HistoryManager._read_event_history() - Code Metrics - Inspection of "Events History with Tests" - FreeOpcUa/python-opcua - Measure and Improve Code Quality continuously with Scrutinizer

Completed

Pull Request — master (#180)

unknown

created 2016-05-10 00:49 UTC

HistoryManager._read_event_history() A

↳ Parent: HistoryManager

Complexity

Conditions

Size

Total Lines

Duplication

Lines	0
Ratio	0 %

Code Coverage

Tests	0
CRAP Score	12

Metric	Value
cc	3
dl	0
loc	19
ccs	0
cts	0
cp	0
crap	12
rs	9.4285

import logging
from datetime import timedelta
from datetime import datetime

from opcua import Subscription
from opcua import ua
from opcua.common import utils
from opcua.common import subscription


class HistoryStorageInterface(object):

    """
    Interface of a history backend.
    Must be implemented by backends
    """

    def new_historized_node(self, node_id, period, count=0):
        """
        Called when a new node is to be historized
        Returns None
        """
        raise NotImplementedError

    def save_node_value(self, node_id, datavalue):
        """
        Called when the value of a historized node has changed and should be saved in history
        Returns None
        """
        raise NotImplementedError

    def read_node_history(self, node_id, start, end, nb_values):
        """
        Called when a client make a history read request for a node
        if start or end is missing then nb_values is used to limit query
        nb_values is the max number of values to read. Ignored if 0
        Start time and end time are inclusive
        Returns a list of DataValues and a continuation point which
        is None if all nodes are read or the ServerTimeStamp of the last rejected DataValue
        """
        raise NotImplementedError

    def new_historized_event(self, source_id, etype, period):
        """
        Called when historization of events is enabled on server side
        FIXME: we may need to store events per nodes in future...
        Returns None
        """
        raise NotImplementedError

    def save_event(self, event):
        """
        Called when a new event has been generated ans should be saved in history
        Returns None
        """
        raise NotImplementedError

    def read_event_history(self, source_id, start, end, nb_values, evfilter):
        """
        Called when a client make a history read request for events
        Start time and end time are inclusive
        Returns a list of Events and a continuation point which
        is None if all events are read or the ServerTimeStamp of the last rejected event
        """
        raise NotImplementedError

    def stop(self):
        """
        Called when the server shuts down
        Can be used to close database connections etc.
        """
        raise NotImplementedError


class HistoryDict(HistoryStorageInterface):
    """
    very minimal history backend storing data in memory using a Python dictionary
    """
    def __init__(self):
        self._datachanges = {}
        self._datachanges_period = {}
        self._events = {}

    def new_historized_node(self, node_id, period, count=0):
        self._datachanges[node_id] = []
        self._datachanges_period[node_id] = period, count

    def save_node_value(self, node_id, datavalue):
        data = self._datachanges[node_id]
        period, count = self._datachanges_period[node_id]
        data.append(datavalue)
        now = datetime.utcnow()
        if period:
            while now - data[0].ServerTimestamp > period:
                data.pop(0)
        if count and len(data) > count:
            data = data[-count:]

    def read_node_history(self, node_id, start, end, nb_values):
        cont = None
        if node_id not in self._datachanges:
            print("Error attempt to read history for a node which is not historized")
            return [], cont
        else:
            if start is None:
                start = ua.DateTimeMinValue
            if end is None:
                end = ua.DateTimeMinValue
            if start == ua.DateTimeMinValue:
                results = [dv for dv in reversed(self._datachanges[node_id]) if start <= dv.ServerTimestamp]
            elif end == ua.DateTimeMinValue:
                results = [dv for dv in self._datachanges[node_id] if start <= dv.ServerTimestamp]
            elif start > end:
                results = [dv for dv in reversed(self._datachanges[node_id]) if end <= dv.ServerTimestamp <= start]

            else:
                results = [dv for dv in self._datachanges[node_id] if start <= dv.ServerTimestamp <= end]
            if nb_values and len(results) > nb_values:
                cont = results[nb_values + 1].ServerTimestamp
                results = results[:nb_values]
            return results, cont

    def new_historized_event(self, source_id, etype, period):
        self._events = []

    def save_event(self, event):
        raise NotImplementedError

    def read_event_history(self, source_id, start, end, nb_values, evfilter):
        raise NotImplementedError

    def stop(self):
        pass


class SubHandler(object):
    def __init__(self, storage):
        self.storage = storage

    def datachange_notification(self, node, val, data):
        self.storage.save_node_value(node.nodeid, data.monitored_item.Value)

    def event_notification(self, event):
        self.storage.save_event(event)


class HistoryManager(object):
    def __init__(self, iserver):
        self.logger = logging.getLogger(__name__)
        self.iserver = iserver
        self.storage = HistoryDict()
        self._sub = None
        self._handlers = {}

    def set_storage(self, storage):
        """
        set the desired HistoryStorageInterface which History Manager will use for historizing
        """
        self.storage = storage

    def _create_subscription(self, handler):
        params = ua.CreateSubscriptionParameters()
        params.RequestedPublishingInterval = 10
        params.RequestedLifetimeCount = 3000
        params.RequestedMaxKeepAliveCount = 10000
        params.MaxNotificationsPerPublish = 0
        params.PublishingEnabled = True
        params.Priority = 0
        return Subscription(self.iserver.isession, params, handler)

    def historize_data_change(self, node, period=timedelta(days=7), count=0):
        """
        subscribe to the nodes' data changes and store the data in the active storage
        """
        if not self._sub:
            self._sub = self._create_subscription(SubHandler(self.storage))
        if node in self._handlers:
            raise ua.UaError("Node {} is already historized".format(node))
        self.storage.new_historized_node(node.nodeid, period, count)
        handler = self._sub.subscribe_data_change(node)
        self._handlers[node] = handler

    def historize_event(self, source, period=timedelta(days=7)):
        """
        subscribe to the source nodes' events and store the data in the active storage; custom event properties included
        """
        if not self._sub:
            self._sub = self._create_subscription(SubHandler(self.storage))
        if source in self._handlers:
            raise ua.UaError("Events from {} are already historized".format(source))

        # get the event types the source node generates and a list of all possible event fields
        event_types, ev_fields = self._get_source_event_data(source)

        self.storage.new_historized_event(source.nodeid, ev_fields, period)

        handler = self._sub.subscribe_events(source)  # FIXME supply list of event types when master is fixed
        self._handlers[source] = handler

    def dehistorize(self, node):
        """
        remove subscription to the node/source which is being historized
        """
        if node in self._handlers:
            self._sub.unsubscribe(self._handlers[node])
            del(self._handlers[node])
        else:
            self.logger.error("History Manager isn't subscribed to %s", node)

    def read_history(self, params):
        """
        Read history for a node
        This is the part AttributeService, but implemented as its own service
        since it requires more logic than other attribute service methods
        """
        results = []
        
        for rv in params.NodesToRead:
            res = self._read_history(params.HistoryReadDetails, rv)
            results.append(res)
        return results
        
    def _read_history(self, details, rv):
        """
        determine if the history read is for a data changes or events; then read the history for that node
        """
        result = ua.HistoryReadResult()
        if isinstance(details, ua.ReadRawModifiedDetails):
            if details.IsReadModified:
                result.HistoryData = ua.HistoryModifiedData()
                # we do not support modified history by design so we return what we have
            else:
                result.HistoryData = ua.HistoryData()
            dv, cont = self._read_datavalue_history(rv, details)
            result.HistoryData.DataValues = dv
            result.ContinuationPoint = cont

        elif isinstance(details, ua.ReadEventDetails):
            result.HistoryData = ua.HistoryEvent()
            # FIXME: filter is a cumbersome type, maybe transform it something easier
            # to handle for storage
            ev, cont = self._read_event_history(rv, details)
            result.HistoryData.Events = ev
            result.ContinuationPoint = cont

        else:
            # we do not currently support the other types, clients can process data themselves
            result.StatusCode = ua.StatusCode(ua.StatusCodes.BadNotImplemented)
        return result

    def _read_datavalue_history(self, rv, details):
        starttime = details.StartTime
        if rv.ContinuationPoint:
            # Spec says we should ignore details if cont point is present
            # but they also say we can use cont point as timestamp to enable stateless
            # implementation. This is contradictory, so we assume details is
            # send correctly with continuation point
            # starttime = bytes_to_datetime(rv.ContinuationPoint)
            starttime = ua.unpack_datetime(utils.Buffer(rv.ContinuationPoint))

        dv, cont = self.storage.read_node_history(rv.NodeId,
                                                  starttime,
                                                  details.EndTime,
                                                  details.NumValuesPerNode)
        if cont:
            # cont = datetime_to_bytes(dv[-1].ServerTimestamp)
            cont = ua.pack_datetime(cont)
        # rv.IndexRange
        # rv.DataEncoding # xml or binary, seems spec say we can ignore that one
        return dv, cont

    def _read_event_history(self, rv, details):
        starttime = details.StartTime
        if rv.ContinuationPoint:
            # Spec says we should ignore details if cont point is present
            # but they also say we can use cont point as timestamp to enable stateless
            # implementation. This is contradictory, so we assume details is
            # send correctly with continuation point
            # starttime = bytes_to_datetime(rv.ContinuationPoint)
            starttime = ua.unpack_datetime(utils.Buffer(rv.ContinuationPoint))

        ev, cont = self.storage.read_event_history(rv.NodeId,
                                                   starttime,
                                                   details.EndTime,
                                                   details.NumValuesPerNode,
                                                   details.Filter)
        if cont:
            # cont = datetime_to_bytes(dv[-1].ServerTimestamp)
            cont = ua.pack_datetime(cont)
        return ev, cont

    def _get_source_event_data(self, source):
        # get all event types which the source node can generate; get the fields of those event types
        event_types = source.get_referenced_nodes(ua.ObjectIds.GeneratesEvent)

        ev_aggregate_fields = []
        for event_type in event_types:
            ev_aggregate_fields.extend((subscription.get_event_properties_from_type_node(event_type)))

        ev_fields = []
        for field in set(ev_aggregate_fields):
            ev_fields.append(field.get_display_name().Text.decode(encoding='utf-8'))
        return event_types, ev_fields

    def update_history(self, params):
        """
        Update history for a node
        This is the part AttributeService, but implemented as its own service
        since it requires more logic than other attribute service methods
        """
        results = []
        for _ in params.HistoryUpdateDetails:
            result = ua.HistoryUpdateResult()
            # we do not accept to rewrite history
            result.StatusCode = ua.StatusCode(ua.StatusCodes.BadNotWritable)
            results.append(results)
        return results

    def stop(self):
        """
        call stop methods of active storage interface whenever the server is stopped
        """
        self.storage.stop()


1	1	import logging
2	1	from datetime import timedelta
3		from datetime import datetime
4	1
5	1	from opcua import Subscription
6	1	from opcua import ua
7		from opcua.common import utils
8		from opcua.common import subscription
9	1
10
11		class HistoryStorageInterface(object):
12
13		"""
14		Interface of a history backend.
15		Must be implemented by backends
16	1	"""
17
18		def new_historized_node(self, node_id, period, count=0):
19		"""
20		Called when a new node is to be historized
21		Returns None
22		"""
23	1	raise NotImplementedError
24
25		def save_node_value(self, node_id, datavalue):
26		"""
27		Called when the value of a historized node has changed and should be saved in history
28		Returns None
29		"""
30	1	raise NotImplementedError
31
32		def read_node_history(self, node_id, start, end, nb_values):
33		"""
34		Called when a client make a history read request for a node
35		if start or end is missing then nb_values is used to limit query
36		nb_values is the max number of values to read. Ignored if 0
37		Start time and end time are inclusive
38		Returns a list of DataValues and a continuation point which
39		is None if all nodes are read or the ServerTimeStamp of the last rejected DataValue
40		"""
41	1	raise NotImplementedError
42
43		def new_historized_event(self, source_id, etype, period):
44		"""
45		Called when historization of events is enabled on server side
46		FIXME: we may need to store events per nodes in future...
47		Returns None
48		"""
49	1	raise NotImplementedError
50
51		def save_event(self, event):
52		"""
53		Called when a new event has been generated ans should be saved in history
54		Returns None
55		"""
56	1	raise NotImplementedError
57
58		def read_event_history(self, source_id, start, end, nb_values, evfilter):
59		"""
60		Called when a client make a history read request for events
61		Start time and end time are inclusive
62		Returns a list of Events and a continuation point which
63		is None if all events are read or the ServerTimeStamp of the last rejected event
64		"""
65	1	raise NotImplementedError
66
67		def stop(self):
68		"""
69		Called when the server shuts down
70		Can be used to close database connections etc.
71		"""
72		raise NotImplementedError
73	1
74
75		class HistoryDict(HistoryStorageInterface):
76		"""
77	1	very minimal history backend storing data in memory using a Python dictionary
78	1	"""
79	1	def __init__(self):
80	1	self._datachanges = {}
81		self._datachanges_period = {}
82	1	self._events = {}
83	1
84	1	def new_historized_node(self, node_id, period, count=0):
85		self._datachanges[node_id] = []
86	1	self._datachanges_period[node_id] = period, count
87	1
88	1	def save_node_value(self, node_id, datavalue):
89	1	data = self._datachanges[node_id]
90	1	period, count = self._datachanges_period[node_id]
91	1	data.append(datavalue)
92	1	now = datetime.utcnow()
93		if period:
94	1	while now - data[0].ServerTimestamp > period:
95	1	data.pop(0)
96		if count and len(data) > count:
97	1	data = data[-count:]
98	1
99	1	def read_node_history(self, node_id, start, end, nb_values):
100		cont = None
101		if node_id not in self._datachanges:
102		print("Error attempt to read history for a node which is not historized")
103	1	return [], cont
104		else:
105	1	if start is None:
106		start = ua.DateTimeMinValue
107	1	if end is None:
108	1	end = ua.DateTimeMinValue
109	1	if start == ua.DateTimeMinValue:
110	1	results = [dv for dv in reversed(self._datachanges[node_id]) if start <= dv.ServerTimestamp]
111	1	elif end == ua.DateTimeMinValue:
112	1	results = [dv for dv in self._datachanges[node_id] if start <= dv.ServerTimestamp]
113		elif start > end:
114		results = [dv for dv in reversed(self._datachanges[node_id]) if end <= dv.ServerTimestamp <= start]
115	1
116	1	else:
117	1	results = [dv for dv in self._datachanges[node_id] if start <= dv.ServerTimestamp <= end]
118	1	if nb_values and len(results) > nb_values:
119	1	cont = results[nb_values + 1].ServerTimestamp
120		results = results[:nb_values]
121	1	return results, cont
122
123		def new_historized_event(self, source_id, etype, period):
124	1	self._events = []
125
126		def save_event(self, event):
127	1	raise NotImplementedError
128
129		def read_event_history(self, source_id, start, end, nb_values, evfilter):
130	1	raise NotImplementedError
131	1
132		def stop(self):
133		pass
134	1
135	1
136	1	class SubHandler(object):
137		def __init__(self, storage):
138	1	self.storage = storage
139	1
140		def datachange_notification(self, node, val, data):
141	1	self.storage.save_node_value(node.nodeid, data.monitored_item.Value)
142
143		def event_notification(self, event):
144		self.storage.save_event(event)
145	1
146	1
147	1	class HistoryManager(object):
148	1	def __init__(self, iserver):
149	1	self.logger = logging.getLogger(__name__)
150	1	self.iserver = iserver
151		self.storage = HistoryDict()
152	1	self._sub = None
153	1	self._handlers = {}
154
155	1	def set_storage(self, storage):
156	1	"""
157	1	set the desired HistoryStorageInterface which History Manager will use for historizing
158	1	"""
159	1	self.storage = storage
160	1
161	1	def _create_subscription(self, handler):
162	1	params = ua.CreateSubscriptionParameters()
163	1	params.RequestedPublishingInterval = 10
164		params.RequestedLifetimeCount = 3000
165	1	params.RequestedMaxKeepAliveCount = 10000
166	1	params.MaxNotificationsPerPublish = 0
167	1	params.PublishingEnabled = True
168	1	params.Priority = 0
169		return Subscription(self.iserver.isession, params, handler)
170	1
171	1	def historize_data_change(self, node, period=timedelta(days=7), count=0):
172	1	"""
173		subscribe to the nodes' data changes and store the data in the active storage
174	1	"""
175	1	if not self._sub:
176	1	self._sub = self._create_subscription(SubHandler(self.storage))
177		if node in self._handlers:
178	1	raise ua.UaError("Node {} is already historized".format(node))
179		self.storage.new_historized_node(node.nodeid, period, count)
180		handler = self._sub.subscribe_data_change(node)
181		self._handlers[node] = handler
182
183		def historize_event(self, source, period=timedelta(days=7)):
184	1	"""
185		subscribe to the source nodes' events and store the data in the active storage; custom event properties included
186	1	"""
187	1	if not self._sub:
188	1	self._sub = self._create_subscription(SubHandler(self.storage))
189	1	if source in self._handlers:
190		raise ua.UaError("Events from {} are already historized".format(source))
191	1
192		# get the event types the source node generates and a list of all possible event fields
193		event_types, ev_fields = self._get_source_event_data(source)
194
195	1	self.storage.new_historized_event(source.nodeid, ev_fields, period)
196	1
197	1	handler = self._sub.subscribe_events(source) # FIXME supply list of event types when master is fixed
198		self._handlers[source] = handler
199
200		def dehistorize(self, node):
201	1	"""
202	1	remove subscription to the node/source which is being historized
203	1	"""
204	1	if node in self._handlers:
205		self._sub.unsubscribe(self._handlers[node])
206		del(self._handlers[node])
207		else:
208		self.logger.error("History Manager isn't subscribed to %s", node)
209
210		def read_history(self, params):
211		"""
212		Read history for a node
213		This is the part AttributeService, but implemented as its own service
214		since it requires more logic than other attribute service methods
215		"""
216	1	results = []
217
218	1	for rv in params.NodesToRead:
219	1	res = self._read_history(params.HistoryReadDetails, rv)
220	1	results.append(res)
221		return results
222
223		def _read_history(self, details, rv):
224		"""
225		determine if the history read is for a data changes or events; then read the history for that node
226		"""
227		result = ua.HistoryReadResult()
228	1	if isinstance(details, ua.ReadRawModifiedDetails):
229		if details.IsReadModified:
230		result.HistoryData = ua.HistoryModifiedData()
231		# we do not support modified history by design so we return what we have
232	1	else:
233		result.HistoryData = ua.HistoryData()
234	1	dv, cont = self._read_datavalue_history(rv, details)
235		result.HistoryData.DataValues = dv
236		result.ContinuationPoint = cont
237
238	1	elif isinstance(details, ua.ReadEventDetails):
239		result.HistoryData = ua.HistoryEvent()
240	1	# FIXME: filter is a cumbersome type, maybe transform it something easier
241		# to handle for storage
242		ev, cont = self._read_event_history(rv, details)
243		result.HistoryData.Events = ev
244		result.ContinuationPoint = cont
245
246		else:
247		# we do not currently support the other types, clients can process data themselves
248		result.StatusCode = ua.StatusCode(ua.StatusCodes.BadNotImplemented)
249		return result
250
251		def _read_datavalue_history(self, rv, details):
252		starttime = details.StartTime
253		if rv.ContinuationPoint:
254	1	# Spec says we should ignore details if cont point is present
255	1	# but they also say we can use cont point as timestamp to enable stateless
256		# implementation. This is contradictory, so we assume details is
257		# send correctly with continuation point
258		# starttime = bytes_to_datetime(rv.ContinuationPoint)
259		starttime = ua.unpack_datetime(utils.Buffer(rv.ContinuationPoint))
260
261		dv, cont = self.storage.read_node_history(rv.NodeId,
262		starttime,
263		details.EndTime,
264		details.NumValuesPerNode)
265		if cont:
266		# cont = datetime_to_bytes(dv[-1].ServerTimestamp)
267		cont = ua.pack_datetime(cont)
268		# rv.IndexRange
269		# rv.DataEncoding # xml or binary, seems spec say we can ignore that one
270		return dv, cont
271
272		def _read_event_history(self, rv, details):
273		starttime = details.StartTime
274		if rv.ContinuationPoint:
275		# Spec says we should ignore details if cont point is present
276		# but they also say we can use cont point as timestamp to enable stateless
277		# implementation. This is contradictory, so we assume details is
278		# send correctly with continuation point
279		# starttime = bytes_to_datetime(rv.ContinuationPoint)
280		starttime = ua.unpack_datetime(utils.Buffer(rv.ContinuationPoint))
281
282		ev, cont = self.storage.read_event_history(rv.NodeId,
283		starttime,
284		details.EndTime,
285		details.NumValuesPerNode,
286		details.Filter)
287		if cont:
288		# cont = datetime_to_bytes(dv[-1].ServerTimestamp)
289		cont = ua.pack_datetime(cont)
290		return ev, cont
291
292		def _get_source_event_data(self, source):
293		# get all event types which the source node can generate; get the fields of those event types
294		event_types = source.get_referenced_nodes(ua.ObjectIds.GeneratesEvent)
295
296		ev_aggregate_fields = []
297		for event_type in event_types:
298		ev_aggregate_fields.extend((subscription.get_event_properties_from_type_node(event_type)))
299
300		ev_fields = []
301		for field in set(ev_aggregate_fields):
302		ev_fields.append(field.get_display_name().Text.decode(encoding='utf-8'))
303		return event_types, ev_fields
304
305		def update_history(self, params):
306		"""
307		Update history for a node
308		This is the part AttributeService, but implemented as its own service
309		since it requires more logic than other attribute service methods
310		"""
311		results = []
312		for _ in params.HistoryUpdateDetails:
313		result = ua.HistoryUpdateResult()
314		# we do not accept to rewrite history
315		result.StatusCode = ua.StatusCode(ua.StatusCodes.BadNotWritable)
316		results.append(results)
317		return results
318
319		def stop(self):
320		"""
321		call stop methods of active storage interface whenever the server is stopped
322		"""
323		self.storage.stop()
324

FreeOpcUa / python-opcua

Pull Request — master (#180)

HistoryManager._read_event_history() A

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