Completed
Pull Request — master (#179)
by Olivier
03:27
created

MonitoredItemService._get_event_fields()   A

Complexity

Conditions 4

Size

Total Lines 16

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 10
CRAP Score 4.5923
Metric Value
cc 4
dl 0
loc 16
ccs 10
cts 15
cp 0.6667
crap 4.5923
rs 9.2
1
"""
2
server side implementation of a subscription object
3
"""
4
5 1
from threading import RLock
6 1
import logging
7 1
import copy
8
9 1
from opcua import ua
10
11
12 1
class MonitoredItemData(object):
13
14 1
    def __init__(self):
15 1
        self.client_handle = None
16 1
        self.callback_handle = None
17 1
        self.monitored_item_id = None
18 1
        self.parameters = None
19 1
        self.mode = None
20 1
        self.mfilter = None
21 1
        self.where_clause_evaluator = None
22
23
24 1
class MonitoredItemService(object):
25
26
    """
27
    implement monitoreditem service for 1 subscription
28
    """
29
30 1
    def __init__(self, isub, aspace):
31 1
        self.logger = logging.getLogger(__name__ + "." + str(isub.data.SubscriptionId))
32 1
        self.isub = isub
33 1
        self.aspace = aspace
34 1
        self._lock = RLock()
35 1
        self._monitored_items = {}
36 1
        self._monitored_events = {}
37 1
        self._monitored_datachange = {}
38 1
        self._monitored_item_counter = 111
39
40 1
    def delete_all_monitored_items(self):
41 1
        self.delete_monitored_items([mdata.monitored_item_id for mdata in self._monitored_items.values()])
42
43 1
    def create_monitored_items(self, params):
44 1
        results = []
45 1
        for item in params.ItemsToCreate:
46 1
            results.append(self._create_monitored_item(item))
47 1
        return results
48
49 1
    def modify_monitored_items(self, params):
50
        results = []
51
        for item in params.ItemsToModify:
52
            results.append(self._modify_monitored_item(item))
53
        return results
54
55 1
    def trigger_datachange(self, handle, nodeid, attr):
56 1
        self.logger.debug("triggering datachange for handle %s, nodeid %s, and attribute %s", handle, nodeid, attr)
57 1
        variant = self.aspace.get_attribute_value(nodeid, attr)
58 1
        self.datachange_callback(handle, variant)
59
60 1
    def _modify_monitored_item(self, params):
61
        with self._lock:
62
            for mdata in self._monitored_items.values():
63
                result = ua.MonitoredItemCreateResult()
64
                if mdata.monitored_item_id == params.MonitoredItemId:
65
                    result.RevisedSamplingInterval = self.isub.data.RevisedPublishingInterval
66
                    result.RevisedQueueSize = params.RequestedParameters.QueueSize
67
                    result.FilterResult = params.RequestedParameters.Filter
68
                    mdata.parameters = result
69
                    return result
70
            # FIXME modify event subscriptions
71
            result = ua.MonitoredItemCreateResult()
72
            result.StatusCode(ua.StatusCodes.BadMonitoredItemIdInvalid)
73
            return result
74
75 1
    def _create_monitored_item(self, params):
76 1
        with self._lock:
77 1
            result = ua.MonitoredItemCreateResult()
78 1
            result.RevisedSamplingInterval = self.isub.data.RevisedPublishingInterval
79 1
            result.RevisedQueueSize = params.RequestedParameters.QueueSize
80 1
            self._monitored_item_counter += 1
81 1
            result.MonitoredItemId = self._monitored_item_counter
82 1
            self.logger.debug("Creating MonitoredItem with id %s", result.MonitoredItemId)
83
84 1
            mdata = MonitoredItemData()
85 1
            mdata.parameters = result
86 1
            mdata.mode = params.MonitoringMode
87 1
            mdata.client_handle = params.RequestedParameters.ClientHandle
88 1
            mdata.mfilter = params.RequestedParameters.Filter
89 1
            mdata.monitored_item_id = result.MonitoredItemId
90
91 1
            self._monitored_items[result.MonitoredItemId] = mdata
92
93 1
            if params.ItemToMonitor.AttributeId == ua.AttributeIds.EventNotifier:
94 1
                self.logger.info("request to subscribe to events for node %s and attribute %s", params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId)
95 1
                ev_notify_byte = self.aspace.get_attribute_value(params.ItemToMonitor.NodeId, ua.AttributeIds.EventNotifier).Value.Value
96 1
                if ev_notify_byte is not None:
97 1
                    if ev_notify_byte & 1 == 0:
98 1
                        result.StatusCode = ua.StatusCode(ua.StatusCodes.BadServiceUnsupported)
99
                else:
100 1
                    result.StatusCode = ua.StatusCode(ua.StatusCodes.BadServiceUnsupported)
101 1
                result.FilterResult = ua.EventFilterResult()
102 1
                for _ in params.RequestedParameters.Filter.SelectClauses:
103 1
                    result.FilterResult.SelectClauseResults.append(ua.StatusCode())
104
                # TODO: spec says we should check WhereClause here
105 1
                mdata.where_clause_evaluator = WhereClauseEvaluator(self.logger, self.aspace, mdata.mfilter.WhereClause)
106 1
                self._monitored_events[params.ItemToMonitor.NodeId] = result.MonitoredItemId
107
            else:
108 1
                self.logger.info("request to subscribe to datachange for node %s and attribute %s", params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId)
109 1
                result.FilterResult = params.RequestedParameters.Filter
110 1
                result.StatusCode, handle = self.aspace.add_datachange_callback(params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId, self.datachange_callback)
111 1
                self.logger.debug("adding callback return status %s and handle %s", result.StatusCode, handle)
112 1
                mdata.callback_handle = handle
113 1
                self._monitored_datachange[handle] = result.MonitoredItemId
114 1
                if result.StatusCode.is_good():
115
                    # force data change event generation
116 1
                    self.trigger_datachange(handle, params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId)
117
118 1
            if not result.StatusCode.is_good():
119 1
                del(self._monitored_items[result.MonitoredItemId])
120 1
                self._monitored_item_counter -= 1
121
122 1
            return result
123
124 1
    def delete_monitored_items(self, ids):
125 1
        self.logger.debug("delete monitored items %s", ids)
126 1
        with self._lock:
127 1
            results = []
128 1
            for mid in ids:
129 1
                results.append(self._delete_monitored_items(mid))
130 1
            return results
131
132 1
    def _delete_monitored_items(self, mid):
133 1
        if mid not in self._monitored_items:
134 1
            return ua.StatusCode(ua.StatusCodes.BadMonitoredItemIdInvalid)
135 1
        for k, v in self._monitored_events.items():
136 1
            if v == mid:
137 1
                self._monitored_events.pop(k)
138 1
                break
139 1
        for k, v in self._monitored_datachange.items():
140 1
            if v == mid:
141 1
                self.aspace.delete_datachange_callback(k)
142 1
                self._monitored_datachange.pop(k)
143 1
                break
144 1
        self._monitored_items.pop(mid)
145 1
        return ua.StatusCode()
146
147 1
    def datachange_callback(self, handle, value, error=None):
148 1
        if error:
149
            self.logger.info("subscription %s: datachange callback called with handle '%s' and erorr '%s'",
150
                             self, handle, error)
151
            self.trigger_statuschange(error)
152
        else:
153 1
            self.logger.info("subscription %s: datachange callback called with handle '%s' and value '%s'",
154
                             self, handle, value.Value)
155 1
            event = ua.MonitoredItemNotification()
156 1
            with self._lock:
157 1
                mid = self._monitored_datachange[handle]
158 1
                mdata = self._monitored_items[mid]
159 1
                event.ClientHandle = mdata.client_handle
160 1
                event.Value = value
161 1
                self.isub.enqueue_datachange_event(mid, event, mdata.parameters.RevisedQueueSize)
162
163 1
    def trigger_event(self, event):
164 1
        with self._lock:
165 1
            if event.SourceNode not in self._monitored_events:
166 1
                self.logger.debug("%s has no subscription for events %s from node: %s",
167
                                  self, event, event.SourceNode)
168 1
                return False
169 1
            self.logger.debug("%s has subscription for events %s from node: %s",
170
                              self, event, event.SourceNode)
171 1
            mid = self._monitored_events[event.SourceNode]
172 1
            if mid not in self._monitored_items:
173
                self.logger.debug("Could not find monitored items for id %s for event %s in subscription %s",
174
                                  mid, event, self)
175
                return False
176 1
            mdata = self._monitored_items[mid]
177 1
            if not mdata.where_clause_evaluator.eval(event):
178
                self.logger.debug("Event does not fit WhereClause, not generating event", mid, event, self)
179
                return
180 1
            fieldlist = ua.EventFieldList()
181 1
            fieldlist.ClientHandle = mdata.client_handle
182 1
            fieldlist.EventFields = self._get_event_fields(mdata.mfilter, event)
183 1
            self.isub.enqueue_event(mid, fieldlist, mdata.parameters.RevisedQueueSize)
184 1
            return True
185
186 1
    def _get_event_fields(self, evfilter, event):
187 1
        fields = []
188 1
        for sattr in evfilter.SelectClauses:
189 1
            try:
190 1
                if not sattr.BrowsePath:
191
                    val = getattr(event, sattr.Attribute.name)
192
                    val = copy.deepcopy(val)
193
                    fields.append(ua.Variant(val))
194
                else:
195 1
                    name = sattr.BrowsePath[0].Name
196 1
                    val = getattr(event, name)
197 1
                    val = copy.deepcopy(val)
198 1
                    fields.append(ua.Variant(val))
199
            except AttributeError:
200
                fields.append(ua.Variant())
201 1
        return fields
202
203 1
    def trigger_statuschange(self, code):
204
        self.isub.enqueue_statuschange(code)
205
206
207 1
class InternalSubscription(object):
208
209 1
    def __init__(self, subservice, data, addressspace, callback):
210 1
        self.logger = logging.getLogger(__name__ + "." + str(data.SubscriptionId))
211 1
        self.aspace = addressspace
212 1
        self.subservice = subservice
213 1
        self.data = data
214 1
        self.callback = callback
215 1
        self.monitored_item_srv = MonitoredItemService(self, addressspace)
216 1
        self.task = None
217 1
        self._lock = RLock()
218 1
        self._triggered_datachanges = {}
219 1
        self._triggered_events = {}
220 1
        self._triggered_statuschanges = []
221 1
        self._notification_seq = 1
222 1
        self._not_acknowledged_results = {}
223 1
        self._startup = True
224 1
        self._keep_alive_count = 0
225 1
        self._publish_cycles_count = 0
226 1
        self._stopev = False
227
228 1
    def __str__(self):
229
        return "Subscription(id:{})".format(self.data.SubscriptionId)
230
231 1
    def start(self):
232 1
        self.logger.debug("starting subscription %s", self.data.SubscriptionId)
233 1
        self._subscription_loop()
234
235 1
    def stop(self):
236 1
        self.logger.debug("stopping subscription %s", self.data.SubscriptionId)
237 1
        self._stopev = True
238 1
        self.monitored_item_srv.delete_all_monitored_items()
239
240 1
    def _subscription_loop(self):
241
        #self.logger.debug("%s loop", self)
242 1
        if not self._stopev:
243 1
            self.subservice.loop.call_later(self.data.RevisedPublishingInterval / 1000.0, self._sub_loop)
244
245 1
    def _sub_loop(self):
246 1
        if self._stopev:
247 1
            return
248 1
        self.publish_results()
249 1
        self._subscription_loop()
250
251 1
    def has_published_results(self):
252 1
        with self._lock:
253 1
            if self._startup or self._triggered_datachanges or self._triggered_events:
254 1
                return True
255 1
            if self._keep_alive_count > self.data.RevisedMaxKeepAliveCount:
256
                self.logger.debug("keep alive count %s is > than max keep alive count %s, sending publish event", self._keep_alive_count, self.data.RevisedMaxKeepAliveCount)
257
                return True
258 1
            self._keep_alive_count += 1
259 1
            return False
260
261 1
    def publish_results(self):
262 1
        if self._publish_cycles_count > self.data.RevisedLifetimeCount:
263
            self.logger.warning("Subscription %s has expired, publish cycle count(%s) > lifetime count (%s)", self, self._publish_cycles_count, self.data.RevisedLifetimeCount)
264
            # FIXME this will never be send since we do not have publish request anyway
265
            self.monitored_item_srv.trigger_statuschange(ua.StatusCode(ua.StatusCodes.BadTimeout))
266
            self._stopev = True
267 1
        result = None
268 1
        with self._lock:
269 1
            if self.has_published_results():  # FIXME: should we pop a publish request here? or we do not care?
270 1
                self._publish_cycles_count += 1
271 1
                result = self._pop_publish_result()
272 1
        if result is not None:
273 1
            self.callback(result)
274
275 1
    def _pop_publish_result(self):
276 1
        result = ua.PublishResult()
277 1
        result.SubscriptionId = self.data.SubscriptionId
278 1
        self._pop_triggered_datachanges(result)
279 1
        self._pop_triggered_events(result)
280 1
        self._pop_triggered_statuschanges(result)
281 1
        self._keep_alive_count = 0
282 1
        self._startup = False
283 1
        result.NotificationMessage.SequenceNumber = self._notification_seq
284 1
        if len(result.NotificationMessage.NotificationData) != 0:
285 1
            self._notification_seq += 1
286 1
            self._not_acknowledged_results[result.NotificationMessage.SequenceNumber] = result
287 1
        result.MoreNotifications = False
288 1
        result.AvailableSequenceNumbers = list(self._not_acknowledged_results.keys())
289 1
        return result
290
291 1
    def _pop_triggered_datachanges(self, result):
292 1
        if self._triggered_datachanges:
293 1
            notif = ua.DataChangeNotification()
294 1
            notif.MonitoredItems = [item for sublist in self._triggered_datachanges.values() for item in sublist]
295 1
            self._triggered_datachanges = {}
296 1
            self.logger.debug("sending datachanges notification with %s events", len(notif.MonitoredItems))
297 1
            result.NotificationMessage.NotificationData.append(notif)
298
299 1
    def _pop_triggered_events(self, result):
300 1
        if self._triggered_events:
301 1
            notif = ua.EventNotificationList()
302 1
            notif.Events = [item for sublist in self._triggered_events.values() for item in sublist]
303 1
            self._triggered_events = {}
304 1
            result.NotificationMessage.NotificationData.append(notif)
305 1
            self.logger.debug("sending event notification with %s events", len(notif.Events))
306
307 1
    def _pop_triggered_statuschanges(self, result):
308 1
        if self._triggered_statuschanges:
309
            notif = ua.StatusChangeNotification()
310
            notif.Status = self._triggered_statuschanges.pop(0)
311
            result.NotificationMessage.NotificationData.append(notif)
312
            self.logger.debug("sending event notification %s", notif.Status)
313
314 1
    def publish(self, acks):
315 1
        self.logger.info("publish request with acks %s", acks)
316 1
        with self._lock:
317 1
            self._publish_cycles_count = 0
318 1
            for nb in acks:
319 1
                if nb in self._not_acknowledged_results:
320 1
                    self._not_acknowledged_results.pop(nb)
321
322 1
    def republish(self, nb):
323
        self.logger.info("re-publish request for ack %s in subscription %s", nb, self)
324
        with self._lock:
325
            if nb in self._not_acknowledged_results:
326
                self.logger.info("re-publishing ack %s in subscription %s", nb, self)
327
                return self._not_acknowledged_results[nb].NotificationMessage
328
            else:
329
                self.logger.info("Error request to re-published non existing ack %s in subscription %s", nb, self)
330
                return ua.NotificationMessage()
331
332 1
    def enqueue_datachange_event(self, mid, eventdata, maxsize):
333 1
        self._enqueue_event(mid, eventdata, maxsize, self._triggered_datachanges)
334
335 1
    def enqueue_event(self, mid, eventdata, maxsize):
336 1
        self._enqueue_event(mid, eventdata, maxsize, self._triggered_events)
337
338 1
    def enqueue_statuschange(self, code):
339
        self._triggered_statuschanges.append(code)
340
341 1
    def _enqueue_event(self, mid, eventdata, size, queue):
342 1
        if mid not in queue:
343 1
            queue[mid] = [eventdata]
344 1
            return
345 1
        if size != 0:
346
            if len(queue[mid]) >= size:
347
                queue[mid].pop(0)
348 1
        queue[mid].append(eventdata)
349
350
351 1
class WhereClauseEvaluator(object):
352 1
    def __init__(self, logger, aspace, whereclause):
353 1
        self.logger = logger
354 1
        self.elements = whereclause.Elements
355 1
        self._aspace = aspace
356
357 1
    def eval(self, event):
358 1
        if not self.elements:
359
            return True
360
        # spec says we should only evaluate first element, which may use other elements
361 1
        try:
362 1
            res = self._eval_el(0, event)
363
        except Exception as ex:
364
            self.logger.warning("Exception while evaluating WhereClause %s for event %s: %s", self.elements, event, ex)
365
            return False
366 1
        return res
367
368 1
    def _eval_el(self, index, event):
369 1
        el = self.elements[index]
370
        #ops = [self._eval_op(op, event) for op in el.FilterOperands]
371 1
        ops = el.FilterOperands  # just to make code more readable
372 1
        if el.FilterOperator == ua.FilterOperator.Equals:
373
            return self._eval_op(ops[0], event) == self._eval_el(ops[1], event)
374 1
        elif el.FilterOperator == ua.FilterOperator.IsNull:
375
            return self._eval_op(ops[0], event) is None  # FIXME: might be too strict
376 1
        elif el.FilterOperator == ua.FilterOperator.GreaterThan:
377
            return self._eval_op(ops[0], event) > self._eval_el(ops[1], event)
378 1
        elif el.FilterOperator == ua.FilterOperator.LessThan:
379
            return self._eval_op(ops[0], event) < self._eval_el(ops[1], event)
380 1
        elif el.FilterOperator == ua.FilterOperator.GreaterThanOrEqual:
381
            return self._eval_op(ops[0], event) >= self._eval_el(ops[1], event)
382 1
        elif el.FilterOperator == ua.FilterOperator.LessThanOrEqual:
383
            return self._eval_op(ops[0], event) <= self._eval_el(ops[1], event)
384 1
        elif el.FilterOperator == ua.FilterOperator.Like:
385
            return self._likeoperator(self._eval_op(ops[0], event), self._eval_el(ops[1], event))
386 1
        elif el.FilterOperator == ua.FilterOperator.Not:
387
            return not self._eval_op(ops[0], event)
388 1
        elif el.FilterOperator == ua.FilterOperator.Between:
389
            return self._eval_el(ops[2], event) >= self._eval_op(ops[0], event) >= self._eval_el(ops[1], event)
390 1
        elif el.FilterOperator == ua.FilterOperator.InList:
391 1
            return self._eval_op(ops[0], event) in [self._eval_op(op, event) for op in ops[1:]]
392
        elif el.FilterOperator == ua.FilterOperator.And:
393
            self.elements(ops[0].Index)
394
            return self._eval_op(ops[0], event) and self._eval_op(ops[1], event)
395
        elif el.FilterOperator == ua.FilterOperator.Or:
396
            return self._eval_op(ops[0], event) or self._eval_el(ops[1], event)
397
        elif el.FilterOperator == ua.FilterOperator.Cast:
398
            self.logger("Cast operand not implemented")
399
            raise NotImplementError
400
        else:
401
            # TODO: implement missing operators
402
            print("WhereClause not implemented for element: %s", el)
403
            raise NotImplementError
404
405 1
    def _like_operator(self, string, pattern):
406
        raise NotImplementError
407
408 1
    def _eval_op(self, op, event):
409
        # seems spec says we should return Null if issues
410 1
        if type(op) is ua.ElementOperand:
411
            el = self.elements[op.FilterOperands[0].Index]
412
            return self._eval_el(el)
413 1
        elif type(op) is ua.AttributeOperand:
414
            if op.BrowsePath:
415
                return getattr(event, op.BrowsePath.Elements[0].TargetName.Name)
416
            else:
417
                return self._aspace.get_attribute_value(event.EventType, op.AttributeId).Value.Value
418
            # FIXME: check, this is probably broken
419 1
        elif type(op) is ua.SimpleAttributeOperand:
420 1
            if op.BrowsePath:
421
                # we only support depth of 1
422 1
                return getattr(event, op.BrowsePath[0].Name)
423
            else:
424
                # TODO: write code for index range.... but doe it make any sense
425 1
                return self._aspace.get_attribute_value(event.EventType, op.AttributeId).Value.Value
426 1
        elif type(op) is ua.LiteralOperand:
427 1
            return op.Value.Value
428
        else:
429
            self.logger.warning("Where clause element % is not of a known type", el)
430
            raise NotImplementError
431
432
433
434