1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
|
/*
* Copyright 2019 Google LLC
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
#include <string>
#include <utility>
#include "absl/strings/str_format.h"
#include "fcp/base/random_token.h"
#include "fcp/tensorflow/external_dataset.h"
#include "fcp/tensorflow/status.h"
#include "tensorflow/core/framework/common_shape_fns.h"
#include "tensorflow/core/framework/dataset.h"
#include "tensorflow/core/framework/op.h"
#include "tensorflow/core/framework/shape_inference.h"
#include "tensorflow/core/lib/core/errors.h"
#include "tensorflow/core/public/version.h"
namespace fcp {
/**
* ExternalDataset op-kernel. Delegates to an ExternalDatasetProvider, found
* from the ExternalDatasetProviderRegistry (a HostObjectRegistry).
*
* Inputs:
* selector: An opaque string scalar. Forwarded to the stub.
* token: String scalar. It should encode a token obtained from
* ExternalDatasetProviderRegistry::Register.
*
* See TensorFlow's guide to making custom dataset ops:
* https://www.tensorflow.org/guide/extend/formats
*/
class ExternalDatasetOp : public tensorflow::data::DatasetOpKernel {
public:
using tensorflow::data::DatasetOpKernel::DatasetOpKernel;
void MakeDataset(tensorflow::OpKernelContext* ctx,
tensorflow::data::DatasetBase** output) override {
tensorflow::tstring token_str;
OP_REQUIRES_OK(ctx,
tensorflow::data::ParseScalarArgument<tensorflow::tstring>(
ctx, "token", &token_str));
absl::Span<char const> token_bytes = token_str;
OP_REQUIRES(ctx, token_bytes.size() == kRandomTokenSizeInBytes,
tensorflow::errors::InvalidArgument(absl::StrFormat(
"Tokens have a fixed size. Expected: %d; Actual %d",
kRandomTokenSizeInBytes, token_bytes.size())));
RandomToken token = RandomToken::FromBytes(token_bytes);
tensorflow::tstring selector_str;
OP_REQUIRES_OK(ctx,
tensorflow::data::ParseScalarArgument<tensorflow::tstring>(
ctx, "selector", &selector_str));
std::optional<std::shared_ptr<ExternalDatasetProvider>> maybe_provider =
ExternalDatasetProviderRegistry::TryLookup(token);
OP_REQUIRES(ctx, maybe_provider.has_value(),
tensorflow::errors::InvalidArgument(
"A dataset provider is not currently registered for the "
"provided token: ",
token.ToPrintableString()));
std::shared_ptr<ExternalDatasetProvider> provider =
*std::move(maybe_provider);
StatusOr<std::unique_ptr<ExternalDataset>> maybe_dataset =
provider->MakeDataset(selector_str);
// The provider might not like the given selector.
if (!maybe_dataset.ok()) {
ctx->SetStatus(ConvertToTensorFlowStatus(maybe_dataset.status()));
return;
}
*output = new Dataset(ctx, std::move(maybe_dataset).value());
}
private:
class Dataset : public tensorflow::data::DatasetBase {
public:
Dataset(tensorflow::OpKernelContext* ctx,
std::unique_ptr<ExternalDataset> stub)
: DatasetBase(tensorflow::data::DatasetContext(ctx)),
stub_(std::move(stub)) {}
std::unique_ptr<tensorflow::data::IteratorBase> MakeIteratorInternal(
const std::string& prefix) const override {
std::unique_ptr<ExternalDatasetIterator> iter = stub_->MakeIterator();
Iterator::Params params{
this, tensorflow::strings::StrCat(prefix, "::ExternalDataset")};
return std::unique_ptr<tensorflow::data::IteratorBase>(
new Iterator(params, std::move(iter)));
}
// Each iterator element is just a scalar string.
const tensorflow::DataTypeVector& output_dtypes() const override {
static auto* const dtypes =
new tensorflow::DataTypeVector({tensorflow::DT_STRING});
return *dtypes;
}
const std::vector<tensorflow::PartialTensorShape>& output_shapes()
const override {
static std::vector<tensorflow::PartialTensorShape>* shapes =
new std::vector<tensorflow::PartialTensorShape>({{}});
return *shapes;
}
std::string DebugString() const override {
return "ExternalDatasetOp::Dataset";
}
tensorflow::Status InputDatasets(
std::vector<const DatasetBase*>* inputs) const override {
// ExternalDatast has no input datasets, so just return OK.
return tensorflow::OkStatus();
}
// The `DatasetBase::CheckExternalState()` method was introduced on 8/7/2019. We
// use the `TF_GRAPH_DEF_VERSION` value (which is updated daily) to determine if
// we should add its override.
#if TF_GRAPH_DEF_VERSION > 125
tensorflow::Status CheckExternalState() const override {
return tensorflow::OkStatus();
}
#endif
protected:
tensorflow::Status AsGraphDefInternal(
tensorflow::data::SerializationContext* ctx, DatasetGraphDefBuilder* b,
tensorflow::Node** output) const override {
return ::tensorflow::errors::Unimplemented(
DebugString(), " does not support serialization.");
}
private:
class Iterator : public tensorflow::data::DatasetIterator<Dataset> {
public:
explicit Iterator(const Params& params,
std::unique_ptr<ExternalDatasetIterator> stub)
: DatasetIterator<Dataset>(params), stub_(std::move(stub)) {}
tensorflow::Status GetNextInternal(
tensorflow::data::IteratorContext* ctx,
std::vector<tensorflow::Tensor>* out_tensors,
bool* end_of_sequence) override {
StatusOr<std::string> maybe_element;
{
absl::MutexLock _(&mu_);
maybe_element = stub_->GetNext();
}
if (maybe_element.ok()) {
std::string element = std::move(maybe_element).value();
// The {} at the end specifies a scalar tensor.
tensorflow::Tensor element_tensor(ctx->allocator({}),
tensorflow::DT_STRING, {});
element_tensor.scalar<tensorflow::tstring>()() = element;
*end_of_sequence = false;
out_tensors->push_back(std::move(element_tensor));
return tensorflow::OkStatus();
} else {
*end_of_sequence = true;
if (maybe_element.status().code() == StatusCode::kOutOfRange) {
return tensorflow::OkStatus();
} else {
return ConvertToTensorFlowStatus(maybe_element.status());
}
}
}
protected:
tensorflow::Status SaveInternal(
// `::tensorflow::data::SerializationContext` argument was added on
// 2020-03-17 when `TF_GRAPH_DEF_VERSION` was defined to 343.
#if TF_GRAPH_DEF_VERSION > 343
tensorflow::data::SerializationContext* ctx,
#endif
tensorflow::data::IteratorStateWriter* writer) override {
return ::tensorflow::errors::Unimplemented(
"Save / Restore of an ExternalDataset iterator is not supported");
}
tensorflow::Status RestoreInternal(
tensorflow::data::IteratorContext* ctx,
tensorflow::data::IteratorStateReader* reader) override {
return ::tensorflow::errors::Unimplemented(
"Save / Restore of an ExternalDataset iterator is not supported");
}
private:
std::unique_ptr<ExternalDatasetIterator> stub_;
absl::Mutex mu_;
};
// Private members of Dataset
std::unique_ptr<ExternalDataset> stub_;
};
};
REGISTER_OP("ExternalDataset")
.Input("token: string")
.Input("selector: string")
.Output("handle: variant")
.SetIsStateful()
.SetShapeFn(tensorflow::shape_inference::ScalarShape);
REGISTER_KERNEL_BUILDER(Name("ExternalDataset").Device(tensorflow::DEVICE_CPU),
ExternalDatasetOp);
} // namespace fcp
|
