Transaction helpers

chamber.utils.transaction

smart_atomic(using=None, savepoint=True, ignore_errors=None, reversion=True)

Like django transaction.smart_atomic() decorator chamber atomic can be used for surrounding method, function or block of code with db atomic block. But because we often uses reversion the atomic is surrounded with create_revision decorator. Reversion can be turned off with reversion argument.

pre_commit(callable, using=None)

Similar to django on_commit helper, but callable function is called just before the data is committed to the database. If no atomic block is activated callable is called immediately.

in_atomic_block(callable, using=None)

The function checks if your code is in the atomic block.

chamber.utils.transaction.UniquePreCommitCallable

One time callable is registered and called only once. But all input parameters are stored inside list of kwargs.

class chamber.utils.transaction.UniquePreCommitCallable

handle()

There should be implemented code that will be invoked after success pass though the code.

_get_unique_id()

The uniqueness of the handler must be somehow defined. You must implement this method to define unique identifier of the handler. By default it is identified with has of the class

chamber.models.handlers.InstanceOneTimePreCommitHandler

Special type of unique handler that is identified with itself and model instance of the input model object.

class chamber.utils.transaction.InstanceOneTimePreCommitHandler

_get_instance()

Returns instance stored in input kwargs which is refreshed from database to get actual state of the model object