/usr/lib/python2.7/dist-packages/twext/protocols/memcache.py is in calendarserver 5.2+dfsg-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 | # -*- test-case-name: twisted.test.test_memcache -*-
# Copyright (c) 2007-2009 Twisted Matrix Laboratories.
# See LICENSE for details.
"""
Memcache client protocol. Memcached is a caching server, storing data in the
form of pairs key/value, and memcache is the protocol to talk with it.
To connect to a server, create a factory for L{MemCacheProtocol}::
from twisted.internet import reactor, protocol
from twisted.protocols.memcache import MemCacheProtocol, DEFAULT_PORT
d = protocol.ClientCreator(reactor, MemCacheProtocol
).connectTCP("localhost", DEFAULT_PORT)
def doSomething(proto):
# Here you call the memcache operations
return proto.set("mykey", "a lot of data")
d.addCallback(doSomething)
reactor.run()
All the operations of the memcache protocol are present, but
L{MemCacheProtocol.set} and L{MemCacheProtocol.get} are the more important.
See U{http://code.sixapart.com/svn/memcached/trunk/server/doc/protocol.txt} for
more information about the protocol.
"""
try:
from collections import deque
except ImportError:
class deque(list):
def popleft(self):
return self.pop(0)
from twisted.protocols.basic import LineReceiver
from twisted.protocols.policies import TimeoutMixin
from twisted.internet.defer import Deferred, fail, TimeoutError
from twext.python.log import Logger
log = Logger()
DEFAULT_PORT = 11211
class NoSuchCommand(Exception):
"""
Exception raised when a non existent command is called.
"""
class ClientError(Exception):
"""
Error caused by an invalid client call.
"""
class ServerError(Exception):
"""
Problem happening on the server.
"""
class Command(object):
"""
Wrap a client action into an object, that holds the values used in the
protocol.
@ivar _deferred: the L{Deferred} object that will be fired when the result
arrives.
@type _deferred: L{Deferred}
@ivar command: name of the command sent to the server.
@type command: C{str}
"""
def __init__(self, command, **kwargs):
"""
Create a command.
@param command: the name of the command.
@type command: C{str}
@param kwargs: this values will be stored as attributes of the object
for future use
"""
self.command = command
self._deferred = Deferred()
for k, v in kwargs.items():
setattr(self, k, v)
def success(self, value):
"""
Shortcut method to fire the underlying deferred.
"""
self._deferred.callback(value)
def fail(self, error):
"""
Make the underlying deferred fails.
"""
self._deferred.errback(error)
class MemCacheProtocol(LineReceiver, TimeoutMixin):
"""
MemCache protocol: connect to a memcached server to store/retrieve values.
@ivar persistentTimeOut: the timeout period used to wait for a response.
@type persistentTimeOut: C{int}
@ivar _current: current list of requests waiting for an answer from the
server.
@type _current: C{deque} of L{Command}
@ivar _lenExpected: amount of data expected in raw mode, when reading for
a value.
@type _lenExpected: C{int}
@ivar _getBuffer: current buffer of data, used to store temporary data
when reading in raw mode.
@type _getBuffer: C{list}
@ivar _bufferLength: the total amount of bytes in C{_getBuffer}.
@type _bufferLength: C{int}
"""
MAX_KEY_LENGTH = 250
def __init__(self, timeOut=60):
"""
Create the protocol.
@param timeOut: the timeout to wait before detecting that the
connection is dead and close it. It's expressed in seconds.
@type timeOut: C{int}
"""
self._current = deque()
self._lenExpected = None
self._getBuffer = None
self._bufferLength = None
self.persistentTimeOut = self.timeOut = timeOut
def timeoutConnection(self):
"""
Close the connection in case of timeout.
"""
for cmd in self._current:
cmd.fail(TimeoutError("Connection timeout"))
self.transport.loseConnection()
def sendLine(self, line):
"""
Override sendLine to add a timeout to response.
"""
if not self._current:
self.setTimeout(self.persistentTimeOut)
LineReceiver.sendLine(self, line)
def rawDataReceived(self, data):
"""
Collect data for a get.
"""
self.resetTimeout()
self._getBuffer.append(data)
self._bufferLength += len(data)
if self._bufferLength >= self._lenExpected + 2:
data = "".join(self._getBuffer)
buf = data[:self._lenExpected]
rem = data[self._lenExpected + 2:]
val = buf
self._lenExpected = None
self._getBuffer = None
self._bufferLength = None
cmd = self._current[0]
cmd.value = val
self.setLineMode(rem)
def cmd_STORED(self):
"""
Manage a success response to a set operation.
"""
self._current.popleft().success(True)
def cmd_NOT_STORED(self):
"""
Manage a specific 'not stored' response to a set operation: this is not
an error, but some condition wasn't met.
"""
self._current.popleft().success(False)
def cmd_END(self):
"""
This the end token to a get or a stat operation.
"""
cmd = self._current.popleft()
if cmd.command == "get":
cmd.success((cmd.flags, cmd.value))
elif cmd.command == "gets":
cmd.success((cmd.flags, cmd.cas, cmd.value))
elif cmd.command == "stats":
cmd.success(cmd.values)
def cmd_NOT_FOUND(self):
"""
Manage error response for incr/decr/delete.
"""
self._current.popleft().success(False)
def cmd_VALUE(self, line):
"""
Prepare the reading a value after a get.
"""
cmd = self._current[0]
if cmd.command == "get":
key, flags, length = line.split()
cas = ""
else:
key, flags, length, cas = line.split()
self._lenExpected = int(length)
self._getBuffer = []
self._bufferLength = 0
if cmd.key != key:
raise RuntimeError("Unexpected commands answer.")
cmd.flags = int(flags)
cmd.length = self._lenExpected
cmd.cas = cas
self.setRawMode()
def cmd_STAT(self, line):
"""
Reception of one stat line.
"""
cmd = self._current[0]
key, val = line.split(" ", 1)
cmd.values[key] = val
def cmd_VERSION(self, versionData):
"""
Read version token.
"""
self._current.popleft().success(versionData)
def cmd_ERROR(self):
"""
An non-existent command has been sent.
"""
log.error("Non-existent command sent.")
cmd = self._current.popleft()
cmd.fail(NoSuchCommand())
def cmd_CLIENT_ERROR(self, errText):
"""
An invalid input as been sent.
"""
log.error("Invalid input: %s" % (errText,))
cmd = self._current.popleft()
cmd.fail(ClientError(errText))
def cmd_SERVER_ERROR(self, errText):
"""
An error has happened server-side.
"""
log.error("Server error: %s" % (errText,))
cmd = self._current.popleft()
cmd.fail(ServerError(errText))
def cmd_DELETED(self):
"""
A delete command has completed successfully.
"""
self._current.popleft().success(True)
def cmd_OK(self):
"""
The last command has been completed.
"""
self._current.popleft().success(True)
def cmd_EXISTS(self):
"""
A C{checkAndSet} update has failed.
"""
self._current.popleft().success(False)
def lineReceived(self, line):
"""
Receive line commands from the server.
"""
self.resetTimeout()
token = line.split(" ", 1)[0]
# First manage standard commands without space
cmd = getattr(self, "cmd_%s" % (token,), None)
if cmd is not None:
args = line.split(" ", 1)[1:]
if args:
cmd(args[0])
else:
cmd()
else:
# Then manage commands with space in it
line = line.replace(" ", "_")
cmd = getattr(self, "cmd_%s" % (line,), None)
if cmd is not None:
cmd()
else:
# Increment/Decrement response
cmd = self._current.popleft()
val = int(line)
cmd.success(val)
if not self._current:
# No pending request, remove timeout
self.setTimeout(None)
def increment(self, key, val=1):
"""
Increment the value of C{key} by given value (default to 1).
C{key} must be consistent with an int. Return the new value.
@param key: the key to modify.
@type key: C{str}
@param val: the value to increment.
@type val: C{int}
@return: a deferred with will be called back with the new value
associated with the key (after the increment).
@rtype: L{Deferred}
"""
return self._incrdecr("incr", key, val)
def decrement(self, key, val=1):
"""
Decrement the value of C{key} by given value (default to 1).
C{key} must be consistent with an int. Return the new value, coerced to
0 if negative.
@param key: the key to modify.
@type key: C{str}
@param val: the value to decrement.
@type val: C{int}
@return: a deferred with will be called back with the new value
associated with the key (after the decrement).
@rtype: L{Deferred}
"""
return self._incrdecr("decr", key, val)
def _incrdecr(self, cmd, key, val):
"""
Internal wrapper for incr/decr.
"""
if not isinstance(key, str):
return fail(ClientError(
"Invalid type for key: %s, expecting a string" % (type(key),)))
if len(key) > self.MAX_KEY_LENGTH:
return fail(ClientError("Key too long"))
fullcmd = "%s %s %d" % (cmd, key, int(val))
self.sendLine(fullcmd)
cmdObj = Command(cmd, key=key)
self._current.append(cmdObj)
return cmdObj._deferred
def replace(self, key, val, flags=0, expireTime=0):
"""
Replace the given C{key}. It must already exist in the server.
@param key: the key to replace.
@type key: C{str}
@param val: the new value associated with the key.
@type val: C{str}
@param flags: the flags to store with the key.
@type flags: C{int}
@param expireTime: if different from 0, the relative time in seconds
when the key will be deleted from the store.
@type expireTime: C{int}
@return: a deferred that will fire with C{True} if the operation has
succeeded, and C{False} with the key didn't previously exist.
@rtype: L{Deferred}
"""
return self._set("replace", key, val, flags, expireTime, "")
def add(self, key, val, flags=0, expireTime=0):
"""
Add the given C{key}. It must not exist in the server.
@param key: the key to add.
@type key: C{str}
@param val: the value associated with the key.
@type val: C{str}
@param flags: the flags to store with the key.
@type flags: C{int}
@param expireTime: if different from 0, the relative time in seconds
when the key will be deleted from the store.
@type expireTime: C{int}
@return: a deferred that will fire with C{True} if the operation has
succeeded, and C{False} with the key already exists.
@rtype: L{Deferred}
"""
return self._set("add", key, val, flags, expireTime, "")
def set(self, key, val, flags=0, expireTime=0):
"""
Set the given C{key}.
@param key: the key to set.
@type key: C{str}
@param val: the value associated with the key.
@type val: C{str}
@param flags: the flags to store with the key.
@type flags: C{int}
@param expireTime: if different from 0, the relative time in seconds
when the key will be deleted from the store.
@type expireTime: C{int}
@return: a deferred that will fire with C{True} if the operation has
succeeded.
@rtype: L{Deferred}
"""
return self._set("set", key, val, flags, expireTime, "")
def checkAndSet(self, key, val, cas, flags=0, expireTime=0):
"""
Change the content of C{key} only if the C{cas} value matches the
current one associated with the key. Use this to store a value which
hasn't been modified since last time you fetched it.
@param key: The key to set.
@type key: C{str}
@param val: The value associated with the key.
@type val: C{str}
@param cas: Unique 64-bit value returned by previous call of C{get}.
@type cas: C{str}
@param flags: The flags to store with the key.
@type flags: C{int}
@param expireTime: If different from 0, the relative time in seconds
when the key will be deleted from the store.
@type expireTime: C{int}
@return: A deferred that will fire with C{True} if the operation has
succeeded, C{False} otherwise.
@rtype: L{Deferred}
"""
return self._set("cas", key, val, flags, expireTime, cas)
def _set(self, cmd, key, val, flags, expireTime, cas):
"""
Internal wrapper for setting values.
"""
if not isinstance(key, str):
return fail(ClientError(
"Invalid type for key: %s, expecting a string" % (type(key),)))
if len(key) > self.MAX_KEY_LENGTH:
return fail(ClientError("Key too long"))
if not isinstance(val, str):
return fail(ClientError(
"Invalid type for value: %s, expecting a string" %
(type(val),)))
if cas:
cas = " " + cas
length = len(val)
fullcmd = "%s %s %d %d %d%s" % (
cmd, key, flags, expireTime, length, cas)
self.sendLine(fullcmd)
self.sendLine(val)
cmdObj = Command(cmd, key=key, flags=flags, length=length)
self._current.append(cmdObj)
return cmdObj._deferred
def append(self, key, val):
"""
Append given data to the value of an existing key.
@param key: The key to modify.
@type key: C{str}
@param val: The value to append to the current value associated with
the key.
@type val: C{str}
@return: A deferred that will fire with C{True} if the operation has
succeeded, C{False} otherwise.
@rtype: L{Deferred}
"""
# Even if flags and expTime values are ignored, we have to pass them
return self._set("append", key, val, 0, 0, "")
def prepend(self, key, val):
"""
Prepend given data to the value of an existing key.
@param key: The key to modify.
@type key: C{str}
@param val: The value to prepend to the current value associated with
the key.
@type val: C{str}
@return: A deferred that will fire with C{True} if the operation has
succeeded, C{False} otherwise.
@rtype: L{Deferred}
"""
# Even if flags and expTime values are ignored, we have to pass them
return self._set("prepend", key, val, 0, 0, "")
def get(self, key, withIdentifier=False):
"""
Get the given C{key}. It doesn't support multiple keys. If
C{withIdentifier} is set to C{True}, the command issued is a C{gets},
that will return the current identifier associated with the value. This
identifier has to be used when issuing C{checkAndSet} update later,
using the corresponding method.
@param key: The key to retrieve.
@type key: C{str}
@param withIdentifier: If set to C{True}, retrieve the current
identifier along with the value and the flags.
@type withIdentifier: C{bool}
@return: A deferred that will fire with the tuple (flags, value) if
C{withIdentifier} is C{False}, or (flags, cas identifier, value)
if C{True}.
@rtype: L{Deferred}
"""
if not isinstance(key, str):
return fail(ClientError(
"Invalid type for key: %s, expecting a string" % (type(key),)))
if len(key) > self.MAX_KEY_LENGTH:
return fail(ClientError("Key too long"))
if withIdentifier:
cmd = "gets"
else:
cmd = "get"
fullcmd = "%s %s" % (cmd, key)
self.sendLine(fullcmd)
cmdObj = Command(cmd, key=key, value=None, flags=0, cas="")
self._current.append(cmdObj)
return cmdObj._deferred
def stats(self, arg=None):
"""
Get some stats from the server. It will be available as a dict.
@param arg: An optional additional string which will be sent along
with the I{stats} command. The interpretation of this value by
the server is left undefined by the memcache protocol
specification.
@type arg: L{NoneType} or L{str}
@return: a deferred that will fire with a C{dict} of the available
statistics.
@rtype: L{Deferred}
"""
cmd = "stats"
if arg:
cmd = "stats " + arg
self.sendLine(cmd)
cmdObj = Command("stats", values={})
self._current.append(cmdObj)
return cmdObj._deferred
def version(self):
"""
Get the version of the server.
@return: a deferred that will fire with the string value of the
version.
@rtype: L{Deferred}
"""
self.sendLine("version")
cmdObj = Command("version")
self._current.append(cmdObj)
return cmdObj._deferred
def delete(self, key):
"""
Delete an existing C{key}.
@param key: the key to delete.
@type key: C{str}
@return: a deferred that will be called back with C{True} if the key
was successfully deleted, or C{False} if not.
@rtype: L{Deferred}
"""
if not isinstance(key, str):
return fail(ClientError(
"Invalid type for key: %s, expecting a string" % (type(key),)))
self.sendLine("delete %s" % key)
cmdObj = Command("delete", key=key)
self._current.append(cmdObj)
return cmdObj._deferred
def flushAll(self):
"""
Flush all cached values.
@return: a deferred that will be called back with C{True} when the
operation has succeeded.
@rtype: L{Deferred}
"""
self.sendLine("flush_all")
cmdObj = Command("flush_all")
self._current.append(cmdObj)
return cmdObj._deferred
__all__ = ["MemCacheProtocol", "DEFAULT_PORT", "NoSuchCommand", "ClientError",
"ServerError"]
|