Merge pull request #1389 from telefonicaid/task/entityNameExp_with_me…

…asures

Evaluate group entityNameExp with a context including measures

CHANGES_NEXT_RELEASE

@@ -1,3 +1,4 @@
+- Add: Evaluate group entityNameExp with a context including measures (#1334)
 - Remove: expressionLanguage field (as it it not longer needed, due to only one expression language is supported, after the removal of legacy expressions in 3.2.0) (#1384)
 - Add: allow update timestamp and other config fields of device
 - Fix: use 'options=upsert' when update ngsiv2 CB entities and appendMode is enabled (#956)

doc/api.md

@@ -190,11 +190,10 @@ Some transformation plugins also allow the use of the following optional fields:
     an expression based on a combination of the reported values. See the
     [Expression Language definition](#expression-language-support) for details
 -   **skipValue**: indicates that if the result of applying `expression` to a measure is equal to the value of
-    `skipValue` then the attribute corresponding to the measure is not sent to CB. In other words, this field **is
-    not an expression**, it is a value that is compared with the result of applying `expression` to a measure. By 
-    default if `skipValue` is not defined then is considered as `null` (i.e. if the result of apply `expression` results 
-    in `null` then corresponding attribute is not sent to CB). It is only used if `expression` is provided (otherwise is 
-    ignored).
+    `skipValue` then the attribute corresponding to the measure is not sent to CB. In other words, this field **is not
+    an expression**, it is a value that is compared with the result of applying `expression` to a measure. By default if
+    `skipValue` is not defined then is considered as `null` (i.e. if the result of apply `expression` results in `null`
+    then corresponding attribute is not sent to CB). It is only used if `expression` is provided (otherwise is ignored).
 -   **entity_name**: the presence of this attribute indicates that the value will not be stored in the original device
     entity but in a new entity with an ID given by this attribute. The type of this additional entity can be configured
     with the `entity_type` attribute. If no type is configured, the device entity type is used instead. Entity names can
@@ -521,6 +520,9 @@ expression. In all cases the following data is available to all expressions:
 -   `subservice`: device subservice
 -   `staticAttributes`: static attributes defined in the device or config group
 
+Additionally, for attribute expressions (`expression`, `entity_name`) and `entityNameExp` measures are avaiable in the
+**context** used to evaluate them.
+
 ### Examples of JEXL expressions
 
 The following table shows expressions and their expected outcomes taking into account the following measures at

lib/services/devices/deviceService.js

@@ -181,6 +181,9 @@ function mergeDeviceWithConfiguration(fields, defaults, deviceData, configuratio
     if (configuration && configuration.explicitAttrs !== undefined && deviceData.explicitAttrs === undefined) {
         deviceData.explicitAttrs = configuration.explicitAttrs;
     }
+    if (configuration && configuration.entityNameExp !== undefined) {
+        deviceData.entityNameExp = configuration.entityNameExp;
+    }
 
     logger.debug(context, 'deviceData after merge with conf: %j', deviceData);
     callback(null, deviceData);

lib/services/ngsi/entities-NGSI-v2.js

@@ -675,6 +675,23 @@ function sendUpdateValueNgsi2(entityName, attributes, typeInformation, token, ca
         }
     }
 
+    // Evaluate entityNameExp with a context including measures
+    if (typeInformation.entityNameExp !== undefined && typeInformation.entityNameExp !== '') {
+        try {
+            logger.debug(context, 'sendUpdateValueNgsi2 entityNameExp %j ', typeInformation.entityNameExp);
+            entityName = expressionPlugin.applyExpression(typeInformation.entityNameExp, ctxt, typeInformation);
+            payload.entities[0].id = entityName;
+            ctxt['entity_name'] = entityName;
+        } catch (e) {
+            logger.debug(
+                context,
+                'Error evaluating expression for entityName: %s with context: %s',
+                typeInformation.entityNameExp,
+                ctxt
+            );
+        }
+    }
+
     logger.debug(context, 'sendUpdateValueNgsi2 currentEntity sorted %j ', currentEntity);
     let timestampValue = undefined;
     // Loop for each final attribute to apply alias, multientity and expressions