Apache::Session::Lock:UsereContributed Perl DocuApache::Session::Lock::File(3)NAMEApache::Session::Lock::File - Provides mutual exclusion using flock
SYNOPSIS
use Apache::Session::Lock::File;
my $locker = new Apache::Session::Lock::File;
$locker->acquire_read_lock($ref);
$locker->acquire_write_lock($ref);
$locker->release_read_lock($ref);
$locker->release_write_lock($ref);
$locker->release_all_locks($ref);
$locker->clean($dir, $age);
DESCRIPTIONApache::Session::Lock::File fulfills the locking interface of
Apache::Session. Mutual exclusion is achieved through the use of
temporary files and the "flock" function.
CONFIGURATION
The module must know where to create its temporary files. You must
pass an argument in the usual Apache::Session style. The name of the
argument is LockDirectory and its value is the path where you want the
lockfiles created. Example:
tie %s, 'Apache::Session::Blah', $id, {LockDirectory => '/var/lock/sessions'}
If you do not supply this argument, temporary files will be created in
/tmp.
NOTES
clean
This module does not unlink temporary files, because it interferes with
proper locking. This can cause problems on certain systems (Linux)
whose file systems (ext2) do not perform well with lots of files in one
directory. To prevent this you should use a script to clean out old
files from your lock directory. The meaning of old is left as a policy
decision for the implementor, but a method is provided for implementing
that policy. You can use the "clean" method of this module to remove
files unmodified in the last $age seconds. Example:
my $l = new Apache::Session::Lock::File;
$l->clean('/var/lock/sessions', 3600) #remove files older than 1 hour
acquire_read_lock
Will do nothing if write lock is in effect, only set readlock flag to
true.
release_read_lock
Will do nothing if write lock is in effect, only set readlock flag to
false.
Win32 and Cygwin
Windows cannot escalate lock, so all locks will be exclusive.
release_read_lock not supported - it is not used by Apache::Session.
When deleting files, they are not locked (Win32 only).
AUTHOR
This module was written by Jeffrey William Baker <jwbaker@acm.org>.
SEE ALSO
Apache::Session
perl v5.18.2 2014-05-14 Apache::Session::Lock::File(3)
