log.pm

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C<Apache2::Log::Request> object to be used with L<LogLevel
methods|/LogLevel_Methods>.

=item since: 2.0.00

=back






=head2 C<$r-E<gt>log_error>

just logs the supplied message (similar to
C<L<$s-E<gt>log_error|/C__s_E_gt_log_error_>> ).

  $r->log_error(@message);

=over 4

=item obj: C<$r>
( C<L<Apache2::RequestRec object|docs::2.0::api::Apache2::RequestRec>> )

=item arg1: C<@message> ( strings ARRAY )

what to log

=item ret: no return value

=item since: 2.0.00


=back

For example:

  $r->log_error("the request is about to end");






=head2 C<$r-E<gt>log_reason>

This function provides a convenient way to log errors in a
preformatted way:

  $r->log_reason($message);
  $r->log_reason($message, $filename);

=over 4

=item obj: C<$r>
( C<L<Apache2::RequestRec object|docs::2.0::api::Apache2::RequestRec>> )

=item arg1: C<$message> ( string )

the message to log

=item opt arg2: C<$filename> ( string )

where to report the error as coming from (e.g. C<__FILE__>)

=item ret: no return value

=item since: 2.0.00

=back

For example:

  $r->log_reason("There is no enough data");

will generate a log entry similar to the following:

  [Fri Sep 24 11:58:36 2004] [error] access to /someuri
  failed for 127.0.0.1, reason: There is no enough data.







=head2 C<$r-E<gt>log_rerror>

This function provides a fine control of when the message is logged,
gives an access to built-in status codes.

  $r->log_rerror($file, $line, $level, $status, @message);

arguments are identical to
C<L<$s-E<gt>log_serror|/C__s_E_gt_log_serror_>>.

=over 4

=item since: 2.0.00

=back

For example:

  use Apache2::Const -compile => qw(:log);
  use APR::Const    -compile => qw(ENOTIME SUCCESS);
  $r->log_rerror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_ERR,
                 APR::Const::SUCCESS, "log_rerror logging at err level");
  
  $r->log_rerror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_DEBUG,
                 APR::Const::ENOTIME, "debug print");





=head2 C<$r-E<gt>warn>

  $r->warn(@warnings);

is the same as:

  $r->log_error(Apache2::Log::LOG_MARK, Apache2::Const::LOG_WARNING,
                APR::Const::SUCCESS, @warnings)

=over 4

=item obj: C<$r>
( C<L<Apache2::RequestRec object|docs::2.0::api::Apache2::RequestRec>> )

=item arg1: C<@warnings> ( strings ARRAY )

array of warning strings

=item ret: no return value

=item since: 2.0.00

=back

For example:

  $r->warn('routine server warning');







=head1 Other Logging Methods

=head2 LogLevel Methods

after getting the log handle with C<L<$s-E<gt>log|/C__s_E_gt_log_>> or
C<L<$r-E<gt>log|/C__s_E_gt_log_>>, use one of the following methods
(corresponding to the C<LogLevel> levels):

  emerg(), alert(), crit(), error(), warn(), notice(), info(), debug()

to control when messages should be logged:

  $s->log->emerg(@message);
  $r->log->emerg(@message);

=over 4

=item obj: C<$slog> ( L<server|/C__s_E_gt_log_> or
L<request|/C__s_E_gt_log_> log handle )

=item arg1: C<@message> ( strings ARRAY )

=item ret: no return value

=item since: 2.0.00

=back

For example if the C<LogLevel> is C<error> and the following code is
executed:

  my $slog = $s->log;
  $slog->debug("just ", "some debug info");
  $slog->warn(@warnings);
  $slog->crit("dying");

only the last command's logging will be performed. This is because
I<warn>, I<debug> and other logging command which are listed right to
I<error> will be disabled.





=head2 C<alert>

See L<LogLevel Methods|/LogLevel_Methods>.



=head2 C<crit>

See L<LogLevel Methods|/LogLevel_Methods>.



=head2 C<debug>

See L<LogLevel Methods|/LogLevel_Methods>.



=head2 C<emerg>

See L<LogLevel Methods|/LogLevel_Methods>.



=head2 C<error>

See L<LogLevel Methods|/LogLevel_Methods>.



=head2 C<info>

See L<LogLevel Methods|/LogLevel_Methods>.



=head2 C<notice>

See L<LogLevel Methods|/LogLevel_Methods>.

Though Apache treats C<notice()> calls as special. The message is
always logged regardless the value of C<ErrorLog>, unless the error
log is set to use syslog. (For details see httpd-2.0/server/log.c.)



=head2 C<warn>

See L<LogLevel Methods|/LogLevel_Methods>.






=head1 General Functions





=head2 C<LOG_MARK>

Though looking like a constant, this is a function, which returns a
list of two items: C<(__FILE__, __LINE__)>, i.e. the file and the line
where the function was called from.

  my ($file, $line) = Apache2::Log::LOG_MARK();

=over 4

=item ret1: C<$file> ( string )

=item ret2: C<$line> ( number )

=item since: 2.0.00

=back

It's mostly useful to be passed as the first argument to those logging
methods, expecting the filename and the line number as the first
arguments (e.g., C<L<$s-E<gt>log_serror|/C__s_E_gt_log_serror_>> and
C<L<$r-E<gt>log_rerror|/C__r_E_gt_log_rerror_>> ).




=head1 Virtual Hosts

Code running from within a virtual host needs to be able to log into
its C<ErrorLog> file, if different from the main log. Calling any of
the logging methods on the C<$r> and C<$s> objects will do the logging
correctly.

If the core C<warn()> is called, it'll be always logged to the main
log file. Here is how to make it log into the vhost F<error_log> file.
Let's say that we start with the following code:

  warn "the code is smoking";

=over

=item 1

First, we need to use mod_perl's logging function, instead of
C<CORE::warn>

Either replace C<warn> with C<Apache2::ServerRec::warn>:

  use Apache2::Log ();
  Apache2::ServerRec::warn("the code is smoking");

or import it into your code:

  use Apache2::ServerRec qw(warn); # override warn locally
  warn "the code is smoking";

or override C<CORE::warn>:

  use Apache2::Log ();
  *CORE::GLOBAL::warn = \&Apache2::ServerRec::warn;
  warn "the code is smoking";

Avoid using the latter suggestion, since it'll affect all the code
running on the server, which may break things. Of course you can
localize that as well:

  use Apache2::Log ();
  local *CORE::GLOBAL::warn = \&Apache2::ServerRec::warn;
  warn "the code is smoking";

Chances are that you need to make the internal Perl warnings go into
the vhost's F<error_log> file as well. Here is how to do that:

  use Apache2::Log ();
  local $SIG{__WARN__} = \&Apache2::ServerRec::warn;
  eval q[my $x = "aaa" + 1;]; # this issues a warning

Notice that it'll override any previous setting you may have had,
disabling modules like C<CGI::Carp> which also use C<$SIG{__WARN__}>

=item 2

Next we need to figure out how to get hold of the vhost's server
object.

Inside HTTP request handlers this is possible via
C<Apache2-E<gt>request|docs::2.0::api::Apache2::RequestUtil/C_request_>. Which
requires either C<L<PerlOptions
+GlobalRequest|docs::2.0::user::config::config/C_GlobalRequest_>>
setting or can be also done at runtime if C<$r> is available:

  use Apache2::RequestUtil ();
  sub handler {
      my $r = shift;
      Apache2::RequestUtil->request($r);
      ...

Outside HTTP handlers at the moment it is not possible, to get hold of
the vhost's F<error_log> file. This shouldn't be a problem for the
code that runs only under mod_perl, since the always available C<$s>
object can invoke a plethora of methods supplied by
C<Apache2::Log>. This is only a problem for modules, which are supposed
to run outside mod_perl as well.

META: To solve this we think to introduce 'PerlOptions +GlobalServer',
a big brother for 'PerlOptions +GlobalRequest', which will be set in
modperl_hook_pre_connection.


=back







=head1 Unsupported API

C<Apache2::Log> also provides auto-generated Perl interface for a few
other methods which aren't tested at the moment and therefore their
API is a subject to change. These methods will be finalized later as a
need arises. If you want to rely on any of the following methods
please contact the L<the mod_perl development mailing
list|maillist::dev> so we can help each other take the steps necessary
to shift the method to an officially supported API.


=head2 C<log_pid>

META: what is this method good for? it just calls getpid and logs
it. In any case it has nothing to do with the logging API. And it uses
static variables, it probably shouldn't be in the Apache public API.

Log the current pid

  Apache2::Log::log_pid($pool, $fname);

=over 4

=item obj: C<$p> ( C<L<APR::Pool object|docs::2.0::api::APR::Pool>> )

The pool to use for logging

=item arg1: C<$fname> ( file path )

The name of the file to log to

=item ret: no return value

=item since: subject to change


=back






=head1 See Also

L<mod_perl 2.0 documentation|docs::2.0::index>.




=head1 Copyright

mod_perl 2.0 and its core modules are copyrighted under
The Apache Software License, Version 2.0.




=head1 Authors

L<The mod_perl development team and numerous
contributors|about::contributors::people>.

=cut