#!@PYTHON@ -tt
#
#	Resource agent for monitoring Azure Scheduled Events
#
# 	License:	GNU General Public License (GPL)
#	(c) 2018 	Tobias Niekamp, Microsoft Corp.
#				and Linux-HA contributors

import os
import sys
import time
import subprocess
import json
try:
		import urllib2
		from urllib2 import URLError
except ImportError:
		import urllib.request as urllib2
		from urllib.error import URLError
import socket
from collections import defaultdict

OCF_FUNCTIONS_DIR = os.environ.get("OCF_FUNCTIONS_DIR", "%s/lib/heartbeat" % os.environ.get("OCF_ROOT"))
sys.path.append(OCF_FUNCTIONS_DIR)
import ocf

##############################################################################


VERSION = "0.10"
USER_AGENT = "Pacemaker-ResourceAgent/%s %s" % (VERSION, ocf.distro())

attr_globalPullState = "azure-events_globalPullState"
attr_lastDocVersion  = "azure-events_lastDocVersion"
attr_curNodeState = "azure-events_curNodeState"
attr_pendingEventIDs = "azure-events_pendingEventIDs"

default_loglevel = ocf.logging.INFO
default_relevantEventTypes = set(["Reboot", "Redeploy"])

global_pullMaxAttempts = 3
global_pullDelaySecs = 1

##############################################################################

class attrDict(defaultdict):
	"""
	A wrapper for accessing dict keys like an attribute
	"""
	def __init__(self, data):
		super(attrDict, self).__init__(attrDict)
		for d in data.keys():
			self.__setattr__(d, data[d])

	def __getattr__(self, key):
		try:
			return self[key]
		except KeyError:
			raise AttributeError(key)

	def __setattr__(self, key, value):
		self[key] = value

##############################################################################

class azHelper:
	"""
	Helper class for Azure's metadata API (including Scheduled Events)
	"""
	metadata_host = "http://169.254.169.254/metadata"
	instance_api  = "instance"
	events_api    = "scheduledevents"
	api_version   = "2019-08-01"

	@staticmethod
	def _sendMetadataRequest(endpoint, postData=None):
		"""
		Send a request to Azure's Azure Metadata Service API
		"""
		url = "%s/%s?api-version=%s" % (azHelper.metadata_host, endpoint, azHelper.api_version)
		data = ""
		ocf.logger.debug("_sendMetadataRequest: begin; endpoint = %s, postData = %s" % (endpoint, postData))
		ocf.logger.debug("_sendMetadataRequest: url = %s" % url)

		if postData and type(postData) != bytes:
			postData = postData.encode()

		req = urllib2.Request(url, postData)
		req.add_header("Metadata", "true")
		req.add_header("User-Agent", USER_AGENT)
		try:
			resp = urllib2.urlopen(req)
		except URLError as e:
			if hasattr(e, 'reason'):
				ocf.logger.warning("Failed to reach the server: %s" % e.reason)
				clusterHelper.setAttr(attr_globalPullState, "IDLE")
			elif hasattr(e, 'code'):
				ocf.logger.warning("The server couldn\'t fulfill the request. Error code: %s" % e.code)
				clusterHelper.setAttr(attr_globalPullState, "IDLE")
		else:
			data = resp.read()
			ocf.logger.debug("_sendMetadataRequest: response = %s" % data)

		if data:
			data = json.loads(data)

		ocf.logger.debug("_sendMetadataRequest: finished")
		return data

	@staticmethod
	def getInstanceInfo():
		"""
		Fetch details about the current VM from Azure's Azure Metadata Service API
		"""
		ocf.logger.debug("getInstanceInfo: begin")

		jsondata = azHelper._sendMetadataRequest(azHelper.instance_api)
		ocf.logger.debug("getInstanceInfo: json = %s" % jsondata)

		if jsondata:
			ocf.logger.debug("getInstanceInfo: finished, returning {}".format(jsondata["compute"]))
			return attrDict(jsondata["compute"])
		else:
			ocf.ocf_exit_reason("getInstanceInfo: Unable to get instance info")
			sys.exit(ocf.OCF_ERR_GENERIC)

	@staticmethod
	def pullScheduledEvents():
		"""
		Retrieve all currently scheduled events via Azure Metadata Service API
		"""
		ocf.logger.debug("pullScheduledEvents: begin")

		jsondata = azHelper._sendMetadataRequest(azHelper.events_api)
		ocf.logger.debug("pullScheduledEvents: json = %s" % jsondata)

		ocf.logger.debug("pullScheduledEvents: finished")
		return attrDict(jsondata)

	@staticmethod
	def forceEvents(eventIDs):
		"""
		Force a set of events to start immediately
		"""
		ocf.logger.debug("forceEvents: begin")

		events = []
		for e in eventIDs:
			events.append({
				"EventId": e,
			})
		postData = {
			"StartRequests" : events
		}
		ocf.logger.info("forceEvents: postData = %s" % postData)
		resp = azHelper._sendMetadataRequest(azHelper.events_api, postData=json.dumps(postData))

		ocf.logger.debug("forceEvents: finished")
		return

##############################################################################

class clusterHelper:
	"""
	Helper functions for Pacemaker control via crm
	"""
	@staticmethod
	def _getLocation(node):
		"""
		Helper function to retrieve local/global attributes
		"""
		if node:
			return ["--node", node]
		else:
			return ["--type", "crm_config"]

	@staticmethod
	def _exec(command, *args):
		"""
		Helper function to execute a UNIX command
		"""
		args = list(args)
		ocf.logger.debug("_exec: begin; command = %s, args = %s" % (command, str(args)))

		def flatten(*n):
			return (str(e) for a in n
				for e in (flatten(*a) if isinstance(a, (tuple, list)) else (str(a),)))
		command = list(flatten([command] + args))
		ocf.logger.debug("_exec: cmd = %s" % " ".join(command))
		try:
			ret = subprocess.check_output(command)
			if type(ret) != str:
				ret = ret.decode()
			ocf.logger.debug("_exec: return = %s" % ret)
			return ret.rstrip()
		except Exception as err:
			ocf.logger.exception(err)
			return None

	@staticmethod
	def setAttr(key, value, node=None):
		"""
		Set the value of a specific global/local attribute in the Pacemaker cluster
		"""
		ocf.logger.debug("setAttr: begin; key = %s, value = %s, node = %s" % (key, value, node))

		if value:
			ret = clusterHelper._exec("crm_attribute",
									  "--name", key,
									  "--update", value,
									  clusterHelper._getLocation(node))
		else:
			ret = clusterHelper._exec("crm_attribute",
									  "--name", key,
									  "--delete",
									  clusterHelper._getLocation(node))

		ocf.logger.debug("setAttr: finished")
		return len(ret) == 0

	@staticmethod
	def getAttr(key, node=None):
		"""
		Retrieve a global/local attribute from the Pacemaker cluster
		"""
		ocf.logger.debug("getAttr: begin; key = %s, node = %s" % (key, node))

		val = clusterHelper._exec("crm_attribute",
								  "--name", key,
								  "--query", "--quiet",
								  "--default", "",
								  clusterHelper._getLocation(node))
		ocf.logger.debug("getAttr: finished")
		if not val:
			return None
		return val if not val.isdigit() else int(val)

	@staticmethod
	def getAllNodes():
		"""
		Get a list of hostnames for all nodes in the Pacemaker cluster
		"""
		ocf.logger.debug("getAllNodes: begin")

		nodes = []
		nodeList = clusterHelper._exec("crm_node", "--list")
		for n in nodeList.split("\n"):
			nodes.append(n.split()[1])
		ocf.logger.debug("getAllNodes: finished; return %s" % str(nodes))

		return nodes

	@staticmethod
	def getHostNameFromAzName(azName):
		"""
		Helper function to get the actual host name from an Azure node name
		"""
		return clusterHelper.getAttr("hostName_%s" % azName)

	@staticmethod
	def removeHoldFromNodes():
		"""
		Remove the ON_HOLD state from all nodes in the Pacemaker cluster
		"""
		ocf.logger.debug("removeHoldFromNodes: begin")

		for n in clusterHelper.getAllNodes():
			if clusterHelper.getAttr(attr_curNodeState, node=n) == "ON_HOLD":
				clusterHelper.setAttr(attr_curNodeState, "AVAILABLE", node=n)
				ocf.logger.info("removeHoldFromNodes: removed ON_HOLD from node %s" % n)

		ocf.logger.debug("removeHoldFromNodes: finished")
		return False

	@staticmethod
	def otherNodesAvailable(exceptNode):
		"""
		Check if there are any nodes (except a given node) in the Pacemaker cluster that have state AVAILABLE
		"""
		ocf.logger.debug("otherNodesAvailable: begin; exceptNode = %s" % exceptNode)

		for n in clusterHelper.getAllNodes():
			state = clusterHelper.getAttr(attr_curNodeState, node=n)
			state = stringToNodeState(state) if state else AVAILABLE
			if state == AVAILABLE and n != exceptNode.hostName:
				ocf.logger.info("otherNodesAvailable: at least %s is available" % n)
				ocf.logger.debug("otherNodesAvailable: finished")
				return True
		ocf.logger.info("otherNodesAvailable: no other nodes are available")
		ocf.logger.debug("otherNodesAvailable: finished")

		return False

	@staticmethod
	def transitionSummary():
		"""
		Get the current Pacemaker transition summary (used to check if all resources are stopped when putting a node standby)
		"""
		# <tniek> Is a global crm_simulate "too much"? Or would it be sufficient it there are no planned transitions for a particular node?
		# # crm_simulate -LS
		# 	Transition Summary:
		# 	 * Promote rsc_SAPHana_HN1_HDB03:0      (Slave -> Master hsr3-db1)
		# 	 * Stop    rsc_SAPHana_HN1_HDB03:1      (hsr3-db0)
		# 	 * Move    rsc_ip_HN1_HDB03     (Started hsr3-db0 -> hsr3-db1)
		# 	 * Start   rsc_nc_HN1_HDB03     (hsr3-db1)
		# # Excepted result when there are no pending actions:
		# 	Transition Summary:
		ocf.logger.debug("transitionSummary: begin")

		summary = clusterHelper._exec("crm_simulate", "-LS")
		if not summary:
			ocf.logger.warning("transitionSummary: could not load transition summary")
			return ""
		if summary.find("Transition Summary:") < 0:
			ocf.logger.debug("transitionSummary: no transactions: %s" % summary)
			return ""
		j=summary.find('Transition Summary:') + len('Transition Summary:')
		l=summary.lower().find('executing cluster transition:')
		ret = list(filter(str.strip, summary[j:l].split("\n")))

		ocf.logger.debug("transitionSummary: finished; return = %s" % str(ret))
		return ret

	@staticmethod
	def listOperationsOnNode(node):
		"""
		Get a list of all current operations for a given node (used to check if any resources are pending)
		"""
		# hsr3-db1:/home/tniek # crm_resource --list-operations -N hsr3-db0
		# rsc_azure-events    (ocf::heartbeat:azure-events):      Started: rsc_azure-events_start_0 (node=hsr3-db0, call=91, rc=0, last-rc-change=Fri Jun  8 22:37:46 2018, exec=115ms): complete
		# rsc_azure-events    (ocf::heartbeat:azure-events):      Started: rsc_azure-events_monitor_10000 (node=hsr3-db0, call=93, rc=0, last-rc-change=Fri Jun  8 22:37:47 2018, exec=197ms): complete
		# rsc_SAPHana_HN1_HDB03   (ocf::suse:SAPHana):    Master: rsc_SAPHana_HN1_HDB03_start_0 (node=hsr3-db0, call=-1, rc=193, last-rc-change=Fri Jun  8 22:37:46 2018, exec=0ms): pending
		# rsc_SAPHanaTopology_HN1_HDB03   (ocf::suse:SAPHanaTopology):    Started: rsc_SAPHanaTopology_HN1_HDB03_start_0 (node=hsr3-db0, call=90, rc=0, last-rc-change=Fri Jun  8 22:37:46 2018, exec=3214ms): complete
		ocf.logger.debug("listOperationsOnNode: begin; node = %s" % node)

		resources = clusterHelper._exec("crm_resource", "--list-operations", "-N", node)
		if len(resources) == 0:
			ret = []
		else:
			ret = resources.split("\n")

		ocf.logger.debug("listOperationsOnNode: finished; return = %s" % str(ret))
		return ret

	@staticmethod
	def noPendingResourcesOnNode(node):
		"""
		Check that there are no pending resources on a given node
		"""
		ocf.logger.debug("noPendingResourcesOnNode: begin; node = %s" % node)

		for r in clusterHelper.listOperationsOnNode(node):
			ocf.logger.debug("noPendingResourcesOnNode: * %s" % r)
			resource = r.split()[-1]
			if resource == "pending":
				ocf.logger.info("noPendingResourcesOnNode: found resource %s that is still pending" % resource)
				ocf.logger.debug("noPendingResourcesOnNode: finished; return = False")
				return False
		ocf.logger.info("noPendingResourcesOnNode: no pending resources on node %s" % node)
		ocf.logger.debug("noPendingResourcesOnNode: finished; return = True")

		return True

	@staticmethod
	def allResourcesStoppedOnNode(node):
		"""
		Check that all resources on a given node are stopped
		"""
		ocf.logger.debug("allResourcesStoppedOnNode: begin; node = %s" % node)

		if clusterHelper.noPendingResourcesOnNode(node):
			if len(clusterHelper.transitionSummary()) == 0:
				ocf.logger.info("allResourcesStoppedOnNode: no pending resources on node %s and empty transition summary" % node)
				ocf.logger.debug("allResourcesStoppedOnNode: finished; return = True")
				return True
			ocf.logger.info("allResourcesStoppedOnNode: transition summary is not empty")
			ocf.logger.debug("allResourcesStoppedOnNode: finished; return = False")
			return False

		ocf.logger.info("allResourcesStoppedOnNode: still pending resources on node %s" % node)
		ocf.logger.debug("allResourcesStoppedOnNode: finished; return = False")
		return False

##############################################################################

AVAILABLE = 0	# Node is online and ready to handle events
STOPPING = 1	# Standby has been triggered, but some resources are still running
IN_EVENT = 2	# All resources are stopped, and event has been initiated via Azure Metadata Service
ON_HOLD = 3		# Node has a pending event that cannot be started there are no other nodes available

def stringToNodeState(name):
	if type(name) == int: return name
	if name == "STOPPING": return STOPPING
	if name == "IN_EVENT": return IN_EVENT
	if name == "ON_HOLD": return ON_HOLD
	return AVAILABLE

def nodeStateToString(state):
	if state == STOPPING: return "STOPPING"
	if state == IN_EVENT: return "IN_EVENT"
	if state == ON_HOLD: return "ON_HOLD"
	return "AVAILABLE"

##############################################################################

class Node:
	"""
	Core class implementing logic for a cluster node
	"""
	def __init__(self, ra):
		self.raOwner  = ra
		self.azInfo   = azHelper.getInstanceInfo()
		self.azName   = self.azInfo.name
		self.hostName = socket.gethostname()
		self.setAttr("azName", self.azName)
		clusterHelper.setAttr("hostName_%s" % self.azName, self.hostName)

	def getAttr(self, key):
		"""
		Get a local attribute
		"""
		return clusterHelper.getAttr(key, node=self.hostName)

	def setAttr(self, key, value):
		"""
		Set a local attribute
		"""
		return clusterHelper.setAttr(key, value, node=self.hostName)

	def selfOrOtherNode(self, node):
		"""
		Helper function to distinguish self/other node
		"""
		return node if node else self.hostName

	def setState(self, state, node=None):
		"""
		Set the state for a given node (or self)
		"""
		node = self.selfOrOtherNode(node)
		ocf.logger.debug("setState: begin; node = %s, state = %s" % (node, nodeStateToString(state)))

		clusterHelper.setAttr(attr_curNodeState, nodeStateToString(state), node=node)

		ocf.logger.debug("setState: finished")

	def getState(self, node=None):
		"""
		Get the state for a given node (or self)
		"""
		node = self.selfOrOtherNode(node)
		ocf.logger.debug("getState: begin; node = %s" % node)

		state = clusterHelper.getAttr(attr_curNodeState, node=node)
		ocf.logger.debug("getState: state = %s" % state)
		ocf.logger.debug("getState: finished")
		if not state:
			return AVAILABLE
		return stringToNodeState(state)

	def setEventIDs(self, eventIDs, node=None):
		"""
		Set pending EventIDs for a given node (or self)
		"""
		node = self.selfOrOtherNode(node)
		ocf.logger.debug("setEventIDs: begin; node = %s, eventIDs = %s" % (node, str(eventIDs)))

		if eventIDs:
			eventIDStr = ",".join(eventIDs)
		else:
			eventIDStr = None
		clusterHelper.setAttr(attr_pendingEventIDs, eventIDStr, node=node)

		ocf.logger.debug("setEventIDs: finished")
		return

	def getEventIDs(self, node=None):
		"""
		Get pending EventIDs for a given node (or self)
		"""
		node = self.selfOrOtherNode(node)
		ocf.logger.debug("getEventIDs: begin; node = %s" % node)

		eventIDStr = clusterHelper.getAttr(attr_pendingEventIDs, node=node)
		if eventIDStr:
			eventIDs = eventIDStr.split(",")
		else:
			eventIDs = None

		ocf.logger.debug("getEventIDs: finished; eventIDs = %s" % str(eventIDs))
		return eventIDs

	def updateNodeStateAndEvents(self, state, eventIDs, node=None):
		"""
		Set the state and pending EventIDs for a given node (or self)
		"""
		ocf.logger.debug("updateNodeStateAndEvents: begin; node = %s, state = %s, eventIDs = %s" % (node, nodeStateToString(state), str(eventIDs)))

		self.setState(state, node=node)
		self.setEventIDs(eventIDs, node=node)

		ocf.logger.debug("updateNodeStateAndEvents: finished")
		return state

	def putNodeStandby(self, node=None):
		"""
		Put self to standby
		"""
		node = self.selfOrOtherNode(node)
		ocf.logger.debug("putNodeStandby: begin; node = %s" % node)

		clusterHelper._exec("crm_attribute",
							"-t", "nodes",
							"-N", node,
							"-n", "standby",
							"-v", "on",
							"--lifetime=forever")

		ocf.logger.debug("putNodeStandby: finished")

	def putNodeOnline(self, node=None):
		"""
		Put self back online
		"""
		node = self.selfOrOtherNode(node)
		ocf.logger.debug("putNodeOnline: begin; node = %s" % node)

		clusterHelper._exec("crm_attribute",
							"-t", "nodes",
							"-N", node,
							"-n", "standby",
							"-v", "off",
							"--lifetime=forever")

		ocf.logger.debug("putNodeOnline: finished")

	def separateEvents(self, events):
		"""
		Split own/other nodes' events
		"""
		ocf.logger.debug("separateEvents: begin; events = %s" % str(events))

		localEvents = []
		remoteEvents = []
		for e in events:
			e = attrDict(e)
			if e.EventType not in self.raOwner.relevantEventTypes:
				continue
			if self.azName in e.Resources:
				localEvents.append(e)
			else:
				remoteEvents.append(e)
		ocf.logger.debug("separateEvents: finished; localEvents = %s, remoteEvents = %s" % (str(localEvents), str(remoteEvents)))
		return (localEvents, remoteEvents)

	def removeOrphanedEvents(self, azEvents):
		"""
		Remove remote events that are already finished
		"""
		ocf.logger.debug("removeOrphanedEvents: begin; azEvents = %s" % str(azEvents))

		azEventIDs = set()
		for e in azEvents:
			azEventIDs.add(e.EventId)
		# for all nodes except self ...
		for n in clusterHelper.getAllNodes():
			if n == self.hostName:
				continue
			curState = self.getState(node=n)
			# ... that still show in an event or shutting down resources ...
			if curState in (STOPPING, IN_EVENT):
				ocf.logger.info("removeOrphanedEvents: node %s has state %s" % (n, curState))
				clusterEventIDs = self.getEventIDs(node=n)
				stillActive = False
				# ... but don't have any more events running according to Azure, ...
				for p in clusterEventIDs:
					if p in azEventIDs:
						ocf.logger.info("removeOrphanedEvents: (at least) event %s on node %s has not yet finished" % (str(p), n))
						stillActive = True
						break
				if not stillActive:
					# ... put them back online.
					ocf.logger.info("removeOrphanedEvents: clusterEvents %s on node %s are not in azEvents %s -> bring node back online" % (str(clusterEventIDs), n, str(azEventIDs)))
					self.putNodeOnline(node=n)

		ocf.logger.debug("removeOrphanedEvents: finished")

	def handleRemoteEvents(self, azEvents):
		"""
		Handle a list of events (as provided by Azure Metadata Service) for other nodes
		"""
		ocf.logger.debug("handleRemoteEvents: begin; hostName = %s, events = %s" % (self.hostName, str(azEvents)))

		if len(azEvents) == 0:
			ocf.logger.debug("handleRemoteEvents: no remote events to handle")
			ocf.logger.debug("handleRemoteEvents: finished")
			return
		eventIDsForNode = {}

		# iterate through all current events as per Azure
		for e in azEvents:
			ocf.logger.info("handleRemoteEvents: handling remote event %s (%s; nodes = %s)" % (e.EventId, e.EventType, str(e.Resources)))
			# before we can force an event to start, we need to ensure all nodes involved have stopped their resources
			if e.EventStatus == "Scheduled":
				allNodesStopped = True
				for azName in e.Resources:
					hostName = clusterHelper.getHostNameFromAzName(azName)
					state = self.getState(node=hostName)
					if state == STOPPING:
						# the only way we can continue is when node state is STOPPING, but all resources have been stopped
						if not clusterHelper.allResourcesStoppedOnNode(hostName):
							ocf.logger.info("handleRemoteEvents: (at least) node %s has still resources running -> wait" % hostName)
							allNodesStopped = False
							break
					elif state in (AVAILABLE, IN_EVENT, ON_HOLD):
						ocf.logger.info("handleRemoteEvents: node %s is still %s -> remote event needs to be picked up locally" % (hostName, nodeStateToString(state)))
						allNodesStopped = False
						break
				if allNodesStopped:
					ocf.logger.info("handleRemoteEvents: nodes %s are stopped -> add remote event %s to force list" % (str(e.Resources), e.EventId))
					for n in e.Resources:
						hostName = clusterHelper.getHostNameFromAzName(n)
						if hostName in eventIDsForNode:
							eventIDsForNode[hostName].append(e.EventId)
						else:
							eventIDsForNode[hostName] = [e.EventId]
			elif e.EventStatus == "Started":
				ocf.logger.info("handleRemoteEvents: remote event already started")

		# force the start of all events whose nodes are ready (i.e. have no more resources running)
		if len(eventIDsForNode.keys()) > 0:
			eventIDsToForce = set([item for sublist in eventIDsForNode.values() for item in sublist])
			ocf.logger.info("handleRemoteEvents: set nodes %s to IN_EVENT; force remote events %s" % (str(eventIDsForNode.keys()), str(eventIDsToForce)))
			for node, eventId in eventIDsForNode.items():
				self.updateNodeStateAndEvents(IN_EVENT, eventId, node=node)
			azHelper.forceEvents(eventIDsToForce)

		ocf.logger.debug("handleRemoteEvents: finished")

	def handleLocalEvents(self, azEvents):
		"""
		Handle a list of own events (as provided by Azure Metadata Service)
		"""
		ocf.logger.debug("handleLocalEvents: begin; hostName = %s, azEvents = %s" % (self.hostName, str(azEvents)))

		azEventIDs = set()
		for e in azEvents:
			azEventIDs.add(e.EventId)

		curState = self.getState()
		clusterEventIDs = self.getEventIDs()
		mayUpdateDocVersion = False
		ocf.logger.info("handleLocalEvents: current state = %s; pending local clusterEvents = %s" % (nodeStateToString(curState), str(clusterEventIDs)))

		# check if there are currently/still events set for the node
		if clusterEventIDs:
			# there are pending events set, so our state must be STOPPING or IN_EVENT
			i = 0; touchedEventIDs = False
			while i < len(clusterEventIDs):
				# clean up pending events that are already finished according to AZ
				if clusterEventIDs[i] not in azEventIDs:
					ocf.logger.info("handleLocalEvents: remove finished local clusterEvent %s" % (clusterEventIDs[i]))
					clusterEventIDs.pop(i)
					touchedEventIDs = True
				else:
					i += 1
			if len(clusterEventIDs) > 0:
				# there are still pending events (either because we're still stopping, or because the event is still in place)
				# either way, we need to wait
				if touchedEventIDs:
					ocf.logger.info("handleLocalEvents: added new local clusterEvent %s" % str(clusterEventIDs))
					self.setEventIDs(clusterEventIDs)
				else:
					ocf.logger.info("handleLocalEvents: no local clusterEvents were updated")
			else:
				# there are no more pending events left after cleanup
				if clusterHelper.noPendingResourcesOnNode(self.hostName):
					# and no pending resources on the node -> set it back online
					ocf.logger.info("handleLocalEvents: all local events finished -> clean up, put node online and AVAILABLE")
					curState = self.updateNodeStateAndEvents(AVAILABLE, None)
					self.putNodeOnline()
					clusterHelper.removeHoldFromNodes()
					# repeat handleLocalEvents() since we changed status to AVAILABLE
				else:
					ocf.logger.info("handleLocalEvents: all local events finished, but some resources have not completed startup yet -> wait")
		else:
			# there are no pending events set for us (yet)
			if curState == AVAILABLE:
				if len(azEventIDs) > 0:
					if clusterHelper.otherNodesAvailable(self):
						ocf.logger.info("handleLocalEvents: can handle local events %s -> set state STOPPING" % (str(azEventIDs)))
						# this will also set mayUpdateDocVersion = True
						curState = self.updateNodeStateAndEvents(STOPPING, azEventIDs)
					else:
						ocf.logger.info("handleLocalEvents: cannot handle azEvents %s (only node available) -> set state ON_HOLD" % str(azEventIDs))
						self.setState(ON_HOLD)
				else:
					ocf.logger.debug("handleLocalEvents: no local azEvents to handle")
			if curState == STOPPING:
				if clusterHelper.noPendingResourcesOnNode(self.hostName):
					ocf.logger.info("handleLocalEvents: all local resources are started properly -> put node standby")
					self.putNodeStandby()
					mayUpdateDocVersion = True
				else:
					ocf.logger.info("handleLocalEvents: some local resources are not clean yet -> wait")

		ocf.logger.debug("handleLocalEvents: finished; mayUpdateDocVersion = %s" % str(mayUpdateDocVersion))
		return mayUpdateDocVersion

##############################################################################

class raAzEvents:
	"""
	Main class for resource agent
	"""
	def __init__(self, relevantEventTypes):
		self.node = Node(self)
		self.relevantEventTypes = relevantEventTypes

	def monitor(self):
		ocf.logger.debug("monitor: begin")

		pullFailedAttemps = 0
		while True:
			# check if another node is pulling at the same time;
			# this should only be a concern for the first pull, as setting up Scheduled Events may take up to 2 minutes.
			if clusterHelper.getAttr(attr_globalPullState) == "PULLING":
				pullFailedAttemps += 1
				if pullFailedAttemps == global_pullMaxAttempts:
					ocf.logger.warning("monitor: exceeded maximum number of attempts (%d) to pull events" % global_pullMaxAttempts)
					ocf.logger.debug("monitor: finished")
					return ocf.OCF_SUCCESS
				else:
					ocf.logger.info("monitor: another node is pulling; retry in %d seconds" % global_pullDelaySecs)
					time.sleep(global_pullDelaySecs)
					continue

			# we can pull safely from Azure Metadata Service
			clusterHelper.setAttr(attr_globalPullState, "PULLING")
			events = azHelper.pullScheduledEvents()
			clusterHelper.setAttr(attr_globalPullState, "IDLE")

			# get current document version
			curDocVersion  = events.DocumentIncarnation
			lastDocVersion = self.node.getAttr(attr_lastDocVersion)
			ocf.logger.debug("monitor: lastDocVersion = %s; curDocVersion = %s" % (lastDocVersion, curDocVersion))

			# split events local/remote
			(localEvents, remoteEvents) = self.node.separateEvents(events.Events)

			# ensure local events are only executing once
			if curDocVersion != lastDocVersion:
				ocf.logger.debug("monitor: curDocVersion has not been handled yet")
				# handleLocalEvents() returns True if mayUpdateDocVersion is True;
				# this is only the case if we can ensure there are no pending events
				if self.node.handleLocalEvents(localEvents):
					ocf.logger.info("monitor: handleLocalEvents completed successfully -> update curDocVersion")
					self.node.setAttr(attr_lastDocVersion, curDocVersion)
				else:
					ocf.logger.debug("monitor: handleLocalEvents still waiting -> keep curDocVersion")
			else:
				ocf.logger.info("monitor: already handled curDocVersion, skip")

			# remove orphaned remote events and then handle the remaining remote events
			self.node.removeOrphanedEvents(remoteEvents)
			self.node.handleRemoteEvents(remoteEvents)
			break

		ocf.logger.debug("monitor: finished")
		return ocf.OCF_SUCCESS

##############################################################################

def setLoglevel(verbose):
	# set up writing into syslog
	loglevel = default_loglevel
	if verbose:
		opener = urllib2.build_opener(urllib2.HTTPHandler(debuglevel=1))
		urllib2.install_opener(opener)
		loglevel = ocf.logging.DEBUG
	ocf.log.setLevel(loglevel)

description = (
	"Microsoft Azure Scheduled Events monitoring agent",
	"""This resource agent implements a monitor for scheduled
(maintenance) events for a Microsoft Azure VM.

If any relevant events are found, it moves all Pacemaker resources
away from the affected node to allow for a graceful shutdown.

	Usage:
		[OCF_RESKEY_eventTypes=VAL] [OCF_RESKEY_verbose=VAL] azure-events ACTION

		action (required): Supported values: monitor, help, meta-data
		eventTypes (optional): List of event types to be considered
				relevant by the resource agent (comma-separated).
				Supported values: Freeze,Reboot,Redeploy
				Default = Reboot,Redeploy
/		verbose (optional): If set to true, displays debug info.
				Default = false

	Deployment:
		crm configure primitive rsc_azure-events ocf:heartbeat:azure-events \
			op monitor interval=10s
		crm configure clone cln_azure-events rsc_azure-events

For further information on Microsoft Azure Scheduled Events, please
refer to the following documentation:
https://docs.microsoft.com/en-us/azure/virtual-machines/linux/scheduled-events
""")

def monitor_action(eventTypes):
	relevantEventTypes = set(eventTypes.split(",") if eventTypes else [])
	ra = raAzEvents(relevantEventTypes)
	return ra.monitor()

def validate_action(eventTypes):
	if eventTypes:
		for event in eventTypes.split(","):
			if event not in ("Freeze", "Reboot", "Redeploy"):
				ocf.ocf_exit_reason("Event type not one of Freeze, Reboot, Redeploy: " + eventTypes)
				return ocf.OCF_ERR_CONFIGURED
	return ocf.OCF_SUCCESS

def main():
	agent = ocf.Agent("azure-events", shortdesc=description[0], longdesc=description[1])
	agent.add_parameter(
		"eventTypes",
		shortdesc="List of resources to be considered",
		longdesc="A comma-separated list of event types that will be handled by this resource agent. (Possible values: Freeze,Reboot,Redeploy)",
		content_type="string",
		default="Reboot,Redeploy")
	agent.add_parameter(
		"verbose",
		shortdesc="Enable verbose agent logging",
		longdesc="Set to true to enable verbose logging",
		content_type="boolean",
		default="false")
	agent.add_action("start", timeout=10, handler=lambda: ocf.OCF_SUCCESS)
	agent.add_action("stop", timeout=10, handler=lambda: ocf.OCF_SUCCESS)
	agent.add_action("validate-all", timeout=20, handler=validate_action)
	agent.add_action("monitor", timeout=240, interval=10, handler=monitor_action)
	setLoglevel(ocf.is_true(ocf.get_parameter("verbose", "false")))
	agent.run()

if __name__ == '__main__':
	main()