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#!/usr/bin/env python3
# -*- encoding: utf-8 -*-
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# to you under the Apache License, Version 2.0 (the
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from abc import abstractmethod
class StatefulComponent(object):
"""Defines a component that saves its internal state using the State interface
When running under effectively once semantics, the state is periodically checkpointed
and is replayed when errors occur to a globally consistent checkpoint.
def init_state(self, state):
"""Initializes the state of the function or operator to that of a previous checkpoint.
This method is invoked when a component is executed as part of a recovery run. In case
there was no prior state associated with the component, the state will be empty.
Stateful Spouts/Bolts are expected to hold on to the state variable to save their
internal state
Note that init_state() is called before initialize()
:param state: the previously saved state of the component.
def pre_save(self):
"""This is a hook for the component to perform some actions just before the
framework saves its state.