/usr/share/pyshared/redis/client.py is in python-redis 2.4.9-1.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
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 1001 1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028 1029 1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143 1144 1145 1146 1147 1148 1149 1150 1151 1152 1153 1154 1155 1156 1157 1158 1159 1160 1161 1162 1163 1164 1165 1166 1167 1168 1169 1170 1171 1172 1173 1174 1175 1176 1177 1178 1179 1180 1181 1182 1183 1184 1185 1186 1187 1188 1189 1190 1191 1192 1193 1194 1195 1196 1197 1198 1199 1200 1201 1202 1203 1204 1205 1206 1207 1208 1209 1210 1211 1212 1213 1214 1215 1216 1217 1218 1219 1220 1221 1222 1223 1224 1225 1226 1227 1228 1229 1230 1231 1232 1233 1234 1235 1236 1237 1238 1239 1240 1241 1242 1243 1244 1245 1246 1247 1248 1249 1250 1251 1252 1253 1254 1255 1256 1257 1258 1259 1260 1261 1262 1263 1264 1265 1266 1267 1268 1269 1270 1271 1272 1273 1274 1275 1276 1277 1278 1279 1280 1281 1282 1283 1284 1285 1286 1287 1288 1289 1290 1291 1292 1293 1294 1295 1296 1297 1298 1299 1300 1301 1302 1303 1304 1305 1306 1307 1308 1309 1310 1311 1312 1313 1314 1315 1316 1317 1318 1319 1320 1321 1322 1323 1324 1325 1326 1327 1328 1329 1330 1331 1332 1333 1334 1335 1336 1337 1338 1339 1340 1341 1342 1343 1344 1345 1346 1347 1348 1349 1350 1351 1352 1353 1354 1355 1356 1357 1358 1359 1360 1361 1362 1363 1364 1365 1366 1367 1368 1369 1370 1371 1372 1373 1374 1375 1376 1377 1378 1379 1380 1381 1382 1383 1384 1385 1386 1387 1388 1389 1390 1391 1392 1393 1394 1395 1396 1397 1398 1399 1400 1401 1402 1403 1404 1405 1406 1407 1408 1409 1410 1411 1412 1413 1414 1415 1416 1417 1418 1419 1420 1421 1422 1423 1424 1425 1426 1427 1428 1429 1430 1431 1432 1433 1434 1435 1436 1437 1438 1439 1440 1441 1442 1443 1444 1445 1446 1447 1448 1449 1450 1451 1452 1453 1454 1455 1456 1457 1458 1459 1460 1461 1462 1463 1464 1465 1466 1467 1468 1469 1470 1471 1472 1473 1474 1475 1476 1477 1478 1479 1480 1481 1482 1483 1484 1485 1486 1487 1488 | from __future__ import with_statement
import datetime
import time
import warnings
from itertools import imap, izip, starmap
from redis.connection import ConnectionPool, UnixDomainSocketConnection
from redis.exceptions import (
ConnectionError,
DataError,
RedisError,
ResponseError,
WatchError,
)
def list_or_args(keys, args):
# returns a single list combining keys and args
try:
i = iter(keys)
# a string can be iterated, but indicates
# keys wasn't passed as a list
if isinstance(keys, basestring):
keys = [keys]
except TypeError:
keys = [keys]
if args:
keys.extend(args)
return keys
def timestamp_to_datetime(response):
"Converts a unix timestamp to a Python datetime object"
if not response:
return None
try:
response = int(response)
except ValueError:
return None
return datetime.datetime.fromtimestamp(response)
def string_keys_to_dict(key_string, callback):
return dict.fromkeys(key_string.split(), callback)
def dict_merge(*dicts):
merged = {}
[merged.update(d) for d in dicts]
return merged
def parse_info(response):
"Parse the result of Redis's INFO command into a Python dict"
info = {}
def get_value(value):
if ',' not in value:
return value
sub_dict = {}
for item in value.split(','):
k, v = item.rsplit('=', 1)
try:
sub_dict[k] = int(v)
except ValueError:
sub_dict[k] = v
return sub_dict
for line in response.splitlines():
if line and not line.startswith('#'):
key, value = line.split(':')
try:
if '.' in value:
info[key] = float(value)
else:
info[key] = int(value)
except ValueError:
info[key] = get_value(value)
return info
def pairs_to_dict(response):
"Create a dict given a list of key/value pairs"
it = iter(response)
return dict(izip(it, it))
def zset_score_pairs(response, **options):
"""
If ``withscores`` is specified in the options, return the response as
a list of (value, score) pairs
"""
if not response or not options['withscores']:
return response
score_cast_func = options.get('score_cast_func', float)
it = iter(response)
return zip(it, imap(score_cast_func, it))
def int_or_none(response):
if response is None:
return None
return int(response)
def float_or_none(response):
if response is None:
return None
return float(response)
def parse_config(response, **options):
# this is stupid, but don't have a better option right now
if options['parse'] == 'GET':
return response and pairs_to_dict(response) or {}
return response == 'OK'
class Redis(object):
"""
Implementation of the Redis protocol.
This abstract class provides a Python interface to all Redis commands
and an implementation of the Redis protocol.
Connection and Pipeline derive from this, implementing how
the commands are sent and received to the Redis server
"""
RESPONSE_CALLBACKS = dict_merge(
string_keys_to_dict(
'AUTH DEL EXISTS EXPIRE EXPIREAT HDEL HEXISTS HMSET MOVE MSETNX '
'PERSIST RENAMENX SADD SISMEMBER SMOVE SETEX SETNX SREM ZADD ZREM',
bool
),
string_keys_to_dict(
'DECRBY GETBIT HLEN INCRBY LINSERT LLEN LPUSHX RPUSHX SCARD '
'SDIFFSTORE SETBIT SETRANGE SINTERSTORE STRLEN SUNIONSTORE ZCARD '
'ZREMRANGEBYRANK ZREMRANGEBYSCORE',
int
),
string_keys_to_dict(
# these return OK, or int if redis-server is >=1.3.4
'LPUSH RPUSH',
lambda r: isinstance(r, long) and r or r == 'OK'
),
string_keys_to_dict('ZSCORE ZINCRBY', float_or_none),
string_keys_to_dict(
'FLUSHALL FLUSHDB LSET LTRIM MSET RENAME '
'SAVE SELECT SET SHUTDOWN SLAVEOF WATCH UNWATCH',
lambda r: r == 'OK'
),
string_keys_to_dict('BLPOP BRPOP', lambda r: r and tuple(r) or None),
string_keys_to_dict('SDIFF SINTER SMEMBERS SUNION',
lambda r: r and set(r) or set()
),
string_keys_to_dict('ZRANGE ZRANGEBYSCORE ZREVRANGE ZREVRANGEBYSCORE',
zset_score_pairs
),
string_keys_to_dict('ZRANK ZREVRANK', int_or_none),
{
'BGREWRITEAOF': lambda r: \
r == 'Background rewriting of AOF file started',
'BGSAVE': lambda r: r == 'Background saving started',
'BRPOPLPUSH': lambda r: r and r or None,
'CONFIG': parse_config,
'HGETALL': lambda r: r and pairs_to_dict(r) or {},
'INFO': parse_info,
'LASTSAVE': timestamp_to_datetime,
'PING': lambda r: r == 'PONG',
'RANDOMKEY': lambda r: r and r or None,
'TTL': lambda r: r != -1 and r or None,
}
)
def __init__(self, host='localhost', port=6379,
db=0, password=None, socket_timeout=None,
connection_pool=None,
charset='utf-8', errors='strict', unix_socket_path=None):
if not connection_pool:
kwargs = {
'db': db,
'password': password,
'socket_timeout': socket_timeout,
'encoding': charset,
'encoding_errors': errors
}
# based on input, setup appropriate connection args
if unix_socket_path:
kwargs.update({
'path': unix_socket_path,
'connection_class': UnixDomainSocketConnection
})
else:
kwargs.update({
'host': host,
'port': port
})
connection_pool = ConnectionPool(**kwargs)
self.connection_pool = connection_pool
self.response_callbacks = self.__class__.RESPONSE_CALLBACKS.copy()
def set_response_callback(self, command, callback):
"Set a custom Response Callback"
self.response_callbacks[command] = callback
def pipeline(self, transaction=True, shard_hint=None):
"""
Return a new pipeline object that can queue multiple commands for
later execution. ``transaction`` indicates whether all commands
should be executed atomically. Apart from making a group of operations
atomic, pipelines are useful for reducing the back-and-forth overhead
between the client and server.
"""
return Pipeline(
self.connection_pool,
self.response_callbacks,
transaction,
shard_hint)
def transaction(self, func, *watches, **kwargs):
"""
Convenience method for executing the callable `func` as a transaction
while watching all keys specified in `watches`. The 'func' callable
should expect a single arguement which is a Pipeline object.
"""
shard_hint = kwargs.pop('shard_hint', None)
with self.pipeline(True, shard_hint) as pipe:
while 1:
try:
pipe.watch(*watches)
func(pipe)
return pipe.execute()
except WatchError:
continue
def lock(self, name, timeout=None, sleep=0.1):
"""
Return a new Lock object using key ``name`` that mimics
the behavior of threading.Lock.
If specified, ``timeout`` indicates a maximum life for the lock.
By default, it will remain locked until release() is called.
``sleep`` indicates the amount of time to sleep per loop iteration
when the lock is in blocking mode and another client is currently
holding the lock.
"""
return Lock(self, name, timeout=timeout, sleep=sleep)
def pubsub(self, shard_hint=None):
"""
Return a Publish/Subscribe object. With this object, you can
subscribe to channels and listen for messages that get published to
them.
"""
return PubSub(self.connection_pool, shard_hint)
#### COMMAND EXECUTION AND PROTOCOL PARSING ####
def execute_command(self, *args, **options):
"Execute a command and return a parsed response"
pool = self.connection_pool
command_name = args[0]
connection = pool.get_connection(command_name, **options)
try:
connection.send_command(*args)
return self.parse_response(connection, command_name, **options)
except ConnectionError:
connection.disconnect()
connection.send_command(*args)
return self.parse_response(connection, command_name, **options)
finally:
pool.release(connection)
def parse_response(self, connection, command_name, **options):
"Parses a response from the Redis server"
response = connection.read_response()
if command_name in self.response_callbacks:
return self.response_callbacks[command_name](response, **options)
return response
#### SERVER INFORMATION ####
def bgrewriteaof(self):
"Tell the Redis server to rewrite the AOF file from data in memory."
return self.execute_command('BGREWRITEAOF')
def bgsave(self):
"""
Tell the Redis server to save its data to disk. Unlike save(),
this method is asynchronous and returns immediately.
"""
return self.execute_command('BGSAVE')
def config_get(self, pattern="*"):
"Return a dictionary of configuration based on the ``pattern``"
return self.execute_command('CONFIG', 'GET', pattern, parse='GET')
def config_set(self, name, value):
"Set config item ``name`` with ``value``"
return self.execute_command('CONFIG', 'SET', name, value, parse='SET')
def dbsize(self):
"Returns the number of keys in the current database"
return self.execute_command('DBSIZE')
def delete(self, *names):
"Delete one or more keys specified by ``names``"
return self.execute_command('DEL', *names)
__delitem__ = delete
def flushall(self):
"Delete all keys in all databases on the current host"
return self.execute_command('FLUSHALL')
def flushdb(self):
"Delete all keys in the current database"
return self.execute_command('FLUSHDB')
def info(self):
"Returns a dictionary containing information about the Redis server"
return self.execute_command('INFO')
def lastsave(self):
"""
Return a Python datetime object representing the last time the
Redis database was saved to disk
"""
return self.execute_command('LASTSAVE')
def ping(self):
"Ping the Redis server"
return self.execute_command('PING')
def save(self):
"""
Tell the Redis server to save its data to disk,
blocking until the save is complete
"""
return self.execute_command('SAVE')
def shutdown(self):
"Shutdown the server"
try:
self.execute_command('SHUTDOWN')
except ConnectionError:
# a ConnectionError here is expected
return
raise RedisError("SHUTDOWN seems to have failed.")
def slaveof(self, host=None, port=None):
"""
Set the server to be a replicated slave of the instance identified
by the ``host`` and ``port``. If called without arguements, the
instance is promoted to a master instead.
"""
if host is None and port is None:
return self.execute_command("SLAVEOF", "NO", "ONE")
return self.execute_command("SLAVEOF", host, port)
#### BASIC KEY COMMANDS ####
def append(self, key, value):
"""
Appends the string ``value`` to the value at ``key``. If ``key``
doesn't already exist, create it with a value of ``value``.
Returns the new length of the value at ``key``.
"""
return self.execute_command('APPEND', key, value)
def decr(self, name, amount=1):
"""
Decrements the value of ``key`` by ``amount``. If no key exists,
the value will be initialized as 0 - ``amount``
"""
return self.execute_command('DECRBY', name, amount)
def exists(self, name):
"Returns a boolean indicating whether key ``name`` exists"
return self.execute_command('EXISTS', name)
__contains__ = exists
def expire(self, name, time):
"Set an expire flag on key ``name`` for ``time`` seconds"
return self.execute_command('EXPIRE', name, time)
def expireat(self, name, when):
"""
Set an expire flag on key ``name``. ``when`` can be represented
as an integer indicating unix time or a Python datetime object.
"""
if isinstance(when, datetime.datetime):
when = int(time.mktime(when.timetuple()))
return self.execute_command('EXPIREAT', name, when)
def get(self, name):
"""
Return the value at key ``name``, or None if the key doesn't exist
"""
return self.execute_command('GET', name)
def __getitem__(self, name):
"""
Return the value at key ``name``, raises a KeyError if the key
doesn't exist.
"""
value = self.get(name)
if value:
return value
raise KeyError(name)
def getbit(self, name, offset):
"Returns a boolean indicating the value of ``offset`` in ``name``"
return self.execute_command('GETBIT', name, offset)
def getset(self, name, value):
"""
Set the value at key ``name`` to ``value`` if key doesn't exist
Return the value at key ``name`` atomically
"""
return self.execute_command('GETSET', name, value)
def incr(self, name, amount=1):
"""
Increments the value of ``key`` by ``amount``. If no key exists,
the value will be initialized as ``amount``
"""
return self.execute_command('INCRBY', name, amount)
def keys(self, pattern='*'):
"Returns a list of keys matching ``pattern``"
return self.execute_command('KEYS', pattern)
def mget(self, keys, *args):
"""
Returns a list of values ordered identically to ``keys``
"""
keys = list_or_args(keys, args)
return self.execute_command('MGET', *keys)
def mset(self, mapping):
"Sets each key in the ``mapping`` dict to its corresponding value"
items = []
for pair in mapping.iteritems():
items.extend(pair)
return self.execute_command('MSET', *items)
def msetnx(self, mapping):
"""
Sets each key in the ``mapping`` dict to its corresponding value if
none of the keys are already set
"""
items = []
for pair in mapping.iteritems():
items.extend(pair)
return self.execute_command('MSETNX', *items)
def move(self, name, db):
"Moves the key ``name`` to a different Redis database ``db``"
return self.execute_command('MOVE', name, db)
def persist(self, name):
"Removes an expiration on ``name``"
return self.execute_command('PERSIST', name)
def randomkey(self):
"Returns the name of a random key"
return self.execute_command('RANDOMKEY')
def rename(self, src, dst):
"""
Rename key ``src`` to ``dst``
"""
return self.execute_command('RENAME', src, dst)
def renamenx(self, src, dst):
"Rename key ``src`` to ``dst`` if ``dst`` doesn't already exist"
return self.execute_command('RENAMENX', src, dst)
def set(self, name, value):
"Set the value at key ``name`` to ``value``"
return self.execute_command('SET', name, value)
__setitem__ = set
def setbit(self, name, offset, value):
"""
Flag the ``offset`` in ``name`` as ``value``. Returns a boolean
indicating the previous value of ``offset``.
"""
value = value and 1 or 0
return self.execute_command('SETBIT', name, offset, value)
def setex(self, name, value, time):
"""
Set the value of key ``name`` to ``value``
that expires in ``time`` seconds
"""
return self.execute_command('SETEX', name, time, value)
def setnx(self, name, value):
"Set the value of key ``name`` to ``value`` if key doesn't exist"
return self.execute_command('SETNX', name, value)
def setrange(self, name, offset, value):
"""
Overwrite bytes in the value of ``name`` starting at ``offset`` with
``value``. If ``offset`` plus the length of ``value`` exceeds the
length of the original value, the new value will be larger than before.
If ``offset`` exceeds the length of the original value, null bytes
will be used to pad between the end of the previous value and the start
of what's being injected.
Returns the length of the new string.
"""
return self.execute_command('SETRANGE', name, offset, value)
def strlen(self, name):
"Return the number of bytes stored in the value of ``name``"
return self.execute_command('STRLEN', name)
def substr(self, name, start, end=-1):
"""
Return a substring of the string at key ``name``. ``start`` and ``end``
are 0-based integers specifying the portion of the string to return.
"""
return self.execute_command('SUBSTR', name, start, end)
def ttl(self, name):
"Returns the number of seconds until the key ``name`` will expire"
return self.execute_command('TTL', name)
def type(self, name):
"Returns the type of key ``name``"
return self.execute_command('TYPE', name)
def watch(self, *names):
"""
Watches the values at keys ``names``, or None if the key doesn't exist
"""
warnings.warn(DeprecationWarning('Call WATCH from a Pipeline object'))
def unwatch(self):
"""
Unwatches the value at key ``name``, or None of the key doesn't exist
"""
warnings.warn(DeprecationWarning('Call UNWATCH from a Pipeline object'))
#### LIST COMMANDS ####
def blpop(self, keys, timeout=0):
"""
LPOP a value off of the first non-empty list
named in the ``keys`` list.
If none of the lists in ``keys`` has a value to LPOP, then block
for ``timeout`` seconds, or until a value gets pushed on to one
of the lists.
If timeout is 0, then block indefinitely.
"""
if timeout is None:
timeout = 0
if isinstance(keys, basestring):
keys = [keys]
else:
keys = list(keys)
keys.append(timeout)
return self.execute_command('BLPOP', *keys)
def brpop(self, keys, timeout=0):
"""
RPOP a value off of the first non-empty list
named in the ``keys`` list.
If none of the lists in ``keys`` has a value to LPOP, then block
for ``timeout`` seconds, or until a value gets pushed on to one
of the lists.
If timeout is 0, then block indefinitely.
"""
if timeout is None:
timeout = 0
if isinstance(keys, basestring):
keys = [keys]
else:
keys = list(keys)
keys.append(timeout)
return self.execute_command('BRPOP', *keys)
def brpoplpush(self, src, dst, timeout=0):
"""
Pop a value off the tail of ``src``, push it on the head of ``dst``
and then return it.
This command blocks until a value is in ``src`` or until ``timeout``
seconds elapse, whichever is first. A ``timeout`` value of 0 blocks
forever.
"""
if timeout is None:
timeout = 0
return self.execute_command('BRPOPLPUSH', src, dst, timeout)
def lindex(self, name, index):
"""
Return the item from list ``name`` at position ``index``
Negative indexes are supported and will return an item at the
end of the list
"""
return self.execute_command('LINDEX', name, index)
def linsert(self, name, where, refvalue, value):
"""
Insert ``value`` in list ``name`` either immediately before or after
[``where``] ``refvalue``
Returns the new length of the list on success or -1 if ``refvalue``
is not in the list.
"""
return self.execute_command('LINSERT', name, where, refvalue, value)
def llen(self, name):
"Return the length of the list ``name``"
return self.execute_command('LLEN', name)
def lpop(self, name):
"Remove and return the first item of the list ``name``"
return self.execute_command('LPOP', name)
def lpush(self, name, *values):
"Push ``values`` onto the head of the list ``name``"
return self.execute_command('LPUSH', name, *values)
def lpushx(self, name, value):
"Push ``value`` onto the head of the list ``name`` if ``name`` exists"
return self.execute_command('LPUSHX', name, value)
def lrange(self, name, start, end):
"""
Return a slice of the list ``name`` between
position ``start`` and ``end``
``start`` and ``end`` can be negative numbers just like
Python slicing notation
"""
return self.execute_command('LRANGE', name, start, end)
def lrem(self, name, value, num=0):
"""
Remove the first ``num`` occurrences of ``value`` from list ``name``
If ``num`` is 0, then all occurrences will be removed
"""
return self.execute_command('LREM', name, num, value)
def lset(self, name, index, value):
"Set ``position`` of list ``name`` to ``value``"
return self.execute_command('LSET', name, index, value)
def ltrim(self, name, start, end):
"""
Trim the list ``name``, removing all values not within the slice
between ``start`` and ``end``
``start`` and ``end`` can be negative numbers just like
Python slicing notation
"""
return self.execute_command('LTRIM', name, start, end)
def rpop(self, name):
"Remove and return the last item of the list ``name``"
return self.execute_command('RPOP', name)
def rpoplpush(self, src, dst):
"""
RPOP a value off of the ``src`` list and atomically LPUSH it
on to the ``dst`` list. Returns the value.
"""
return self.execute_command('RPOPLPUSH', src, dst)
def rpush(self, name, *values):
"Push ``values`` onto the tail of the list ``name``"
return self.execute_command('RPUSH', name, *values)
def rpushx(self, name, value):
"Push ``value`` onto the tail of the list ``name`` if ``name`` exists"
return self.execute_command('RPUSHX', name, value)
def sort(self, name, start=None, num=None, by=None, get=None,
desc=False, alpha=False, store=None):
"""
Sort and return the list, set or sorted set at ``name``.
``start`` and ``num`` allow for paging through the sorted data
``by`` allows using an external key to weight and sort the items.
Use an "*" to indicate where in the key the item value is located
``get`` allows for returning items from external keys rather than the
sorted data itself. Use an "*" to indicate where int he key
the item value is located
``desc`` allows for reversing the sort
``alpha`` allows for sorting lexicographically rather than numerically
``store`` allows for storing the result of the sort into
the key ``store``
"""
if (start is not None and num is None) or \
(num is not None and start is None):
raise RedisError("``start`` and ``num`` must both be specified")
pieces = [name]
if by is not None:
pieces.append('BY')
pieces.append(by)
if start is not None and num is not None:
pieces.append('LIMIT')
pieces.append(start)
pieces.append(num)
if get is not None:
# If get is a string assume we want to get a single value.
# Otherwise assume it's an interable and we want to get multiple
# values. We can't just iterate blindly because strings are
# iterable.
if isinstance(get, basestring):
pieces.append('GET')
pieces.append(get)
else:
for g in get:
pieces.append('GET')
pieces.append(g)
if desc:
pieces.append('DESC')
if alpha:
pieces.append('ALPHA')
if store is not None:
pieces.append('STORE')
pieces.append(store)
return self.execute_command('SORT', *pieces)
#### SET COMMANDS ####
def sadd(self, name, *values):
"Add ``value(s)`` to set ``name``"
return self.execute_command('SADD', name, *values)
def scard(self, name):
"Return the number of elements in set ``name``"
return self.execute_command('SCARD', name)
def sdiff(self, keys, *args):
"Return the difference of sets specified by ``keys``"
keys = list_or_args(keys, args)
return self.execute_command('SDIFF', *keys)
def sdiffstore(self, dest, keys, *args):
"""
Store the difference of sets specified by ``keys`` into a new
set named ``dest``. Returns the number of keys in the new set.
"""
keys = list_or_args(keys, args)
return self.execute_command('SDIFFSTORE', dest, *keys)
def sinter(self, keys, *args):
"Return the intersection of sets specified by ``keys``"
keys = list_or_args(keys, args)
return self.execute_command('SINTER', *keys)
def sinterstore(self, dest, keys, *args):
"""
Store the intersection of sets specified by ``keys`` into a new
set named ``dest``. Returns the number of keys in the new set.
"""
keys = list_or_args(keys, args)
return self.execute_command('SINTERSTORE', dest, *keys)
def sismember(self, name, value):
"Return a boolean indicating if ``value`` is a member of set ``name``"
return self.execute_command('SISMEMBER', name, value)
def smembers(self, name):
"Return all members of the set ``name``"
return self.execute_command('SMEMBERS', name)
def smove(self, src, dst, value):
"Move ``value`` from set ``src`` to set ``dst`` atomically"
return self.execute_command('SMOVE', src, dst, value)
def spop(self, name):
"Remove and return a random member of set ``name``"
return self.execute_command('SPOP', name)
def srandmember(self, name):
"Return a random member of set ``name``"
return self.execute_command('SRANDMEMBER', name)
def srem(self, name, *values):
"Remove ``values`` from set ``name``"
return self.execute_command('SREM', name, *values)
def sunion(self, keys, *args):
"Return the union of sets specifiued by ``keys``"
keys = list_or_args(keys, args)
return self.execute_command('SUNION', *keys)
def sunionstore(self, dest, keys, *args):
"""
Store the union of sets specified by ``keys`` into a new
set named ``dest``. Returns the number of keys in the new set.
"""
keys = list_or_args(keys, args)
return self.execute_command('SUNIONSTORE', dest, *keys)
#### SORTED SET COMMANDS ####
def zadd(self, name, value=None, score=None, **pairs):
"""
For each kwarg in ``pairs``, add that item and it's score to the
sorted set ``name``.
The ``value`` and ``score`` arguments are deprecated.
"""
all_pairs = []
if value is not None or score is not None:
if value is None or score is None:
raise RedisError("Both 'value' and 'score' must be specified " \
"to ZADD")
warnings.warn(DeprecationWarning(
"Passing 'value' and 'score' has been deprecated. " \
"Please pass via kwargs instead."))
all_pairs.append(score)
all_pairs.append(value)
for pair in pairs.iteritems():
all_pairs.append(pair[1])
all_pairs.append(pair[0])
return self.execute_command('ZADD', name, *all_pairs)
def zcard(self, name):
"Return the number of elements in the sorted set ``name``"
return self.execute_command('ZCARD', name)
def zcount(self, name, min, max):
return self.execute_command('ZCOUNT', name, min, max)
def zincrby(self, name, value, amount=1):
"Increment the score of ``value`` in sorted set ``name`` by ``amount``"
return self.execute_command('ZINCRBY', name, amount, value)
def zinterstore(self, dest, keys, aggregate=None):
"""
Intersect multiple sorted sets specified by ``keys`` into
a new sorted set, ``dest``. Scores in the destination will be
aggregated based on the ``aggregate``, or SUM if none is provided.
"""
return self._zaggregate('ZINTERSTORE', dest, keys, aggregate)
def zrange(self, name, start, end, desc=False, withscores=False,
score_cast_func=float):
"""
Return a range of values from sorted set ``name`` between
``start`` and ``end`` sorted in ascending order.
``start`` and ``end`` can be negative, indicating the end of the range.
``desc`` a boolean indicating whether to sort the results descendingly
``withscores`` indicates to return the scores along with the values.
The return type is a list of (value, score) pairs
``score_cast_func`` a callable used to cast the score return value
"""
if desc:
return self.zrevrange(name, start, end, withscores)
pieces = ['ZRANGE', name, start, end]
if withscores:
pieces.append('withscores')
options = {'withscores': withscores, 'score_cast_func': score_cast_func}
return self.execute_command(*pieces, **options)
def zrangebyscore(self, name, min, max,
start=None, num=None, withscores=False, score_cast_func=float):
"""
Return a range of values from the sorted set ``name`` with scores
between ``min`` and ``max``.
If ``start`` and ``num`` are specified, then return a slice
of the range.
``withscores`` indicates to return the scores along with the values.
The return type is a list of (value, score) pairs
`score_cast_func`` a callable used to cast the score return value
"""
if (start is not None and num is None) or \
(num is not None and start is None):
raise RedisError("``start`` and ``num`` must both be specified")
pieces = ['ZRANGEBYSCORE', name, min, max]
if start is not None and num is not None:
pieces.extend(['LIMIT', start, num])
if withscores:
pieces.append('withscores')
options = {'withscores': withscores, 'score_cast_func': score_cast_func}
return self.execute_command(*pieces, **options)
def zrank(self, name, value):
"""
Returns a 0-based value indicating the rank of ``value`` in sorted set
``name``
"""
return self.execute_command('ZRANK', name, value)
def zrem(self, name, *values):
"Remove member ``values`` from sorted set ``name``"
return self.execute_command('ZREM', name, *values)
def zremrangebyrank(self, name, min, max):
"""
Remove all elements in the sorted set ``name`` with ranks between
``min`` and ``max``. Values are 0-based, ordered from smallest score
to largest. Values can be negative indicating the highest scores.
Returns the number of elements removed
"""
return self.execute_command('ZREMRANGEBYRANK', name, min, max)
def zremrangebyscore(self, name, min, max):
"""
Remove all elements in the sorted set ``name`` with scores
between ``min`` and ``max``. Returns the number of elements removed.
"""
return self.execute_command('ZREMRANGEBYSCORE', name, min, max)
def zrevrange(self, name, start, num, withscores=False,
score_cast_func=float):
"""
Return a range of values from sorted set ``name`` between
``start`` and ``num`` sorted in descending order.
``start`` and ``num`` can be negative, indicating the end of the range.
``withscores`` indicates to return the scores along with the values
The return type is a list of (value, score) pairs
``score_cast_func`` a callable used to cast the score return value
"""
pieces = ['ZREVRANGE', name, start, num]
if withscores:
pieces.append('withscores')
options = {'withscores': withscores, 'score_cast_func': score_cast_func}
return self.execute_command(*pieces, **options)
def zrevrangebyscore(self, name, max, min,
start=None, num=None, withscores=False, score_cast_func=float):
"""
Return a range of values from the sorted set ``name`` with scores
between ``min`` and ``max`` in descending order.
If ``start`` and ``num`` are specified, then return a slice
of the range.
``withscores`` indicates to return the scores along with the values.
The return type is a list of (value, score) pairs
``score_cast_func`` a callable used to cast the score return value
"""
if (start is not None and num is None) or \
(num is not None and start is None):
raise RedisError("``start`` and ``num`` must both be specified")
pieces = ['ZREVRANGEBYSCORE', name, max, min]
if start is not None and num is not None:
pieces.extend(['LIMIT', start, num])
if withscores:
pieces.append('withscores')
options = {'withscores': withscores, 'score_cast_func': score_cast_func}
return self.execute_command(*pieces, **options)
def zrevrank(self, name, value):
"""
Returns a 0-based value indicating the descending rank of
``value`` in sorted set ``name``
"""
return self.execute_command('ZREVRANK', name, value)
def zscore(self, name, value):
"Return the score of element ``value`` in sorted set ``name``"
return self.execute_command('ZSCORE', name, value)
def zunionstore(self, dest, keys, aggregate=None):
"""
Union multiple sorted sets specified by ``keys`` into
a new sorted set, ``dest``. Scores in the destination will be
aggregated based on the ``aggregate``, or SUM if none is provided.
"""
return self._zaggregate('ZUNIONSTORE', dest, keys, aggregate)
def _zaggregate(self, command, dest, keys, aggregate=None):
pieces = [command, dest, len(keys)]
if isinstance(keys, dict):
keys, weights = keys.keys(), keys.values()
else:
weights = None
pieces.extend(keys)
if weights:
pieces.append('WEIGHTS')
pieces.extend(weights)
if aggregate:
pieces.append('AGGREGATE')
pieces.append(aggregate)
return self.execute_command(*pieces)
#### HASH COMMANDS ####
def hdel(self, name, *keys):
"Delete ``keys`` from hash ``name``"
return self.execute_command('HDEL', name, *keys)
def hexists(self, name, key):
"Returns a boolean indicating if ``key`` exists within hash ``name``"
return self.execute_command('HEXISTS', name, key)
def hget(self, name, key):
"Return the value of ``key`` within the hash ``name``"
return self.execute_command('HGET', name, key)
def hgetall(self, name):
"Return a Python dict of the hash's name/value pairs"
return self.execute_command('HGETALL', name)
def hincrby(self, name, key, amount=1):
"Increment the value of ``key`` in hash ``name`` by ``amount``"
return self.execute_command('HINCRBY', name, key, amount)
def hkeys(self, name):
"Return the list of keys within hash ``name``"
return self.execute_command('HKEYS', name)
def hlen(self, name):
"Return the number of elements in hash ``name``"
return self.execute_command('HLEN', name)
def hset(self, name, key, value):
"""
Set ``key`` to ``value`` within hash ``name``
Returns 1 if HSET created a new field, otherwise 0
"""
return self.execute_command('HSET', name, key, value)
def hsetnx(self, name, key, value):
"""
Set ``key`` to ``value`` within hash ``name`` if ``key`` does not
exist. Returns 1 if HSETNX created a field, otherwise 0.
"""
return self.execute_command("HSETNX", name, key, value)
def hmset(self, name, mapping):
"""
Sets each key in the ``mapping`` dict to its corresponding value
in the hash ``name``
"""
if not mapping:
raise DataError("'hmset' with 'mapping' of length 0")
items = []
for pair in mapping.iteritems():
items.extend(pair)
return self.execute_command('HMSET', name, *items)
def hmget(self, name, keys):
"Returns a list of values ordered identically to ``keys``"
return self.execute_command('HMGET', name, *keys)
def hvals(self, name):
"Return the list of values within hash ``name``"
return self.execute_command('HVALS', name)
def publish(self, channel, message):
"""
Publish ``message`` on ``channel``.
Returns the number of subscribers the message was delivered to.
"""
return self.execute_command('PUBLISH', channel, message)
class PubSub(object):
"""
PubSub provides publish, subscribe and listen support to Redis channels.
After subscribing to one or more channels, the listen() method will block
until a message arrives on one of the subscribed channels. That message
will be returned and it's safe to start listening again.
"""
def __init__(self, connection_pool, shard_hint=None):
self.connection_pool = connection_pool
self.shard_hint = shard_hint
self.connection = None
self.channels = set()
self.patterns = set()
self.subscription_count = 0
self.subscribe_commands = set(
('subscribe', 'psubscribe', 'unsubscribe', 'punsubscribe')
)
def execute_command(self, *args, **kwargs):
"Execute a publish/subscribe command"
if self.connection is None:
self.connection = self.connection_pool.get_connection(
'pubsub',
self.shard_hint
)
connection = self.connection
try:
connection.send_command(*args)
return self.parse_response()
except ConnectionError:
connection.disconnect()
# resubscribe to all channels and patterns before
# resending the current command
for channel in self.channels:
self.subscribe(channel)
for pattern in self.patterns:
self.psubscribe(pattern)
connection.send_command(*args)
return self.parse_response()
def parse_response(self):
"Parse the response from a publish/subscribe command"
response = self.connection.read_response()
if response[0] in self.subscribe_commands:
self.subscription_count = response[2]
# if we've just unsubscribed from the remaining channels,
# release the connection back to the pool
if not self.subscription_count:
self.connection_pool.release(self.connection)
self.connection = None
return response
def psubscribe(self, patterns):
"Subscribe to all channels matching any pattern in ``patterns``"
if isinstance(patterns, basestring):
patterns = [patterns]
for pattern in patterns:
self.patterns.add(pattern)
return self.execute_command('PSUBSCRIBE', *patterns)
def punsubscribe(self, patterns=[]):
"""
Unsubscribe from any channel matching any pattern in ``patterns``.
If empty, unsubscribe from all channels.
"""
if isinstance(patterns, basestring):
patterns = [patterns]
for pattern in patterns:
try:
self.patterns.remove(pattern)
except KeyError:
pass
return self.execute_command('PUNSUBSCRIBE', *patterns)
def subscribe(self, channels):
"Subscribe to ``channels``, waiting for messages to be published"
if isinstance(channels, basestring):
channels = [channels]
for channel in channels:
self.channels.add(channel)
return self.execute_command('SUBSCRIBE', *channels)
def unsubscribe(self, channels=[]):
"""
Unsubscribe from ``channels``. If empty, unsubscribe
from all channels
"""
if isinstance(channels, basestring):
channels = [channels]
for channel in channels:
try:
self.channels.remove(channel)
except KeyError:
pass
return self.execute_command('UNSUBSCRIBE', *channels)
def listen(self):
"Listen for messages on channels this client has been subscribed to"
while self.subscription_count:
r = self.parse_response()
if r[0] == 'pmessage':
msg = {
'type': r[0],
'pattern': r[1],
'channel': r[2],
'data': r[3]
}
else:
msg = {
'type': r[0],
'pattern': None,
'channel': r[1],
'data': r[2]
}
yield msg
class Pipeline(Redis):
"""
Pipelines provide a way to transmit multiple commands to the Redis server
in one transmission. This is convenient for batch processing, such as
saving all the values in a list to Redis.
All commands executed within a pipeline are wrapped with MULTI and EXEC
calls. This guarantees all commands executed in the pipeline will be
executed atomically.
Any command raising an exception does *not* halt the execution of
subsequent commands in the pipeline. Instead, the exception is caught
and its instance is placed into the response list returned by execute().
Code iterating over the response list should be able to deal with an
instance of an exception as a potential value. In general, these will be
ResponseError exceptions, such as those raised when issuing a command
on a key of a different datatype.
"""
UNWATCH_COMMANDS = set(('DISCARD', 'EXEC', 'UNWATCH'))
def __init__(self, connection_pool, response_callbacks, transaction,
shard_hint):
self.connection_pool = connection_pool
self.connection = None
self.response_callbacks = response_callbacks
self.transaction = transaction
self.shard_hint = shard_hint
self.watching = False
self.reset()
def __enter__(self):
return self
def __exit__(self, exc_type, exc_value, traceback):
self.reset()
def reset(self):
self.command_stack = []
# make sure to reset the connection state in the event that we were
# watching something
if self.watching and self.connection:
try:
# call this manually since our unwatch or
# immediate_execute_command methods can call reset()
self.connection.send_command('UNWATCH')
self.connection.read_response()
except ConnectionError:
# disconnect will also remove any previous WATCHes
self.connection.disconnect()
# clean up the other instance attributes
self.watching = False
self.explicit_transaction = False
# we can safely return the connection to the pool here since we're
# sure we're no longer WATCHing anything
if self.connection:
self.connection_pool.release(self.connection)
self.connection = None
def multi(self):
"""
Start a transactional block of the pipeline after WATCH commands
are issued. End the transactional block with `execute`.
"""
if self.explicit_transaction:
raise RedisError('Cannot issue nested calls to MULTI')
if self.command_stack:
raise RedisError('Commands without an initial WATCH have already '
'been issued')
self.explicit_transaction = True
def execute_command(self, *args, **kwargs):
if (self.watching or args[0] == 'WATCH') and \
not self.explicit_transaction:
return self.immediate_execute_command(*args, **kwargs)
return self.pipeline_execute_command(*args, **kwargs)
def immediate_execute_command(self, *args, **options):
"""
Execute a command immediately, but don't auto-retry on a
ConnectionError if we're already WATCHing a variable. Used when
issuing WATCH or subsequent commands retrieving their values but before
MULTI is called.
"""
command_name = args[0]
conn = self.connection
# if this is the first call, we need a connection
if not conn:
conn = self.connection_pool.get_connection(command_name,
self.shard_hint)
self.connection = conn
try:
conn.send_command(*args)
return self.parse_response(conn, command_name, **options)
except ConnectionError:
conn.disconnect()
# if we're not already watching, we can safely retry the command
# assuming it was a connection timeout
if not self.watching:
conn.send_command(*args)
return self.parse_response(conn, command_name, **options)
self.reset()
raise
def pipeline_execute_command(self, *args, **options):
"""
Stage a command to be executed when execute() is next called
Returns the current Pipeline object back so commands can be
chained together, such as:
pipe = pipe.set('foo', 'bar').incr('baz').decr('bang')
At some other point, you can then run: pipe.execute(),
which will execute all commands queued in the pipe.
"""
self.command_stack.append((args, options))
return self
def _execute_transaction(self, connection, commands):
all_cmds = ''.join(starmap(connection.pack_command,
[args for args, options in commands]))
connection.send_packed_command(all_cmds)
# we don't care about the multi/exec any longer
commands = commands[1:-1]
# parse off the response for MULTI and all commands prior to EXEC.
# the only data we care about is the response the EXEC
# which is the last command
for i in range(len(commands)+1):
self.parse_response(connection, '_')
# parse the EXEC.
response = self.parse_response(connection, '_')
if response is None:
raise WatchError("Watched variable changed.")
if len(response) != len(commands):
raise ResponseError("Wrong number of response items from "
"pipeline execution")
# We have to run response callbacks manually
data = []
for r, cmd in izip(response, commands):
if not isinstance(r, Exception):
args, options = cmd
command_name = args[0]
if command_name in self.response_callbacks:
r = self.response_callbacks[command_name](r, **options)
data.append(r)
return data
def _execute_pipeline(self, connection, commands):
# build up all commands into a single request to increase network perf
all_cmds = ''.join(starmap(connection.pack_command,
[args for args, options in commands]))
connection.send_packed_command(all_cmds)
return [self.parse_response(connection, args[0], **options)
for args, options in commands]
def parse_response(self, connection, command_name, **options):
result = super(Pipeline, self).parse_response(
connection, command_name, **options)
if command_name in self.UNWATCH_COMMANDS:
self.watching = False
elif command_name == 'WATCH':
self.watching = True
return result
def execute(self):
"Execute all the commands in the current pipeline"
stack = self.command_stack
if self.transaction or self.explicit_transaction:
stack = [(('MULTI' ,), {})] + stack + [(('EXEC', ), {})]
execute = self._execute_transaction
else:
execute = self._execute_pipeline
conn = self.connection
if not conn:
conn = self.connection_pool.get_connection('MULTI', self.shard_hint)
# assign to self.connection so reset() releases the connection
# back to the pool after we're done
self.connection = conn
try:
return execute(conn, stack)
except ConnectionError:
conn.disconnect()
# if we were watching a variable, the watch is no longer valid since
# this connection has died. raise a WatchError, which indicates
# the user should retry his transaction. If this is more than a
# temporary failure, the WATCH that the user next issue will fail,
# propegating the real ConnectionError
if self.watching:
raise WatchError("A ConnectionError occured on while watching "
"one or more keys")
# otherwise, it's safe to retry since the transaction isn't
# predicated on any state
return execute(conn, stack)
finally:
self.reset()
def watch(self, *names):
"""
Watches the values at keys ``names``
"""
if self.explicit_transaction:
raise RedisError('Cannot issue a WATCH after a MULTI')
return self.execute_command('WATCH', *names)
def unwatch(self):
"""
Unwatches all previously specified keys
"""
return self.watching and self.execute_command('UNWATCH') or True
class LockError(RedisError):
"Errors thrown from the Lock"
pass
class Lock(object):
"""
A shared, distributed Lock. Using Redis for locking allows the Lock
to be shared across processes and/or machines.
It's left to the user to resolve deadlock issues and make sure
multiple clients play nicely together.
"""
LOCK_FOREVER = float(2**31+1) # 1 past max unix time
def __init__(self, redis, name, timeout=None, sleep=0.1):
"""
Create a new Lock instnace named ``name`` using the Redis client
supplied by ``redis``.
``timeout`` indicates a maximum life for the lock.
By default, it will remain locked until release() is called.
``sleep`` indicates the amount of time to sleep per loop iteration
when the lock is in blocking mode and another client is currently
holding the lock.
Note: If using ``timeout``, you should make sure all the hosts
that are running clients are within the same timezone and are using
a network time service like ntp.
"""
self.redis = redis
self.name = name
self.acquired_until = None
self.timeout = timeout
self.sleep = sleep
if self.timeout and self.sleep > self.timeout:
raise LockError("'sleep' must be less than 'timeout'")
def __enter__(self):
return self.acquire()
def __exit__(self, exc_type, exc_value, traceback):
self.release()
def acquire(self, blocking=True):
"""
Use Redis to hold a shared, distributed lock named ``name``.
Returns True once the lock is acquired.
If ``blocking`` is False, always return immediately. If the lock
was acquired, return True, otherwise return False.
"""
sleep = self.sleep
timeout = self.timeout
while 1:
unixtime = int(time.time())
if timeout:
timeout_at = unixtime + timeout
else:
timeout_at = Lock.LOCK_FOREVER
timeout_at = float(timeout_at)
if self.redis.setnx(self.name, timeout_at):
self.acquired_until = timeout_at
return True
# We want blocking, but didn't acquire the lock
# check to see if the current lock is expired
existing = float(self.redis.get(self.name) or 1)
if existing < unixtime:
# the previous lock is expired, attempt to overwrite it
existing = float(self.redis.getset(self.name, timeout_at) or 1)
if existing < unixtime:
# we successfully acquired the lock
self.acquired_until = timeout_at
return True
if not blocking:
return False
time.sleep(sleep)
def release(self):
"Releases the already acquired lock"
if self.acquired_until is None:
raise ValueError("Cannot release an unlocked lock")
existing = float(self.redis.get(self.name) or 1)
# if the lock time is in the future, delete the lock
if existing >= self.acquired_until:
self.redis.delete(self.name)
self.acquired_until = None
|