212 lines
8.2 KiB
Python
212 lines
8.2 KiB
Python
# Copyright 2019 The TensorFlow Authors. All Rights Reserved.
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#
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# Licensed under the Apache License, Version 2.0 (the "License");
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# you may not use this file except in compliance with the License.
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# You may obtain a copy of the License at
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#
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# http://www.apache.org/licenses/LICENSE-2.0
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#
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# Unless required by applicable law or agreed to in writing, software
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# distributed under the License is distributed on an "AS IS" BASIS,
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# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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# See the License for the specific language governing permissions and
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# limitations under the License.
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# ==============================================================================
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"""Classes and functions implementing Layer SavedModel serialization."""
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import tensorflow.compat.v2 as tf
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from keras.mixed_precision import policy
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from keras.saving.legacy import serialization
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from keras.saving.legacy.saved_model import base_serialization
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from keras.saving.legacy.saved_model import constants
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from keras.saving.legacy.saved_model import save_impl
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from keras.saving.legacy.saved_model import serialized_attributes
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class LayerSavedModelSaver(base_serialization.SavedModelSaver):
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"""Implements Layer SavedModel serialization."""
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@property
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def object_identifier(self):
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return constants.LAYER_IDENTIFIER
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@property
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def python_properties(self):
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# TODO(kathywu): Add python property validator
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return self._python_properties_internal()
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def _python_properties_internal(self):
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"""Returns dictionary of all python properties."""
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# TODO(kathywu): Add support for metrics serialization.
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# TODO(kathywu): Synchronize with the keras spec (go/keras-json-spec)
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# once the python config serialization has caught up.
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metadata = dict(
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name=self.obj.name,
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trainable=self.obj.trainable,
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expects_training_arg=self.obj._expects_training_arg,
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dtype=policy.serialize(self.obj._dtype_policy),
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batch_input_shape=getattr(self.obj, "_batch_input_shape", None),
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stateful=self.obj.stateful,
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must_restore_from_config=self.obj._must_restore_from_config,
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preserve_input_structure_in_config=self.obj._preserve_input_structure_in_config, # noqa: E501
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autocast=self.obj._autocast,
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)
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metadata.update(get_serialized(self.obj))
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if self.obj.input_spec is not None:
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# Layer's input_spec has already been type-checked in the property
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# setter.
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metadata["input_spec"] = tf.nest.map_structure(
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lambda x: serialization.serialize_keras_object(x)
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if x
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else None,
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self.obj.input_spec,
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)
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if self.obj.activity_regularizer is not None and hasattr(
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self.obj.activity_regularizer, "get_config"
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):
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metadata[
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"activity_regularizer"
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] = serialization.serialize_keras_object(
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self.obj.activity_regularizer
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)
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if self.obj._build_input_shape is not None:
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metadata["build_input_shape"] = self.obj._build_input_shape
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return metadata
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def objects_to_serialize(self, serialization_cache):
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return self._get_serialized_attributes(
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serialization_cache
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).objects_to_serialize
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def functions_to_serialize(self, serialization_cache):
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return self._get_serialized_attributes(
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serialization_cache
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).functions_to_serialize
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def _get_serialized_attributes(self, serialization_cache):
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"""Generates or retrieves serialized attributes from cache."""
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keras_cache = serialization_cache.setdefault(
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constants.KERAS_CACHE_KEY, {}
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)
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if self.obj in keras_cache:
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return keras_cache[self.obj]
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serialized_attr = keras_cache[
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self.obj
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] = serialized_attributes.SerializedAttributes.new(self.obj)
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if (
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save_impl.should_skip_serialization(self.obj)
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or self.obj._must_restore_from_config
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):
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return serialized_attr
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object_dict, function_dict = self._get_serialized_attributes_internal(
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serialization_cache
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)
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serialized_attr.set_and_validate_objects(object_dict)
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serialized_attr.set_and_validate_functions(function_dict)
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return serialized_attr
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def _get_serialized_attributes_internal(self, serialization_cache):
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"""Returns dictionary of serialized attributes."""
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objects = save_impl.wrap_layer_objects(self.obj, serialization_cache)
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functions = save_impl.wrap_layer_functions(
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self.obj, serialization_cache
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)
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# Attribute validator requires that the default save signature is added
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# to function dict, even if the value is None.
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functions["_default_save_signature"] = None
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return objects, functions
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# TODO(kathywu): Move serialization utils (and related utils from
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# generic_utils.py) to a separate file.
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def get_serialized(obj):
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with serialization.skip_failed_serialization():
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# Store the config dictionary, which may be used when reviving the
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# object. When loading, the program will attempt to revive the object
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# from config, and if that fails, the object will be revived from the
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# SavedModel.
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return serialization.serialize_keras_object(obj)
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class InputLayerSavedModelSaver(base_serialization.SavedModelSaver):
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"""InputLayer serialization."""
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@property
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def object_identifier(self):
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return constants.INPUT_LAYER_IDENTIFIER
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@property
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def python_properties(self):
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return dict(
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class_name=type(self.obj).__name__,
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name=self.obj.name,
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dtype=self.obj.dtype,
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sparse=self.obj.sparse,
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ragged=self.obj.ragged,
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batch_input_shape=self.obj._batch_input_shape,
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config=self.obj.get_config(),
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)
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def objects_to_serialize(self, serialization_cache):
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return {}
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def functions_to_serialize(self, serialization_cache):
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return {}
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class RNNSavedModelSaver(LayerSavedModelSaver):
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"""RNN layer serialization."""
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@property
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def object_identifier(self):
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return constants.RNN_LAYER_IDENTIFIER
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def _get_serialized_attributes_internal(self, serialization_cache):
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objects, functions = super()._get_serialized_attributes_internal(
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serialization_cache
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)
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states = tf.__internal__.tracking.wrap(self.obj.states)
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# SaveModel require all the objects to be Trackable when saving. If the
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# states is still a tuple after wrap_or_unwrap, it means it doesn't
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# contain any trackable item within it, eg empty tuple or (None, None)
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# for stateless ConvLSTM2D. We convert them to list so that
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# wrap_or_unwrap can make it a Trackable again for saving. When loaded,
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# ConvLSTM2D is able to handle the tuple/list conversion.
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if isinstance(states, tuple):
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states = tf.__internal__.tracking.wrap(list(states))
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objects["states"] = states
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return objects, functions
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class VocabularySavedModelSaver(LayerSavedModelSaver):
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"""Handles vocabulary layer serialization.
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This class is needed for StringLookup, IntegerLookup, and TextVectorization,
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which all have a vocabulary as part of the config. Currently, we keep this
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vocab as part of the config until saving, when we need to clear it to avoid
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initializing a StaticHashTable twice (once when restoring the config and
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once when restoring restoring module resources). After clearing the vocab,
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we persist a property to the layer indicating it was constructed with a
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vocab.
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"""
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@property
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def python_properties(self):
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# TODO(kathywu): Add python property validator
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metadata = self._python_properties_internal()
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# Clear the vocabulary from the config during saving.
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metadata["config"]["vocabulary"] = None
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# Persist a property to track that a vocabulary was passed on
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# construction.
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metadata["config"][
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"has_input_vocabulary"
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] = self.obj._has_input_vocabulary
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return metadata
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