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# to you under the Apache License, Version 2.0 (the
# "License"); you may not use this file except in compliance
# with the License.  You may obtain a copy of the License at
#
#   http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing,
# software distributed under the License is distributed on an
# "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
# KIND, either express or implied.  See the License for the
# specific language governing permissions and limitations
# under the License.

import logging
import socket
import threading
import time

# these allow discovery of IP addresses assigned to the VM.
# making these optional in case of ancient installs that don't
# have provided python-pypcap or python-dpkt packages
global haveIpDiscovery
haveIpDiscovery = False
try:
	import dpkt, pcap
	haveIpDiscovery = True
except ImportError:
	pass
	
from struct import pack

from tashi.rpycservices.rpyctypes import InstanceState, TashiException, Errors, Instance
from tashi import boolean, vmStates, ConnectionManager

class NodeManagerService(object):
	"""RPC handler for the NodeManager

	   Perhaps in the future I can hide the dfs from the
	   VmControlInterface and do all dfs operations here?"""

	def __init__(self, config, vmm):
		# XXXstroucki: vmm will wait for this constructor to complete
		self.hostname = socket.gethostname()
		self.config = config
		self.vmm = vmm
		self.cmHost = self.config.get("NodeManagerService", "clusterManagerHost")
		self.cmPort = int(self.config.get("NodeManagerService", "clusterManagerPort"))
		self.authAndEncrypt = boolean(self.config.get('Security', 'authAndEncrypt'))
		if self.authAndEncrypt:
			self.username = self.config.get('AccessClusterManager', 'username')
			self.password = self.config.get('AccessClusterManager', 'password')
		else:
			self.username = None
			self.password = None
		self.log = logging.getLogger(__file__)
		self.convertExceptions = boolean(self.config.get('NodeManagerService', 'convertExceptions'))
		self.registerFrequency = float(self.config.get('NodeManagerService', 'registerFrequency'))
		self.statsInterval = float(self.config.get('NodeManagerService', 'statsInterval', default = 0))
		self.registerHost = boolean(self.config.get('NodeManagerService', 'registerHost'))
		try:
			self.cm = ConnectionManager(self.username, self.password, self.cmPort)[self.cmHost]
		except:
			self.log.exception("Could not connect to CM")
			# XXXstroucki: raise?
			return

		self.accountingHost = self.config.get('NodeManagerService', 'accountingHost')
		self.accountingPort = self.config.getint('NodeManagerService', 'accountingPort')

		self.notifyCM = []

		self.__initAccounting()

		self.id = None
		# XXXstroucki this fn could be in this level maybe?
		self.host = self.vmm.getHostInfo(self)

		# populate self.instances
		self.__loadVmInfo()

		# try to add myself to the list of available hosts
		# is this useful, or too dangerous to consider?
		if self.registerHost:
			self.__registerHost()

		# XXXstroucki: should make an effort to retry
		# This can time out now with an exception
		self.id = self.cm.registerNodeManager(self.host, self.instances.values())

		# make arp monitoring optional
		self.haveIpDiscovery = False
		if "haveIpDiscovery" in globals():
			self.haveIpDiscovery = haveIpDiscovery

		# start service threads
		threading.Thread(name="registerWithClusterManager", target=self.__registerWithClusterManager).start()
		threading.Thread(name="statsThread", target=self.__statsThread).start()
		if self.haveIpDiscovery:
			threading.Thread(name="arpMonitorThread", target=self.__arpMonitorThread, args=(config,)).start()
		else:
			self.log.warning("Disabling ARP monitoring thread")

	def __initAccounting(self):
		self.accountBuffer = []
		self.accountLines = 0
		self.accountingClient = None
		try:
			if (self.accountingHost is not None) and \
						(self.accountingPort is not None):
				self.accountingClient = ConnectionManager(self.username, self.password, self.accountingPort)[self.accountingHost]
		except:
			self.log.exception("Could not init accounting")

	def __loadVmInfo(self):
		try:
			self.instances = self.vmm.getInstances()
		except Exception:
			self.log.exception('Failed to obtain VM info')
			self.instances = {}

	# send data to CM
	# XXXstroucki adapt this for accounting?
	def __flushNotifyCM(self):
		# send data to CM, adding message to buffer if
		# it fails
		try:
			notifyCM = []
			try:
				while (len(self.notifyCM) > 0):
					# XXXstroucki ValueError: need more than 1 value to unpack
					# observed here. How?
					value = self.notifyCM.pop(0)
					try:
						(instanceId, newInst, old, success) = value
					except:
						self.log.exception("problem with value: %s" % value)
					try:
						self.cm.vmUpdate(instanceId, newInst, old)
					except TashiException, e:
						notifyCM.append((instanceId, newInst, old, success))
						if (e.errno != Errors.IncorrectVmState):
							raise
					except:
						notifyCM.append((instanceId, newInst, old, success))
						raise
					else:
						success()
			finally:
				if len(notifyCM) > 0:
					self.notifyCM.append(notifyCM)
		except Exception, e:
			self.log.exception('Failed to send data to the CM')

		#toSleep = start - time.time() + self.registerFrequency
		#if (toSleep > 0):
			#time.sleep(toSleep)

	def __ACCOUNTFLUSH(self):
		try:
			if (self.accountingClient is not None):
				self.accountingClient.record(self.accountBuffer)
			self.accountLines = 0
			self.accountBuffer = []
		except:
			self.log.exception("Failed to flush accounting data")


	def __ACCOUNT(self, text, instance=None, host=None):
		now = time.time()
		instanceText = None
		hostText = None

		if instance is not None:
			try:
				instanceText = 'Instance(%s)' % (instance)
			except:
				self.log.exception("Invalid instance data")

		if host is not None:
			try:
				hostText = "Host(%s)" % (host)
			except:
				self.log.exception("Invalid host data")

		secondary = ','.join(filter(None, (hostText, instanceText)))

		line = "%s|%s|%s" % (now, text, secondary)

		self.accountBuffer.append(line)
		self.accountLines += 1

		# XXXstroucki think about force flush every so often
		if (self.accountLines > 0):
			self.__ACCOUNTFLUSH()


	# service thread function
	def __registerWithClusterManager(self):
		happy = False
		while True:
			#self.__ACCOUNT("TESTING")
			start = time.time()
			try:
				instances = self.instances.values()
				self.id = self.cm.registerNodeManager(self.host, instances)
				if not happy:
					happy = True
					self.log.info("Registered with the CM")

			except Exception:
				self.log.exception('Failed to register with the CM')
				happy = False

			# make sure we flush our notification buffers
			# if we have good comms with the CM
			if happy:
				self.__flushNotifyCM()

			toSleep = start - time.time() + self.registerFrequency
			if (toSleep > 0):
				time.sleep(toSleep)

	#Convert a string of 6 characters of ethernet address into a colon separated hex string
	def __stringToMac(self, a):
		# XXXstroucki: enforce string length?
		b = ":".join(s.encode("hex") for s in a)
		return b

	def __updateInstance(self, mac, ip):
		for vmId in self.instances.keys():
			try:
				instance = self.instances.get(vmId, None)
				if (not instance):
					continue
				for i in range(0, len(instance.nics)): 
					nic = instance.nics[i]
					if (nic.mac == mac):
						self.log.debug('Detected IP address: %s for hardware address: %s' % (ip, mac))
						nic.ip = ip
			except:
				self.log.exception('updateInstance threw an exception (vmid %d)' % vmId)

	# service thread function
	def __arpMonitorThread(self, conf):
		try:
			pc = pcap.pcap()
			# Look for ARP or DHCP traffic
			pc.setfilter('arp or udp port 67')
	
			for ts, pkt in pc:
				e = dpkt.ethernet.Ethernet(pkt)
				if e.type == dpkt.ethernet.ETH_TYPE_IP:
					ip = e.data
					udp = ip.data
					dhcp = dpkt.dhcp.DHCP(udp.data)
					if dhcp.op == dpkt.dhcp.DHCPACK or dhcp.op == dpkt.dhcp.DHCPOFFER:
						macaddress = self.__stringToMac(dhcp.chaddr)
						ipaddress = socket.inet_ntoa(pack("!I",dhcp.ciaddr))
						self.__updateInstance(macaddress, ipaddress)
				elif e.type == dpkt.ethernet.ETH_TYPE_ARP:
					a = e.data
					if a.op == dpkt.arp.ARP_OP_REPLY:
						ipaddress = socket.inet_ntoa(a.spa)
						macaddress = self.__stringToMac(a.sha)
						self.__updateInstance(macaddress, ipaddress)
		except:
			self.log.exception('arpMonitorThread threw an exception')

	# service thread function
	def __statsThread(self):
		if (self.statsInterval == 0):
			return
		while True:
			try:
				publishList = []
				for vmId in self.instances.keys():
					try:
						instance = self.instances.get(vmId, None)
						if (not instance):
							continue
						_id = instance.id
						stats = self.vmm.getStats(vmId)
						for stat in stats:
							publishList.append({"vm_%d_%s" % (_id, stat):stats[stat]})
					except:
						self.log.exception('statsThread threw an exception')
				if (len(publishList) > 0):
					# XXXstroucki: no publisher currently
					pass
					#tashi.publisher.publishList(publishList)
			except:
				self.log.exception('statsThread threw an exception')
			time.sleep(self.statsInterval)

	def __registerHost(self):
		# populate some defaults
		# XXXstroucki: I think it's better if the nodemanager fills these in
		# properly when registering with the clustermanager
		memory = 0
		cores = 0
		version = "empty"
		rv = self.cm.registerHost(self.hostname, memory, cores, version)

	def __getInstance(self, vmId):
		instance = self.instances.get(vmId, None)
		if instance is not None:
			return instance

		# refresh self.instances if not found
		self.__loadVmInfo()
		instance = self.instances.get(vmId, None)
		if instance is not None:
			return instance


		raise TashiException(d={'errno':Errors.NoSuchVmId,'msg':"There is no vmId %d on this host" % (vmId)})

	# remote
	# Called from VMM to update self.instances
	# but only changes are Exited, MigrateTrans and Running
	# qemu.py calls this in the matchSystemPids thread
	# xenpv.py: i have no real idea why it is called there
	def vmStateChange(self, vmId, old, cur):
		try:
			instance = self.__getInstance(vmId)
		except TashiException, e:
			if e.errno == Errors.NoSuchVmId:
				self.log.warning("Asked to change state for unknown VM. Has it not completed starting yet?")
				return False
			else:
				raise

		before = instance.state
		if (instance.state == cur):
			# Don't do anything if state is what it should be
			return True

		if (old and instance.state != old):
			# make a note of mismatch, but go on.
			# the VMM should know best
			self.log.warning('VM state was %s, call indicated %s' % (vmStates[instance.state], vmStates[old]))

		instance.state = cur

		self.__ACCOUNT("NM VM STATE CHANGE", instance=instance)

		newInst = Instance(d={'state':cur})
		success = lambda: None

		# if this instance was in MigrateTrans, and has exited
		# then don't tell the CM; it is the source instance
		# exiting, and the CM should have updated its information
		# to the target instance's info.
		# Otherwise, send the state change up to the CM

		if before == InstanceState.MigrateTrans and cur == InstanceState.Exited:
			pass
		else:
			self.notifyCM.append((instance.id, newInst, old, success))
			self.__flushNotifyCM()

		# cache change locally
		self.instances[vmId] = instance

		if (cur == InstanceState.Exited):
			# At this point, the VMM will clean up,
			# so forget about this instance
			del self.instances[vmId]

		return True

	# remote
	def createInstance(self, instance):
		vmId = instance.vmId
		self.instances[vmId] = instance


	# remote
	def instantiateVm(self, instance):
		# XXXstroucki: check my capacity before instantiating

		self.__ACCOUNT("NM VM INSTANTIATE", instance=instance)
		try:
			vmId = self.vmm.instantiateVm(instance)
			#instance.vmId = vmId
			#instance.state = InstanceState.Running
			#self.instances[vmId] = instance
			return vmId
		except:
			self.log.exception("Failed to start instance")

	# remote
	def suspendVm(self, vmId, destination):
		instance = self.__getInstance(vmId)
		self.__ACCOUNT("NM VM SUSPEND", instance=instance)

		instance.state = InstanceState.Suspending
		self.instances[vmId] = instance
		threading.Thread(target=self.vmm.suspendVm, args=(vmId, destination)).start()

	# called by resumeVm as thread
	def __resumeVmHelper(self, instance, name):
		self.vmm.resumeVmHelper(instance, name)
		# XXXstroucki should the VMM be responsible for setting
		# state? It should know better.
		instance.state = InstanceState.Running
		newInstance = Instance(d={'id':instance.id,'state':instance.state})
		success = lambda: None
		self.notifyCM.append((newInstance.id, newInstance, InstanceState.Resuming, success))
		self.__flushNotifyCM()

	# remote
	def resumeVm(self, instance, name):
		self.__ACCOUNT("NM VM RESUME", instance=instance)
		instance.state = InstanceState.Resuming
		instance.hostId = self.id
		try:
			instance.vmId = self.vmm.resumeVm(instance, name)
			self.instances[instance.vmId] = instance
			threading.Thread(target=self.__resumeVmHelper, args=(instance, name)).start()
		except:
			self.log.exception('resumeVm failed')
			raise TashiException(d={'errno':Errors.UnableToResume,'msg':"resumeVm failed on the node manager"})
		return instance.vmId

	# remote
	def prepReceiveVm(self, instance, source):
		self.__ACCOUNT("NM VM MIGRATE RECEIVE PREP")
		instance.vmId = -1
		transportCookie = self.vmm.prepReceiveVm(instance, source.name)
		return transportCookie

	# remote
	def prepSourceVm(self, vmId):
		instance = self.__getInstance(vmId)
		self.__ACCOUNT("NM VM MIGRATE SOURCE PREP", instance=instance)
		instance.state = InstanceState.MigratePrep
		self.instances[vmId] = instance

	# called by migrateVm as thread
	# XXXstroucki migrate out?
	def __migrateVmHelper(self, instance, target, transportCookie):
		self.vmm.migrateVm(instance.vmId, target.name, transportCookie)
		# removal from self.instances done by communication from
		# VMM as part of above migrateVm function
		return

	# remote
	# XXXstroucki migrate out?
	def migrateVm(self, vmId, target, transportCookie):
		instance = self.__getInstance(vmId)
		self.__ACCOUNT("NM VM MIGRATE", instance=instance)
		instance.state = InstanceState.MigrateTrans
		self.instances[vmId] = instance
		threading.Thread(name="migrateVmHelper", target=self.__migrateVmHelper, args=(instance, target, transportCookie)).start()
		return

	# called by receiveVm as thread
	# XXXstroucki migrate in?
	def __receiveVmHelper(self, instance, transportCookie):
		vmId = self.vmm.receiveVm(transportCookie)
		instance.state = InstanceState.Running
		instance.hostId = self.id
		instance.vmId = vmId
		self.instances[vmId] = instance
		newInstance = Instance(d={'id':instance.id,'state':instance.state,'vmId':instance.vmId,'hostId':instance.hostId})
		success = lambda: None
		self.notifyCM.append((newInstance.id, newInstance, InstanceState.MigrateTrans, success))
		self.__flushNotifyCM()

	# remote
	# XXXstroucki migrate in?
	def receiveVm(self, instance, transportCookie):
		instance.state = InstanceState.MigrateTrans
		# XXXstroucki new vmId is not known yet until VM is received
		#vmId = instance.vmId
		#self.instances[vmId] = instance
		self.__ACCOUNT("NM VM MIGRATE RECEIVE", instance=instance)
		threading.Thread(target=self.__receiveVmHelper, args=(instance, transportCookie)).start()
		return

	# remote
	def pauseVm(self, vmId):
		instance = self.__getInstance(vmId)
		self.__ACCOUNT("NM VM PAUSE", instance=instance)
		instance.state = InstanceState.Pausing
		self.instances[vmId] = instance
		self.vmm.pauseVm(vmId)
		instance.state = InstanceState.Paused
		self.instances[vmId] = instance

	# remote
	def unpauseVm(self, vmId):
		instance = self.__getInstance(vmId)
		self.__ACCOUNT("NM VM UNPAUSE", instance=instance)
		instance.state = InstanceState.Unpausing
		self.instances[vmId] = instance
		self.vmm.unpauseVm(vmId)
		instance.state = InstanceState.Running
		self.instances[vmId] = instance

	# remote
	def shutdownVm(self, vmId):
		instance = self.__getInstance(vmId)
		self.__ACCOUNT("NM VM SHUTDOWN", instance=instance)
		instance.state = InstanceState.ShuttingDown
		self.instances[vmId] = instance
		self.vmm.shutdownVm(vmId)

	# remote
	def destroyVm(self, vmId):
		instance = self.__getInstance(vmId)
		self.__ACCOUNT("NM VM DESTROY", instance=instance)
		instance.state = InstanceState.Destroying
		self.instances[vmId] = instance
		self.vmm.destroyVm(vmId)

	# remote
	def getVmInfo(self, vmId):
		instance = self.__getInstance(vmId)
		return instance

	# remote
	def vmmSpecificCall(self, vmId, arg):
		return self.vmm.vmmSpecificCall(vmId, arg)

	# remote
	def listVms(self):
		return self.instances.keys()

	# remote
	def liveCheck(self):
		return "alive"