tf.estimator.CheckpointSaverListener

Interface for listeners that take action before or after checkpoint save.

View aliases

Compat aliases for migration

See Migration guide for more details.

tf.compat.v1.estimator.CheckpointSaverListener, tf.compat.v1.train.CheckpointSaverListener

CheckpointSaverListener triggers only in steps when CheckpointSaverHook is triggered, and provides callbacks at the following points:

• before using the session
• before each call to Saver.save()
• after each call to Saver.save()
• at the end of session

To use a listener, implement a class and pass the listener to a CheckpointSaverHook, as in this example:

class ExampleCheckpointSaverListener(CheckpointSaverListener):
  def begin(self):
    # You can add ops to the graph here.
    print('Starting the session.')
    self.your_tensor = ...

  def before_save(self, session, global_step_value):
    print('About to write a checkpoint')

  def after_save(self, session, global_step_value):
    print('Done writing checkpoint.')
    if decided_to_stop_training():
      return True

  def end(self, session, global_step_value):
    print('Done with the session.')

...
listener = ExampleCheckpointSaverListener()
saver_hook = tf.estimator.CheckpointSaverHook(
    checkpoint_dir, listeners=[listener])
with
tf.compat.v1.train.MonitoredTrainingSession(chief_only_hooks=[saver_hook]):
  ...

A CheckpointSaverListener may simply take some action after every checkpoint save. It is also possible for the listener to use its own schedule to act less frequently, e.g. based on global_step_value. In this case, implementors should implement the end() method to handle actions related to the last checkpoint save. But the listener should not act twice if after_save() already handled this last checkpoint save.

A CheckpointSaverListener can request training to be stopped, by returning True in after_save. Please note that, in replicated distributed training setting, only chief should use this behavior. Otherwise each worker will do their own evaluation, which may be wasteful of resources.

Methods

after_save

View source

after_save(
    session, global_step_value
)

before_save

View source

before_save(
    session, global_step_value
)

begin

View source

begin()

end

View source

end(
    session, global_step_value
)