Completed
Pull Request — master (#200)
by Olivier
03:33
created

MonitoredItemService.trigger_statuschange()   A

Complexity

Conditions 1

Size

Total Lines 2

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 1
CRAP Score 1

Importance

Changes 0
Metric Value
cc 1
dl 0
loc 2
ccs 1
cts 1
cp 1
crap 1
rs 10
c 0
b 0
f 0
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.mode = None
19 1
        self.filter = None
20 1
        self.mvalue = MonitoredItemValues()
21
        self.where_clause_evaluator = None
22
        self.queue_size = 0
23 1
24
25
class MonitoredItemValues(object):
26
27
    def __init__(self):
28
        self.current_value = None
29 1
        self.old_value = None
30 1
31 1
    def set_current_value(self, cur_val):
32 1
        self.old_value = self.current_value
33 1
        self.current_value = cur_val
34 1
35 1
    def get_current_value(self):
36 1
        return self.current_value
37 1
38
    def get_old_value(self):
39 1
        return self.old_value
40 1
41
42 1
class MonitoredItemService(object):
43 1
44 1
    """
45 1
    implement monitoreditem service for 1 subscription
46 1
    """
47
48 1
    def __init__(self, isub, aspace):
49
        self.logger = logging.getLogger(__name__ + "." + str(isub.data.SubscriptionId))
50
        self.isub = isub
51
        self.aspace = aspace
52
        self._lock = RLock()
53
        self._monitored_items = {}
54 1
        self._monitored_events = {}
55 1
        self._monitored_datachange = {}
56 1
        self._monitored_item_counter = 111
57 1
58
    def delete_all_monitored_items(self):
59 1
        self.delete_monitored_items([mdata.monitored_item_id for mdata in self._monitored_items.values()])
60
61
    def create_monitored_items(self, params):
62
        results = []
63
        for item in params.ItemsToCreate:
64
            with self._lock:
65
                if item.ItemToMonitor.AttributeId == ua.AttributeIds.EventNotifier:
66
                    result = self._create_events_monitored_item(item)
67
                else:
68
                    result = self._create_data_change_monitored_item(item)
69
            results.append(result)
70
        return results
71
72
    def modify_monitored_items(self, params):
73
        results = []
74 1
        for item in params.ItemsToModify:
75 1
            results.append(self._modify_monitored_item(item))
76 1
        return results
77 1
78 1
    def trigger_datachange(self, handle, nodeid, attr):
79 1
        self.logger.debug("triggering datachange for handle %s, nodeid %s, and attribute %s", handle, nodeid, attr)
80 1
        variant = self.aspace.get_attribute_value(nodeid, attr)
81 1
        self.datachange_callback(handle, variant)
82
83 1
    def _modify_monitored_item(self, params):
84 1
        with self._lock:
85 1
            for mdata in self._monitored_items.values():
86 1
                result = ua.MonitoredItemModifyResult()
87 1
                if mdata.monitored_item_id == params.MonitoredItemId:
88 1
                    result.RevisedSamplingInterval = params.RequestedParameters.SamplingInterval
89
                    result.RevisedQueueSize = params.RequestedParameters.QueueSize
90 1
                    if params.RequestedParameters.Filter is not None:
91
                        mdata.filter = params.RequestedParameters.Filter
92 1
                    mdata.queue_size = params.RequestedParameters.QueueSize
93 1
                    return result
94 1
            result = ua.MonitoredItemModifyResult()
95 1
            result.StatusCode(ua.StatusCodes.BadMonitoredItemIdInvalid)
96 1
            return result
97 1
98
    def _commit_monitored_item(self, result, mdata):
99 1
        if result.StatusCode.is_good():
100 1
            self._monitored_items[result.MonitoredItemId] = mdata
101 1
            self._monitored_item_counter += 1
102 1
103
    def _make_monitored_item_common(self, params):
104 1
        result = ua.MonitoredItemCreateResult()
105
        result.RevisedSamplingInterval = self.isub.data.RevisedPublishingInterval
106 1
        result.RevisedQueueSize = params.RequestedParameters.QueueSize
107 1
        self._monitored_item_counter += 1
108 1
        result.MonitoredItemId = self._monitored_item_counter
109 1
        self.logger.debug("Creating MonitoredItem with id %s", result.MonitoredItemId)
110 1
111 1
        mdata = MonitoredItemData()
112 1
        mdata.mode = params.MonitoringMode
113
        mdata.client_handle = params.RequestedParameters.ClientHandle
114 1
        mdata.monitored_item_id = result.MonitoredItemId
115
        mdata.queue_size = params.RequestedParameters.QueueSize
116 1
        mdata.filter = params.RequestedParameters.Filter
117 1
118 1
        return result, mdata
119
120 1
    def _create_events_monitored_item(self, params):
121
        self.logger.info("request to subscribe to events for node %s and attribute %s",
122 1
                         params.ItemToMonitor.NodeId,
123 1
                         params.ItemToMonitor.AttributeId)
124 1
125 1
        result, mdata = self._make_monitored_item_common(params)
126 1
        ev_notify_byte = self.aspace.get_attribute_value(params.ItemToMonitor.NodeId, ua.AttributeIds.EventNotifier).Value.Value
127 1
        if ev_notify_byte is None or ev_notify_byte & 1 == 0:
128 1
            result.StatusCode = ua.StatusCode(ua.StatusCodes.BadServiceUnsupported)
129
            return result
130 1
        # result.FilterResult = ua.EventFilterResult()  # spec says we can ignore if not error
131 1
        mdata.where_clause_evaluator = WhereClauseEvaluator(self.logger, self.aspace, mdata.filter.WhereClause)
132 1
        self._commit_monitored_item(result, mdata)
133 1
        if params.ItemToMonitor.NodeId not in self._monitored_events:
134 1
            self._monitored_events[params.ItemToMonitor.NodeId] = []
135 1
        self._monitored_events[params.ItemToMonitor.NodeId].append(result.MonitoredItemId)
136 1
        return result
137 1
138 1
    def _create_data_change_monitored_item(self, params):
139 1
        self.logger.info("request to subscribe to datachange for node %s and attribute %s",
140 1
                         params.ItemToMonitor.NodeId,
141 1
                         params.ItemToMonitor.AttributeId)
142 1
143 1
        result, mdata = self._make_monitored_item_common(params)
144
        result.FilterResult = params.RequestedParameters.Filter
145 1
        result.StatusCode, handle = self.aspace.add_datachange_callback(params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId, self.datachange_callback)
146 1
        self.logger.debug("adding callback return status %s and handle %s", result.StatusCode, handle)
147
        mdata.callback_handle = handle
148
        self._commit_monitored_item(result, mdata)
149
        if result.StatusCode.is_good():
150 1
            self._monitored_datachange[handle] = result.MonitoredItemId
151 1
            # force data change event generation
152 1
            self.trigger_datachange(handle, params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId)
153 1
        return result
154 1
155 1
    def delete_monitored_items(self, ids):
156 1
        self.logger.debug("delete monitored items %s", ids)
157 1
        with self._lock:
158
            results = []
159 1
            for mid in ids:
160 1
                results.append(self._delete_monitored_items(mid))
161 1
            return results
162 1
163 1
    def _delete_monitored_items(self, mid):
164 1
        if mid not in self._monitored_items:
165 1
            return ua.StatusCode(ua.StatusCodes.BadMonitoredItemIdInvalid)
166 1
        for k, v in self._monitored_events.items():
167
            if mid in v:
168
                v.remove(mid)
169 1
                if not v:
170 1
                    self._monitored_events.pop(k)
171 1
                break
172 1
        for k, v in self._monitored_datachange.items():
173 1
            if v == mid:
174 1
                self.aspace.delete_datachange_callback(k)
175
                self._monitored_datachange.pop(k)
176 1
                break
177 1
        self._monitored_items.pop(mid)
178 1
        return ua.StatusCode()
179 1
180 1
    def datachange_callback(self, handle, value, error=None):
181
        if error:
182
            self.logger.info("subscription %s: datachange callback called with handle '%s' and erorr '%s'", self,
183
                             handle, error)
184
            self.trigger_statuschange(error)
185
        else:
186 1
            self.logger.info("subscription %s: datachange callback called with handle '%s' and value '%s'", self,
187 1
                             handle, value.Value)
188 1
            event = ua.MonitoredItemNotification()
189 1
            with self._lock:
190
                mid = self._monitored_datachange[handle]
191
                mdata = self._monitored_items[mid]
192 1
                mdata.mvalue.set_current_value(value.Value.Value)
193
                if mdata.filter is not None:
194 1
                    deadband_flag_pass = self.deadband_callback(mdata.mvalue, mdata.filter)
195
                else:
196
                    deadband_flag_pass = True
197
                if deadband_flag_pass:
198 1
                    event.ClientHandle = mdata.client_handle
199
                    event.Value = value
200 1
                    self.isub.enqueue_datachange_event(mid, event, mdata.queue_size)
201 1
202 1
    def deadband_callback(self, values, flt):
203 1
        if (values.get_old_value() is not None) or \
204 1
                ((abs(values.get_current_value() - values.get_old_value())) > flt.DeadbandValue):
205 1
            return True
206 1
        else:
207 1
            return False
208 1
209 1
    def trigger_event(self, event):
210 1
        with self._lock:
211 1
            if event.SourceNode not in self._monitored_events:
212 1
                self.logger.debug("%s has no subscription for events %s from node: %s",
213 1
                                  self, event, event.SourceNode)
214 1
                return False
215 1
            self.logger.debug("%s has subscription for events %s from node: %s",
216 1
                              self, event, event.SourceNode)
217 1
            mids = self._monitored_events[event.SourceNode]
218
            for mid in mids:
219 1
                self._trigger_event(event, mid)
220
221
    def _trigger_event(self, event, mid):
222 1
        if mid not in self._monitored_items:
223 1
            self.logger.debug("Could not find monitored items for id %s for event %s in subscription %s", mid, event, self)
224 1
            return
225
        mdata = self._monitored_items[mid]
226 1
        if not mdata.where_clause_evaluator.eval(event):
227 1
            self.logger.info("%s, %s, Event %s does not fit WhereClause, not generating event", self, mid, event)
228 1
            return
229 1
        fieldlist = ua.EventFieldList()
230
        fieldlist.ClientHandle = mdata.client_handle
231 1
        fieldlist.EventFields = event.to_event_fields(mdata.filter.SelectClauses)
232
        self.isub.enqueue_event(mid, fieldlist, mdata.queue_size)
233 1
234 1
    def trigger_statuschange(self, code):
235
        self.isub.enqueue_statuschange(code)
236 1
237 1
238 1
class InternalSubscription(object):
239 1
240 1
    def __init__(self, subservice, data, addressspace, callback):
241
        self.logger = logging.getLogger(__name__)
242 1
        self.aspace = addressspace
243 1
        self.subservice = subservice
244 1
        self.data = data
245 1
        self.callback = callback
246 1
        self.monitored_item_srv = MonitoredItemService(self, addressspace)
247
        self.task = None
248
        self._lock = RLock()
249 1
        self._triggered_datachanges = {}
250 1
        self._triggered_events = {}
251
        self._triggered_statuschanges = []
252 1
        self._notification_seq = 1
253 1
        self._not_acknowledged_results = {}
254
        self._startup = True
255
        self._keep_alive_count = 0
256
        self._publish_cycles_count = 0
257
        self._stopev = False
258 1
259 1
    def __str__(self):
260 1
        return "Subscription(id:{})".format(self.data.SubscriptionId)
261 1
262 1
    def start(self):
263 1
        self.logger.debug("starting subscription %s", self.data.SubscriptionId)
264 1
        self._subscription_loop()
265
266 1
    def stop(self):
267 1
        self.logger.debug("stopping subscription %s", self.data.SubscriptionId)
268 1
        self._stopev = True
269 1
        self.monitored_item_srv.delete_all_monitored_items()
270 1
271 1
    def _subscription_loop(self):
272 1
        if not self._stopev:
273 1
            self.subservice.loop.call_later(self.data.RevisedPublishingInterval / 1000.0, self._sub_loop)
274 1
275 1
    def _sub_loop(self):
276 1
        if self._stopev:
277 1
            return
278 1
        self.publish_results()
279 1
        self._subscription_loop()
280 1
281
    def has_published_results(self):
282 1
        with self._lock:
283 1
            if self._startup or self._triggered_datachanges or self._triggered_events:
284 1
                return True
285 1
            if self._keep_alive_count > self.data.RevisedMaxKeepAliveCount:
286 1
                self.logger.debug("keep alive count %s is > than max keep alive count %s, sending publish event", self._keep_alive_count, self.data.RevisedMaxKeepAliveCount)
287 1
                return True
288 1
            self._keep_alive_count += 1
289
            return False
290 1
291 1
    def publish_results(self):
292 1
        if self._publish_cycles_count > self.data.RevisedLifetimeCount:
293 1
            self.logger.warning("Subscription %s has expired, publish cycle count(%s) > lifetime count (%s)", self, self._publish_cycles_count, self.data.RevisedLifetimeCount)
294 1
            # FIXME this will never be send since we do not have publish request anyway
295 1
            self.monitored_item_srv.trigger_statuschange(ua.StatusCode(ua.StatusCodes.BadTimeout))
296 1
            self._stopev = True
297
        result = None
298 1
        with self._lock:
299 1
            if self.has_published_results():  # FIXME: should we pop a publish request here? or we do not care?
300
                self._publish_cycles_count += 1
301
                result = self._pop_publish_result()
302
        if result is not None:
303
            self.callback(result)
304
305 1
    def _pop_publish_result(self):
306 1
        result = ua.PublishResult()
307 1
        result.SubscriptionId = self.data.SubscriptionId
308 1
        self._pop_triggered_datachanges(result)
309 1
        self._pop_triggered_events(result)
310 1
        self._pop_triggered_statuschanges(result)
311 1
        self._keep_alive_count = 0
312
        self._startup = False
313 1
        result.NotificationMessage.SequenceNumber = self._notification_seq
314
        if len(result.NotificationMessage.NotificationData) != 0:
315
            self._notification_seq += 1
316
            self._not_acknowledged_results[result.NotificationMessage.SequenceNumber] = result
317
        result.MoreNotifications = False
318
        result.AvailableSequenceNumbers = list(self._not_acknowledged_results.keys())
319
        return result
320
321
    def _pop_triggered_datachanges(self, result):
322
        if self._triggered_datachanges:
323 1
            notif = ua.DataChangeNotification()
324 1
            notif.MonitoredItems = [item for sublist in self._triggered_datachanges.values() for item in sublist]
325
            self._triggered_datachanges = {}
326 1
            self.logger.debug("sending datachanges notification with %s events", len(notif.MonitoredItems))
327 1
            result.NotificationMessage.NotificationData.append(notif)
328
329 1
    def _pop_triggered_events(self, result):
330
        if self._triggered_events:
331
            notif = ua.EventNotificationList()
332 1
            notif.Events = [item for sublist in self._triggered_events.values() for item in sublist]
333 1
            self._triggered_events = {}
334 1
            result.NotificationMessage.NotificationData.append(notif)
335 1
            self.logger.debug("sending event notification with %s events", len(notif.Events))
336 1
337
    def _pop_triggered_statuschanges(self, result):
338
        if self._triggered_statuschanges:
339 1
            notif = ua.StatusChangeNotification()
340
            notif.Status = self._triggered_statuschanges.pop(0)
341
            result.NotificationMessage.NotificationData.append(notif)
342
            self.logger.debug("sending event notification %s", notif.Status)
343
344
    def publish(self, acks):
345
        self.logger.info("publish request with acks %s", acks)
346
        with self._lock:
347
            self._publish_cycles_count = 0
348
            for nb in acks:
349
                if nb in self._not_acknowledged_results:
350
                    self._not_acknowledged_results.pop(nb)
351
352
    def republish(self, nb):
353
        self.logger.info("re-publish request for ack %s in subscription %s", nb, self)
354
        with self._lock:
355
            if nb in self._not_acknowledged_results:
356
                self.logger.info("re-publishing ack %s in subscription %s", nb, self)
357
                return self._not_acknowledged_results[nb].NotificationMessage
358
            else:
359
                self.logger.info("Error request to re-published non existing ack %s in subscription %s", nb, self)
360
                return ua.NotificationMessage()
361
362
    def enqueue_datachange_event(self, mid, eventdata, maxsize):
363
        self._enqueue_event(mid, eventdata, maxsize, self._triggered_datachanges)
364
365
    def enqueue_event(self, mid, eventdata, maxsize):
366
        self._enqueue_event(mid, eventdata, maxsize, self._triggered_events)
367
368
    def enqueue_statuschange(self, code):
369
        self._triggered_statuschanges.append(code)
370
371
    def _enqueue_event(self, mid, eventdata, size, queue):
372
        if mid not in queue:
373
            queue[mid] = [eventdata]
374
            return
375
        if size != 0:
376
            if len(queue[mid]) >= size:
377
                queue[mid].pop(0)
378
        queue[mid].append(eventdata)
379
380
381
class WhereClauseEvaluator(object):
382
    def __init__(self, logger, aspace, whereclause):
383
        self.logger = logger
384
        self.elements = whereclause.Elements
385
        self._aspace = aspace
386
387
    def eval(self, event):
388
        if not self.elements:
389
            return True
390
        # spec says we should only evaluate first element, which may use other elements
391
        try:
392
            res = self._eval_el(0, event)
393
        except Exception as ex:
394
            self.logger.warning("Exception while evaluating WhereClause %s for event %s: %s", self.elements, event, ex)
395
            return False
396
        return res
397
398
    def _eval_el(self, index, event):
399
        el = self.elements[index]
400
        #ops = [self._eval_op(op, event) for op in el.FilterOperands]
401
        ops = el.FilterOperands  # just to make code more readable
402
        if el.FilterOperator == ua.FilterOperator.Equals:
403
            return self._eval_op(ops[0], event) == self._eval_el(ops[1], event)
404
        elif el.FilterOperator == ua.FilterOperator.IsNull:
405
            return self._eval_op(ops[0], event) is None  # FIXME: might be too strict
406
        elif el.FilterOperator == ua.FilterOperator.GreaterThan:
407
            return self._eval_op(ops[0], event) > self._eval_el(ops[1], event)
408
        elif el.FilterOperator == ua.FilterOperator.LessThan:
409
            return self._eval_op(ops[0], event) < self._eval_el(ops[1], event)
410
        elif el.FilterOperator == ua.FilterOperator.GreaterThanOrEqual:
411
            return self._eval_op(ops[0], event) >= self._eval_el(ops[1], event)
412
        elif el.FilterOperator == ua.FilterOperator.LessThanOrEqual:
413
            return self._eval_op(ops[0], event) <= self._eval_el(ops[1], event)
414
        elif el.FilterOperator == ua.FilterOperator.Like:
415
            return self._likeoperator(self._eval_op(ops[0], event), self._eval_el(ops[1], event))
416
        elif el.FilterOperator == ua.FilterOperator.Not:
417
            return not self._eval_op(ops[0], event)
418
        elif el.FilterOperator == ua.FilterOperator.Between:
419
            return self._eval_el(ops[2], event) >= self._eval_op(ops[0], event) >= self._eval_el(ops[1], event)
420
        elif el.FilterOperator == ua.FilterOperator.InList:
421
            return self._eval_op(ops[0], event) in [self._eval_op(op, event) for op in ops[1:]]
422
        elif el.FilterOperator == ua.FilterOperator.And:
423
            self.elements(ops[0].Index)
424
            return self._eval_op(ops[0], event) and self._eval_op(ops[1], event)
425
        elif el.FilterOperator == ua.FilterOperator.Or:
426
            return self._eval_op(ops[0], event) or self._eval_el(ops[1], event)
427
        elif el.FilterOperator == ua.FilterOperator.Cast:
428
            self.logger.warn("Cast operand not implemented, assuming True")
429
            return True
430
        elif el.FilterOperator == ua.FilterOperator.OfType:
431
            self.logger.warn("OfType operand not implemented, assuming True")
432
            return True
433
        else:
434
            # TODO: implement missing operators
435
            print("WhereClause not implemented for element: %s", el)
436
            raise NotImplementedError
437
438
    def _like_operator(self, string, pattern):
439
        raise NotImplementedError
440
441
    def _eval_op(self, op, event):
442
        # seems spec says we should return Null if issues
443
        if type(op) is ua.ElementOperand:
444
            return self._eval_el(op.Index, event)
445
        elif type(op) is ua.AttributeOperand:
446
            if op.BrowsePath:
447
                return getattr(event, op.BrowsePath.Elements[0].TargetName.Name)
448
            else:
449
                return self._aspace.get_attribute_value(event.EventType, op.AttributeId).Value.Value
450
            # FIXME: check, this is probably broken
451
        elif type(op) is ua.SimpleAttributeOperand:
452
            if op.BrowsePath:
453
                # we only support depth of 1
454
                return getattr(event, op.BrowsePath[0].Name)
455
            else:
456
                # TODO: write code for index range.... but doe it make any sense
457
                return self._aspace.get_attribute_value(event.EventType, op.AttributeId).Value.Value
458
        elif type(op) is ua.LiteralOperand:
459
            return op.Value.Value
460
        else:
461
            self.logger.warning("Where clause element % is not of a known type", op)
462
            raise NotImplementedError
463
464
465
466