1# Copyright 2019 Google LLC 2# 3# Licensed under the Apache License, Version 2.0 (the "License"); 4# you may not use this file except in compliance with the License. 5# You may obtain a copy of the License at 6# 7# http://www.apache.org/licenses/LICENSE-2.0 8# 9# Unless required by applicable law or agreed to in writing, software 10# distributed under the License is distributed on an "AS IS" BASIS, 11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 12# See the License for the specific language governing permissions and 13# limitations under the License. 14 15"""Provides the 'ExternalDataset' implementation of tf.Data.Dataset. 16 17This wraps the generated op (in external_dataset_py_wrapper). 18""" 19 20from __future__ import absolute_import 21from __future__ import division 22from __future__ import print_function 23 24 25import tensorflow as tf 26 27from fcp.tensorflow import gen_external_dataset_py 28 29_external_dataset_so = tf.load_op_library( 30 tf.compat.v1.resource_loader.get_path_to_datafile( 31 "./_external_dataset_op.so")) 32 33 34class ExternalDataset(tf.data.Dataset): 35 """An ExternalDataset is defined by whomever is running the graph. 36 37 To use an ExternalDataset, the graph must be fed a 'token' indicating what 38 external dataset to use. It also takes a 'selector' input - an opaque string, 39 to be interpreted by that external implementation. 40 """ 41 42 def __init__(self, token, selector): 43 token = tf.convert_to_tensor(token, dtype=tf.string, name="token") 44 selector = tf.convert_to_tensor(selector, dtype=tf.string, name="selector") 45 variant_tensor = gen_external_dataset_py.ExternalDataset( 46 token=token, selector=selector) 47 super(ExternalDataset, self).__init__(variant_tensor) 48 49 @property 50 def element_spec(self): 51 return tf.TensorSpec([], tf.string) 52 53 def _inputs(self): 54 return [] 55