#
#
-# Copyright (C) 2009 Google Inc.
+# Copyright (C) 2009, 2010 Google Inc.
#
# This program is free software; you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
from ganeti import errors
from ganeti import confd
from ganeti import ssconf
+from ganeti import compat
+from ganeti import netutils
class ConfdAsyncUDPClient(daemon.AsyncUDPSocket):
implement a non-asyncore based client library.
"""
- def __init__(self, client):
+ def __init__(self, client, family):
"""Constructor for ConfdAsyncUDPClient
@type client: L{ConfdClient}
@param client: client library, to pass the datagrams to
"""
- daemon.AsyncUDPSocket.__init__(self)
+ daemon.AsyncUDPSocket.__init__(self, family)
self.client = client
# this method is overriding a daemon.AsyncUDPSocket method
@ivar request: the request data
@ivar args: any extra arguments for the callback
@ivar expiry: the expiry timestamp of the request
+ @ivar sent: the set of contacted peers
+ @ivar rcvd: the set of peers who replied
"""
- def __init__(self, request, args, expiry):
+ def __init__(self, request, args, expiry, sent):
self.request = request
self.args = args
self.expiry = expiry
+ self.sent = frozenset(sent)
+ self.rcvd = set()
class ConfdClient:
raise errors.ProgrammerError("callback must be callable")
self.UpdatePeerList(peers)
+ self._SetPeersAddressFamily()
self._hmac_key = hmac_key
- self._socket = ConfdAsyncUDPClient(self)
+ self._socket = ConfdAsyncUDPClient(self, self._family)
self._callback = callback
self._confd_port = port
self._logger = logger
self._requests = {}
if self._confd_port is None:
- self._confd_port = utils.GetDaemonPort(constants.CONFD)
+ self._confd_port = netutils.GetDaemonPort(constants.CONFD)
def UpdatePeerList(self, peers):
"""Update the list of peers
)
self._callback(client_reply)
- def SendRequest(self, request, args=None, coverage=None, async=True):
+ def SendRequest(self, request, args=None, coverage=0, async=True):
"""Send a confd request to some MCs
@type request: L{objects.ConfdRequest}
@type args: tuple
@param args: additional callback arguments
@type coverage: integer
- @param coverage: number of remote nodes to contact
+ @param coverage: number of remote nodes to contact; if default
+ (0), it will use a reasonable default
+ (L{ganeti.constants.CONFD_DEFAULT_REQ_COVERAGE}), if -1 is
+ passed, it will use the maximum number of peers, otherwise the
+ number passed in will be used
@type async: boolean
@param async: handle the write asynchronously
"""
- if coverage is None:
+ if coverage == 0:
coverage = min(len(self._peers), constants.CONFD_DEFAULT_REQ_COVERAGE)
+ elif coverage == -1:
+ coverage = len(self._peers)
if coverage > len(self._peers):
raise errors.ConfdClientError("Not enough MCs known to provide the"
raise errors.ConfdClientError("Request too big")
expire_time = now + constants.CONFD_CLIENT_EXPIRE_TIMEOUT
- self._requests[request.rsalt] = _Request(request, args, expire_time)
+ self._requests[request.rsalt] = _Request(request, args, expire_time,
+ targets)
if not async:
self.FlushSendQueue()
self._logger.debug("Discarding unknown (expired?) reply: %s" % err)
return
+ rq.rcvd.add(ip)
+
client_reply = ConfdUpcallPayload(salt=salt,
type=UPCALL_REPLY,
server_reply=answer,
"""
return self._socket.process_next_packet(timeout=timeout)
+ @staticmethod
+ def _NeededReplies(peer_cnt):
+ """Compute the minimum safe number of replies for a query.
+
+ The algorithm is designed to work well for both small and big
+ number of peers:
+ - for less than three, we require all responses
+ - for less than five, we allow one miss
+ - otherwise, half the number plus one
+
+ This guarantees that we progress monotonically: 1->1, 2->2, 3->2,
+ 4->2, 5->3, 6->3, 7->4, etc.
+
+ @type peer_cnt: int
+ @param peer_cnt: the number of peers contacted
+ @rtype: int
+ @return: the number of replies which should give a safe coverage
+
+ """
+ if peer_cnt < 3:
+ return peer_cnt
+ elif peer_cnt < 5:
+ return peer_cnt - 1
+ else:
+ return int(peer_cnt/2) + 1
+
+ def WaitForReply(self, salt, timeout=constants.CONFD_CLIENT_EXPIRE_TIMEOUT):
+ """Wait for replies to a given request.
+
+ This method will wait until either the timeout expires or a
+ minimum number (computed using L{_NeededReplies}) of replies are
+ received for the given salt. It is useful when doing synchronous
+ calls to this library.
+
+ @param salt: the salt of the request we want responses for
+ @param timeout: the maximum timeout (should be less or equal to
+ L{ganeti.constants.CONFD_CLIENT_EXPIRE_TIMEOUT}
+ @rtype: tuple
+ @return: a tuple of (timed_out, sent_cnt, recv_cnt); if the
+ request is unknown, timed_out will be true and the counters
+ will be zero
+
+ """
+ def _CheckResponse():
+ if salt not in self._requests:
+ # expired?
+ if self._logger:
+ self._logger.debug("Discarding unknown/expired request: %s" % salt)
+ return MISSING
+ rq = self._requests[salt]
+ if len(rq.rcvd) >= expected:
+ # already got all replies
+ return (False, len(rq.sent), len(rq.rcvd))
+ # else wait, using default timeout
+ self.ReceiveReply()
+ raise utils.RetryAgain()
+
+ MISSING = (True, 0, 0)
+
+ if salt not in self._requests:
+ return MISSING
+ # extend the expire time with the current timeout, so that we
+ # don't get the request expired from under us
+ rq = self._requests[salt]
+ rq.expiry += timeout
+ sent = len(rq.sent)
+ expected = self._NeededReplies(sent)
+
+ try:
+ return utils.Retry(_CheckResponse, 0, timeout)
+ except utils.RetryTimeout:
+ if salt in self._requests:
+ rq = self._requests[salt]
+ return (True, len(rq.sent), len(rq.rcvd))
+ else:
+ return MISSING
+
+ def _SetPeersAddressFamily(self):
+ if not self._peers:
+ raise errors.ConfdClientError("Peer list empty")
+ try:
+ peer = self._peers[0]
+ self._family = netutils.IPAddress.GetAddressFamily(peer)
+ for peer in self._peers[1:]:
+ if netutils.IPAddress.GetAddressFamily(peer) != self._family:
+ raise errors.ConfdClientError("Peers must be of same address family")
+ except errors.IPAddressError:
+ raise errors.ConfdClientError("Peer address %s invalid" % peer)
+
# UPCALL_REPLY: server reply upcall
# has all ConfdUpcallPayload fields populated
"""Have all the registered queries received at least an answer?
"""
- return utils.all(self._answers.values())
+ return compat.all(self._answers.values())
def _HandleExpire(self, up):
# if we have no answer we have received none, before the expiration.
self._callback(up)
+class StoreResultCallback:
+ """Callback that simply stores the most recent answer.
+
+ @ivar _answers: dict of salt to (have_answer, reply)
+
+ """
+ _NO_KEY = (False, None)
+
+ def __init__(self):
+ """Constructor for StoreResultCallback
+
+ """
+ # answers contains a dict of salt -> best result
+ self._answers = {}
+
+ def GetResponse(self, salt):
+ """Return the best match for a salt
+
+ """
+ return self._answers.get(salt, self._NO_KEY)
+
+ def _HandleExpire(self, up):
+ """Expiration handler.
+
+ """
+ if up.salt in self._answers and self._answers[up.salt] == self._NO_KEY:
+ del self._answers[up.salt]
+
+ def _HandleReply(self, up):
+ """Handle a single confd reply, and decide whether to filter it.
+
+ """
+ self._answers[up.salt] = (True, up)
+
+ def __call__(self, up):
+ """Filtering callback
+
+ @type up: L{ConfdUpcallPayload}
+ @param up: upper callback
+
+ """
+ if up.type == UPCALL_REPLY:
+ self._HandleReply(up)
+ elif up.type == UPCALL_EXPIRE:
+ self._HandleExpire(up)
+
+
def GetConfdClient(callback):
"""Return a client configured using the given callback.