Author image Marvin Humphrey
and 1 contributors

NAME

KinoSearch::Store::SharedLock - Shared (read) lock.

SYNOPSIS

    my $lock_factory = KinoSearch::Store::LockFactory->new(
        folder    => $folder,
        agent_id  => $hostname,
    );
    my $shlock = $lock_factory->make_shared_lock(
        lock_name => 'snapshot_6r',
        timeout   => 5000,
    );

DESCRIPTION

SharedLock's interface is nearly identical to that of its parent class KinoSearch::Store::Lock, taking the same constructor arguments and implementing the same list of methods. It differs from Lock only in the semantics of two methods.

First, obtain() will not fail if another lock is held against the resource identified by lock_name (though it might fail for other reasons).

Second, is_locked() returns true so long as some lock, somewhere is holding a lock on lock_name. That lock could be this instance, or it could be another -- so is entirely possible to call release() successfully on a SharedLock object yet still have is_locked() return true.

As currently implemented, SharedLock differs from Lock in that each caller gets its own lockfile. Lockfiles still have filenames which begin with the lock name and end with ".lock", but each is also assigned a unique number which gets pasted between: "foo-44.lock" instead of "foo.lock". A SharedLock is considered fully released when no lock files with a given lock name are left.

CONSTRUCTORS

new( [labeled params] )

    my $shlock = KinoSearch::Store::SharedLock->new(
        lock_name => 'commit',           # required
        timeout   => 5000,               # default: 0
        folder    => $folder,            # required
        agent_id  => $hostname,          # required
    );
  • folder - The KinoSearch::Store::Folder where the lock file will reside.

  • lock_name - String identifying the resource to be locked.

  • agent_id - A per-machine identifier, usually the host name.

  • timeout - Time in milliseconds to keep retrying before abandoning the attempt to obtain() a lock.

INHERITANCE

KinoSearch::Store::SharedLock isa KinoSearch::Store::Lock isa KinoSearch::Obj.

COPYRIGHT

Copyright 2005-2009 Marvin Humphrey

LICENSE, DISCLAIMER, BUGS, etc.

See KinoSearch version 0.30.