forked from apache/cassandra-python-driver
-
Notifications
You must be signed in to change notification settings - Fork 0
Expand file tree
/
Copy pathconnection.py
More file actions
1137 lines (965 loc) · 43.3 KB
/
connection.py
File metadata and controls
1137 lines (965 loc) · 43.3 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
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
# Copyright DataStax, Inc.
#
# 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.
from __future__ import absolute_import # to enable import io from stdlib
from collections import defaultdict, deque
import errno
from functools import wraps, partial
from heapq import heappush, heappop
import io
import logging
import six
from six.moves import range
import socket
import struct
import sys
from threading import Thread, Event, RLock
import time
try:
import ssl
except ImportError:
ssl = None # NOQA
if 'gevent.monkey' in sys.modules:
from gevent.queue import Queue, Empty
else:
from six.moves.queue import Queue, Empty # noqa
from cassandra import ConsistencyLevel, AuthenticationFailed, OperationTimedOut, ProtocolVersion
from cassandra.marshal import int32_pack
from cassandra.protocol import (ReadyMessage, AuthenticateMessage, OptionsMessage,
StartupMessage, ErrorMessage, CredentialsMessage,
QueryMessage, ResultMessage, ProtocolHandler,
InvalidRequestException, SupportedMessage,
AuthResponseMessage, AuthChallengeMessage,
AuthSuccessMessage, ProtocolException,
RegisterMessage)
from cassandra.util import OrderedDict
log = logging.getLogger(__name__)
# We use an ordered dictionary and specifically add lz4 before
# snappy so that lz4 will be preferred. Changing the order of this
# will change the compression preferences for the driver.
locally_supported_compressions = OrderedDict()
try:
import lz4
except ImportError:
pass
else:
# The compress and decompress functions we need were moved from the lz4 to
# the lz4.block namespace, so we try both here.
try:
from lz4 import block as lz4_block
except ImportError:
lz4_block = lz4
# Cassandra writes the uncompressed message length in big endian order,
# but the lz4 lib requires little endian order, so we wrap these
# functions to handle that
def lz4_compress(byts):
# write length in big-endian instead of little-endian
return int32_pack(len(byts)) + lz4_block.compress(byts)[4:]
def lz4_decompress(byts):
# flip from big-endian to little-endian
return lz4_block.decompress(byts[3::-1] + byts[4:])
locally_supported_compressions['lz4'] = (lz4_compress, lz4_decompress)
try:
import snappy
except ImportError:
pass
else:
# work around apparently buggy snappy decompress
def decompress(byts):
if byts == '\x00':
return ''
return snappy.decompress(byts)
locally_supported_compressions['snappy'] = (snappy.compress, decompress)
PROTOCOL_VERSION_MASK = 0x7f
HEADER_DIRECTION_FROM_CLIENT = 0x00
HEADER_DIRECTION_TO_CLIENT = 0x80
HEADER_DIRECTION_MASK = 0x80
frame_header_v1_v2 = struct.Struct('>BbBi')
frame_header_v3 = struct.Struct('>BhBi')
class _Frame(object):
def __init__(self, version, flags, stream, opcode, body_offset, end_pos):
self.version = version
self.flags = flags
self.stream = stream
self.opcode = opcode
self.body_offset = body_offset
self.end_pos = end_pos
def __eq__(self, other): # facilitates testing
if isinstance(other, _Frame):
return (self.version == other.version and
self.flags == other.flags and
self.stream == other.stream and
self.opcode == other.opcode and
self.body_offset == other.body_offset and
self.end_pos == other.end_pos)
return NotImplemented
def __str__(self):
return "ver({0}); flags({1:04b}); stream({2}); op({3}); offset({4}); len({5})".format(self.version, self.flags, self.stream, self.opcode, self.body_offset, self.end_pos - self.body_offset)
NONBLOCKING = (errno.EAGAIN, errno.EWOULDBLOCK)
class ConnectionException(Exception):
"""
An unrecoverable error was hit when attempting to use a connection,
or the connection was already closed or defunct.
"""
def __init__(self, message, host=None):
Exception.__init__(self, message)
self.host = host
class ConnectionShutdown(ConnectionException):
"""
Raised when a connection has been marked as defunct or has been closed.
"""
pass
class ProtocolVersionUnsupported(ConnectionException):
"""
Server rejected startup message due to unsupported protocol version
"""
def __init__(self, host, startup_version):
msg = "Unsupported protocol version on %s: %d" % (host, startup_version)
super(ProtocolVersionUnsupported, self).__init__(msg, host)
self.startup_version = startup_version
class ConnectionBusy(Exception):
"""
An attempt was made to send a message through a :class:`.Connection` that
was already at the max number of in-flight operations.
"""
pass
class ProtocolError(Exception):
"""
Communication did not match the protocol that this driver expects.
"""
pass
def defunct_on_error(f):
@wraps(f)
def wrapper(self, *args, **kwargs):
try:
return f(self, *args, **kwargs)
except Exception as exc:
self.defunct(exc)
return wrapper
DEFAULT_CQL_VERSION = '3.0.0'
if six.PY3:
def int_from_buf_item(i):
return i
else:
int_from_buf_item = ord
class Connection(object):
CALLBACK_ERR_THREAD_THRESHOLD = 100
in_buffer_size = 4096
out_buffer_size = 4096
cql_version = None
no_compact = False
protocol_version = ProtocolVersion.MAX_SUPPORTED
keyspace = None
compression = True
compressor = None
decompressor = None
ssl_options = None
last_error = None
# The current number of operations that are in flight. More precisely,
# the number of request IDs that are currently in use.
in_flight = 0
# Max concurrent requests allowed per connection. This is set optimistically high, allowing
# all request ids to be used in protocol version 3+. Normally concurrency would be controlled
# at a higher level by the application or concurrent.execute_concurrent. This attribute
# is for lower-level integrations that want some upper bound without reimplementing.
max_in_flight = 2 ** 15
# A set of available request IDs. When using the v3 protocol or higher,
# this will not initially include all request IDs in order to save memory,
# but the set will grow if it is exhausted.
request_ids = None
# Tracks the highest used request ID in order to help with growing the
# request_ids set
highest_request_id = 0
is_defunct = False
is_closed = False
lock = None
user_type_map = None
msg_received = False
is_unsupported_proto_version = False
is_control_connection = False
signaled_error = False # used for flagging at the pool level
allow_beta_protocol_version = False
_iobuf = None
_current_frame = None
_socket = None
_socket_impl = socket
_ssl_impl = ssl
_check_hostname = False
def __init__(self, host='127.0.0.1', port=9042, authenticator=None,
ssl_options=None, sockopts=None, compression=True,
cql_version=None, protocol_version=ProtocolVersion.MAX_SUPPORTED, is_control_connection=False,
user_type_map=None, connect_timeout=None, allow_beta_protocol_version=False, no_compact=False):
self.host = host
self.port = port
self.authenticator = authenticator
self.ssl_options = ssl_options.copy() if ssl_options else None
self.sockopts = sockopts
self.compression = compression
self.cql_version = cql_version
self.protocol_version = protocol_version
self.is_control_connection = is_control_connection
self.user_type_map = user_type_map
self.connect_timeout = connect_timeout
self.allow_beta_protocol_version = allow_beta_protocol_version
self.no_compact = no_compact
self._push_watchers = defaultdict(set)
self._requests = {}
self._iobuf = io.BytesIO()
if ssl_options:
self._check_hostname = bool(self.ssl_options.pop('check_hostname', False))
if self._check_hostname:
if not getattr(ssl, 'match_hostname', None):
raise RuntimeError("ssl_options specify 'check_hostname', but ssl.match_hostname is not provided. "
"Patch or upgrade Python to use this option.")
if protocol_version >= 3:
self.max_request_id = min(self.max_in_flight - 1, (2 ** 15) - 1)
# Don't fill the deque with 2**15 items right away. Start with some and add
# more if needed.
initial_size = min(300, self.max_in_flight)
self.request_ids = deque(range(initial_size))
self.highest_request_id = initial_size - 1
else:
self.max_request_id = min(self.max_in_flight, (2 ** 7) - 1)
self.request_ids = deque(range(self.max_request_id + 1))
self.highest_request_id = self.max_request_id
self.lock = RLock()
self.connected_event = Event()
@classmethod
def initialize_reactor(cls):
"""
Called once by Cluster.connect(). This should be used by implementations
to set up any resources that will be shared across connections.
"""
pass
@classmethod
def handle_fork(cls):
"""
Called after a forking. This should cleanup any remaining reactor state
from the parent process.
"""
pass
@classmethod
def create_timer(cls, timeout, callback):
raise NotImplementedError()
@classmethod
def factory(cls, host, timeout, *args, **kwargs):
"""
A factory function which returns connections which have
succeeded in connecting and are ready for service (or
raises an exception otherwise).
"""
start = time.time()
kwargs['connect_timeout'] = timeout
conn = cls(host, *args, **kwargs)
elapsed = time.time() - start
conn.connected_event.wait(timeout - elapsed)
if conn.last_error:
if conn.is_unsupported_proto_version:
raise ProtocolVersionUnsupported(host, conn.protocol_version)
raise conn.last_error
elif not conn.connected_event.is_set():
conn.close()
raise OperationTimedOut("Timed out creating connection (%s seconds)" % timeout)
else:
return conn
def _connect_socket(self):
sockerr = None
addresses = socket.getaddrinfo(self.host, self.port, socket.AF_UNSPEC, socket.SOCK_STREAM)
if not addresses:
raise ConnectionException("getaddrinfo returned empty list for %s" % (self.host,))
for (af, socktype, proto, canonname, sockaddr) in addresses:
try:
self._socket = self._socket_impl.socket(af, socktype, proto)
if self.ssl_options:
if not self._ssl_impl:
raise RuntimeError("This version of Python was not compiled with SSL support")
self._socket = self._ssl_impl.wrap_socket(self._socket, **self.ssl_options)
self._socket.settimeout(self.connect_timeout)
self._socket.connect(sockaddr)
self._socket.settimeout(None)
if self._check_hostname:
ssl.match_hostname(self._socket.getpeercert(), self.host)
sockerr = None
break
except socket.error as err:
if self._socket:
self._socket.close()
self._socket = None
sockerr = err
if sockerr:
raise socket.error(sockerr.errno, "Tried connecting to %s. Last error: %s" % ([a[4] for a in addresses], sockerr.strerror or sockerr))
if self.sockopts:
for args in self.sockopts:
self._socket.setsockopt(*args)
def close(self):
raise NotImplementedError()
def defunct(self, exc):
with self.lock:
if self.is_defunct or self.is_closed:
return
self.is_defunct = True
exc_info = sys.exc_info()
# if we are not handling an exception, just use the passed exception, and don't try to format exc_info with the message
if any(exc_info):
log.debug("Defuncting connection (%s) to %s:",
id(self), self.host, exc_info=exc_info)
else:
log.debug("Defuncting connection (%s) to %s: %s",
id(self), self.host, exc)
self.last_error = exc
self.close()
self.error_all_requests(exc)
self.connected_event.set()
return exc
def error_all_requests(self, exc):
with self.lock:
requests = self._requests
self._requests = {}
if not requests:
return
new_exc = ConnectionShutdown(str(exc))
def try_callback(cb):
try:
cb(new_exc)
except Exception:
log.warning("Ignoring unhandled exception while erroring requests for a "
"failed connection (%s) to host %s:",
id(self), self.host, exc_info=True)
# run first callback from this thread to ensure pool state before leaving
cb, _, _ = requests.popitem()[1]
try_callback(cb)
if not requests:
return
# additional requests are optionally errored from a separate thread
# The default callback and retry logic is fairly expensive -- we don't
# want to tie up the event thread when there are many requests
def err_all_callbacks():
for cb, _, _ in requests.values():
try_callback(cb)
if len(requests) < Connection.CALLBACK_ERR_THREAD_THRESHOLD:
err_all_callbacks()
else:
# daemon thread here because we want to stay decoupled from the cluster TPE
# TODO: would it make sense to just have a driver-global TPE?
t = Thread(target=err_all_callbacks)
t.daemon = True
t.start()
def get_request_id(self):
"""
This must be called while self.lock is held.
"""
try:
return self.request_ids.popleft()
except IndexError:
new_request_id = self.highest_request_id + 1
# in_flight checks should guarantee this
assert new_request_id <= self.max_request_id
self.highest_request_id = new_request_id
return self.highest_request_id
def handle_pushed(self, response):
log.debug("Message pushed from server: %r", response)
for cb in self._push_watchers.get(response.event_type, []):
try:
cb(response.event_args)
except Exception:
log.exception("Pushed event handler errored, ignoring:")
def send_msg(self, msg, request_id, cb, encoder=ProtocolHandler.encode_message, decoder=ProtocolHandler.decode_message, result_metadata=None):
if self.is_defunct:
raise ConnectionShutdown("Connection to %s is defunct" % self.host)
elif self.is_closed:
raise ConnectionShutdown("Connection to %s is closed" % self.host)
# queue the decoder function with the request
# this allows us to inject custom functions per request to encode, decode messages
self._requests[request_id] = (cb, decoder, result_metadata)
msg = encoder(msg, request_id, self.protocol_version, compressor=self.compressor, allow_beta_protocol_version=self.allow_beta_protocol_version)
self.push(msg)
return len(msg)
def wait_for_response(self, msg, timeout=None):
return self.wait_for_responses(msg, timeout=timeout)[0]
def wait_for_responses(self, *msgs, **kwargs):
"""
Returns a list of (success, response) tuples. If success
is False, response will be an Exception. Otherwise, response
will be the normal query response.
If fail_on_error was left as True and one of the requests
failed, the corresponding Exception will be raised.
"""
if self.is_closed or self.is_defunct:
raise ConnectionShutdown("Connection %s is already closed" % (self, ))
timeout = kwargs.get('timeout')
fail_on_error = kwargs.get('fail_on_error', True)
waiter = ResponseWaiter(self, len(msgs), fail_on_error)
# busy wait for sufficient space on the connection
messages_sent = 0
while True:
needed = len(msgs) - messages_sent
with self.lock:
available = min(needed, self.max_request_id - self.in_flight + 1)
request_ids = [self.get_request_id() for _ in range(available)]
self.in_flight += available
for i, request_id in enumerate(request_ids):
self.send_msg(msgs[messages_sent + i],
request_id,
partial(waiter.got_response, index=messages_sent + i))
messages_sent += available
if messages_sent == len(msgs):
break
else:
if timeout is not None:
timeout -= 0.01
if timeout <= 0.0:
raise OperationTimedOut()
time.sleep(0.01)
try:
return waiter.deliver(timeout)
except OperationTimedOut:
raise
except Exception as exc:
self.defunct(exc)
raise
def register_watcher(self, event_type, callback, register_timeout=None):
"""
Register a callback for a given event type.
"""
self._push_watchers[event_type].add(callback)
self.wait_for_response(
RegisterMessage(event_list=[event_type]),
timeout=register_timeout)
def register_watchers(self, type_callback_dict, register_timeout=None):
"""
Register multiple callback/event type pairs, expressed as a dict.
"""
for event_type, callback in type_callback_dict.items():
self._push_watchers[event_type].add(callback)
self.wait_for_response(
RegisterMessage(event_list=type_callback_dict.keys()),
timeout=register_timeout)
def control_conn_disposed(self):
self.is_control_connection = False
self._push_watchers = {}
@defunct_on_error
def _read_frame_header(self):
buf = self._iobuf.getvalue()
pos = len(buf)
if pos:
version = int_from_buf_item(buf[0]) & PROTOCOL_VERSION_MASK
if version > ProtocolVersion.MAX_SUPPORTED:
raise ProtocolError("This version of the driver does not support protocol version %d" % version)
frame_header = frame_header_v3 if version >= 3 else frame_header_v1_v2
# this frame header struct is everything after the version byte
header_size = frame_header.size + 1
if pos >= header_size:
flags, stream, op, body_len = frame_header.unpack_from(buf, 1)
if body_len < 0:
raise ProtocolError("Received negative body length: %r" % body_len)
self._current_frame = _Frame(version, flags, stream, op, header_size, body_len + header_size)
return pos
def _reset_frame(self):
self._iobuf = io.BytesIO(self._iobuf.read())
self._iobuf.seek(0, 2) # io.SEEK_END == 2 (constant not present in 2.6)
self._current_frame = None
def process_io_buffer(self):
while True:
if not self._current_frame:
pos = self._read_frame_header()
else:
pos = self._iobuf.tell()
if not self._current_frame or pos < self._current_frame.end_pos:
# we don't have a complete header yet or we
# already saw a header, but we don't have a
# complete message yet
return
else:
frame = self._current_frame
self._iobuf.seek(frame.body_offset)
msg = self._iobuf.read(frame.end_pos - frame.body_offset)
self.process_msg(frame, msg)
self._reset_frame()
@defunct_on_error
def process_msg(self, header, body):
self.msg_received = True
stream_id = header.stream
if stream_id < 0:
callback = None
decoder = ProtocolHandler.decode_message
result_metadata = None
else:
try:
callback, decoder, result_metadata = self._requests.pop(stream_id)
# This can only happen if the stream_id was
# removed due to an OperationTimedOut
except KeyError:
return
with self.lock:
self.request_ids.append(stream_id)
try:
response = decoder(header.version, self.user_type_map, stream_id,
header.flags, header.opcode, body, self.decompressor, result_metadata)
except Exception as exc:
log.exception("Error decoding response from Cassandra. "
"%s; buffer: %r", header, self._iobuf.getvalue())
if callback is not None:
callback(exc)
self.defunct(exc)
return
try:
if stream_id >= 0:
if isinstance(response, ProtocolException):
if 'unsupported protocol version' in response.message:
self.is_unsupported_proto_version = True
else:
log.error("Closing connection %s due to protocol error: %s", self, response.summary_msg())
self.defunct(response)
if callback is not None:
callback(response)
else:
self.handle_pushed(response)
except Exception:
log.exception("Callback handler errored, ignoring:")
@defunct_on_error
def _send_options_message(self):
if self.cql_version is None and (not self.compression or not locally_supported_compressions):
log.debug("Not sending options message for new connection(%s) to %s "
"because compression is disabled and a cql version was not "
"specified", id(self), self.host)
self._compressor = None
self.cql_version = DEFAULT_CQL_VERSION
self._send_startup_message(no_compact=self.no_compact)
else:
log.debug("Sending initial options message for new connection (%s) to %s", id(self), self.host)
self.send_msg(OptionsMessage(), self.get_request_id(), self._handle_options_response)
@defunct_on_error
def _handle_options_response(self, options_response):
if self.is_defunct:
return
if not isinstance(options_response, SupportedMessage):
if isinstance(options_response, ConnectionException):
raise options_response
else:
log.error("Did not get expected SupportedMessage response; "
"instead, got: %s", options_response)
raise ConnectionException("Did not get expected SupportedMessage "
"response; instead, got: %s"
% (options_response,))
log.debug("Received options response on new connection (%s) from %s",
id(self), self.host)
supported_cql_versions = options_response.cql_versions
remote_supported_compressions = options_response.options['COMPRESSION']
if self.cql_version:
if self.cql_version not in supported_cql_versions:
raise ProtocolError(
"cql_version %r is not supported by remote (w/ native "
"protocol). Supported versions: %r"
% (self.cql_version, supported_cql_versions))
else:
self.cql_version = supported_cql_versions[0]
self._compressor = None
compression_type = None
if self.compression:
overlap = (set(locally_supported_compressions.keys()) &
set(remote_supported_compressions))
if len(overlap) == 0:
log.debug("No available compression types supported on both ends."
" locally supported: %r. remotely supported: %r",
locally_supported_compressions.keys(),
remote_supported_compressions)
else:
compression_type = None
if isinstance(self.compression, six.string_types):
# the user picked a specific compression type ('snappy' or 'lz4')
if self.compression not in remote_supported_compressions:
raise ProtocolError(
"The requested compression type (%s) is not supported by the Cassandra server at %s"
% (self.compression, self.host))
compression_type = self.compression
else:
# our locally supported compressions are ordered to prefer
# lz4, if available
for k in locally_supported_compressions.keys():
if k in overlap:
compression_type = k
break
# set the decompressor here, but set the compressor only after
# a successful Ready message
self._compressor, self.decompressor = \
locally_supported_compressions[compression_type]
self._send_startup_message(compression_type, no_compact=self.no_compact)
@defunct_on_error
def _send_startup_message(self, compression=None, no_compact=False):
log.debug("Sending StartupMessage on %s", self)
opts = {}
if compression:
opts['COMPRESSION'] = compression
if no_compact:
opts['NO_COMPACT'] = 'true'
sm = StartupMessage(cqlversion=self.cql_version, options=opts)
self.send_msg(sm, self.get_request_id(), cb=self._handle_startup_response)
log.debug("Sent StartupMessage on %s", self)
@defunct_on_error
def _handle_startup_response(self, startup_response, did_authenticate=False):
if self.is_defunct:
return
if isinstance(startup_response, ReadyMessage):
if self.authenticator:
log.warning("An authentication challenge was not sent, "
"this is suspicious because the driver expects "
"authentication (configured authenticator = %s)",
self.authenticator.__class__.__name__)
log.debug("Got ReadyMessage on new connection (%s) from %s", id(self), self.host)
if self._compressor:
self.compressor = self._compressor
self.connected_event.set()
elif isinstance(startup_response, AuthenticateMessage):
log.debug("Got AuthenticateMessage on new connection (%s) from %s: %s",
id(self), self.host, startup_response.authenticator)
if self.authenticator is None:
raise AuthenticationFailed('Remote end requires authentication.')
if isinstance(self.authenticator, dict):
log.debug("Sending credentials-based auth response on %s", self)
cm = CredentialsMessage(creds=self.authenticator)
callback = partial(self._handle_startup_response, did_authenticate=True)
self.send_msg(cm, self.get_request_id(), cb=callback)
else:
log.debug("Sending SASL-based auth response on %s", self)
self.authenticator.server_authenticator_class = startup_response.authenticator
initial_response = self.authenticator.initial_response()
initial_response = "" if initial_response is None else initial_response
self.send_msg(AuthResponseMessage(initial_response), self.get_request_id(), self._handle_auth_response)
elif isinstance(startup_response, ErrorMessage):
log.debug("Received ErrorMessage on new connection (%s) from %s: %s",
id(self), self.host, startup_response.summary_msg())
if did_authenticate:
raise AuthenticationFailed(
"Failed to authenticate to %s: %s" %
(self.host, startup_response.summary_msg()))
else:
raise ConnectionException(
"Failed to initialize new connection to %s: %s"
% (self.host, startup_response.summary_msg()))
elif isinstance(startup_response, ConnectionShutdown):
log.debug("Connection to %s was closed during the startup handshake", (self.host))
raise startup_response
else:
msg = "Unexpected response during Connection setup: %r"
log.error(msg, startup_response)
raise ProtocolError(msg % (startup_response,))
@defunct_on_error
def _handle_auth_response(self, auth_response):
if self.is_defunct:
return
if isinstance(auth_response, AuthSuccessMessage):
log.debug("Connection %s successfully authenticated", self)
self.authenticator.on_authentication_success(auth_response.token)
if self._compressor:
self.compressor = self._compressor
self.connected_event.set()
elif isinstance(auth_response, AuthChallengeMessage):
response = self.authenticator.evaluate_challenge(auth_response.challenge)
msg = AuthResponseMessage("" if response is None else response)
log.debug("Responding to auth challenge on %s", self)
self.send_msg(msg, self.get_request_id(), self._handle_auth_response)
elif isinstance(auth_response, ErrorMessage):
log.debug("Received ErrorMessage on new connection (%s) from %s: %s",
id(self), self.host, auth_response.summary_msg())
raise AuthenticationFailed(
"Failed to authenticate to %s: %s" %
(self.host, auth_response.summary_msg()))
elif isinstance(auth_response, ConnectionShutdown):
log.debug("Connection to %s was closed during the authentication process", self.host)
raise auth_response
else:
msg = "Unexpected response during Connection authentication to %s: %r"
log.error(msg, self.host, auth_response)
raise ProtocolError(msg % (self.host, auth_response))
def set_keyspace_blocking(self, keyspace):
if not keyspace or keyspace == self.keyspace:
return
query = QueryMessage(query='USE "%s"' % (keyspace,),
consistency_level=ConsistencyLevel.ONE)
try:
result = self.wait_for_response(query)
except InvalidRequestException as ire:
# the keyspace probably doesn't exist
raise ire.to_exception()
except Exception as exc:
conn_exc = ConnectionException(
"Problem while setting keyspace: %r" % (exc,), self.host)
self.defunct(conn_exc)
raise conn_exc
if isinstance(result, ResultMessage):
self.keyspace = keyspace
else:
conn_exc = ConnectionException(
"Problem while setting keyspace: %r" % (result,), self.host)
self.defunct(conn_exc)
raise conn_exc
def set_keyspace_async(self, keyspace, callback):
"""
Use this in order to avoid deadlocking the event loop thread.
When the operation completes, `callback` will be called with
two arguments: this connection and an Exception if an error
occurred, otherwise :const:`None`.
This method will always increment :attr:`.in_flight` attribute, even if
it doesn't need to make a request, just to maintain an
":attr:`.in_flight` is incremented" invariant.
"""
# Here we increment in_flight unconditionally, whether we need to issue
# a request or not. This is bad, but allows callers -- specifically
# _set_keyspace_for_all_conns -- to assume that we increment
# self.in_flight during this call. This allows the passed callback to
# safely call HostConnection{Pool,}.return_connection on this
# Connection.
#
# We use a busy wait on the lock here because:
# - we'll only spin if the connection is at max capacity, which is very
# unlikely for a set_keyspace call
# - it allows us to avoid signaling a condition every time a request completes
while True:
with self.lock:
if self.in_flight < self.max_request_id:
self.in_flight += 1
break
time.sleep(0.001)
if not keyspace or keyspace == self.keyspace:
callback(self, None)
return
query = QueryMessage(query='USE "%s"' % (keyspace,),
consistency_level=ConsistencyLevel.ONE)
def process_result(result):
if isinstance(result, ResultMessage):
self.keyspace = keyspace
callback(self, None)
elif isinstance(result, InvalidRequestException):
callback(self, result.to_exception())
else:
callback(self, self.defunct(ConnectionException(
"Problem while setting keyspace: %r" % (result,), self.host)))
# We've incremented self.in_flight above, so we "have permission" to
# acquire a new request id
request_id = self.get_request_id()
self.send_msg(query, request_id, process_result)
@property
def is_idle(self):
return not self.msg_received
def reset_idle(self):
self.msg_received = False
def __str__(self):
status = ""
if self.is_defunct:
status = " (defunct)"
elif self.is_closed:
status = " (closed)"
return "<%s(%r) %s:%d%s>" % (self.__class__.__name__, id(self), self.host, self.port, status)
__repr__ = __str__
class ResponseWaiter(object):
def __init__(self, connection, num_responses, fail_on_error):
self.connection = connection
self.pending = num_responses
self.fail_on_error = fail_on_error
self.error = None
self.responses = [None] * num_responses
self.event = Event()
def got_response(self, response, index):
with self.connection.lock:
self.connection.in_flight -= 1
if isinstance(response, Exception):
if hasattr(response, 'to_exception'):
response = response.to_exception()
if self.fail_on_error:
self.error = response
self.event.set()
else:
self.responses[index] = (False, response)
else:
if not self.fail_on_error:
self.responses[index] = (True, response)
else:
self.responses[index] = response
self.pending -= 1
if not self.pending:
self.event.set()
def deliver(self, timeout=None):
"""
If fail_on_error was set to False, a list of (success, response)
tuples will be returned. If success is False, response will be
an Exception. Otherwise, response will be the normal query response.
If fail_on_error was left as True and one of the requests
failed, the corresponding Exception will be raised. Otherwise,
the normal response will be returned.
"""
self.event.wait(timeout)
if self.error:
raise self.error
elif not self.event.is_set():
raise OperationTimedOut()
else:
return self.responses
class HeartbeatFuture(object):
def __init__(self, connection, owner):
self._exception = None
self._event = Event()
self.connection = connection
self.owner = owner
log.debug("Sending options message heartbeat on idle connection (%s) %s",
id(connection), connection.host)
with connection.lock:
if connection.in_flight <= connection.max_request_id:
connection.in_flight += 1
connection.send_msg(OptionsMessage(), connection.get_request_id(), self._options_callback)
else:
self._exception = Exception("Failed to send heartbeat because connection 'in_flight' exceeds threshold")
self._event.set()
def wait(self, timeout):
self._event.wait(timeout)
if self._event.is_set():
if self._exception:
raise self._exception
else:
raise OperationTimedOut("Connection heartbeat timeout after %s seconds" % (timeout,), self.connection.host)
def _options_callback(self, response):
if isinstance(response, SupportedMessage):
log.debug("Received options response on connection (%s) from %s",
id(self.connection), self.connection.host)
else:
if isinstance(response, ConnectionException):
self._exception = response
else:
self._exception = ConnectionException("Received unexpected response to OptionsMessage: %s"
% (response,))
self._event.set()
class ConnectionHeartbeat(Thread):
def __init__(self, interval_sec, get_connection_holders, timeout):
Thread.__init__(self, name="Connection heartbeat")
self._interval = interval_sec
self._timeout = timeout
self._get_connection_holders = get_connection_holders
self._shutdown_event = Event()
self.daemon = True
self.start()
class ShutdownException(Exception):
pass
def run(self):