/ 
DBIx-Class-Async-0.33
/ DBIx::Class::Async::TxnGuard

NAME

DBIx::Class::Async::TxnGuard - Transaction guard for DBIx::Class::Async

VERSION

Version 0.33

SYNOPSIS

use DBIx::Class::Async::TxnGuard;

# Typically created by DBIx::Class::Async::Schema
my $guard = $schema->txn_scope_guard;

# Perform async operations
$schema->resultset('User')->create({
    name  => 'Alice',
    email => 'alice@example.com',
})->then(sub {
    my ($user) = @_;
    # If successful, commit the transaction
    $guard->commit;
    return Future->done($user);
})->catch(sub {
    my ($error) = @_;
    # On error, rollback (automatic when $guard goes out of scope)
    return Future->fail($error);
});

# OR use with scope guard pattern
{
    my $guard = $schema->txn_scope_guard;

    # Multiple async operations
    my $result1 = $schema->resultset('User')->find(1);
    my $result2 = $schema->resultset('Order')->create({ user_id => 1 });

    # Wait for both to complete
    Future->wait_all($result1, $result2)->then(sub {
        # Both succeeded - commit
        $guard->commit;
    })->catch(sub {
        # One failed - rollback (automatic)
    });
    # $guard goes out of scope here
    # If not committed, auto-rollback occurs
}

DESCRIPTION

DBIx::Class::Async::TxnGuard provides a transaction guard object for managing database transactions in DBIx::Class::Async. It implements the scope guard pattern where a transaction is automatically rolled back if the guard object is destroyed without an explicit commit.

This class is typically created by calling txn_scope_guard on a DBIx::Class::Async::Schema instance and is used to manage transaction boundaries in asynchronous code.

CONSTRUCTOR

new

my $guard = DBIx::Class::Async::TxnGuard->new(
    schema => $schema,  # DBIx::Class::Async::Schema instance
);

Creates a new transaction guard.

Parameters
schema

A DBIx::Class::Async::Schema instance. Required.

Returns

A new DBIx::Class::Async::TxnGuard object.

METHODS

commit

$guard->commit;

Marks the transaction for commit.

Returns

True (1) on success.

Notes

Calling this method prevents the automatic rollback that would normally occur when the guard object is destroyed. The actual commit operation is performed by the underlying transaction management system.

rollback

$guard->rollback;

Marks the transaction for rollback.

Returns

True (1) on success.

Notes

This method is called automatically by the destructor if commit was not called. It signals to the underlying transaction management system that the transaction should be rolled back.

DESTROY

When a DBIx::Class::Async::TxnGuard object is destroyed (goes out of scope), its destructor automatically calls rollback unless commit was explicitly called. This implements the scope guard pattern:

{
    my $guard = $schema->txn_scope_guard;
    # ... perform operations ...
    # If $guard goes out of scope without commit(),
    # rollback happens automatically
}

This ensures that transactions are properly cleaned up even if exceptions occur or the code path doesn't reach an explicit commit call.

USAGE PATTERNS

Basic Scope Guard

{
    my $guard = $schema->txn_scope_guard;

    # Perform async operations
    $schema->resultset('User')->create($data)
           ->then(sub  { $guard->commit })
           ->catch(sub { # rollback happens automatically });

    # $guard goes out of scope here
    # Auto-rollback if not committed
}

Manual Control

my $guard = $schema->txn_scope_guard;

# Long-running operations
perform_async_work()->then(sub {
    if (successful) {
        $guard->commit;
    }
    # No need to explicitly rollback - it happens on destruction
});

# Keep $guard in scope until work is complete
undef $guard;  # Force destruction if needed

Nested Transactions

# Outer transaction
my $outer_guard = $schema->txn_scope_guard;

# Some operations
$schema->resultset('User')->update($update_data);

{
    # Inner transaction (savepoint)
    my $inner_guard = $schema->txn_scope_guard;

    $schema->resultset('Order')->create($order_data)
        ->then(sub { $inner_guard->commit })
        ->catch(sub {
            # Inner transaction rolls back
            # Outer transaction continues
        });

    # $inner_guard goes out of scope
}

# Continue with outer transaction
$outer_guard->commit;

LIMITATIONS

  • The actual transaction management is handled by the underlying DBIx::Class::Async system. This class only provides the guard interface.

  • In asynchronous contexts, the timing of transaction boundaries can be complex. Ensure all async operations within a transaction complete before the guard goes out of scope.

  • Nested transactions may not be fully supported by all database backends in the async worker model.

SEE ALSO

AUTHOR

Mohammad Sajid Anwar, <mohammad.anwar at yahoo.com>

REPOSITORY

https://github.com/manwar/DBIx-Class-Async

BUGS

Please report any bugs or feature requests through the web interface at https://github.com/manwar/DBIx-Class-Async/issues. I will be notified and then you'll automatically be notified of progress on your bug as I make changes.

SUPPORT

You can find documentation for this module with the perldoc command.

perldoc DBIx::Class::Async::TxnGuard

You can also look for information at:

LICENSE AND COPYRIGHT

Copyright (C) 2026 Mohammad Sajid Anwar.

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.