Completed
Pull Request — master (#179)
by Olivier
03:37
created

WhereClauseEvaluator._like_operator()   A

Complexity

Conditions 1

Size

Total Lines 2

Duplication

Lines 0
Ratio 0 %

Code Coverage

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