IndigoPerl build).

Any help would be appreciated.

Walter Gildersleeve
Freiburg, Germany

NullBock wrote:
> Hi,
>
> I've been trying all day to get Apache to pipe log messages to a Perl
> script. Shouldn't be too difficult, but it simply isn't working.
> Here's my configuration entry:
>
> CustomLog "|logs/custom_log.pl" combined
>
> I've tried this both in VirtualHost directives and outside of them.
> I've also tried prepending "perl" and an absolute path to the perl
> executable, and using an absolute path to the script. Using a custom
> log to a simple log file works fine.
>
> And here's the logs/custom_log.pl file:
>
> #!usr/bin/perl -w
> open LOG_OUT, "> logs/custom.log" or die $!;
> print LOG_OUT "this is a test\n";
> while (<STDIN>) {
> print LOG_OUT $_;
> }
>
> I've also tried using an absolute path to the custom.log file. The
> script runs fine when I call it from the command line in the Apache
> root.
>

Maybe you want to reset $| (in your Perl script) to autoflush the
output...

Xicheng

Davide Bianchi wrote:
> On 2006-08-16, NullBock <noted_rogue@easypeas.net> wrote:
> > I've been trying all day to get Apache to pipe log messages to a Perl
>
> > And here's the logs/custom_log.pl file:
> >
> > #!usr/bin/perl -w
>
> What's this? A relative path or what? Shouldn't be #!/usr/bin/perl ?
>
> > This is on WinXP,
>
> And on WinXP there is /usr/bin ?
>
> Davide

Good eye, Davide. Didn't help, though. Win32 doesn't use the shebang
line, so it could be anything. I even tried giving an absolute path to
the Perl executable, no dice.

I do suspect it's a Windows problem, I hope a solveable one. I was
hoping someone had some experience with it...

Walter

Xicheng Jia wrote:
>
> Maybe you want to reset $| (in your Perl script) to autoflush the
> output...
>
> Xicheng

Hi Xicheng,

Tried it without luck. The custom.log file isn't even being created!

So here's the reworked Perl script, with your and Davide's suggestions
(plus a bit better error handling):

#!/usr/bin/perl -w
open LOG_OUT, "> logs/custom.log" or *LOG_OUT = *STDOUT;
select *LOG_OUT;
$| = 1;
print "this is a test\n";
while (<STDIN>) {
print $_;
}

Walter

P.S. What I forgot to mention in my first post: nothing shows up in
the error log about this, even if I set the log level to debug.

"NullBock" <noted_rogue@easypeas.net> schreef in bericht
news:1155851777.123801.321620@p79g2000cwp.googlegr oups.com...
> Davide Bianchi wrote:
> > On 2006-08-16, NullBock <noted_rogue@easypeas.net> wrote:
> > > #!usr/bin/perl -w
> Good eye, Davide. Didn't help, though. Win32 doesn't use the shebang
> line, so it could be anything. I even tried giving an absolute path to
> the Perl executable, no dice.
>
> I do suspect it's a Windows problem, I hope a solveable one.

Assuming perl.exe is available via path _before_ logon, try
CustomLog "| perl logs/custom_log.pl" combined

otherwise add the local full path -and perhaps even the extention-

Note: open LOG_OUT, "> logs/custom.log" or die $!;
will overwrite the log at every restart of the service.

HansH

HansH wrote:
> Assuming perl.exe is available via path _before_ logon, try
> CustomLog "| perl logs/custom_log.pl" combined
>
> otherwise add the local full path -and perhaps even the extention-

It worked! Thought I'd already tried it, but there you go. Ended up
having to add the absolute path with extension, even though the perl
executable was on the PATH. Now I've got a problem printing the actual
events (ie, the while loop doesn't execute)--I'm going to go to sleep,
and deal with it tomorrow.

> Note: open LOG_OUT, "> logs/custom.log" or die $!;
> will overwrite the log at every restart of the service.
>
> HansH

I know. This is just a quick hack to see if I can get it to work.

Thanks, Walter

"NullBock" <noted_rogue@easypeas.net> schreef in bericht
news:1155854870.653610.154540@i42g2000cwa.googlegr oups.com...
> > Assuming perl.exe is available via path _before_ logon, try
> > CustomLog "| perl logs/custom_log.pl" combined
> >
> > otherwise add the local full path -and perhaps even the extention-
>
> It worked! Thought I'd already tried it, but there you go. Ended up
> having to add the absolute path with extension, even though the perl
> executable was on the PATH. Now I've got a problem printing the actual
> events (ie, the while loop doesn't execute)--I'm going to go to sleep,
> and deal with it tomorrow.
>
Apache might be writing single character line ends where perl _on_windows_
is expecting two characters. Try changing the input seperator by adding on
top of your script
$/ = "\012"; # LineFeed without preceding CarriageReturn

Don´t forget to flush the output by $| = 1;

What _is_ written to the file anyway?

HansH

HansH wrote:
> Apache might be writing single character line ends where perl _on_windows_
> is expecting two characters. Try changing the input seperator by adding on
> top of your script
> $/ = "\012"; # LineFeed without preceding CarriageReturn
>
> Don´t forget to flush the output by $| = 1;
>
> What _is_ written to the file anyway?
>
> HansH

Hi HansH,

I tried it, but it didn't seem to do anything. Here's the Perl script
now:

#!/usr/bin/perl -w
open LOG_OUT, "> logs/custom.log" or *LOG_OUT = *STDOUT;
select *LOG_OUT;
$| = 1;
$/ = "\012";
print "this is a test\n";
while (<STDIN>) {
print "gonna print STDIN text\n";
print $_;
}

When I run it from the command line and type "another," this is the
output:

this is a test
gonna print STDIN text
another

But from Apache, only

this is a test

is printed, nothing more. Here's the complete VirtualHost config
entry:

<VirtualHost *:80>
ServerName 127.0.0.1
CustomLog "| C:/indigoperl/perl/bin/perl.exe logs/custom_log.pl"
combined
# CustomLog logs/custom.log combined
DocumentRoot "J:/apache/htdocs"
</VirtualHost>

If I use the static CustomLog entry instead of the Perl one, it does
what you'd expect, ie:

127.0.0.1 - - [18/Aug/2006:11:04:48 +0200] "GET /index.htm HTTP/1.1"
304 0 "-" "Mozilla/5.0 (Windows; U; Windows NT 5.1; en-US; rv:1.8.0.1)
Gecko/20060111 Firefox/1.5.0.1"

after going to localhost/index.htm

This might be moving into a Perl question--maybe I should ask in the
Perl group. I'll also trying running it with a different script
language, and see what that does.

Walter