Completed
Pull Request — master (#179)
by Olivier
03:25
created

WhereClauseEvaluator.__init__()   A

Complexity

Conditions 1

Size

Total Lines 4

Duplication

Lines 0
Ratio 0 %

Code Coverage

Tests 0
CRAP Score 2

Importance

Changes 2
Bugs 0 Features 0
Metric Value
cc 1
c 2
b 0
f 0
dl 0
loc 4
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
            results.append(self._create_monitored_item(item))
47
        return results
48 1
49
    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 1
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
        self.datachange_callback(handle, variant)
59 1
60
    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 1
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
            self.logger.debug("Creating MonitoredItem with id %s", result.MonitoredItemId)
83 1
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
            mdata.monitored_item_id = result.MonitoredItemId
90 1
91
            self._monitored_items[result.MonitoredItemId] = mdata
92 1
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
                if self.aspace.get_attribute_value(params.ItemToMonitor.NodeId, ua.AttributeIds.EventNotifier).Value.Value != 1:
96 1
                    result.StatusCode = ua.StatusCode(ua.StatusCodes.BadServiceUnsupported)
97 1
                result.FilterResult = ua.EventFilterResult()
98 1
                for _ in params.RequestedParameters.Filter.SelectClauses:
99
                    result.FilterResult.SelectClauseResults.append(ua.StatusCode())
100 1
                # FIXME: where clause result
101
                mdata.where_clause_evaluator = WhereClauseEvaluator(self.logger, self.aspace, mdata.mfilter.WhereClause)
102 1
                self._monitored_events[params.ItemToMonitor.NodeId] = result.MonitoredItemId
103 1
            else:
104 1
                self.logger.info("request to subscribe to datachange for node %s and attribute %s", params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId)
105 1
                result.FilterResult = params.RequestedParameters.Filter
106 1
                result.StatusCode, handle = self.aspace.add_datachange_callback(params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId, self.datachange_callback)
107 1
                self.logger.debug("adding callback return status %s and handle %s", result.StatusCode, handle)
108 1
                mdata.callback_handle = handle
109
                self._monitored_datachange[handle] = result.MonitoredItemId
110 1
                if result.StatusCode.is_good():
111
                    # force data change event generation
112 1
                    self.trigger_datachange(handle, params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId)
113 1
114 1
            if not result.StatusCode.is_good():
115
                del(self._monitored_items[result.MonitoredItemId])
116 1
                self._monitored_item_counter -= 1
117
118 1
            return result
119 1
120 1
    def delete_monitored_items(self, ids):
121 1
        self.logger.debug("delete monitored items %s", ids)
122 1
        with self._lock:
123 1
            results = []
124 1
            for mid in ids:
125
                results.append(self._delete_monitored_items(mid))
126 1
            return results
127 1
128 1
    def _delete_monitored_items(self, mid):
129 1
        if mid not in self._monitored_items:
130 1
            return ua.StatusCode(ua.StatusCodes.BadMonitoredItemIdInvalid)
131 1
        for k, v in self._monitored_events.items():
132 1
            if v == mid:
133 1
                self._monitored_events.pop(k)
134 1
                break
135 1
        for k, v in self._monitored_datachange.items():
136 1
            if v == mid:
137 1
                self.aspace.delete_datachange_callback(k)
138 1
                self._monitored_datachange.pop(k)
139 1
                break
140
        self._monitored_items.pop(mid)
141 1
        return ua.StatusCode()
142 1
143
    def datachange_callback(self, handle, value, error=None):
144
        if error:
145
            self.logger.info("subscription %s: datachange callback called with handle '%s' and erorr '%s'",
146 1
                             self, handle, error)
147 1
            self.trigger_statuschange(error)
148 1
        else:
149 1
            self.logger.info("subscription %s: datachange callback called with handle '%s' and value '%s'",
150 1
                             self, handle, value.Value)
151 1
            event = ua.MonitoredItemNotification()
152 1
            with self._lock:
153 1
                mid = self._monitored_datachange[handle]
154
                mdata = self._monitored_items[mid]
155 1
                event.ClientHandle = mdata.client_handle
156 1
                event.Value = value
157 1
                self.isub.enqueue_datachange_event(mid, event, mdata.parameters.RevisedQueueSize)
158 1
159 1
    def trigger_event(self, event):
160 1
        with self._lock:
161 1
            if event.SourceNode not in self._monitored_events:
162 1
                self.logger.debug("%s has no subscription for events %s from node: %s",
163
                                  self, event, event.SourceNode)
164
                return False
165 1
            self.logger.debug("%s has subscription for events %s from node: %s",
166 1
                              self, event, event.SourceNode)
167 1
            mid = self._monitored_events[event.SourceNode]
168 1
            if mid not in self._monitored_items:
169 1
                self.logger.debug("Could not find monitored items for id %s for event %s in subscription %s",
170 1
                                  mid, event, self)
171
                return False
172 1
            mdata = self._monitored_items[mid]
173 1
            if not mdata.where_clause_evaluator.eval(event):
174 1
                self.logger.debug("Event does not fit WhereClause, not generating event", mid, event, self)
175 1
                return
176 1
            fieldlist = ua.EventFieldList()
177
            fieldlist.ClientHandle = mdata.client_handle
178
            fieldlist.EventFields = self._get_event_fields(mdata.mfilter, event)
179
            self.isub.enqueue_event(mid, fieldlist, mdata.parameters.RevisedQueueSize)
180
            return True
181
182 1
    def _get_event_fields(self, evfilter, event):
183 1
        fields = []
184 1
        for sattr in evfilter.SelectClauses:
185 1
            try:
186 1
                if not sattr.BrowsePath:
187 1
                    val = getattr(event, sattr.Attribute.name)
188 1
                    val = copy.deepcopy(val)
189
                    fields.append(ua.Variant(val))
190 1
                else:
191
                    name = sattr.BrowsePath[0].Name
192
                    val = getattr(event, name)
193
                    val = copy.deepcopy(val)
194 1
                    fields.append(ua.Variant(val))
195
            except AttributeError:
196 1
                fields.append(ua.Variant())
197 1
        return fields
198 1
199 1
    def trigger_statuschange(self, code):
200 1
        self.isub.enqueue_statuschange(code)
201 1
202 1
203 1
class InternalSubscription(object):
204 1
205 1
    def __init__(self, subservice, data, addressspace, callback):
206 1
        self.logger = logging.getLogger(__name__ + "." + str(data.SubscriptionId))
207 1
        self.aspace = addressspace
208 1
        self.subservice = subservice
209 1
        self.data = data
210 1
        self.callback = callback
211 1
        self.monitored_item_srv = MonitoredItemService(self, addressspace)
212 1
        self.task = None
213 1
        self._lock = RLock()
214
        self._triggered_datachanges = {}
215 1
        self._triggered_events = {}
216
        self._triggered_statuschanges = []
217
        self._notification_seq = 1
218 1
        self._not_acknowledged_results = {}
219 1
        self._startup = True
220 1
        self._keep_alive_count = 0
221
        self._publish_cycles_count = 0
222 1
        self._stopev = False
223 1
224 1
    def __str__(self):
225 1
        return "Subscription(id:{})".format(self.data.SubscriptionId)
226
227 1
    def start(self):
228
        self.logger.debug("starting subscription %s", self.data.SubscriptionId)
229 1
        self._subscription_loop()
230 1
231
    def stop(self):
232 1
        self.logger.debug("stopping subscription %s", self.data.SubscriptionId)
233 1
        self._stopev = True
234 1
        self.monitored_item_srv.delete_all_monitored_items()
235 1
236 1
    def _subscription_loop(self):
237
        #self.logger.debug("%s loop", self)
238 1
        if not self._stopev:
239 1
            self.subservice.loop.call_later(self.data.RevisedPublishingInterval / 1000.0, self._sub_loop)
240 1
241 1
    def _sub_loop(self):
242 1
        if self._stopev:
243
            return
244
        self.publish_results()
245 1
        self._subscription_loop()
246 1
247
    def has_published_results(self):
248 1
        with self._lock:
249 1
            if self._startup or self._triggered_datachanges or self._triggered_events:
250
                return True
251
            if self._keep_alive_count > self.data.RevisedMaxKeepAliveCount:
252
                self.logger.debug("keep alive count %s is > than max keep alive count %s, sending publish event", self._keep_alive_count, self.data.RevisedMaxKeepAliveCount)
253
                return True
254 1
            self._keep_alive_count += 1
255 1
            return False
256 1
257 1
    def publish_results(self):
258 1
        if self._publish_cycles_count > self.data.RevisedLifetimeCount:
259 1
            self.logger.warning("Subscription %s has expired, publish cycle count(%s) > lifetime count (%s)", self, self._publish_cycles_count, self.data.RevisedLifetimeCount)
260 1
            # FIXME this will never be send since we do not have publish request anyway
261
            self.monitored_item_srv.trigger_statuschange(ua.StatusCode(ua.StatusCodes.BadTimeout))
262 1
            self._stopev = True
263 1
        result = None
264 1
        with self._lock:
265 1
            if self.has_published_results():  # FIXME: should we pop a publish request here? or we do not care?
266 1
                self._publish_cycles_count += 1
267 1
                result = self._pop_publish_result()
268 1
        if result is not None:
269 1
            self.callback(result)
270 1
271 1
    def _pop_publish_result(self):
272 1
        result = ua.PublishResult()
273 1
        result.SubscriptionId = self.data.SubscriptionId
274 1
        self._pop_triggered_datachanges(result)
275 1
        self._pop_triggered_events(result)
276 1
        self._pop_triggered_statuschanges(result)
277
        self._keep_alive_count = 0
278 1
        self._startup = False
279 1
        result.NotificationMessage.SequenceNumber = self._notification_seq
280 1
        if len(result.NotificationMessage.NotificationData) != 0:
281 1
            self._notification_seq += 1
282 1
            self._not_acknowledged_results[result.NotificationMessage.SequenceNumber] = result
283 1
        result.MoreNotifications = False
284 1
        result.AvailableSequenceNumbers = list(self._not_acknowledged_results.keys())
285
        return result
286 1
287 1
    def _pop_triggered_datachanges(self, result):
288 1
        if self._triggered_datachanges:
289 1
            notif = ua.DataChangeNotification()
290 1
            notif.MonitoredItems = [item for sublist in self._triggered_datachanges.values() for item in sublist]
291 1
            self._triggered_datachanges = {}
292 1
            self.logger.debug("sending datachanges notification with %s events", len(notif.MonitoredItems))
293
            result.NotificationMessage.NotificationData.append(notif)
294 1
295 1
    def _pop_triggered_events(self, result):
296
        if self._triggered_events:
297
            notif = ua.EventNotificationList()
298
            notif.Events = [item for sublist in self._triggered_events.values() for item in sublist]
299
            self._triggered_events = {}
300
            result.NotificationMessage.NotificationData.append(notif)
301 1
            self.logger.debug("sending event notification with %s events", len(notif.Events))
302 1
303 1
    def _pop_triggered_statuschanges(self, result):
304 1
        if self._triggered_statuschanges:
305 1
            notif = ua.StatusChangeNotification()
306 1
            notif.Status = self._triggered_statuschanges.pop(0)
307 1
            result.NotificationMessage.NotificationData.append(notif)
308
            self.logger.debug("sending event notification %s", notif.Status)
309 1
310
    def publish(self, acks):
311
        self.logger.info("publish request with acks %s", acks)
312
        with self._lock:
313
            self._publish_cycles_count = 0
314
            for nb in acks:
315
                if nb in self._not_acknowledged_results:
316
                    self._not_acknowledged_results.pop(nb)
317
318
    def republish(self, nb):
319 1
        self.logger.info("re-publish request for ack %s in subscription %s", nb, self)
320 1
        with self._lock:
321
            if nb in self._not_acknowledged_results:
322 1
                self.logger.info("re-publishing ack %s in subscription %s", nb, self)
323 1
                return self._not_acknowledged_results[nb].NotificationMessage
324
            else:
325 1
                self.logger.info("Error request to re-published non existing ack %s in subscription %s", nb, self)
326
                return ua.NotificationMessage()
327
328 1
    def enqueue_datachange_event(self, mid, eventdata, maxsize):
329 1
        self._enqueue_event(mid, eventdata, maxsize, self._triggered_datachanges)
330 1
331 1
    def enqueue_event(self, mid, eventdata, maxsize):
332 1
        self._enqueue_event(mid, eventdata, maxsize, self._triggered_events)
333
334
    def enqueue_statuschange(self, code):
335 1
        self._triggered_statuschanges.append(code)
336
337
    def _enqueue_event(self, mid, eventdata, size, queue):
338
        if mid not in queue:
339
            queue[mid] = [eventdata]
340
            return
341
        if size != 0:
342
            if len(queue[mid]) >= size:
343
                queue[mid].pop(0)
344
        queue[mid].append(eventdata)
345
346
347
class WhereClauseEvaluator(object):
348
    def __init__(self, logger, aspace, whereclause):
349
        self.logger = logger
350
        self.elements = whereclause.Elements
351
        self._aspace = aspace
352
353
    def eval(self, event):
354
        if not self.elements:
355
            return True
356
        # spec says we should only evaluate first element, which may use other elements
357
        try:
358
            res = self._eval_el(0, event)
359
        except Exception as ex:
360
            self.logger.warning("Exception while evaluating WhereClause %s for event %s: %s", self.elements, event, ex)
361
            return False
362
        return res
363
364
    def _eval_el(self, index, event):
365
        el = self.elements[index]
366
        if el.FilterOperator == ua.FilterOperator.And:
367
            self.elements(el.FilterOperands[0].Index)
368
            return self._eval_op(el.FilterOperands[0], event) and self._eval_op(el.FilterOperands[1], event)
369
        elif el.FilterOperator == ua.FilterOperator.Or:
370
            return self._eval_op(el.FilterOperands[0], event) or self._eval_el(el.FilterOperands[1], event)
371
        elif el.FilterOperator == ua.FilterOperator.InList:
372
            return self._eval_op(el.FilterOperands[0], event) in [self._eval_op(op, event) for op in el.FilterOperands[1:]]
373
        elif el.FilterOperator == ua.FilterOperator.Equals:
374
            return self._eval_op(el.FilterOperands[0], event) == self._eval_el(el.FilterOperands[1], event)
375
        elif el.FilterOperator == ua.FilterOperator.IsNull:
376
            return self._eval_op(el.FilterOperands[0], event) is None  # FIXME: might be too strict
377
        elif el.FilterOperator == ua.FilterOperator.LessThan:
378
            return self._eval_op(el.FilterOperands[0], event) < self._eval_el(el.FilterOperands[1], event)
379
        elif el.FilterOperator == ua.FilterOperator.LessThanOrEqual:
380
            return self._eval_op(el.FilterOperands[0], event) < self._eval_el(el.FilterOperands[1], event)
381
        else:
382
            # TODO: implement missing operators
383
            print("WhereClause not implemented for element: %s", el)
384
385
    def _eval_op(self, op, event):
386
        # seems spec says we should return Null if issues
387
        if type(op) is ua.ElementOperand:
388
            el = self.elements[op.FilterOperands[0].Index]
389
            return self._eval_el(el)
390
        elif type(op) is ua.AttributeOperand:
391
            if op.BrowsePath:
392
                return getattr(event, op.BrowsePath.Elements[0].TargetName.Name)
393
            else:
394
                return self._aspace.get_attribute_value(event.EventType, op.AttributeId).Value.Value
395
            # FIXME: check, this is probably broken
396
        elif type(op) is ua.SimpleAttributeOperand:
397
            if op.BrowsePath:
398
                # we only support depth of 1
399
                return getattr(event, op.BrowsePath[0].BrowseName.Name)
400
            else:
401
                # TODO: write code for index range.... but doe it make any sense
402
                return self._aspace.get_attribute_value(event.EventType, op.AttributeId).Value.Value
403
        elif type(op) is ua.LiteralOperand:
404
            return op.Value.Value
405
        else:
406
            self.logger.warning("Where clause element % is not of a known type", el)
407
408
409
410