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Commit 693aaf79 authored by Julien Muchembled's avatar Julien Muchembled
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client: prepare merge of ConnectionPool inside Application

parent 305dda86
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neo/client/app.py
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......@@ -14,943 +14,86 @@
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import heapq
import time
try:
from ZODB._compat import dumps, loads, _protocol
except ImportError:
from cPickle import dumps, loads
_protocol = 1
from ZODB.POSException import UndoError, ConflictError, ReadConflictError
from . import OLD_ZODB
if OLD_ZODB:
from ZODB.ConflictResolution import ResolvedSerial
from persistent.TimeStamp import TimeStamp
import random, time
from neo.lib import logging
from neo.lib.compress import decompress_list, getCompress
from neo.lib.protocol import NodeTypes, Packets, \
INVALID_PARTITION, MAX_TID, ZERO_HASH, ZERO_TID
from neo.lib.util import makeChecksum, dump
from neo.lib.locking import Empty, Lock
from neo.lib.locking import Lock
from neo.lib.protocol import NodeTypes, Packets
from neo.lib.connection import MTClientConnection, ConnectionClosed
from .exception import (NEOStorageError, NEOStorageCreationUndoneError,
NEOStorageReadRetry, NEOStorageNotFoundError, NEOPrimaryMasterLost)
from .handlers import storage, master
from neo.lib.threaded_app import ThreadedApplication
from .cache import ClientCache
from .pool import ConnectionPool
from .transactions import TransactionContainer
from neo.lib.util import p64, u64, parseMasterList
CHECKED_SERIAL = object()
try:
from Signals.Signals import SignalHandler
except ImportError:
SignalHandler = None
if SignalHandler:
import signal
SignalHandler.registerHandler(signal.SIGUSR2, logging.reopen)
class Application(ThreadedApplication):
"""The client node application."""
# For tests only. Do not touch. We want tpc_finish to always recover when
# the transaction is really committed, no matter for how long the master
# is unreachable.
max_reconnection_to_master = float('inf')
def __init__(self, master_nodes, name, compress=True, cache_size=None,
**kw):
super(Application, self).__init__(parseMasterList(master_nodes),
name, **kw)
# Internal Attributes common to all thread
self._db = None
self.cp = ConnectionPool(self)
self.primary_master_node = None
self.trying_master_node = None
# no self-assigned UUID, primary master will supply us one
self._cache = ClientCache() if cache_size is None else \
ClientCache(max_size=cache_size)
self._loading_oid = None
self.new_oid_list = ()
self.last_oid = '\0' * 8
self.storage_event_handler = storage.StorageEventHandler(self)
self.storage_bootstrap_handler = storage.StorageBootstrapHandler(self)
self.storage_handler = storage.StorageAnswersHandler(self)
self.primary_handler = master.PrimaryAnswersHandler(self)
self.primary_bootstrap_handler = master.PrimaryBootstrapHandler(self)
self.notifications_handler = master.PrimaryNotificationsHandler( self)
self._txn_container = TransactionContainer()
# Lock definition :
# _load_lock is used to make loading and storing atomic
lock = Lock()
self._load_lock_acquire = lock.acquire
self._load_lock_release = lock.release
# _oid_lock is used in order to not call multiple oid
# generation at the same time
lock = Lock()
self._oid_lock_acquire = lock.acquire
self._oid_lock_release = lock.release
lock = Lock()
# _cache_lock is used for the client cache
self._cache_lock_acquire = lock.acquire
self._cache_lock_release = lock.release
# _connecting_to_master_node is used to prevent simultaneous master
# node connection attempts
self._connecting_to_master_node = Lock()
self.compress = getCompress(compress)
def __getattr__(self, attr):
if attr in ('last_tid', 'pt'):
self._getMasterConnection()
# XXX: There's still a risk that we get disconnected from the
# master at this precise moment and for 'pt', we'd raise
# AttributeError. Should we catch it and loop until it
# succeeds?
return self.__getattribute__(attr)
def log(self):
super(Application, self).log()
logging.info("%r", self._cache)
@property
def txn_contexts(self):
# do not iter lazily to avoid race condition
return self._txn_container.values
def _waitAnyMessage(self, queue, block=True):
"""
Handle all pending packets.
block
If True (default), will block until at least one packet was
received.
"""
pending = self.dispatcher.pending
get = queue.get
_handlePacket = self._handlePacket
while pending(queue):
try:
conn, packet, kw = get(block)
except Empty:
break
block = False
try:
_handlePacket(conn, packet, kw)
except (ConnectionClosed, NEOStorageReadRetry):
# We also catch NEOStorageReadRetry for ObjectUndoSerial.
pass
def _waitAnyTransactionMessage(self, txn_context, block=True):
"""
Just like _waitAnyMessage, but for per-transaction exchanges, rather
than per-thread.
"""
queue = txn_context.queue
self.setHandlerData(txn_context)
from neo.lib.exception import NodeNotReady
from .exception import NEOPrimaryMasterLost
# How long before we might retry a connection to a node to which connection
# failed in the past.
MAX_FAILURE_AGE = 600
class ConnectionPool(object):
"""This class manages a pool of connections to storage nodes."""
# XXX: This is not a pool anymore.
def __init__(self, app):
self.app = app
# Define a lock in order to create one connection to
# a storage node at a time to avoid multiple connections
# to the same node.
self._lock = Lock()
self.node_failure_dict = {}
def _initNodeConnection(self, node):
"""Init a connection to a given storage node."""
app = self.app
if app.master_conn is None:
raise NEOPrimaryMasterLost
conn = MTClientConnection(app, app.storage_event_handler, node,
dispatcher=app.dispatcher)
p = Packets.RequestIdentification(NodeTypes.CLIENT,
app.uuid, None, app.name, (), app.id_timestamp)
try:
self._waitAnyMessage(queue, block=block)
finally:
# Don't leave access to thread context, even if a raise happens.
self.setHandlerData(None)
if txn_context.conflict_dict:
self._handleConflicts(txn_context)
def _askStorage(self, conn, packet, **kw):
""" Send a request to a storage node and process its answer """
return self._ask(conn, packet, handler=self.storage_handler, **kw)
def _askPrimary(self, packet, **kw):
""" Send a request to the primary master and process its answer """
return self._ask(self._getMasterConnection(), packet,
handler=self.primary_handler, **kw)
def _getMasterConnection(self):
""" Connect to the primary master node on demand """
# For performance reasons, get 'master_conn' without locking.
result = self.master_conn
if result is None:
# If not connected, 'master_conn' must be tested again while we have
# the lock, to avoid concurrent threads reconnecting.
with self._connecting_to_master_node:
result = self.master_conn
if result is None:
self.new_oid_list = ()
result = self.master_conn = self._connectToPrimaryNode()
return result
def _connectToPrimaryNode(self):
"""
Lookup for the current primary master node
"""
logging.debug('connecting to primary master...')
self.start()
index = -1
fail_count = 0
ask = self._ask
handler = self.primary_bootstrap_handler
while 1:
self.ignore_invalidations = True
# Get network connection to primary master
while fail_count < self.max_reconnection_to_master:
self.nm.reset()
if self.primary_master_node is not None:
# If I know a primary master node, pinpoint it.
node = self.primary_master_node
self.primary_master_node = None
else:
# Otherwise, check one by one.
master_list = self.nm.getMasterList()
if not master_list:
# XXX: On shutdown, it already happened that this list
# is empty, leading to ZeroDivisionError. This
# looks a minor issue so let's wait to have more
# information.
logging.error('%r', self.__dict__)
index = (index + 1) % len(master_list)
node = master_list[index]
# Connect to master
conn = MTClientConnection(self,
self.notifications_handler,
node=node,
dispatcher=self.dispatcher)
p = Packets.RequestIdentification(
NodeTypes.CLIENT, self.uuid, None, self.name, (), None)
try:
ask(conn, p, handler=handler)
except ConnectionClosed:
fail_count += 1
else:
self.primary_master_node = node
break
else:
raise NEOPrimaryMasterLost(
"Too many connection failures to the primary master")
logging.info('Connected to %s', self.primary_master_node)
try:
# Request identification and required informations to be
# operational. Might raise ConnectionClosed so that the new
# primary can be looked-up again.
logging.info('Initializing from master')
ask(conn, Packets.AskPartitionTable(), handler=handler)
ask(conn, Packets.AskLastTransaction(), handler=handler)
if self.pt.operational():
break
except ConnectionClosed:
logging.error('Connection to %s lost', self.trying_master_node)
self.primary_master_node = None
fail_count += 1
logging.info("Connected and ready")
app._ask(conn, p, handler=app.storage_bootstrap_handler)
except ConnectionClosed:
logging.error('Connection to %r failed', node)
except NodeNotReady:
logging.info('%r not ready', node)
else:
logging.info('Connected %r', node)
# Make sure this node will be considered for the next reads
# even if there was a previous recent failure.
self.node_failure_dict.pop(node.getUUID(), None)
return conn
self.node_failure_dict[node.getUUID()] = time.time() + MAX_FAILURE_AGE
def getCellSortKey(self, cell, random=random.random):
# Prefer a node that didn't fail recently.
failure = self.node_failure_dict.get(cell.getUUID())
if failure:
if time.time() < failure:
# Or order by date of connection failure.
return failure
# Do not use 'del' statement: we didn't lock, so another
# thread might have removed uuid from node_failure_dict.
self.node_failure_dict.pop(cell.getUUID(), None)
# A random one, connected or not, is a trivial and quite efficient way
# to distribute the load evenly. On write accesses, a client connects
# to all nodes of touched cells, but before that, or if a client is
# specialized to only do read-only accesses, it should not limit
# itself to only use the first connected nodes.
return random()
def getConnForNode(self, node):
"""Return a locked connection object to a given node
If no connection exists, create a new one"""
conn = node._connection # XXX
if node.isRunning() if conn is None else not node._identified:
with self._lock:
conn = node._connection # XXX
if conn is None:
return self._initNodeConnection(node)
return conn
def registerDB(self, db, limit):
self._db = db
def getDB(self):
return self._db
def new_oid(self):
"""Get a new OID."""
self._oid_lock_acquire()
try:
if not self.new_oid_list:
# Get new oid list from master node
# we manage a list of oid here to prevent
# from asking too many time new oid one by one
# from master node
self._askPrimary(Packets.AskNewOIDs(100))
if not self.new_oid_list:
raise NEOStorageError('new_oid failed')
self.last_oid = oid = self.new_oid_list.pop()
return oid
finally:
self._oid_lock_release()
def getObjectCount(self):
# return the last OID used, this is inaccurate
return int(u64(self.last_oid))
def _askStorageForRead(self, object_id, packet, askStorage=None):
cp = self.cp
pt = self.pt
# BBB: On Py2, it can be a subclass of bytes (binary from zodbpickle).
if isinstance(object_id, bytes):
object_id = pt.getPartition(object_id)
if askStorage is None:
askStorage = self._askStorage
# Failure condition with minimal overhead: most of the time, only the
# following line is executed. In case of storage errors, we retry each
# node at least once, without looping forever.
failed = 0
while 1:
cell_list = pt.getCellList(object_id, True)
cell_list.sort(key=cp.getCellSortKey)
for cell in cell_list:
node = cell.getNode()
conn = cp.getConnForNode(node)
def closeAll(self):
with self._lock:
for node in self.app.nm.getStorageList():
conn = node._connection # XXX
if conn is not None:
try:
return askStorage(conn, packet)
except ConnectionClosed:
pass
except NEOStorageReadRetry, e:
if e.args[0]:
continue
failed += 1
if not pt.filled():
raise NEOPrimaryMasterLost
if len(cell_list) < failed: # too many failures
raise NEOStorageError('no storage available')
# Do not retry too quickly, for example
# when there's an incoming PT update.
self.sync()
def load(self, oid, tid=None, before_tid=None):
"""
Internal method which manage load, loadSerial and loadBefore.
OID and TID (serial) parameters are expected packed.
oid
OID of object to get.
tid
If given, the exact serial at which OID is desired.
before_tid should be None.
before_tid
If given, the excluded upper bound serial at which OID is desired.
serial should be None.
Return value: (3-tuple)
- Object data (None if object creation was undone).
- Serial of given data.
- Next serial at which object exists, or None. Only set when tid
parameter is not None.
Exceptions:
NEOStorageError
technical problem
NEOStorageNotFoundError
object exists but no data satisfies given parameters
NEOStorageDoesNotExistError
object doesn't exist
NEOStorageCreationUndoneError
object existed, but its creation was undone
Note that loadSerial is used during conflict resolution to load
object's current version, which is not visible to us normally (it was
committed after our snapshot was taken).
"""
# TODO:
# - rename parameters (here? and in handlers & packet definitions)
acquire = self._cache_lock_acquire
release = self._cache_lock_release
# XXX: Consider using a more fine-grained lock.
self._load_lock_acquire()
try:
acquire()
try:
result = self._loadFromCache(oid, tid, before_tid)
if result:
return result
self._loading_oid = oid
finally:
release()
# When not bound to a ZODB Connection, load() may be the
# first method called and last_tid may still be None.
# This happens, for example, when opening the DB.
if not (tid or before_tid) and self.last_tid:
# Do not get something more recent than the last invalidation
# we got from master.
before_tid = p64(u64(self.last_tid) + 1)
data, tid, next_tid, _ = self._loadFromStorage(oid, tid, before_tid)
acquire()
try:
if self._loading_oid:
# Common case (no race condition).
self._cache.store(oid, data, tid, next_tid)
elif self._loading_invalidated:
# oid has just been invalidated.
if not next_tid:
next_tid = self._loading_invalidated
self._cache.store(oid, data, tid, next_tid)
# Else, we just reconnected to the master.
finally:
release()
finally:
self._load_lock_release()
return data, tid, next_tid
def _loadFromStorage(self, oid, at_tid, before_tid):
def askStorage(conn, packet):
tid, next_tid, compression, checksum, data, data_tid \
= self._askStorage(conn, packet)
if data or checksum != ZERO_HASH:
if checksum != makeChecksum(data):
logging.error('wrong checksum from %s for oid %s',
conn, dump(oid))
raise NEOStorageReadRetry(False)
return (decompress_list[compression](data),
tid, next_tid, data_tid)
raise NEOStorageCreationUndoneError(dump(oid))
return self._askStorageForRead(oid,
Packets.AskObject(oid, at_tid, before_tid),
askStorage)
def _loadFromCache(self, oid, at_tid=None, before_tid=None):
"""
Load from local cache, return None if not found.
"""
if at_tid:
result = self._cache.load(oid, at_tid + '*')
assert not result or result[1] == at_tid
return result
return self._cache.load(oid, before_tid)
def tpc_begin(self, storage, transaction, tid=None, status=' '):
"""Begin a new transaction."""
# First get a transaction, only one is allowed at a time
txn_context = self._txn_container.new(transaction)
# use the given TID or request a new one to the master
answer_ttid = self._askPrimary(Packets.AskBeginTransaction(tid))
if answer_ttid is None:
raise NEOStorageError('tpc_begin failed')
assert tid in (None, answer_ttid), (tid, answer_ttid)
txn_context.Storage = storage
txn_context.ttid = answer_ttid
def store(self, oid, serial, data, version, transaction):
"""Store object."""
logging.debug('storing oid %s serial %s', dump(oid), dump(serial))
if not serial: # BBB
serial = ZERO_TID
self._store(self._txn_container.get(transaction), oid, serial, data)
def _store(self, txn_context, oid, serial, data, data_serial=None):
ttid = txn_context.ttid
if data is None:
# This is some undo: either a no-data object (undoing object
# creation) or a back-pointer to an earlier revision (going back to
# an older object revision).
compressed_data = ''
compression = 0
checksum = ZERO_HASH
else:
assert data_serial is None
size, compression, compressed_data = self.compress(data)
checksum = makeChecksum(compressed_data)
txn_context.data_size += size
# Store object in tmp cache
packet = Packets.AskStoreObject(oid, serial, compression,
checksum, compressed_data, data_serial, ttid)
txn_context.data_dict[oid] = data, serial, txn_context.write(
self, packet, oid, oid=oid, serial=serial)
while txn_context.data_size >= self._cache.max_size:
self._waitAnyTransactionMessage(txn_context)
self._waitAnyTransactionMessage(txn_context, False)
def _handleConflicts(self, txn_context):
data_dict = txn_context.data_dict
pop_conflict = txn_context.conflict_dict.popitem
resolved_dict = txn_context.resolved_dict
tryToResolveConflict = txn_context.Storage.tryToResolveConflict
while 1:
# We iterate over conflict_dict, and clear it,
# because new items may be added by calls to _store.
# This is also done atomically, to avoid race conditions
# with PrimaryNotificationsHandler.notifyDeadlock
try:
oid, serial = pop_conflict()
except KeyError:
return
try:
data, old_serial, _ = data_dict.pop(oid)
except KeyError:
assert oid is None, (oid, serial)
# Storage refused us from taking object lock, to avoid a
# possible deadlock. TID is actually used for some kind of
# "locking priority": when a higher value has the lock,
# this means we stored objects "too late", and we would
# otherwise cause a deadlock.
# To recover, we must ask storages to release locks we
# hold (to let possibly-competing transactions acquire
# them), and requeue our already-sent store requests.
ttid = txn_context.ttid
logging.info('Deadlock avoidance triggered for TXN %s'
' with new locking TID %s', dump(ttid), dump(serial))
txn_context.locking_tid = serial
packet = Packets.AskRebaseTransaction(ttid, serial)
for uuid in txn_context.conn_dict:
self._askStorageForWrite(txn_context, uuid, packet)
else:
if data is CHECKED_SERIAL:
raise ReadConflictError(oid=oid,
serials=(serial, old_serial))
# TODO: data can be None if a conflict happens during undo
if data:
txn_context.data_size -= len(data)
if self.last_tid < serial:
self.sync() # possible late invalidation (very rare)
try:
data = tryToResolveConflict(oid, serial, old_serial, data)
except ConflictError:
logging.info(
'Conflict resolution failed for %s@%s with %s',
dump(oid), dump(old_serial), dump(serial))
# With recent ZODB, get_pickle_metadata (from ZODB.utils)
# does not support empty values, so do not pass 'data'
# in this case.
raise ConflictError(oid=oid, serials=(serial, old_serial),
data=data or None)
else:
logging.info(
'Conflict resolution succeeded for %s@%s with %s',
dump(oid), dump(old_serial), dump(serial))
# Mark this conflict as resolved
resolved_dict[oid] = serial
# Try to store again
self._store(txn_context, oid, serial, data)
def _askStorageForWrite(self, txn_context, uuid, packet):
conn = txn_context.conn_dict[uuid]
try:
return conn.ask(packet, queue=txn_context.queue)
except AttributeError:
if conn is not None:
raise
except ConnectionClosed:
txn_context.conn_dict[uuid] = None
def waitResponses(self, queue):
"""Wait for all requests to be answered (or their connection to be
detected as closed)"""
pending = self.dispatcher.pending
_waitAnyMessage = self._waitAnyMessage
while pending(queue):
_waitAnyMessage(queue)
def waitStoreResponses(self, txn_context):
queue = txn_context.queue
pending = self.dispatcher.pending
_waitAnyTransactionMessage = self._waitAnyTransactionMessage
while pending(queue):
_waitAnyTransactionMessage(txn_context)
if txn_context.data_dict:
raise NEOStorageError('could not store/check all oids')
def tpc_vote(self, transaction):
"""Store current transaction."""
txn_context = self._txn_container.get(transaction)
self.waitStoreResponses(txn_context)
ttid = txn_context.ttid
ext = transaction._extension
ext = dumps(ext, _protocol) if ext else ''
# user and description are cast to str in case they're unicode.
# BBB: This is not required anymore with recent ZODB.
packet = Packets.AskStoreTransaction(ttid, str(transaction.user),
str(transaction.description), ext, txn_context.cache_dict)
queue = txn_context.queue
conn_dict = txn_context.conn_dict
# Ask in parallel all involved storage nodes to commit object metadata.
# Nodes that store the transaction metadata get a special packet.
trans_nodes = txn_context.write(self, packet, ttid)
packet = Packets.AskVoteTransaction(ttid)
for uuid in conn_dict:
if uuid not in trans_nodes:
self._askStorageForWrite(txn_context, uuid, packet)
self.waitStoreResponses(txn_context)
if None in conn_dict.itervalues(): # unlikely
# If some writes failed, we must first check whether
# all oids have been locked by at least one node.
failed = {node.getUUID(): node.isRunning()
for node in self.nm.getStorageList()
if conn_dict.get(node.getUUID(), 0) is None}
if txn_context.lockless_dict:
getCellList = self.pt.getCellList
for offset, uuid_set in txn_context.lockless_dict.iteritems():
for cell in getCellList(offset):
uuid = cell.getUUID()
if not (uuid in failed or uuid in uuid_set):
break
else:
# Very unlikely. Instead of raising, we could recover
# the transaction by doing something similar to
# deadlock avoidance; that would be done before voting.
# But it's not worth the complexity.
raise NEOStorageError(
'partition %s not fully write-locked' % offset)
failed = [uuid for uuid, running in failed.iteritems() if running]
# If there are running nodes for which some writes failed, ask the
# master whether they can be disconnected while keeping the cluster
# operational. If possible, this will happen during tpc_finish.
if failed:
try:
self._askPrimary(Packets.FailedVote(ttid, failed))
except ConnectionClosed:
pass
txn_context.voted = True
# We must not go further if connection to master was lost since
# tpc_begin, to lower the probability of failing during tpc_finish.
# IDEA: We can improve in 2 opposite directions:
# - In the case of big transactions, it would be useful to
# also detect failures earlier.
# - If possible, recover from master failure.
if txn_context.error:
raise NEOStorageError(txn_context.error)
if OLD_ZODB:
return [(oid, ResolvedSerial)
for oid in txn_context.resolved_dict]
return txn_context.resolved_dict
def tpc_abort(self, transaction):
"""Abort current transaction."""
txn_context = self._txn_container.pop(transaction)
if txn_context is None:
return
# We want that the involved nodes abort a transaction after any
# other packet sent by the client for this transaction. IOW, if we
# already have a connection with a storage node, potentially with
# a pending write, aborting only via the master may lead to a race
# condition. The consequence would be that storage nodes lock oids
# forever.
p = Packets.AbortTransaction(txn_context.ttid, ())
for conn in txn_context.conn_dict.itervalues():
if conn is not None:
try:
conn.send(p)
except ConnectionClosed:
pass
# Because we want to be sure that the involved nodes are notified,
# we still have to send the full list to the master. Most of the
# time, the storage nodes get 2 AbortTransaction packets, and the
# second one is rarely useful. Another option would be that the
# storage nodes keep a list of aborted transactions, but the
# difficult part would be to avoid a memory leak.
try:
notify = self.master_conn.send
except AttributeError:
pass
else:
try:
notify(Packets.AbortTransaction(txn_context.ttid,
txn_context.conn_dict))
except ConnectionClosed:
pass
# We don't need to flush queue, as it won't be reused by future
# transactions (deleted on next line & indexed by transaction object
# instance).
self.dispatcher.forget_queue(txn_context.queue, flush_queue=False)
def tpc_finish(self, transaction, f=None):
"""Finish current transaction
To avoid inconsistencies between several databases involved in the
same transaction, an IStorage implementation must do its best not to
fail in tpc_finish. In particular, making a transaction permanent
should ideally be as simple as switching a bit permanently.
In NEO, all the data (with the exception of the tid, simply because
it is not known yet) is already flushed on disk at the end on the vote.
During tpc_finish, all nodes storing the transaction metadata are asked
to commit by saving the new tid and flushing again: for SQL backends,
it's just an UPDATE of 1 cell. At last, the metadata is moved to
a final place so that the new transaction is readable, but this is
something that can always be replayed (during the verification phase)
if any failure happens.
"""
txn_container = self._txn_container
if not txn_container.get(transaction).voted:
self.tpc_vote(transaction)
checked_list = []
self._load_lock_acquire()
try:
# Call finish on master
txn_context = txn_container.pop(transaction)
cache_dict = txn_context.cache_dict
checked_list = [oid for oid, data in cache_dict.iteritems()
if data is CHECKED_SERIAL]
for oid in checked_list:
del cache_dict[oid]
ttid = txn_context.ttid
p = Packets.AskFinishTransaction(ttid, cache_dict, checked_list)
try:
tid = self._askPrimary(p, cache_dict=cache_dict, callback=f)
assert tid
except ConnectionClosed:
tid = self._getFinalTID(ttid)
if not tid:
raise
return tid
finally:
self._load_lock_release()
def _getFinalTID(self, ttid):
try:
p = Packets.AskFinalTID(ttid)
while 1:
try:
tid = self._askPrimary(p)
break
except ConnectionClosed:
pass
if tid == MAX_TID:
while 1:
try:
return self._askStorageForRead(ttid, p)
except NEOPrimaryMasterLost:
pass
elif tid:
return tid
except Exception:
logging.exception("Failed to get final tid for TXN %s",
dump(ttid))
def undo(self, undone_tid, txn):
txn_context = self._txn_container.get(txn)
txn_info, txn_ext = self._getTransactionInformation(undone_tid)
txn_oid_list = txn_info['oids']
# Regroup objects per partition, to ask a minimum set of storage.
partition_oid_dict = {}
for oid in txn_oid_list:
partition = self.pt.getPartition(oid)
try:
oid_list = partition_oid_dict[partition]
except KeyError:
oid_list = partition_oid_dict[partition] = []
oid_list.append(oid)
# Ask storage the undo serial (serial at which object's previous data
# is)
getCellList = self.pt.getCellList
getCellSortKey = self.cp.getCellSortKey
getConnForNode = self.cp.getConnForNode
queue = self._thread_container.queue
ttid = txn_context.ttid
undo_object_tid_dict = {}
snapshot_tid = p64(u64(self.last_tid) + 1)
kw = {
'queue': queue,
'partition_oid_dict': partition_oid_dict,
'undo_object_tid_dict': undo_object_tid_dict,
}
while partition_oid_dict:
for partition, oid_list in partition_oid_dict.iteritems():
cell_list = [cell
for cell in getCellList(partition, readable=True)
# Exclude nodes that may have missed previous resolved
# conflicts. For example, if a network failure happened
# only between the client and the storage, the latter would
# still be readable until we commit.
if txn_context.conn_dict.get(cell.getUUID(), 0) is not None]
storage_conn = getConnForNode(
min(cell_list, key=getCellSortKey).getNode())
storage_conn.ask(Packets.AskObjectUndoSerial(ttid,
snapshot_tid, undone_tid, oid_list),
partition=partition, **kw)
# Wait for all AnswerObjectUndoSerial. We might get
# OidNotFoundError, meaning that objects in transaction's oid_list
# do not exist any longer. This is the symptom of a pack, so forbid
# undoing transaction when it happens.
try:
self.waitResponses(queue)
except NEOStorageNotFoundError:
self.dispatcher.forget_queue(queue)
raise UndoError('non-undoable transaction')
# Send undo data to all storage nodes.
for oid in txn_oid_list:
current_serial, undo_serial, is_current = undo_object_tid_dict[oid]
if is_current:
data = None
else:
# Serial being undone is not the latest version for this
# object. This is an undo conflict, try to resolve it.
try:
# Load the latest version we are supposed to see
if current_serial == ttid:
# XXX: see TODO below
data = txn_context.cache_dict[oid]
else:
data = self.load(oid, current_serial)[0]
# Load the version we were undoing to
undo_data = self.load(oid, undo_serial)[0]
except NEOStorageNotFoundError:
raise UndoError('Object not found while resolving undo '
'conflict')
# Resolve conflict
try:
data = txn_context.Storage.tryToResolveConflict(
oid, current_serial, undone_tid, undo_data, data)
except ConflictError:
raise UndoError('Some data were modified by a later ' \
'transaction', oid)
undo_serial = None
# TODO: The situation is similar to deadlock avoidance.
# Reenable the cache size limit to avoid OOM when there's
# a huge amount conflicting data, and get the data back
# from the storage when it's not in cache_dict anymore.
txn_context.cache_size = - float('inf')
self._store(txn_context, oid, current_serial, data, undo_serial)
self.waitStoreResponses(txn_context)
return None, txn_oid_list
def _getTransactionInformation(self, tid):
return self._askStorageForRead(tid,
Packets.AskTransactionInformation(tid))
def undoLog(self, first, last, filter=None, block=0):
# XXX: undoLog is broken
if last < 0:
# See FileStorage.py for explanation
last = first - last
# First get a list of transactions from all storage nodes.
# Each storage node will return TIDs only for UP_TO_DATE state and
# FEEDING state cells
queue = self._thread_container.queue
packet = Packets.AskTIDs(first, last, INVALID_PARTITION)
tid_set = set()
for storage_node in self.pt.getNodeSet(True):
conn = self.cp.getConnForNode(storage_node)
if conn is None:
continue
conn.ask(packet, queue=queue, tid_set=tid_set)
# Wait for answers from all storages.
# TODO: Results are incomplete when readable cells move concurrently
# from one storage to another. We detect when this happens and
# retry.
self.waitResponses(queue)
# Reorder tids
ordered_tids = sorted(tid_set, reverse=True)
logging.debug("UndoLog tids %s", map(dump, ordered_tids))
# For each transaction, get info
undo_info = []
append = undo_info.append
for tid in ordered_tids:
(txn_info, txn_ext) = self._getTransactionInformation(tid)
if filter is None or filter(txn_info):
txn_info.pop('packed')
txn_info.pop("oids")
if txn_ext:
txn_info.update(loads(txn_ext))
append(txn_info)
if len(undo_info) >= last - first:
break
# Check we return at least one element, otherwise call
# again but extend offset
if len(undo_info) == 0 and not block:
undo_info = self.undoLog(first=first, last=last*5, filter=filter,
block=1)
return undo_info
def transactionLog(self, start, stop, limit):
tid_list = []
# request a tid list for each partition
for offset in xrange(self.pt.getPartitions()):
r = self._askStorageForRead(offset,
Packets.AskTIDsFrom(start, stop, limit, offset))
if r:
tid_list = list(heapq.merge(tid_list, r))
if len(tid_list) >= limit:
del tid_list[limit:]
stop = tid_list[-1]
# request transactions informations
txn_list = []
append = txn_list.append
tid = None
for tid in tid_list:
(txn_info, txn_ext) = self._getTransactionInformation(tid)
txn_info['ext'] = loads(txn_ext) if txn_ext else {}
append(txn_info)
return (tid, txn_list)
def history(self, oid, size=1, filter=None):
packet = Packets.AskObjectHistory(oid, 0, size)
result = []
# history_list is already sorted descending (by the storage)
for serial, size in self._askStorageForRead(oid, packet):
txn_info, txn_ext = self._getTransactionInformation(serial)
# create history dict
txn_info.pop('id')
txn_info.pop('oids')
txn_info.pop('packed')
txn_info['tid'] = serial
txn_info['version'] = ''
txn_info['size'] = size
if filter is None or filter(txn_info):
result.append(txn_info)
if txn_ext:
txn_info.update(loads(txn_ext))
return result
def importFrom(self, storage, source):
# TODO: The main difference with BaseStorage implementation is that
# preindex can't be filled with the result 'store' (tid only
# known after 'tpc_finish'. This method could be dropped if we
# implemented IStorageRestoreable (a wrapper around source would
# still be required for partial import).
preindex = {}
for transaction in source.iterator():
tid = transaction.tid
self.tpc_begin(storage, transaction, tid, transaction.status)
for r in transaction:
oid = r.oid
try:
pre = preindex[oid]
except KeyError:
try:
pre = self.load(oid)[1]
except NEOStorageNotFoundError:
pre = ZERO_TID
self.store(oid, pre, r.data, r.version, transaction)
preindex[oid] = tid
conflicted = self.tpc_vote(transaction)
assert not conflicted, conflicted
real_tid = self.tpc_finish(transaction)
assert real_tid == tid, (real_tid, tid)
from .iterator import iterator
def sync(self):
self._askPrimary(Packets.Ping())
def pack(self, t):
tid = TimeStamp(*time.gmtime(t)[:5] + (t % 60, )).raw()
if tid == ZERO_TID:
raise NEOStorageError('Invalid pack time')
self._askPrimary(Packets.AskPack(tid))
# XXX: this is only needed to make ZODB unit tests pass.
# It should not be otherwise required (clients should be free to load
# old data as long as it is available in cache, event if it was pruned
# by a pack), so don't bother invalidating on other clients.
self._cache_lock_acquire()
try:
self._cache.clear()
finally:
self._cache_lock_release()
def getLastTID(self, oid):
return self.load(oid)[1]
def checkCurrentSerialInTransaction(self, oid, serial, transaction):
self._checkCurrentSerialInTransaction(
self._txn_container.get(transaction), oid, serial)
def _checkCurrentSerialInTransaction(self, txn_context, oid, serial):
ttid = txn_context.ttid
# ZODB.Connection performs calls 'checkCurrentSerialInTransaction'
# after stores, and skips oids that have been successfully stored.
assert oid not in txn_context.cache_dict, oid
assert oid not in txn_context.data_dict, oid
packet = Packets.AskCheckCurrentSerial(ttid, oid, serial)
txn_context.data_dict[oid] = CHECKED_SERIAL, serial, txn_context.write(
self, packet, oid, oid=oid, serial=serial)
self._waitAnyTransactionMessage(txn_context, False)
conn.setReconnectionNoDelay()
conn.close()
neo/client/pool.py deleted 100644 → 0
View file @ 305dda86
#
# Copyright (C) 2006-2017 Nexedi SA
#
# 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 the Free Software Foundation; either version 2
# of the License, or (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <http://www.gnu.org/licenses/>.
import random, time
from neo.lib import logging
from neo.lib.locking import Lock
from neo.lib.protocol import NodeTypes, Packets
from neo.lib.connection import MTClientConnection, ConnectionClosed
from neo.lib.exception import NodeNotReady
from .exception import NEOPrimaryMasterLost
# How long before we might retry a connection to a node to which connection
# failed in the past.
MAX_FAILURE_AGE = 600
class ConnectionPool(object):
"""This class manages a pool of connections to storage nodes."""
# XXX: This is not a pool anymore.
def __init__(self, app):
self.app = app
# Define a lock in order to create one connection to
# a storage node at a time to avoid multiple connections
# to the same node.
self._lock = Lock()
self.node_failure_dict = {}
def _initNodeConnection(self, node):
"""Init a connection to a given storage node."""
app = self.app
if app.master_conn is None:
raise NEOPrimaryMasterLost
conn = MTClientConnection(app, app.storage_event_handler, node,
dispatcher=app.dispatcher)
p = Packets.RequestIdentification(NodeTypes.CLIENT,
app.uuid, None, app.name, (), app.id_timestamp)
try:
app._ask(conn, p, handler=app.storage_bootstrap_handler)
except ConnectionClosed:
logging.error('Connection to %r failed', node)
except NodeNotReady:
logging.info('%r not ready', node)
else:
logging.info('Connected %r', node)
# Make sure this node will be considered for the next reads
# even if there was a previous recent failure.
self.node_failure_dict.pop(node.getUUID(), None)
return conn
self.node_failure_dict[node.getUUID()] = time.time() + MAX_FAILURE_AGE
def getCellSortKey(self, cell, random=random.random):
# Prefer a node that didn't fail recently.
failure = self.node_failure_dict.get(cell.getUUID())
if failure:
if time.time() < failure:
# Or order by date of connection failure.
return failure
# Do not use 'del' statement: we didn't lock, so another
# thread might have removed uuid from node_failure_dict.
self.node_failure_dict.pop(cell.getUUID(), None)
# A random one, connected or not, is a trivial and quite efficient way
# to distribute the load evenly. On write accesses, a client connects
# to all nodes of touched cells, but before that, or if a client is
# specialized to only do read-only accesses, it should not limit
# itself to only use the first connected nodes.
return random()
def getConnForNode(self, node):
"""Return a locked connection object to a given node
If no connection exists, create a new one"""
conn = node._connection # XXX
if node.isRunning() if conn is None else not node._identified:
with self._lock:
conn = node._connection # XXX
if conn is None:
return self._initNodeConnection(node)
return conn
def closeAll(self):
with self._lock:
for node in self.app.nm.getStorageList():
conn = node._connection # XXX
if conn is not None:
conn.setReconnectionNoDelay()
conn.close()
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