|File::Flock::Retry(3pm)||User Contributed Perl Documentation||File::Flock::Retry(3pm)|
NAME¶File::Flock::Retry - Yet another flock module
VERSION¶This document describes version 0.631 of File::Flock::Retry (from Perl distribution File-Flock-Retry), released on 2019-03-12.
use File::Flock::Retry; # try to acquire exclusive lock. if fail to acquire lock within 60s, die. my $lock = File::Flock::Retry->lock($file); # explicitly unlock $lock->release; # automatically unlock if object is DESTROY-ed. undef $lock;
DESCRIPTION¶This is yet another flock module. It is a more lightweight alternative to File::Flock with some other differences:
- OO interface only
- Autoretry (by default for 60s) when trying to acquire lock
I prefer this approach to blocking/waiting indefinitely or failing immediately.
CAVEATS¶Not yet tested on Windows. Some filesystems do not support inode?
$lock = File::Flock::Retry->lock($path, \%opts)
Attempt to acquire an exclusive lock on $path. By default, $path will be created if not already exists (see "mode"). If $path is already locked by another process, will retry every second for a number of seconds (by default 60). Will die if failed to acquire lock after all retries.
Will automatically unlock if $lock goes out of scope. Upon unlock, will remove $path if it was created by "lock" and is still empty (this behavior is the same as "File::Flock").
Integer. Default: O_CREAT | O_RDWR.
File open mode, to be passed to Perl's "sysopen()". For example, if you want to avoid race condition between creating and locking the file, you might want to use "O_CREAT | O_EXCL | O_RDWR" to fail when the file already exists. Note that the constants are available after you do a "use Fcntl ':DEFAULT';".
Integer. Default: 60.
Number of retries (equals number of seconds, since retry is done every second).
Boolean. Default: 0.
By default, an exclusive lock (LOCK_EX) is attempted. However, if this option is set to true, a shared lock (LOCK_SH) is attempted.
Unlock. will remove lock file if it was created by "lock" and is still empty (this behavior is the same as "File::Flock").
Synonym for "unlock".
my $fh = $lock->handle;
Return the file handle.
HOMEPAGE¶Please visit the project's homepage at <https://metacpan.org/release/File-Flock-Retry>.
SOURCE¶Source repository is at <https://github.com/perlancar/perl-File-Flock-Retry>.
BUGS¶Please report any bugs or feature requests on the bugtracker website <https://rt.cpan.org/Public/Dist/Display.html?Name=File-Flock-Retry>
When submitting a bug or request, please include a test-file or a patch to an existing test-file that illustrates the bug or desired feature.
SEE ALSO¶File::Flock, a bit too heavy in terms of dependencies and startup overhead, for my taste. It depends on things like File::Slurp and Data::Structure::Util (which loads Digest::MD5, Storable, among others).
File::Flock::Tiny which is also tiny, but does not have the autoremove and autoretry capability which I want. See also: <https://github.com/trinitum/perl-File-Flock-Tiny/issues/1>
flock() Perl function.
An alternative to flock() is just using sysopen() with O_CREAT|O_EXCL mode to create lock files. This is supported on more filesystems (particularly network filesystems which lack flock()).
COPYRIGHT AND LICENSE¶This software is copyright (c) 2019, 2017, 2015, 2014 by firstname.lastname@example.org.
This is free software; you can redistribute it and/or modify it under the same terms as the Perl 5 programming language system itself.