=head1 NAME Apache2::Log - Perl API for Apache Logging Methods =head1 Synopsis # in startup.pl #-------------- use Apache2::Log; use Apache2::Const -compile => qw(OK :log); use APR::Const -compile => qw(:error SUCCESS); my $s = Apache2::ServerUtil->server; $s->log_error("server: log_error"); $s->log_serror(__FILE__, __LINE__, Apache2::Const::LOG_ERR, APR::Const::SUCCESS, "log_serror logging at err level"); $s->log_serror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_DEBUG, APR::Const::ENOTIME, "debug print"); Apache2::ServerRec->log_error("routine warning"); Apache2::ServerRec::warn("routine warning"); # in a handler #------------- package Foo; use strict; use warnings FATAL => 'all'; use Apache2::Log; use Apache2::Const -compile => qw(OK :log); use APR::Const -compile => qw(:error SUCCESS); sub handler { my $r = shift; $r->log_error("request: log_error"); my $rlog = $r->log; for my $level qw(emerg alert crit error warn notice info debug) { no strict 'refs'; $rlog->$level($package, "request: $level log level"); } # can use server methods as well my $s = $r->server; $s->log_error("server: log_error"); $r->log_rerror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_DEBUG, APR::Const::ENOTIME, "in debug"); $s->log_serror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_INFO, APR::Const::SUCCESS, "server info"); $s->log_serror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_ERR, APR::Const::ENOTIME, "fatal error"); $r->log_reason("fatal error"); $r->warn('routine request warning'); $s->warn('routine server warning'); return Apache2::Const::OK; } 1; # in a registry script # httpd.conf: PerlOptions +GlobalRequest use Apache2::ServerRec qw(warn); # override warn locally print "Content-type: text/plain\n\n"; warn "my warning"; =head1 Description C provides the Perl API for Apache logging methods. Depending on the the current C setting, only logging with the same log level or higher will be loaded. For example if the current C is set to I, only messages with log level of the level I or higher (I, I, I and I) will be logged. Therefore this: $r->log_rerror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_WARNING, APR::Const::ENOTIME, "warning!"); will log the message, but this one won't: $r->log_rerror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_INFO, APR::Const::ENOTIME, "just an info"); It will be logged only if the server log level is set to I or I. C is set in the configuration file, but can be changed using the Cloglevel()|docs::2.0::api::Apache2::ServerRec/C_loglevel_>> method. The filename and the line number of the caller are logged only if C is used (because that's how Apache 2.0 logging mechanism works). Note: On Win32 Apache attempts to lock all writes to a file whenever it's opened for append (which is the case with logging functions), as Unix has this behavior built-in, while Win32 does not. Therefore C functions could be slower than Perl's print()/warn(). =head1 Constants Log level constants can be compiled all at once: use Apache2::Const -compile => qw(:log); or individually: use Apache2::Const -compile => qw(LOG_DEBUG LOG_INFO); =head2 LogLevel Constants The following constants (sorted from the most severe level to the least severe) are used in logging methods to specify the log level at which the message should be logged: =head3 C =head3 C =head3 C =head3 C =head3 C =head3 C =head3 C =head3 C =head2 Other Constants Make sure to compile the APR status constants before using them. For example to compile C and all the APR error status constants do: use APR::Const -compile => qw(:error SUCCESS); Here is the rest of the logging related constants: =head3 C used to mask off the level value, to make sure that the log level's value is within the proper bits range. e.g.: $loglevel &= LOG_LEVELMASK; =head3 C used to give content handlers the option of including the error text in the C sent back to the client. When C is passed to C the error message will be saved in the C<$r>'s notes table, keyed to the string I<"error-notes">, if and only if the severity level of the message is C or greater and there are no other I<"error-notes"> entry already set in the request record's notes table. Once the I<"error-notes"> entry is set, it is up to the error handler to determine whether this text should be sent back to the client. For example: use Apache2::Const -compile => qw(:log); use APR::Const -compile => qw(ENOTIME); $r->log_rerror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_ERR|Apache2::Const::LOG_TOCLIENT, APR::Const::ENOTIME, "request log_rerror"); now the log message can be retrieved via: $r->notes->get("error-notes"); Remember that client-generated text streams sent back to the client B be escaped to prevent CSS attacks. =head3 C is useful for startup message where no timestamps, logging level is wanted. For example: use Apache2::Const -compile => qw(:log); use APR::Const -compile => qw(SUCCESS); $s->log_serror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_INFO, APR::Const::SUCCESS, "This log message comes with a header"); will print: [Wed May 14 16:47:09 2003] [info] This log message comes with a header whereas, when C is binary ORed as in: use Apache2::Const -compile => qw(:log); use APR::Const -compile => qw(SUCCESS); $s->log_serror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_INFO|Apache2::Const::LOG_STARTUP, APR::Const::SUCCESS, "This log message comes with no header"); then the logging will be: This log message comes with no header =head1 Server Logging Methods =head2 C<$s-Elog> get a log handle which can be used to L. my $slog = $s->log; =over 4 =item obj: C<$s> ( C> ) =item ret: C<$slog> ( C object ) C object to be used with L. =item since: 2.0.00 =back =head2 C<$s-Elog_error> just logs the supplied message to I $s->log_error(@message); =over 4 =item obj: C<$s> ( C> ) =item arg1: C<@message> ( strings ARRAY ) what to log =item ret: no return value =item since: 2.0.00 =back For example: $s->log_error("running low on memory"); =head2 C<$s-Elog_serror> This function provides a fine control of when the message is logged, gives an access to built-in status codes. $s->log_serror($file, $line, $level, $status, @message); =over 4 =item obj: C<$s> ( C> ) =item arg1: C<$file> ( string ) The file in which this function is called =item arg2: C<$line> ( number ) The line number on which this function is called =item arg3: C<$level> ( C> ) The level of this error message =item arg4: C<$status> ( C> ) The status code from the last command (similar to $! in perl), usually C> or coming from an L. =item arg5: C<@message> ( strings ARRAY ) The log message(s) =item ret: no return value =item since: 2.0.00 =back For example: use Apache2::Const -compile => qw(:log); use APR::Const -compile => qw(ENOTIME SUCCESS); $s->log_serror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_ERR, APR::Const::SUCCESS, "log_serror logging at err level"); $s->log_serror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_DEBUG, APR::Const::ENOTIME, "debug print"); =head2 C<$s-Ewarn> $s->warn(@warnings); is the same as: $s->log_serror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_WARNING, APR::Const::SUCCESS, @warnings) =over 4 =item obj: C<$s> ( C> ) =item arg1: C<@warnings> ( strings ARRAY ) array of warning strings =item ret: no return value =item since: 2.0.00 =back For example: $s->warn('routine server warning'); =head1 Request Logging Methods =head2 C<$r-Elog> get a log handle which can be used to L. $rlog = $r->log; =over 4 =item obj: C<$r> ( C> ) =item ret: C<$rlog> ( C object ) C object to be used with L. =item since: 2.0.00 =back =head2 C<$r-Elog_error> just logs the supplied message (similar to Clog_error|/C__s_E_gt_log_error_>> ). $r->log_error(@message); =over 4 =item obj: C<$r> ( C> ) =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-Elog_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> ) =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-Elog_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 Clog_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-Ewarn> $r->warn(@warnings); is the same as: $r->log_rerror(Apache2::Log::LOG_MARK, Apache2::Const::LOG_WARNING, APR::Const::SUCCESS, @warnings) =over 4 =item obj: C<$r> ( C> ) =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 Clog|/C__s_E_gt_log_>> or Clog|/C__s_E_gt_log_>>, use one of the following methods (corresponding to the C 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 or L log handle ) =item arg1: C<@message> ( strings ARRAY ) =item ret: no return value =item since: 2.0.00 =back For example if the C is C and the following code is executed: my $slog = $s->log; $slog->debug("just ", "some debug info"); $slog->warn(@warnings); $slog->crit("dying"); only the last command's logging will be performed. This is because I, I and other logging command which are listed right to I will be disabled. =head2 C See L. =head2 C See L. =head2 C See L. =head2 C See L. =head2 C See L. =head2 C See L. =head2 C See L. Though Apache treats C calls as special. The message is always logged regardless the value of C, unless the error log is set to use syslog. (For details see httpd-2.0/server/log.c.) =head2 C See L. =head1 General Functions =head2 C Though looking like a constant, this is a function, which returns a list of two items: C<(__FILE__, __LINE__)>, i.e. the file and the line where the function was called from. my ($file, $line) = Apache2::Log::LOG_MARK(); =over 4 =item ret1: C<$file> ( string ) =item ret2: C<$line> ( number ) =item since: 2.0.00 =back It's mostly useful to be passed as the first argument to those logging methods, expecting the filename and the line number as the first arguments (e.g., Clog_serror|/C__s_E_gt_log_serror_>> and Clog_rerror|/C__r_E_gt_log_rerror_>> ). =head1 Virtual Hosts Code running from within a virtual host needs to be able to log into its C file, if different from the main log. Calling any of the logging methods on the C<$r> and C<$s> objects will do the logging correctly. If the core C is called, it'll be always logged to the main log file. Here is how to make it log into the vhost F 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 Either replace C with C: 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: 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 file as well. Here is how to do that: use Apache2::Log (); local $SIG{__WARN__} = \&Apache2::ServerRec::warn; eval q[my $x = "aaa" + 1;]; # this issues a warning Notice that it'll override any previous setting you may have had, disabling modules like C which also use C<$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 Crequest|docs::2.0::api::Apache2::RequestUtil/C_request_>>. Which requires either C> 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 file. This shouldn't be a problem for the code that runs only under mod_perl, since the always available C<$s> object can invoke a plethora of methods supplied by C. This is only a problem for modules, which are supposed to run outside mod_perl as well. META: To solve this we think to introduce 'PerlOptions +GlobalServer', a big brother for 'PerlOptions +GlobalRequest', which will be set in modperl_hook_pre_connection. =back =head1 Unsupported API C also provides auto-generated Perl interface for a few other methods which aren't tested at the moment and therefore their API is a subject to change. These methods will be finalized later as a need arises. If you want to rely on any of the following methods please contact the L so we can help each other take the steps necessary to shift the method to an officially supported API. =head2 C META: what is this method good for? it just calls getpid and logs it. In any case it has nothing to do with the logging API. And it uses static variables, it probably shouldn't be in the Apache public API. Log the current pid Apache2::Log::log_pid($pool, $fname); =over 4 =item obj: C<$p> ( C> ) 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. =head1 Copyright mod_perl 2.0 and its core modules are copyrighted under The Apache Software License, Version 2.0. =head1 Authors L. =cut