KiokuDB::Backend::Role::TXN - Backend level transaction support.

    package MyBackend;
    use Moose;

    with qw(
        KiokuDB::Backend
        KiokuDB::Backend::Role::TXN
    );

    sub txn_begin { ... }
    sub txn_commit { ... }
    sub txn_rollback { ... }

This API is inspired by standard database transactions much like you get with DBI.

This is the low level interface required by txn_do in KiokuDB.

txn_do $code, %callbacks

This method should evaluate the code reference in the context of a transaction, inside an eval. If any errors are caught the transaction should be aborted, otherwise it should be committed. This is much like txn_do in DBIx::Class::Schema.

The rollback callback should be fired when the transaction will be aborted.

txn_begin [ $parent_txn ]

Begin a new transaction.

This method can return a transaction handle that will later be passed to txn_commit or txn_rollback as necessary.

The current handle will be passed to nested calls to txn_begin.

txn_commit $txn

Commit the transaction.

txn_rollback $txn

Rollback the transaction.