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""" |
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server side implementation of a subscription object |
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""" |
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import logging |
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from asyncua import ua |
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from typing import Dict |
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from .address_space import AddressSpace |
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class MonitoredItemData: |
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def __init__(self): |
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self.client_handle = None |
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self.callback_handle = None |
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self.monitored_item_id = None |
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self.mode = None |
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self.filter = None |
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self.mvalue = MonitoredItemValues() |
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self.where_clause_evaluator = None |
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self.queue_size = 0 |
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class MonitoredItemValues: |
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def __init__(self): |
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self.current_value = None |
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self.old_value = None |
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def set_current_value(self, cur_val): |
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self.old_value = self.current_value |
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self.current_value = cur_val |
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def get_current_value(self): |
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return self.current_value |
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def get_old_value(self): |
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return self.old_value |
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class MonitoredItemService: |
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""" |
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Implements monitored item service for one subscription |
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""" |
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def __init__(self, isub, aspace: AddressSpace): |
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self.logger = logging.getLogger(f"{__name__}.{isub.data.SubscriptionId}") |
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self.isub = isub |
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self.aspace: AddressSpace = aspace |
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self._monitored_items: Dict[int, MonitoredItemData] = {} |
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self._monitored_events = {} |
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self._monitored_datachange: Dict[int, int] = {} |
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self._monitored_item_counter = 111 |
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def __str__(self): |
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return f"MonitoredItemService({self.isub.data.SubscriptionId})" |
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def delete_all_monitored_items(self): |
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self.delete_monitored_items([mdata.monitored_item_id for mdata in self._monitored_items.values()]) |
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async def create_monitored_items(self, params: ua.CreateMonitoredItemsParameters): |
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results = [] |
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for item in params.ItemsToCreate: |
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if item.ItemToMonitor.AttributeId == ua.AttributeIds.EventNotifier: |
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result = self._create_events_monitored_item(item) |
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else: |
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result = await self._create_data_change_monitored_item(item) |
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results.append(result) |
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return results |
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def modify_monitored_items(self, params: ua.ModifyMonitoredItemsParameters): |
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results = [] |
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for item in params.ItemsToModify: |
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results.append(self._modify_monitored_item(item)) |
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return results |
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async def trigger_datachange(self, handle, nodeid, attr): |
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self.logger.debug("triggering datachange for handle %s, nodeid %s, and attribute %s", handle, nodeid, attr) |
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dv = self.aspace.read_attribute_value(nodeid, attr) |
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await self.datachange_callback(handle, dv) |
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def _modify_monitored_item(self, params: ua.MonitoredItemModifyRequest): |
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for mdata in self._monitored_items.values(): |
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result = ua.MonitoredItemModifyResult() |
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if mdata.monitored_item_id == params.MonitoredItemId: |
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result.RevisedSamplingInterval = params.RequestedParameters.SamplingInterval |
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result.RevisedQueueSize = params.RequestedParameters.QueueSize |
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if params.RequestedParameters.Filter is not None: |
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mdata.filter = params.RequestedParameters.Filter |
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mdata.queue_size = params.RequestedParameters.QueueSize |
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return result |
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result = ua.MonitoredItemModifyResult() |
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result.StatusCode(ua.StatusCodes.BadMonitoredItemIdInvalid) |
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return result |
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94
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def _commit_monitored_item(self, result, mdata: MonitoredItemData): |
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if result.StatusCode.is_good(): |
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self._monitored_items[result.MonitoredItemId] = mdata |
97
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98
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def _make_monitored_item_common(self, params): |
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result = ua.MonitoredItemCreateResult() |
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result.RevisedSamplingInterval = self.isub.data.RevisedPublishingInterval |
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result.RevisedQueueSize = params.RequestedParameters.QueueSize |
102
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self._monitored_item_counter += 1 |
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result.MonitoredItemId = self._monitored_item_counter |
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self.logger.debug("Creating MonitoredItem with id %s", result.MonitoredItemId) |
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mdata = MonitoredItemData() |
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mdata.mode = params.MonitoringMode |
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mdata.client_handle = params.RequestedParameters.ClientHandle |
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mdata.monitored_item_id = result.MonitoredItemId |
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mdata.queue_size = params.RequestedParameters.QueueSize |
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mdata.filter = params.RequestedParameters.Filter |
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return result, mdata |
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def _create_events_monitored_item(self, params: ua.MonitoredItemCreateRequest): |
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self.logger.info("request to subscribe to events for node %s and attribute %s", params.ItemToMonitor.NodeId, |
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params.ItemToMonitor.AttributeId) |
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result, mdata = self._make_monitored_item_common(params) |
118
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ev_notify_byte = self.aspace.read_attribute_value(params.ItemToMonitor.NodeId, |
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ua.AttributeIds.EventNotifier).Value.Value |
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if ev_notify_byte is None or not ua.ua_binary.test_bit(ev_notify_byte, ua.EventNotifier.SubscribeToEvents): |
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result.StatusCode = ua.StatusCode(ua.StatusCodes.BadServiceUnsupported) |
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return result |
124
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# result.FilterResult = ua.EventFilterResult() # spec says we can ignore if not error |
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mdata.where_clause_evaluator = WhereClauseEvaluator(self.logger, self.aspace, mdata.filter.WhereClause) |
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self._commit_monitored_item(result, mdata) |
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if params.ItemToMonitor.NodeId not in self._monitored_events: |
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self._monitored_events[params.ItemToMonitor.NodeId] = [] |
129
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self._monitored_events[params.ItemToMonitor.NodeId].append(result.MonitoredItemId) |
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return result |
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132
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async def _create_data_change_monitored_item(self, params: ua.MonitoredItemCreateRequest): |
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self.logger.info("request to subscribe to datachange for node %s and attribute %s", params.ItemToMonitor.NodeId, |
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params.ItemToMonitor.AttributeId) |
135
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136
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result, mdata = self._make_monitored_item_common(params) |
137
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result.FilterResult = params.RequestedParameters.Filter |
138
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result.StatusCode, handle = self.aspace.add_datachange_callback( |
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params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId, self.datachange_callback) |
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self.logger.debug("adding callback return status %s and handle %s", result.StatusCode, handle) |
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mdata.callback_handle = handle |
143
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self._commit_monitored_item(result, mdata) |
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if result.StatusCode.is_good(): |
145
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self._monitored_datachange[handle] = result.MonitoredItemId |
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# force data change event generation |
147
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await self.trigger_datachange(handle, params.ItemToMonitor.NodeId, params.ItemToMonitor.AttributeId) |
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return result |
149
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150
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def delete_monitored_items(self, ids): |
151
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self.logger.debug("delete monitored items %s", ids) |
152
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# with self._lock: |
153
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results = [] |
154
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for mid in ids: |
155
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results.append(self._delete_monitored_items(mid)) |
156
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return results |
157
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158
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def _delete_monitored_items(self, mid: int): |
159
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if mid not in self._monitored_items: |
160
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return ua.StatusCode(ua.StatusCodes.BadMonitoredItemIdInvalid) |
161
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for k, v in self._monitored_events.items(): |
162
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if mid in v: |
163
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v.remove(mid) |
164
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if not v: |
165
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self._monitored_events.pop(k) |
166
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break |
167
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for k, v in self._monitored_datachange.items(): |
168
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if v == mid: |
169
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self.aspace.delete_datachange_callback(k) |
170
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self._monitored_datachange.pop(k) |
171
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break |
172
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self._monitored_items.pop(mid) |
173
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return ua.StatusCode() |
174
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175
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async def datachange_callback(self, handle: int, value, error=None): |
176
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if error: |
177
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self.logger.info("subscription %s: datachange callback called with handle '%s' and error '%s'", self, |
178
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handle, error) |
179
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await self.trigger_statuschange(error) |
180
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else: |
181
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# self.logger.info(f"subscription {self}: datachange callback called " |
182
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# f"with handle '{handle}' and value '{value.Value}'") |
183
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event = ua.MonitoredItemNotification() |
184
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mid = self._monitored_datachange[handle] |
185
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mdata = self._monitored_items[mid] |
186
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mdata.mvalue.set_current_value(value.Value.Value) |
187
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if mdata.filter: |
188
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deadband_flag_pass = self.deadband_callback(mdata.mvalue, mdata.filter) |
189
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else: |
190
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deadband_flag_pass = True |
191
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if deadband_flag_pass: |
192
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event.ClientHandle = mdata.client_handle |
193
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event.Value = value |
194
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await self.isub.enqueue_datachange_event(mid, event, mdata.queue_size) |
195
|
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|
196
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def deadband_callback(self, values, flt): |
197
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if flt.DeadbandType == ua.DeadbandType.None_ or values.get_old_value() is None: |
198
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return True |
199
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|
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if flt.DeadbandType == ua.DeadbandType.Absolute and \ |
200
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|
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((abs(values.get_current_value() - values.get_old_value())) > flt.DeadbandValue): |
201
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return True |
202
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|
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if flt.DeadbandType == ua.DeadbandType.Percent: |
203
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self.logger.warning("DeadbandType Percent is not implemented !") |
204
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return True |
205
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return False |
206
|
|
|
|
207
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async def trigger_event(self, event): |
208
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if event.emitting_node not in self._monitored_events: |
209
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self.logger.debug("%s has NO subscription for events %s from node: %s", self, event, event.emitting_node) |
210
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return False |
211
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self.logger.debug("%s has subscription for events %s from node: %s", self, event, event.emitting_node) |
212
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|
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mids = self._monitored_events[event.emitting_node] |
213
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for mid in mids: |
214
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await self._trigger_event(event, mid) |
215
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return True |
216
|
|
|
|
217
|
|
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async def _trigger_event(self, event, mid: int): |
218
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if mid not in self._monitored_items: |
219
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self.logger.debug("Could not find monitored items for id %s for event %s in subscription %s", mid, event, |
220
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self) |
221
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return |
222
|
|
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mdata = self._monitored_items[mid] |
223
|
|
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if not mdata.where_clause_evaluator.eval(event): |
224
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self.logger.info("%s, %s, Event %s does not fit WhereClause, not generating event", self, mid, event) |
225
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return |
226
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|
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fieldlist = ua.EventFieldList() |
227
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|
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fieldlist.ClientHandle = mdata.client_handle |
228
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fieldlist.EventFields = event.to_event_fields(mdata.filter.SelectClauses) |
229
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await self.isub.enqueue_event(mid, fieldlist, mdata.queue_size) |
230
|
|
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|
231
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async def trigger_statuschange(self, code): |
232
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await self.isub.enqueue_statuschange(code) |
233
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|
234
|
|
|
|
235
|
|
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class WhereClauseEvaluator: |
236
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def __init__(self, logger, aspace: AddressSpace, whereclause): |
237
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self.logger = logger |
238
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self.elements = whereclause.Elements |
239
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self._aspace = aspace |
240
|
|
|
|
241
|
|
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def eval(self, event): |
242
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|
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if not self.elements: |
243
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|
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return True |
244
|
|
|
# spec says we should only evaluate first element, which may use other elements |
245
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|
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try: |
246
|
|
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res = self._eval_el(0, event) |
247
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except Exception as ex: |
248
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|
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self.logger.exception("Exception while evaluating WhereClause %s for event %s: %s", self.elements, event, |
249
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|
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ex) |
250
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|
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return False |
251
|
|
|
return res |
252
|
|
|
|
253
|
|
|
def _eval_el(self, index, event): |
254
|
|
|
el = self.elements[index] |
255
|
|
|
# ops = [self._eval_op(op, event) for op in el.FilterOperands] |
256
|
|
|
ops = el.FilterOperands # just to make code more readable |
257
|
|
|
if el.FilterOperator == ua.FilterOperator.Equals: |
258
|
|
|
return self._eval_op(ops[0], event) == self._eval_op(ops[1], event) |
259
|
|
|
if el.FilterOperator == ua.FilterOperator.IsNull: |
260
|
|
|
return self._eval_op(ops[0], event) is None # FIXME: might be too strict |
261
|
|
|
if el.FilterOperator == ua.FilterOperator.GreaterThan: |
262
|
|
|
return self._eval_op(ops[0], event) > self._eval_op(ops[1], event) |
263
|
|
|
if el.FilterOperator == ua.FilterOperator.LessThan: |
264
|
|
|
return self._eval_op(ops[0], event) < self._eval_op(ops[1], event) |
265
|
|
|
if el.FilterOperator == ua.FilterOperator.GreaterThanOrEqual: |
266
|
|
|
return self._eval_op(ops[0], event) >= self._eval_op(ops[1], event) |
267
|
|
|
if el.FilterOperator == ua.FilterOperator.LessThanOrEqual: |
268
|
|
|
return self._eval_op(ops[0], event) <= self._eval_op(ops[1], event) |
269
|
|
|
if el.FilterOperator == ua.FilterOperator.Like: |
270
|
|
|
return self._like_operator(self._eval_op(ops[0], event), self._eval_op(ops[1], event)) |
271
|
|
|
if el.FilterOperator == ua.FilterOperator.Not: |
272
|
|
|
return not self._eval_op(ops[0], event) |
273
|
|
|
if el.FilterOperator == ua.FilterOperator.Between: |
274
|
|
|
return self._eval_op(ops[2], event) >= self._eval_op(ops[0], event) >= self._eval_op(ops[1], event) |
275
|
|
|
if el.FilterOperator == ua.FilterOperator.InList: |
276
|
|
|
return self._eval_op(ops[0], event) in [self._eval_op(op, event) for op in ops[1:]] |
277
|
|
|
if el.FilterOperator == ua.FilterOperator.And: |
278
|
|
|
self.elements(ops[0].Index) |
279
|
|
|
return self._eval_op(ops[0], event) and self._eval_op(ops[1], event) |
280
|
|
|
if el.FilterOperator == ua.FilterOperator.Or: |
281
|
|
|
return self._eval_op(ops[0], event) or self._eval_op(ops[1], event) |
282
|
|
|
if el.FilterOperator == ua.FilterOperator.Cast: |
283
|
|
|
self.logger.warn("Cast operand not implemented, assuming True") |
284
|
|
|
return True |
285
|
|
|
if el.FilterOperator == ua.FilterOperator.OfType: |
286
|
|
|
return event.EventType == self._eval_op(ops[0], event) |
287
|
|
|
# TODO: implement missing operators |
288
|
|
|
self.logger.warning("WhereClause not implemented for element: %s", el) |
289
|
|
|
raise NotImplementedError |
290
|
|
|
|
291
|
|
|
def _like_operator(self, string, pattern): |
292
|
|
|
raise NotImplementedError |
293
|
|
|
|
294
|
|
|
def _eval_op(self, op, event): |
295
|
|
|
# seems spec says we should return Null if issues |
296
|
|
|
if isinstance(op, ua.ElementOperand): |
297
|
|
|
return self._eval_el(op.Index, event) |
298
|
|
|
if isinstance(op, ua.AttributeOperand): |
299
|
|
|
if op.BrowsePath: |
300
|
|
|
return getattr(event, op.BrowsePath.Elements[0].TargetName.Name) |
301
|
|
|
return self._aspace.read_attribute_value(event.EventType, op.AttributeId).Value.Value |
302
|
|
|
# FIXME: check, this is probably broken |
303
|
|
|
if isinstance(op, ua.SimpleAttributeOperand): |
304
|
|
|
if op.BrowsePath: |
305
|
|
|
# we only support depth of 1 |
306
|
|
|
return getattr(event, op.BrowsePath[0].Name) |
307
|
|
|
# TODO: write code for index range.... but doe it make any sense |
308
|
|
|
return self._aspace.read_attribute_value(event.EventType, op.AttributeId).Value.Value |
309
|
|
|
if isinstance(op, ua.LiteralOperand): |
310
|
|
|
return op.Value.Value |
311
|
|
|
self.logger.warning("Where clause element % is not of a known type", op) |
312
|
|
|
raise NotImplementedError |
313
|
|
|
|