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Apache::Log - Perl API for Apache Logging Methods |
Apache::LOG_EMERGApache::LOG_ALERTApache::LOG_CRITApache::LOG_ERRApache::LOG_WARNINGApache::LOG_NOTICEApache::LOG_INFOApache::LOG_DEBUG
Apache::Log - Perl API for Apache Logging Methods
#in startup.pl #------------- use Apache::Log;
use Apache::Const -compile => qw(OK :log); use APR::Const -compile => qw(:error SUCCESS);
my $s = Apache->server;
$s->log_error("server: log_error");
$s->log_serror(__FILE__, __LINE__, Apache::LOG_ERR,
APR::SUCCESS, "log_serror logging at err level");
$s->log_serror(Apache::Log::LOG_MARK, Apache::LOG_DEBUG,
APR::ENOTIME, "debug print");
Apache::Server->log_error("routine warning");
Apache->warn("routine warning");
Apache::warn("routine warning");
Apache::Server->warn("routine warning");
#in a handler #------------ package Foo;
use strict; use warnings FATAL => 'all';
use Apache::Log;
use Apache::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(Apache::Log::LOG_MARK, Apache::LOG_DEBUG,
APR::ENOTIME, "in debug");
$s->log_serror(Apache::Log::LOG_MARK, Apache::LOG_INFO,
APR::SUCESS, "server info");
$s->log_serror(Apache::Log::LOG_MARK, Apache::LOG_ERR,
APR::ENOTIME, "fatal error");
$s->warn('routine server warning');
return Apache::OK;
}
1;
Apache::Log provides the Perl API for Apache logging methods.
Depending on the the current LogLevel setting, only logging with
the same log level or higher will be loaded. For example if the
current LogLevel is set to warning, only messages with log level
of the level warning or higher (err, crit, elert and
emerg) will be logged. Therefore this:
$r->log_rerror(Apache::Log::LOG_MARK, Apache::LOG_WARNING,
APR::ENOTIME, "warning!");
will log the message, but this one won't:
$r->log_rerror(Apache::Log::LOG_MARK, Apache::LOG_INFO,
APR::ENOTIME, "just an info");
It will be logged only if the server log level is set to info or
debug. LogLevel is set in the configuration file, but can be
changed using the
$s->loglevel()|docs::2.0::api::Apache::Server/C_loglevel_
method.
The filename and the line number of the caller are logged only if
Apache::LOG_DEBUG 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
Apache::Log functions could be slower than Perl's print()/warn().
Log level constants can be compiled all at once:
use Apache::Const -compile => qw(:log);
or individually:
use Apache::Const -compile => qw(LOG_DEBUG LOG_INFO);
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:
Apache::LOG_EMERG
Apache::LOG_ALERT
Apache::LOG_CRIT
Apache::LOG_ERR
Apache::LOG_WARNING
Apache::LOG_NOTICE
Apache::LOG_INFO
Apache::LOG_DEBUG
Make sure to compile the APR status constants before using them. For
example to compile APR::SUCESS and all the APR error status
constants do:
use APR::Const -compile => qw(:error SUCCESS);
Here is the rest of the logging related constants:
Apache::LOG_LEVELMASKused 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;
Apache::LOG_TOCLIENTused to give content handlers the option of including the error text
in the ErrorDocument sent back to the client. When
Apache::LOG_TOCLIENT is passed to log_rerror() the error message
will be saved in the $r's notes table, keyed to the string
``error-notes'', if and only if the severity level of the message is
Apache::LOG_WARNING or greater and there are no other
``error-notes'' entry already set in the request record's notes
table. Once the ``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 Apache::Const -compile => qw(:log);
use APR::Const -compile => qw(ENOTIME);
$r->log_rerror(Apache::Log::LOG_MARK,
Apache::LOG_ERR|Apache::LOG_TOCLIENT,
APR::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 MUST be escaped to prevent CSS attacks.
Apache::LOG_STARTUPis useful for startup message where no timestamps, logging level is wanted. For example:
use Apache::Const -compile => qw(:log);
use APR::Const -compile => qw(SUCCESS);
$s->log_serror(Apache::Log::LOG_MARK,
Apache::LOG_INFO,
APR::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 Apache::LOG_STARTUP is binary ORed as in:
use Apache::Const -compile => qw(:log);
use APR::Const -compile => qw(SUCCESS);
$s->log_serror(Apache::Log::LOG_MARK,
Apache::LOG_INFO|Apache::LOG_STARTUP,
APR::SUCCESS,
"This log message comes with no header");
then the logging will be:
This log message comes with no header
$s->log_errorjust logs the supplied message to error_log
$s->log_error(@message);
$s
( Apache::ServerRec object|docs::2.0::api::Apache::ServerRec )@message ( strings ARRAY )For example:
$s->log_error("running low on memory");
$s->log_serrorThis 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);
$s
( Apache::ServerRec object|docs::2.0::api::Apache::ServerRec )$file ( string )$line ( number )$level
( Apache::LOG_* constant|/LogLevel_Constants )$status
( APR::Const status constant|docs::2.0::api::APR::Const )APR::Const constant|docs::2.0::api::APR::Const or coming from an
exception object.
@message ( strings ARRAY )message(s)
For example:
use Apache::Const -compile => qw(:log);
use APR::Const -compile => qw(ENOTIME SUCCESS);
$s->log_serror(Apache::Log::LOG_MARK, Apache::LOG_ERR,
APR::SUCCESS, "log_serror logging at err level");
$s->log_serror(Apache::Log::LOG_MARK, Apache::LOG_DEBUG,
APR::ENOTIME, "debug print");
$s->logget a log handle which can be used to log messages of different levels.
my $slog = $s->log;
$s
( Apache::ServerRec object|docs::2.0::api::Apache::ServerRec )$slog ( Apache::Log::Server object )Apache::Log::Server object to be used with LogLevel methods.
$r->log_errorjust logs the supplied message (similar to
$s->log_error|/C__s_E_gt_log_error_ ).
$r->log_error(@message);
$r
( Apache::RequestRec object|docs::2.0::api::Apache::RequestRec )@message ( strings ARRAY )For example:
$r->log_error("the request is about to end");
$r->log_rerrorThis 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
$s->log_serror|/C__s_E_gt_log_serror_.
For example:
use Apache::Const -compile => qw(:log);
use APR::Const -compile => qw(ENOTIME SUCCESS);
$r->log_rerror(Apache::Log::LOG_MARK, Apache::LOG_ERR,
APR::SUCCESS, "log_rerror logging at err level");
$r->log_rerror(Apache::Log::LOG_MARK, Apache::LOG_DEBUG,
APR::ENOTIME, "debug print");
$r->logget a log handle which can be used to log messages of different levels.
$rlog = $r->log;
$r
( Apache::RequestRec object|docs::2.0::api::Apache::RequestRec )$rlog ( Apache::Log::Request object )Apache::Log::Request object to be used with LogLevel methods.
after getting the log handle with $s->log|/C__s_E_gt_log_ or
$r->log|/C__s_E_gt_log_, use one of the following methods
(corresponding to the 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);
$slog ( server or
request log handle )@message ( strings ARRAY )For example if the LogLevel is error and the following code is
executed:
my $slog = $s->log;
$slog->debug("just ", "some debug info");
$slog->warn(@warnings);
$slog->crit("dying");
only the last command's logging will be performed. This is because warn, debug and other logging command which are listed right to error will be disabled.
emergSee LogLevel Methods.
alertSee LogLevel Methods.
critSee LogLevel Methods.
errorSee LogLevel Methods.
warnSee LogLevel Methods.
noticeSee LogLevel Methods.
infoSee LogLevel Methods.
debugSee LogLevel Methods.
LOG_MARKThough looking like a constant, this is a function, which returns a
list of two items: (__FILE__, __LINE__), i.e. the file and the line
where the function was called from.
my($file, $line) = Apache::Log::LOG_MARK();
$file ( string )$line ( number )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., $s->log_serror|/C__s_E_gt_log_serror_ and
$r->log_rerror|/C__r_E_gt_log_rerror_ ).
$s->warn$s->warn(@warnings);
is the same as:
$s->log_error(Apache::Log::LOG_MARK, Apache::LOG_WARNING,
APR::SUCCESS, @warnings)
For example:
$s->warn('routine server warning');
Apache->warn
Apache::warnApache->warn(@warnings);
Apache::Log also provides auto-generated Perl interface for a few
other methods which aren't tested at the moment and therefore their
API is a subject to change. These methods will be finalized later as a
need arises. If you want to rely on any of the following methods
please contact the the mod_perl development mailing list so we can help each other take the steps necessary
to shift the method to an officially supported API.
log_pidMETA: what is this method good for? it just calls getpid and logs it. In any case it has nothing to do with the logging API. And it uses static variables, it probably shouldn't be in the Apache public API.
Log the current pid
Apache::Log::log_pid($pool, $fname);
$p ( APR::Pool object|docs::2.0::api::APR::Pool )$fname ( file path )
mod_perl 2.0 and its core modules are copyrighted under The Apache Software License, Version 2.0.
The mod_perl development team and numerous contributors.
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Apache::Log - Perl API for Apache Logging Methods |