/ 
Test-NoLeaks-0.02
River stage zero No dependents
/ Test::NoLeaks

NAME

Test::NoLeaks - Memory and file descriptor leak detector

VERSION

0.02

SYNOPSYS

use Test::NoLeaks;

test_noleaks (
    code          => sub{
      # code that might leak
    },
    track_memory  => 1,
    track_fds     => 1,
    passes        => 2,
    warmup_passes => 1,
    tolerate_hits => 0,
);

test_noleaks (
    code          => sub { ... },
    track_memory  => 1,
    passes        => 2,
);

# old-school way
use Test::More;
use Test::NoLeaks qw/noleaks/;
ok noleaks(
    code          => sub { ... },
    track_memory  => ...,
    track_fds     => ...,
    passes        => ...,
    warmup_passes => ...,
  ), "non-leaked code description";

DESCRIPTION

It is hard to track memory leaks. There are a lot of perl modules (e.g. Test::LeakTrace), that try to detect and point leaks. Unfortunately, they do not always work, and they are rather limited because they are not able to detect leaks in XS-code or external libraries.

Instead of examining perl internals, this module offers a bit naive empirical approach: let the suspicious code to be launched in infinite loop some time and watch (via tools like top)if the memory consumption by perl process increses over time. If it does, while it is expected to be constant (stabilized), then, surely, there are leaks.

This approach is able only to detect and not able to point them. The module Test::NoLeaks implements the general idea of the approach, which might be enough in many cases.

INTERFACE

test_noleaks

noleaks

The mandatory hash has the following members

  • code

    Suspicious for leaks subroutine, that will be executed multiple times.

  • track_memory

  • track_fds

    Track memory or file descriptor leaks. At leas one of them should be specified.

    In Unices, every socket is file descriptor too, so, track_fds will be able to track unclosed sockets, i.e. network connections.

  • passes

    How many times code should be executed. If memory leak is too small, number of passes should be large enough to trigger additional pages allocation for perl process, and the leak will be detected.

    Page size is 4kb on linux, so, if code leaks 4 bytes on every pass, then 1024 passes should be specified.

    In general, the more passes are specified, the more chance to detect possible leaks.

    Default value is 100. Minimal value is 2.

  • warmup_passes

    How many times the code should be executed before module starts tracking resources consumption on executing the code passes times.

    If you have caches, memoizes etc., then warmup_passes is your friend.

    Default value is 0.

  • tolerate_hits

    How many passes, which considered leaked, should be ingnored, i.e. maximal number of possible false leak reports.

    Even if your code has no leaks, it might cause perl interpreter allocate additional memory pages, e.g. due to memory fragmentation. Those allocations are legal, and should not be treated as leaks.

    Default value is 0.

SOURCE CODE

GitHub

AUTHOR

binary.com, <perl at binary.com>

BUGS

Please report any bugs or feature requests to https://github.com/binary-com/perl-Test-NoLeaks/issues.

LICENSE AND COPYRIGHT

Copyright (C) 2015 binary.com

This program is free software; you can redistribute it and/or modify it under the terms of the the Artistic License (2.0). You may obtain a copy of the full license at:

http://www.perlfoundation.org/artistic_license_2_0

Any use, modification, and distribution of the Standard or Modified Versions is governed by this Artistic License. By using, modifying or distributing the Package, you accept this license. Do not use, modify, or distribute the Package, if you do not accept this license.

If your Modified Version has been derived from a Modified Version made by someone other than you, you are nevertheless required to ensure that your Modified Version complies with the requirements of this license.

This license does not grant you the right to use any trademark, service mark, tradename, or logo of the Copyright Holder.

This license includes the non-exclusive, worldwide, free-of-charge patent license to make, have made, use, offer to sell, sell, import and otherwise transfer the Package with respect to any patent claims licensable by the Copyright Holder that are necessarily infringed by the Package. If you institute patent litigation (including a cross-claim or counterclaim) against any party alleging that the Package constitutes direct or contributory patent infringement, then this Artistic License to you shall terminate on the date that such litigation is filed.

Disclaimer of Warranty: THE PACKAGE IS PROVIDED BY THE COPYRIGHT HOLDER AND CONTRIBUTORS "AS IS' AND WITHOUT ANY EXPRESS OR IMPLIED WARRANTIES. THE IMPLIED WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, OR NON-INFRINGEMENT ARE DISCLAIMED TO THE EXTENT PERMITTED BY YOUR LOCAL LAW. UNLESS REQUIRED BY LAW, NO COPYRIGHT HOLDER OR CONTRIBUTOR WILL BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, OR CONSEQUENTIAL DAMAGES ARISING IN ANY WAY OUT OF THE USE OF THE PACKAGE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.