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Commit 5155ff33 authored by Yoshinori Okuji's avatar Yoshinori Okuji
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Implement a recovery step. Not tested well. 

git-svn-id: https://svn.erp5.org/repos/neo/branches/prototype3@27 71dcc9de-d417-0410-9af5-da40c76e7ee4
parent fd22e3e6
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Showing with 562 additions and 176 deletions
neo/connection.py
View file @ 5155ff33
......@@ -44,6 +44,9 @@ class BaseConnection(object):
def getEventManager(self):
return self.em
def getUUID(self):
return None
class ListeningConnection(BaseConnection):
"""A listen connection."""
def __init__(self, event_manager, handler, addr = None, **kw):
......
neo/handler.py
View file @ 5155ff33
......@@ -6,8 +6,8 @@ from neo.connection import ServerConnection
from protocol import ERROR, REQUEST_NODE_IDENTIFICATION, ACCEPT_NODE_IDENTIFICATION, \
PING, PONG, ASK_PRIMARY_MASTER, ANSWER_PRIMARY_MASTER, ANNOUNCE_PRIMARY_MASTER, \
REELECT_PRIMARY_MASTER, NOTIFY_NODE_INFORMATION, START_OPERATION, \
STOP_OPERATION, ASK_FINISHING_TRANSACTIONS, ANSWER_FINISHING_TRANSACTIONS, \
FINISH_TRANSACTIONS, \
STOP_OPERATION, ASK_LAST_IDS, ANSWER_LAST_IDS, ASK_PARTITION_TABLE, \
ANSWER_PARTITION_TABLE, SEND_PARTITION_TABLE, NOTIFY_PARTITION_CHANGES, \
NOT_READY_CODE, OID_NOT_FOUND_CODE, SERIAL_NOT_FOUND_CODE, TID_NOT_FOUND_CODE, \
PROTOCOL_ERROR_CODE, TIMEOUT_ERROR_CODE, BROKEN_NODE_DISALLOWED_CODE, \
INTERNAL_ERROR_CODE
......@@ -125,6 +125,30 @@ class EventHandler(object):
def handleNotifyNodeInformation(self, conn, packet, node_list):
self.handleUnexpectedPacket(conn, packet)
def handleAskLastIDs(self, conn, packet):
self.handleUnexpectedPacket(conn, packet)
def handleAnswerLastIDs(self, conn, packet, loid, ltid, lptid):
self.handleUnexpectedPacket(conn, packet)
def handleAskPartitionTable(self, conn, packet, offset_list):
self.handleUnexpectedPacket(conn, packet)
def handleAnswerPartitionTable(self, conn, packet, row_list):
self.handleUnexpectedPacket(conn, packet)
def handleSendPartitionTable(self, conn, packet, row_list):
self.handleUnexpectedPacket(conn, packet)
def handleNotifyPartitionChanges(self, conn, packet, cell_list):
self.handleUnexpectedPacket(conn, packet)
def handleStartOperation(self, conn, packet):
self.handleUnexpectedPacket(conn, packet)
def handleStopOperation(self, conn, packet):
self.handleUnexpectedPacket(conn, packet)
# Error packet handlers.
handleNotReady = handleUnexpectedPacket
......@@ -158,6 +182,14 @@ class EventHandler(object):
d[ANNOUNCE_PRIMARY_MASTER] = self.handleAnnouncePrimaryMaster
d[REELECT_PRIMARY_MASTER] = self.handleReelectPrimaryMaster
d[NOTIFY_NODE_INFORMATION] = self.handleNotifyNodeInformation
d[ASK_LAST_IDS] = self.handleAskLastIDs
d[ANSWER_LAST_IDS] = self.handleAnswerLastIDs
d[ASK_PARTITION_TABLE] = self.handleAskPartitionTable
d[ANSWER_PARTITION_TABLE] = self.handleAnswerPartitionTable
d[SEND_PARTITION_TABLE] = self.handleSendPartitionTable
d[NOTIFY_PARTITION_CHANGES] = self.handleNotifyPartitionChanges
d[START_OPERATION] = self.handleStartOperation
d[STOP_OPERATION] = self.handleStopOperation
self.packet_dispatch_table = d
......
neo/master/app.py
View file @ 5155ff33
......@@ -14,6 +14,8 @@ from neo.util import dump
from neo.connection import ListeningConnection, ClientConnection, ServerConnection
from neo.exception import ElectionFailure, PrimaryFailure
from neo.master.election import ElectionEventHandler
from neo.master.recovery import RecoveryEventHandler
from neo.pt import PartitionTable
class Application(object):
"""The master node application."""
......@@ -37,6 +39,7 @@ class Application(object):
# Internal attributes.
self.em = EventManager()
self.nm = NodeManager()
self.pt = PartitionTable(self.num_partitions, self.num_replicas)
self.primary = None
self.primary_master_node = None
......@@ -55,6 +58,8 @@ class Application(object):
self.ltid = INVALID_TID
# The last Partition Table ID.
self.lptid = INVALID_PTID
# The target node's uuid to request next.
self.target_uuid = None
def run(self):
"""Make sure that the status is sane and start a loop."""
......@@ -78,9 +83,7 @@ class Application(object):
while 1:
try:
if self.primary:
while 1:
self.startRecovery()
self.playPrimaryRole()
self.playPrimaryRole()
else:
self.playSecondaryRole()
raise RuntimeError, 'should not reach here'
......@@ -246,7 +249,9 @@ class Application(object):
conn.close()
bootstrap = False
def broadcastNodeStateChange(self, node):
def broadcastNodeInformation(self, node):
"""Broadcast a Notify Node Information packet."""
node_type = node.getNodeType()
state = node.getState()
uuid = node.getUUID()
ip_address, port = node.getServer()
......@@ -255,194 +260,136 @@ class Application(object):
if port is None:
port = 0
if isinstance(node, ClientNode):
# Notify secondary master nodes and storage nodes of
# the removal of the client node.
if node_type == CLIENT_NODE_TYPE:
# Only to master nodes and storage nodes.
for c in em.getConnectionList():
if c.getUUID() is not None:
n = nm.getNodeByUUID(uuid)
n = nm.getNodeByUUID(c.getUUID())
if isinstance(n, (MasterNode, StorageNode)):
p = Packet()
p.notifyNodeStateChange(c.getNextId(),
CLIENT_NODE_TYPE,
ip_address, port,
uuid, state)
node_list = (node_type, ip_address, port, uuid, state)
p.notifyNodeStateChange(c.getNextId(), node_list)
c.addPacket(p)
elif isinstance(node, MasterNode):
for c in em.getConnectionList():
if c.getUUID() is not None:
p = Packet()
p.notifyNodeStateChange(c.getNextId(),
MASTER_NODE_TYPE,
ip_address, port,
uuid, state)
c.addPacket(p)
elif isinstance(node, StorageNode):
elif isinstance(node, (MasterNode, StorageNode)):
for c in em.getConnectionList():
if c.getUUID() is not None:
p = Packet()
p.notifyNodeStateChange(c.getNextId(),
STORAGE_NODE_TYPE,
ip_address, port,
uuid, state)
node_list = (node_type, ip_address, port, uuid, state)
p.notifyNodeStateChange(c.getNextId(), node_list)
c.addPacket(p)
else:
raise Runtime, 'unknown node type'
def playPrimaryRoleServerIterator(self):
"""Handle events for a server connection."""
def recoverStatus(self):
logging.info('begin the recovery of the status')
handler = RecoveryEventHandler(self)
em = self.em
nm = self.nm
while 1:
method, conn = self.event[0], self.event[1]
logging.debug('method is %r, conn is %s:%d',
method, conn.ip_address, conn.port)
if method is self.CONNECTION_ACCEPTED:
pass
elif method in (self.CONNECTION_CLOSED, self.TIMEOUT_EXPIRED):
uuid = conn.getUUID()
if uuid is not None:
# If the peer is identified, mark it as temporarily down or down.
node = nm.getNodeByUUID(uuid)
if isinstance(node, ClientNode):
node.setState(DOWN_STATE)
self.broadcastNodeStateChange(node)
# For now, down client nodes simply get forgotten.
nm.remove(node)
elif isinstance(node, MasterNode):
if node.getState() not in (BROKEN_STATE, DOWN_STATE):
node.setState(TEMPORARILY_DOWN_STATE)
self.broadcastNodeStateChange(node)
elif isinstance(node, StorageNode):
if node.getState() not in (BROKEN_STATE, DOWN_STATE):
node.setState(TEMPORARILY_DOWN_STATE)
self.broadcastNodeStateChange(node)
# FIXME check the partition table.
self.pt.setTemporarilyDown(node.getUUID())
if self.ready and self.pt.fatal():
logging.critical('the storage nodes are not enough')
self.ready = False
self.broadcast
# FIXME update the database.
else:
raise RuntimeError, 'unknown node type'
return
elif method is self.PEER_BROKEN:
uuid = conn.getUUID()
if uuid is not None:
# If the peer is identified, mark it as broken.
node = nm.getNodeByUUID(uuid)
node.setState(BROKEN_STATE)
return
elif method is self.PACKET_RECEIVED:
if node is not None and node.getState() != BROKEN_STATE:
node.setState(RUNNING_STATE)
packet = self.event[2]
t = packet.getType()
try:
if t == ERROR:
code, msg = packet.decode()
if code in (PROTOCOL_ERROR_CODE, TIMEOUT_ERROR_CODE,
BROKEN_NODE_DISALLOWED_CODE):
# In those cases, it is better to assume that I am unusable.
logging.critical(msg)
raise RuntimeError, msg
else:
# Otherwise, the peer has an error.
logging.error('an error happened at the peer %s:%d',
conn.ip_address, conn.port)
if node is not None:
node.setState(BROKEN_STATE)
conn.close()
return
elif t == PING:
logging.info('got a keep-alive message from %s:%d; overloaded?',
conn.ip_address, conn.port)
conn.addPacket(Packet().pong(packet.getId()))
elif t == PONG:
pass
elif t == REQUEST_NODE_IDENTIFICATION:
node_type, uuid, ip_address, port, name = packet.decode()
if node_type != MASTER_NODE_TYPE:
logging.info('reject a connection from a non-master')
conn.addPacket(Packet().notReady(packet.getId(),
'retry later'))
conn.abort()
continue
if name != self.name:
logging.info('reject an alien cluster')
conn.addPacket(Packet().protocolError(packet.getId(),
'invalid cluster name'))
conn.abort()
continue
node = self.nm.getNodeByServer(ip_address, port)
if node is None:
node = MasterNode(ip_address, port, uuid)
self.nm.add(node)
self.unconnected_master_node_set.add((ip_address, port))
else:
# Trust the UUID sent by the peer.
if node.getUUID() != uuid:
node.setUUID(uuid)
conn.setUUID(uuid)
p = Packet()
p.acceptNodeIdentification(packet.getId(), MASTER_NODE_TYPE,
self.uuid, self.ip_address, self.port)
conn.addPacket(p)
conn.expectMessage()
elif t == ASK_PRIMARY_MASTER:
if node is None:
raise ProtocolError(packet, 'not identified')
ltid, loid = packet.decode()
# Make sure that every connection has the status recovery event handler.
for conn in em.getConnectionList():
conn.setHandler(handler)
p = Packet()
if self.primary:
uuid = self.uuid
elif self.primary_master_node is not None:
uuid = self.primary_master_node.getUUID()
else:
uuid = INVALID_UUID
known_master_list = []
for n in self.nm.getMasterNodeList():
info = n.getServer() + (n.getUUID() or INVALID_UUID,)
known_master_list.append(info)
p.answerPrimaryMaster(packet.getId(), self.ltid, self.loid,
uuid, known_master_list)
conn.addPacket(p)
if self.primary and (self.ltid < ltid or self.loid < loid):
# I am not really primary... So restart the election.
raise ElectionFailure, 'not a primary master any longer'
elif t == ANNOUNCE_PRIMARY_MASTER:
if node is None:
raise ProtocolError(packet, 'not identified')
if self.primary:
# I am also the primary... So restart the election.
raise ElectionFailure, 'another primary arises'
self.primary = False
self.primary_master_node = node
logging.info('%s:%d is the primary' % node.getServer())
elif t == REELECT_PRIMARY_MASTER:
raise ElectionFailure, 'reelection requested'
else:
raise ProtocolError(packet, 'unexpected packet 0x%x' % t)
except ProtocolError, m:
logging.debug('protocol problem %s', m[1])
conn.addPacket(Packet().protocolError(m[0].getId(), m[1]))
conn.abort()
prev_lptid = None
self.loid = INVALID_OID
self.ltid = INVALID_TID
self.lptid = None
while 1:
self.target_uuid = None
self.pt.clear()
if self.lptid is not None:
# I need to retrieve last ids again.
logging.debug('resending Ask Last IDs')
for conn in em.getConnectionList():
uuid = conn.getUUID()
if uuid is not None:
node = nm.getNodeByUUID(uuid)
if isinstance(node, StorageNode) \
and node.getState() == RUNNING_STATE:
p = Packet()
msg_id = conn.getNextId()
p.askLastIDs(msg_id)
conn.addPacket(p)
conn.expectMessage(msg_id)
# Wait for at least one storage node to appear.
while self.target_uuid is None:
em.poll(1)
# Wait a bit.
t = time()
while time() < t + 5:
em.poll(1)
# Now I have at least one to ask.
prev_lptid = self.lptid
node = nm.getNodeByUUID(uuid)
if node.getState() != RUNNING_STATE:
# Weird. It's dead.
logging.info('the target storage node is dead')
continue
for conn in em.getConnectionList():
if conn.getUUID() == self.lptid:
break
else:
raise RuntimeError, 'unexpected event %r' % (method,)
# Why?
logging.info('no connection to the target storage node')
continue
if self.lptid == INVALID_PTID:
# This looks like the first time. So make a fresh table.
logging.debug('creating a new partition table')
self.pt.make(nm.getStorageNodeList())
else:
# Obtain a partition table. It is necessary to split this message
# because the packet size can be huge.
logging.debug('asking a partition table to %s:%d', *(node.getServer()))
start = 0
size = self.num_partitions
while size:
len = min(1000, size)
msg_id = conn.getNextId()
p = Packet()
p.askPartitionTable(msg_id, range(start, start + len))
conn.addPacket(p)
conn.expectMessage(msg_id)
size -= len
start += len
t = time()
while 1:
em.poll(1)
if node.getState() != RUNNING_STATE:
# Dead.
break
if self.pt.filled() or t + 30 < time():
break
if self.lptid != prev_lptid or not self.pt.filled():
# I got something newer or the target is dead.
continue
# Wait until the cluster gets operational or the Partition Table ID
# turns out to be not the latest.
logging.debug('waiting for the cluster to be operational')
while 1:
em.poll(1)
if self.pt.operational():
break
if self.lptid != prev_lptid:
break
if self.lptid != prev_lptid:
# I got something newer.
continue
break
def playPrimaryRole(self):
logging.info('play the primary role')
self.ready = False
self.recoverStatus()
raise NotImplementedError
def playSecondaryRole(self):
......
neo/master/election.py
View file @ 5155ff33
......@@ -38,6 +38,8 @@ class ElectionEventHandler(MasterEventHandler):
if node.getState() == RUNNING_STATE:
app.unconnected_master_node_set.add(addr)
node.setState(TEMPORARILY_DOWN_STATE)
elif node.getState() == TEMPORARILY_DOWN_STATE:
app.unconnected_master_node_set.add(addr)
MasterEventHandler.connectionFailed(self, conn)
def connectionClosed(self, conn):
......@@ -243,3 +245,36 @@ class ElectionEventHandler(MasterEventHandler):
def handleReelectPrimaryMaster(self, conn, packet):
raise ElectionFailure, 'reelection requested'
def handleNotifyNodeInformation(self, conn, packet, node_list):
if isinstance(conn, ClientConnection):
self.handleUnexpectedPacket(conn, packet)
else:
uuid = conn.getUUID()
if uuid is None:
self.handleUnexpectedPacket(conn, packet)
return
app = self.app
for node_type, ip_address, port, uuid, state in node_list:
if node_type != MASTER_NODE:
# No interest.
continue
# Register new master nodes.
addr = (ip_address, port)
if app.server == addr:
# This is self.
continue
else:
n = app.nm.getNodeByServer(addr)
if n is None:
n = MasterNode(server = addr)
app.nm.add(n)
app.unconnected_master_node_set.add(addr)
if uuid != INVALID_UUID:
# If I don't know the UUID yet, believe what the peer
# told me at the moment.
if n.getUUID() is None:
n.setUUID(uuid)
neo/master/recovery.py 0 → 100644
View file @ 5155ff33
import logging
from neo.protocol import MASTER_NODE_TYPE, \
RUNNING_STATE, BROKEN_STATE, TEMPORARILY_DOWN_STATE, DOWN_STATE
from neo.master.handler import MasterEventHandler
from neo.exception import ElectionFailure
from neo.protocol import Packet, INVALID_UUID
from neo.util import dump
class RecoveryEventHandler(MasterEventHandler):
"""This class deals with events for a recovery phase."""
def connectionClosed(self, conn):
uuid = conn.getUUID()
if uuid is not None:
app = self.app
node = app.nm.getNodeByUUID(uuid)
if node.getState() == RUNNING_STATE:
node.setState(TEMPORARILY_DOWN_STATE)
app.broadcastNodeInformation(node)
if isinstance(node, ClientNode):
# If this node is a client, just forget it.
app.nm.remove(node)
MasterEventHandler.connectionClosed(self, conn)
def timeoutExpired(self, conn):
uuid = conn.getUUID()
if uuid is not None:
app = self.app
node = app.nm.getNodeByUUID(uuid)
if node.getState() == RUNNING_STATE:
node.setState(TEMPORARILY_DOWN_STATE)
app.broadcastNodeInformation(node)
if isinstance(node, ClientNode):
# If this node is a client, just forget it.
app.nm.remove(node)
MasterEventHandler.timeoutExpired(self, conn)
def peerBroken(self, conn):
uuid = conn.getUUID()
if uuid is not None:
app = self.app
node = app.nm.getNodeByUUID(uuid)
if node.getState() != BROKEN_STATE:
node.setState(BROKEN_STATE)
app.broadcastNodeInformation(node)
if isinstance(node, ClientNode):
# If this node is a client, just forget it.
app.nm.remove(node)
MasterEventHandler.peerBroken(self, conn)
def packetReceived(self, conn, packet):
node = self.app.nm.getNodeByServer(conn.getAddress())
if node.getState() in (TEMPORARILY_DOWN_STATE, DOWN_STATE):
node.setState(RUNNING_STATE)
app.broadcastNodeInformation(node)
MasterEventHandler.packetReceived(self, conn, packet)
def handleRequestNodeIdentification(self, conn, packet, node_type,
uuid, ip_address, port, name):
app = self.app
if node_type not in (MASTER_NODE_TYPE, STORAGE_NODE_TYPE):
logging.info('reject a connection from a client')
conn.addPacket(Packet().notReady(packet.getId(), 'retry later'))
conn.abort()
return
if name != app.name:
logging.error('reject an alien cluster')
conn.addPacket(Packet().protocolError(packet.getId(),
'invalid cluster name'))
conn.abort()
return
addr = (ip_address, port)
node = app.nm.getNodeByServer(addr)
if node is None:
if node_type == MASTER_NODE_TYPE:
node = MasterNode(server = addr, uuid = uuid)
else:
node = StorageNode(server = address, uuid = uuid)
app.nm.add(node)
else:
# If this node is broken, reject it.
if node.getState() == BROKEN_STATE:
if node.getUUID() == uuid:
p = Packet()
p.brokenNodeDisallowedError(packet.getId(), 'go away')
conn.addPacket(p)
conn.abort()
return
else:
node.setUUID(uuid)
node.setState(RUNNING_STATE)
app.broadcastNodeInformation(node)
conn.setUUID(uuid)
p = Packet()
p.acceptNodeIdentification(packet.getId(), MASTER_NODE_TYPE,
app.uuid, app.server[0], app.server[1])
conn.addPacket(p)
# Next, the peer should ask a primary master node.
conn.expectMessage()
def handleAskPrimaryMaster(self, conn, packet):
uuid = conn.getUUID()
if uuid is None:
self.handleUnexpectedPacket(conn, packet)
return
app = self.app
# Merely tell the peer that I am the primary master node.
# It is not necessary to send known master nodes, because
# I must send all node information immediately.
p = Packet()
p.answerPrimaryMaster(packet.getId(), app.uuid, [])
conn.addPacket(p)
# Send the information.
node_list = []
for n in app.nm.getNodeList():
ip_address, port = n.getServer()
node_list.append((n.getNodeType(), ip_address, port,
n.getUUID() or INVALID_UUID, n.getState()))
if len(node_list) == 10000:
# Ugly, but it is necessary to split a packet, if it is too big.
p = Packet()
p.notifyNodeInformation(conn.getNextId(), node_list)
conn.addPacket(p)
del node_list[:]
p = Packet()
p.notifyNodeInformation(conn.getNextId(), node_list)
conn.addPacket(p)
# If this is a storage node, ask the last IDs.
node = app.nm.getNodeByUUID(uuid)
if isinstance(node, StorageNode):
p = Packet()
msg_id = conn.getNextId()
p.askLastIDs(msg_id)
conn.addPacket(p)
conn.expectMessage(msg_id)
def handleAnnouncePrimaryMaster(self, conn, packet):
uuid = conn.getUUID()
if uuid is None:
self.handleUnexpectedPacket(conn, packet)
return
# I am also the primary... So restart the election.
raise ElectionFailure, 'another primary arises'
def handleReelectPrimaryMaster(self, conn, packet):
raise ElectionFailure, 'reelection requested'
def handleNotifyNodeInformation(self, conn, packet, node_list):
uuid = conn.getUUID()
if uuid is None:
self.handleUnexpectedPacket(conn, packet)
return
app = self.app
for node_type, ip_address, port, uuid, state in node_list:
if node_type != CLIENT_NODE:
# No interest.
continue
if uuid == INVALID_UUID:
# No interest.
continue
if app.uuid == uuid:
# This looks like me...
if state == RUNNING_STATE:
# Yes, I know it.
continue
else:
# What?! What happened to me?
raise RuntimeError, 'I was told that I am bad'
addr = (ip_address, port)
node = app.nm.getNodeByUUID(uuid)
if node is None:
node = app.nm.getNodeByServer(addr)
if node is None:
# I really don't know such a node. What is this?
continue
else:
if node.getServer() != addr:
# This is different from what I know.
continue
if node.getState() == state:
# No change. Don't care.
continue
if state == RUNNING_STATE:
# No problem.
continue
# Something wrong happened possibly. Cut the connection to this node,
# if any, and notify the information to others.
# XXX this can be very slow.
for c in app.em.getConnectionList():
if c.getUUID() == uuid:
c.close()
node.setState(state)
app.broadcastNodeInformation(node)
def handleAnswerLastIDs(self, conn, packet, loid, ltid, lptid):
uuid = conn.getUUID()
if uuid is None:
self.handleUnexpectedPacket(conn, packet)
return
node = app.nm.getNodeByUUID(uuid)
if not isinstance(node, StorageNode):
self.handleUnexpectedPacket(conn, packet)
return
# If the target is still unknown, set it to this node for now.
if app.target_uuid is None:
app.target_uuid = uuid
# Get max values.
if app.loid < loid:
app.loid = loid
if app.ltid < ltid:
app.ltid = ltid
if app.lptid is None or app.lptid < lptid:
app.lptid = lptid
# I need to use the node which has the max Partition Table ID.
app.target_uuid = uuid
elif app.lptid == lptid and app.target_uuid is None:
app.target_uuid = uuid
def handleAnswerPartitionTable(self, conn, packet, cell_list):
uuid = conn.getUUID()
if uuid is None:
self.handleUnexpectedPacket(conn, packet)
return
app = self.app
node = app.nm.getNodeByUUID(uuid)
if not isinstance(node, StorageNode):
self.handleUnexpectedPacket(conn, packet)
return
if uuid != app.target_uuid:
# If this is not from a target node, ignore it.
return
for offset, cell_list in row_list:
if offset >= app.num_partitions or app.pt.hasOffset(offset):
# There must be something wrong.
self.handleUnexpectedPacket(conn, packet)
return
for uuid, state in cell_list:
n = app.nm.getNodeByUUID(uuid)
if n is None:
n = StorageNode(uuid = uuid)
n.setState(TEMPORARILY_DOWN_STATE)
app.nm.add(n)
app.pt.setCell(offset, n, state)
neo/protocol.py
View file @ 5155ff33
......@@ -496,4 +496,4 @@ class Packet(object):
def _decodeStopOperation(self):
pass
decode_table[START_OPERATION] = _decodeStopOperation
decode_table[STOP_OPERATION] = _decodeStopOperation
neo/pt.py 0 → 100644
View file @ 5155ff33
import logging
from neo.protocol import UP_TO_DATE_STATE, OUT_OF_DATE_STATE, FEEDING_STATE, \
DISCARDED_STATE
class Cell(object):
"""This class represents a cell in a partition table."""
def __init__(self, node, state = UP_TO_DATE_STATE):
self.node = node
self.state = state
def getState(self):
return self.state
def setState(self, state):
self.state = state
def getNode(self):
return self.node
def getNodeState(self):
"""This is a short hand."""
return self.node.getState()
class PartitionTable(object):
"""This class manages a partition table."""
def __init__(self, num_partitions, num_replicas):
self.np = num_partitions
self.nr = num_replicas
self.num_filled_rows = 0
self.partition_list = [None] * num_partitions
def clear(self):
"""Forget an existing partition table."""
self.num_filled_rows = 0
self.partition_list = [None] * self.np
def make(self, node_list):
"""Make a new partition table from scratch."""
# First, filter the list of nodes.
node_list = [n for n in node_list \
if n.getState() == RUNNING_STATE and n.getUUID() is not None]
if len(node_list) == 0:
# Impossible.
raise RuntimeError, \
'cannot make a partition table with an empty storage node list'
# Take it into account that the number of storage nodes may be less than the
# number of replicas.
repeats = min(self.nr, len(node_list))
index = 0
for offset in xrange(self.np):
row = []
for i in xrange(repeats):
row.append(Cell(node_list[index]))
index += 1
if index == len(uuid_list):
index = 0
self.partition_list[offset] = row
self.num_filled_rows = self.np
def setCell(self, offset, node, state):
row = self.partition_list[offset]
if row is None:
# Create a new row.
row = [Cell(node, state)]
self.partition_list[offset]
self.num_filled_rows += 1
else:
# XXX this can be slow, but it is necessary to remove a duplicate,
# if any.
for cell in row:
if cell.getNode() == node:
row.remove(cell)
break
row.append(Cell(node, state))
def filled(self):
return self.num_filled_rows == self.np
def hasOffset(self, offset):
return self.partition_list[offset] is not None
def operational(self):
if not self.filled():
return False
# FIXME it is better to optimize this code, as this could be extremely
# slow. The possible fix is to have a handler to notify a change on
# a node state, and record which rows are ready.
for row in self.partition_list:
for cell in row:
if cell.getState() == UP_TO_DATE_STATE \
and cell.getNodeState() == RUNNING_STATE:
break
else:
return False
return True
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