This repository was archived by the owner on Mar 31, 2026. It is now read-only.
-
Notifications
You must be signed in to change notification settings - Fork 104
Expand file tree
/
Copy pathsnapshot.py
More file actions
747 lines (703 loc) · 28.9 KB
/
snapshot.py
File metadata and controls
747 lines (703 loc) · 28.9 KB
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
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
# Copyright 2016 Google LLC All rights reserved.
#
# 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.
# This file is automatically generated by CrossSync. Do not edit manually.
"""Model a set of read-only queries to a database as a snapshot."""
import functools
from typing import List, Optional, Union
from google.api_core import gapic_v1
from google.api_core.exceptions import (
Aborted,
InternalServerError,
InvalidArgument,
ServiceUnavailable,
)
from google.protobuf.struct_pb2 import Struct
from google.cloud.aio._cross_sync import CrossSync
from google.cloud.spanner_v1._helpers import _retry
from google.cloud.spanner_v1.streamed import StreamedResultSet
from google.cloud.spanner_v1._helpers import (
AtomicCounter,
_augment_error_with_request_id,
_check_rst_stream_error,
_make_value_pb,
_merge_query_options,
_metadata_with_leader_aware_routing,
_metadata_with_prefix,
_SessionWrapper,
_validate_client_context,
_merge_client_context,
_merge_request_options,
)
from google.cloud.spanner_v1._opentelemetry_tracing import add_span_event, trace_call
from google.cloud.spanner_v1.metrics.metrics_capture import MetricsCapture
from google.cloud.spanner_v1.types import MultiplexedSessionPrecommitToken
from google.cloud.spanner_v1.types.mutation import Mutation
from google.cloud.spanner_v1.types.result_set import PartialResultSet, ResultSet
from google.cloud.spanner_v1.types.spanner import (
BeginTransactionRequest,
ExecuteSqlRequest,
PartitionOptions,
PartitionQueryRequest,
PartitionReadRequest,
ReadRequest,
RequestOptions,
)
from google.cloud.spanner_v1.types.transaction import (
Transaction,
TransactionOptions,
TransactionSelector,
)
_STREAM_RESUMPTION_INTERNAL_ERROR_MESSAGES = (
"RST_STREAM",
"Received unexpected EOS on DATA frame from server",
)
def _restart_on_unavailable(
method,
request,
metadata=None,
trace_name=None,
session=None,
attributes=None,
transaction=None,
transaction_selector=None,
observability_options=None,
request_id_manager=None,
resource_info=None,
):
"""Restart iteration after :exc:`.ServiceUnavailable`.
:type method: callable
:param method: function returning iterator
:type request: proto
:param request: request proto to call the method with
:type transaction: :class:`google.cloud.spanner_v1.snapshot._SnapshotBase`
:param transaction: Snapshot or Transaction class object based on the type of transaction
:type transaction_selector: :class:`transaction_pb2.TransactionSelector`
:param transaction_selector: Transaction selector object to be used in request if transaction is not passed,
if both transaction_selector and transaction are passed, then transaction is given priority.
"""
resume_token: bytes = b""
item_buffer: List[PartialResultSet] = []
if transaction is not None:
transaction_selector = transaction._build_transaction_selector_pb()
elif transaction_selector is None:
raise InvalidArgument(
"Either transaction or transaction_selector should be set"
)
request.transaction = transaction_selector
iterator = None
attempt = 1
nth_request = getattr(request_id_manager, "_next_nth_request", 0)
current_request_id = None
while True:
try:
if iterator is None:
with trace_call(
trace_name,
session,
attributes,
observability_options=observability_options,
metadata=metadata,
) as span, MetricsCapture(resource_info):
(
call_metadata,
current_request_id,
) = request_id_manager.metadata_and_request_id(
nth_request, attempt, metadata, span
)
iterator = CrossSync._Sync_Impl.run_if_async(
method, request=request, metadata=call_metadata
)
item: PartialResultSet
for item in iterator:
item_buffer.append(item)
if transaction is not None:
transaction._update_for_result_set_pb(item)
if (
item._pb is not None
and item._pb.HasField("precommit_token")
and (transaction is not None)
):
transaction._update_for_precommit_token_pb(item.precommit_token)
if item.resume_token:
resume_token = item.resume_token
break
except ServiceUnavailable:
del item_buffer[:]
request.resume_token = resume_token
if transaction is not None:
transaction_selector = transaction._build_transaction_selector_pb()
request.transaction = transaction_selector
attempt += 1
iterator = None
continue
except InternalServerError as exc:
resumable_error = any(
(
resumable_message in exc.message
for resumable_message in _STREAM_RESUMPTION_INTERNAL_ERROR_MESSAGES
)
)
if not resumable_error:
raise _augment_error_with_request_id(exc, current_request_id)
del item_buffer[:]
request.resume_token = resume_token
if transaction is not None:
transaction_selector = transaction._build_transaction_selector_pb()
attempt += 1
request.transaction = transaction_selector
iterator = None
continue
except Exception as exc:
raise _augment_error_with_request_id(exc, current_request_id)
if len(item_buffer) == 0:
break
for item in item_buffer:
yield item
del item_buffer[:]
class _SnapshotBase(_SessionWrapper):
"""Base class for Snapshot.
Allows reuse of API request methods with different transaction selector.
:type session: :class:`~google.cloud.spanner_v1.session.Session`
:param session: the session used to perform transaction operations.
"""
_read_only: bool = True
_multi_use: bool = False
def __init__(self, session, client_context=None):
super().__init__(session)
self._client_context = _validate_client_context(client_context)
self._execute_sql_request_count: int = 0
self._read_request_count: int = 0
self._transaction_id: Optional[bytes] = None
self._precommit_token: Optional[MultiplexedSessionPrecommitToken] = None
self._lock: CrossSync._Sync_Impl.Lock = CrossSync._Sync_Impl.Lock()
@property
def _resource_info(self):
"""Resource information for metrics labels."""
database = self._session._database
return {
"project": database._instance._client.project,
"instance": database._instance.instance_id,
"database": database.database_id,
}
def begin(self) -> bytes:
"""Begins a transaction on the database.
:rtype: bytes
:returns: identifier for the transaction.
:raises ValueError: if the transaction has already begun."""
return self._begin_transaction()
def read(
self,
table,
columns,
keyset,
index="",
limit=0,
partition=None,
request_options=None,
data_boost_enabled=False,
directed_read_options=None,
*,
retry=gapic_v1.method.DEFAULT,
timeout=gapic_v1.method.DEFAULT,
column_info=None,
lazy_decode=False,
):
"""Perform a ``StreamingRead`` API request for rows in a table."""
if self._read_request_count > 0:
if not self._multi_use:
raise ValueError("Cannot re-use single-use snapshot.")
if self._transaction_id is None:
raise ValueError("Transaction has not begun.")
session = self._session
database = session._database
api = database.spanner_api
metadata = _metadata_with_prefix(database.name)
if not self._read_only and database._route_to_leader_enabled:
metadata.append(
_metadata_with_leader_aware_routing(database._route_to_leader_enabled)
)
client_context = _merge_client_context(
database._instance._client._client_context, self._client_context
)
request_options = _merge_request_options(request_options, client_context)
if request_options is None:
request_options = RequestOptions()
elif type(request_options) is dict:
request_options = RequestOptions(request_options)
if self._read_only:
request_options.transaction_tag = None
if (
directed_read_options is None
and database._directed_read_options is not None
):
directed_read_options = database._directed_read_options
elif self.transaction_tag is not None:
request_options.transaction_tag = self.transaction_tag
read_request = ReadRequest(
session=session.name,
table=table,
columns=columns,
key_set=keyset._to_pb(),
index=index,
limit=limit,
partition_token=partition,
request_options=request_options,
data_boost_enabled=data_boost_enabled,
directed_read_options=directed_read_options,
)
streaming_read_method = functools.partial(
api.streaming_read,
request=read_request,
metadata=metadata,
retry=retry,
timeout=timeout,
)
return self._get_streamed_result_set(
method=streaming_read_method,
request=read_request,
metadata=metadata,
trace_attributes={
"table_id": table,
"columns": columns,
"request_options": request_options,
},
column_info=column_info,
lazy_decode=lazy_decode,
)
def execute_sql(
self,
sql,
params=None,
param_types=None,
query_mode=None,
query_options=None,
request_options=None,
last_statement=False,
partition=None,
retry=gapic_v1.method.DEFAULT,
timeout=gapic_v1.method.DEFAULT,
data_boost_enabled=False,
directed_read_options=None,
column_info=None,
lazy_decode=False,
):
"""Perform an ``ExecuteStreamingSql`` API request."""
if self._read_request_count > 0:
if not self._multi_use:
raise ValueError("Cannot re-use single-use snapshot.")
if self._transaction_id is None:
raise ValueError("Transaction has not begun.")
if params is not None:
params_pb = Struct(
fields={key: _make_value_pb(value) for key, value in params.items()}
)
else:
params_pb = {}
session = self._session
database = session._database
api = database.spanner_api
metadata = _metadata_with_prefix(database.name)
if not self._read_only and database._route_to_leader_enabled:
metadata.append(
_metadata_with_leader_aware_routing(database._route_to_leader_enabled)
)
default_query_options = database._instance._client._query_options
query_options = _merge_query_options(default_query_options, query_options)
client_context = _merge_client_context(
database._instance._client._client_context, self._client_context
)
request_options = _merge_request_options(request_options, client_context)
if request_options is None:
request_options = RequestOptions()
elif type(request_options) is dict:
request_options = RequestOptions(request_options)
if self._read_only:
request_options.transaction_tag = None
if (
directed_read_options is None
and database._directed_read_options is not None
):
directed_read_options = database._directed_read_options
elif self.transaction_tag is not None:
request_options.transaction_tag = self.transaction_tag
execute_sql_request = ExecuteSqlRequest(
session=session.name,
sql=sql,
params=params_pb,
param_types=param_types,
query_mode=query_mode,
partition_token=partition,
seqno=self._execute_sql_request_count,
query_options=query_options,
request_options=request_options,
last_statement=last_statement,
data_boost_enabled=data_boost_enabled,
directed_read_options=directed_read_options,
)
execute_streaming_sql_method = functools.partial(
api.execute_streaming_sql,
request=execute_sql_request,
metadata=metadata,
retry=retry,
timeout=timeout,
)
return self._get_streamed_result_set(
method=execute_streaming_sql_method,
request=execute_sql_request,
metadata=metadata,
trace_attributes={"db.statement": sql, "request_options": request_options},
column_info=column_info,
lazy_decode=lazy_decode,
)
def _get_streamed_result_set(
self, method, request, metadata, trace_attributes, column_info, lazy_decode
):
"""Returns the streamed result set for a read or execute SQL request."""
session = self._session
database = session._database
is_execute_sql_request = isinstance(request, ExecuteSqlRequest)
trace_method_name = "execute_sql" if is_execute_sql_request else "read"
trace_name = f"CloudSpanner.{type(self).__name__}.{trace_method_name}"
is_inline_begin = False
if self._transaction_id is None:
is_inline_begin = True
self._lock.acquire()
try:
iterator = _restart_on_unavailable(
method=method,
request=request,
session=session,
metadata=metadata,
trace_name=trace_name,
attributes=trace_attributes,
transaction=self,
observability_options=getattr(database, "observability_options", None),
request_id_manager=database,
resource_info=self._resource_info,
)
if is_execute_sql_request:
self._execute_sql_request_count += 1
self._read_request_count += 1
streamed_result_set_args = {
"response_iterator": iterator,
"column_info": column_info,
"lazy_decode": lazy_decode,
}
if self._multi_use:
streamed_result_set_args["source"] = self
return StreamedResultSet(**streamed_result_set_args)
finally:
if is_inline_begin:
self._lock.release()
def partition_read(
self,
table,
columns,
keyset,
index="",
partition_size_bytes=None,
max_partitions=None,
*,
retry=gapic_v1.method.DEFAULT,
timeout=gapic_v1.method.DEFAULT,
):
"""Perform a ``PartitionRead`` API request for rows in a table."""
if self._transaction_id is None:
raise ValueError("Transaction has not begun.")
if not self._multi_use:
raise ValueError("Cannot partition a single-use transaction.")
session = self._session
database = session._database
api = database.spanner_api
metadata = _metadata_with_prefix(database.name)
if database._route_to_leader_enabled:
metadata.append(
_metadata_with_leader_aware_routing(database._route_to_leader_enabled)
)
transaction = self._build_transaction_selector_pb()
partition_options = PartitionOptions(
partition_size_bytes=partition_size_bytes, max_partitions=max_partitions
)
partition_read_request = PartitionReadRequest(
session=session.name,
table=table,
columns=columns,
key_set=keyset._to_pb(),
transaction=transaction,
index=index,
partition_options=partition_options,
)
trace_attributes = {"table_id": table, "columns": columns}
can_include_index = index != "" and index is not None
if can_include_index:
trace_attributes["index"] = index
with trace_call(
f"CloudSpanner.{type(self).__name__}.partition_read",
session,
extra_attributes=trace_attributes,
observability_options=getattr(database, "observability_options", None),
metadata=metadata,
) as span, MetricsCapture(self._resource_info):
nth_request = getattr(database, "_next_nth_request", 0)
attempt = AtomicCounter()
def attempt_tracking_method():
all_metadata = database.metadata_with_request_id(
nth_request, attempt.increment(), metadata, span
)
partition_read_method = functools.partial(
api.partition_read,
request=partition_read_request,
metadata=all_metadata,
retry=retry,
timeout=timeout,
)
return partition_read_method()
response = _retry(
attempt_tracking_method,
allowed_exceptions={InternalServerError: _check_rst_stream_error},
)
return [partition.partition_token for partition in response.partitions]
def partition_query(
self,
sql,
params=None,
param_types=None,
partition_size_bytes=None,
max_partitions=None,
*,
retry=gapic_v1.method.DEFAULT,
timeout=gapic_v1.method.DEFAULT,
):
"""Perform a ``PartitionQuery`` API request."""
if self._transaction_id is None:
raise ValueError("Transaction has not begun.")
if not self._multi_use:
raise ValueError("Cannot partition a single-use transaction.")
if params is not None:
params_pb = Struct(
fields={key: _make_value_pb(value) for key, value in params.items()}
)
else:
params_pb = Struct()
session = self._session
database = session._database
api = database.spanner_api
metadata = _metadata_with_prefix(database.name)
if database._route_to_leader_enabled:
metadata.append(
_metadata_with_leader_aware_routing(database._route_to_leader_enabled)
)
transaction = self._build_transaction_selector_pb()
partition_options = PartitionOptions(
partition_size_bytes=partition_size_bytes, max_partitions=max_partitions
)
partition_query_request = PartitionQueryRequest(
session=session.name,
sql=sql,
transaction=transaction,
params=params_pb,
param_types=param_types,
partition_options=partition_options,
)
trace_attributes = {"db.statement": sql}
with trace_call(
f"CloudSpanner.{type(self).__name__}.partition_query",
session,
trace_attributes,
observability_options=getattr(database, "observability_options", None),
metadata=metadata,
) as span, MetricsCapture(self._resource_info):
nth_request = getattr(database, "_next_nth_request", 0)
attempt = AtomicCounter()
def attempt_tracking_method():
all_metadata = database.metadata_with_request_id(
nth_request, attempt.increment(), metadata, span
)
partition_query_method = functools.partial(
api.partition_query,
request=partition_query_request,
metadata=all_metadata,
retry=retry,
timeout=timeout,
)
return partition_query_method()
response = _retry(
attempt_tracking_method,
allowed_exceptions={InternalServerError: _check_rst_stream_error},
)
return [partition.partition_token for partition in response.partitions]
def _begin_transaction(
self, mutation: Mutation = None, transaction_tag: str = None
) -> bytes:
"""Begins a transaction on the database."""
if self._transaction_id is not None:
raise ValueError("Transaction has already begun.")
if not self._multi_use:
raise ValueError("Cannot begin a single-use transaction.")
if self._read_request_count > 0:
raise ValueError("Read-only transaction already pending")
session = self._session
database = session._database
api = database.spanner_api
metadata = _metadata_with_prefix(database.name)
if not self._read_only and database._route_to_leader_enabled:
metadata.append(
_metadata_with_leader_aware_routing(database._route_to_leader_enabled)
)
begin_request_kwargs = {
"session": session.name,
"options": self._build_transaction_selector_pb().begin,
"mutation_key": mutation,
}
request_options = begin_request_kwargs.get("request_options")
client_context = _merge_client_context(
database._instance._client._client_context, self._client_context
)
request_options = _merge_request_options(request_options, client_context)
if transaction_tag:
if request_options is None:
request_options = RequestOptions()
request_options.transaction_tag = transaction_tag
if request_options:
begin_request_kwargs["request_options"] = request_options
with trace_call(
name=f"CloudSpanner.{type(self).__name__}.begin",
session=session,
observability_options=getattr(database, "observability_options", None),
metadata=metadata,
) as span, MetricsCapture(self._resource_info):
nth_request = getattr(database, "_next_nth_request", 0)
attempt = AtomicCounter()
def wrapped_method():
begin_transaction_request = BeginTransactionRequest(
**begin_request_kwargs
)
call_metadata, error_augmenter = database.with_error_augmentation(
nth_request, attempt.increment(), metadata, span
)
begin_transaction_method = functools.partial(
api.begin_transaction,
request=begin_transaction_request,
metadata=call_metadata,
)
with error_augmenter:
return begin_transaction_method()
def before_next_retry(nth_retry, delay_in_seconds):
add_span_event(
span=span,
event_name="Transaction Begin Attempt Failed. Retrying",
event_attributes={
"attempt": nth_retry,
"sleep_seconds": delay_in_seconds,
},
)
transaction_pb: Transaction = _retry(
wrapped_method,
before_next_retry=before_next_retry,
allowed_exceptions={
InternalServerError: _check_rst_stream_error,
Aborted: None,
},
)
self._update_for_transaction_pb(transaction_pb)
return self._transaction_id
def _build_transaction_options_pb(self) -> TransactionOptions:
"""Builds and returns the transaction options for this snapshot."""
raise NotImplementedError
def _build_transaction_selector_pb(self) -> TransactionSelector:
"""Builds and returns a transaction selector for this snapshot."""
if self._transaction_id is not None:
return TransactionSelector(id=self._transaction_id)
options = self._build_transaction_options_pb()
if not self._multi_use:
return TransactionSelector(single_use=options)
return TransactionSelector(begin=options)
def _update_for_result_set_pb(
self, result_set_pb: Union[ResultSet, PartialResultSet]
) -> None:
"""Updates the snapshot for the given result set."""
if result_set_pb.metadata and result_set_pb.metadata.transaction:
self._update_for_transaction_pb(result_set_pb.metadata.transaction)
def _update_for_transaction_pb(self, transaction_pb: Transaction) -> None:
"""Updates the snapshot for the given transaction."""
if self._transaction_id is None and transaction_pb.id:
self._transaction_id = transaction_pb.id
if transaction_pb._pb.HasField("precommit_token"):
self._update_for_precommit_token_pb_unsafe(transaction_pb.precommit_token)
def _update_for_precommit_token_pb(
self, precommit_token_pb: MultiplexedSessionPrecommitToken
) -> None:
"""Updates the snapshot for the given multiplexed session precommit token."""
with self._lock:
self._update_for_precommit_token_pb_unsafe(precommit_token_pb)
def _update_for_precommit_token_pb_unsafe(
self, precommit_token_pb: MultiplexedSessionPrecommitToken
) -> None:
"""Updates the snapshot for the given multiplexed session precommit token."""
if (
self._precommit_token is None
or precommit_token_pb.seq_num > self._precommit_token.seq_num
):
self._precommit_token = precommit_token_pb
class Snapshot(_SnapshotBase):
"""Allow a set of reads / SQL statements with shared staleness."""
def __init__(
self,
session,
read_timestamp=None,
min_read_timestamp=None,
max_staleness=None,
exact_staleness=None,
multi_use=False,
transaction_id=None,
client_context=None,
):
super(Snapshot, self).__init__(session, client_context=client_context)
opts = [read_timestamp, min_read_timestamp, max_staleness, exact_staleness]
flagged = [opt for opt in opts if opt is not None]
if len(flagged) > 1:
raise ValueError("Supply zero or one options.")
if multi_use:
if min_read_timestamp is not None or max_staleness is not None:
raise ValueError(
"'multi_use' is incompatible with 'min_read_timestamp' / 'max_staleness'"
)
self._transaction_read_timestamp = None
self._strong = len(flagged) == 0
self._read_timestamp = read_timestamp
self._min_read_timestamp = min_read_timestamp
self._max_staleness = max_staleness
self._exact_staleness = exact_staleness
self._multi_use = multi_use
self._transaction_id = transaction_id
def _build_transaction_options_pb(self) -> TransactionOptions:
"""Builds and returns transaction options for this snapshot."""
read_only_pb_args = dict(return_read_timestamp=True)
if self._read_timestamp:
read_only_pb_args["read_timestamp"] = self._read_timestamp
elif self._min_read_timestamp:
read_only_pb_args["min_read_timestamp"] = self._min_read_timestamp
elif self._max_staleness:
read_only_pb_args["max_staleness"] = self._max_staleness
elif self._exact_staleness:
read_only_pb_args["exact_staleness"] = self._exact_staleness
else:
read_only_pb_args["strong"] = True
read_only_pb = TransactionOptions.ReadOnly(**read_only_pb_args)
return TransactionOptions(read_only=read_only_pb)
def _update_for_transaction_pb(self, transaction_pb: Transaction) -> None:
"""Updates the snapshot for the given transaction."""
super(Snapshot, self)._update_for_transaction_pb(transaction_pb)
if transaction_pb.read_timestamp is not None:
self._transaction_read_timestamp = transaction_pb.read_timestamp