Transaction helpers

chamber.utils.transaction.atomic

atomic()

Like django transaction.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

transaction_signals()

Decorator that is used for automatic invoking on success signals. Function or handler registered with on_success function is executed if block of code will not thrown exception. Its behaviour is very similar to atomic block, if you will inherit these decorators the event will be invoked until after the completion of last decorated code.

atomic_with_signals()

Combination of atomic and transaction_signals.

on_success()

Function for on success handlers registration. If thransaction signals are not activated (decorator transaction_signals is not used) the handler will be invoked immediately.

chamber.utils.transaction.OnSuccessHandler

Handler that can be used for implementation tasks that should be called only after successful pass throught code. Hanlder is automatically registered inside its constructior.

class chamber.utils.transaction.OnSuccessHandler

__init__(using=None, **kwargs)

Constructor of success handler accepts input data in kwargs and using where you can define database

handle(**kwargs)

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

chamber.utils.transaction.OneTimeOnSuccessHandler

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

class chamber.utils.transaction.OneTimeOnSuccessHandler

handle(**kwargs_list)

There should be implemented code that will be invoked after success pass though the code. Difference from OnSuccessHandler.handle is that kwargs is stored inside list in the order how handlers was created

_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.utils.transaction.InstanceOneTimeOnSuccessHandler

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

class chamber.utils.transaction.InstanceOneTimeOnSuccessHandler

_get_instance()

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