store / recover previous jextctxt

CHANGES_NEXT_RELEASE

@@ -1,3 +1,4 @@
+- Add: store (and recover) previous jexlctxt and make available in current jexlctxt (#1690)
 - Fix: set polling and transport for autoprovisioned devices
 - Add: option to force to use CB flow control with new API field useCBflowControl at group and device device level  (#1420)
 - Add: useCBflowControl config setting (IOTA_CB_FLOW_CONTROL env var) to set CB flow control behaviour at instance level (#1420)

doc/api.md

@@ -623,6 +623,7 @@ expression. In all cases the following data is available to all expressions:
 -   `service`: device service (`Fiware-Service`)
 -   `subservice`: device subservice (`Fiware-ServicePath`)
 -   `staticAttributes`: static attributes defined in the device or config group
+-   `oldCtxt`: previous JEXL context (related to last processed measure)
 
 Additionally, for attribute expressions (`expression`, `entity_name`), `entityNameExp` and metadata expressions
 (`expression`) the following is available in the **context** used to evalute:
@@ -1998,10 +1999,11 @@ the API resource fields and the same fields in the database model.
 | `internal_attributes` | ✓        | `array`   |            | List of internal attributes with free format for specific IoT Agent configuration.                                                                                                                                                                                                                                                                                                                                         |
 | `explicitAttrs`       | ✓        | `boolean` | ✓          | Field to support selective ignore of measures so that IOTA doesn’t progress. See details in [specific section](#explicitly-defined-attributes-explicitattrs)                                                                                                                                                                                                                                                               |
 | `ngsiVersion`         | ✓        | `string`  |            | string value used in mixed mode to switch between **NGSI-v2** and **NGSI-LD** payloads. The default is `v2`. When not running in mixed mode, this field is ignored.                                                                                                                                                                                                                                                        |
-| `payloadType`         | ✓        | `string`  |            | optional string value used to switch between **IoTAgent**, **NGSI-v2** and **NGSI-LD** measure payloads types. Possible values are: `iotagent`, `ngsiv2` or `ngsild`. The default is `iotagent`.                                                                                                                                                                                                                          |
-| `storeLastMeasure`    | ✓        | `boolean` |            | Store in device last measure received. See more info [in this section](admin.md#storelastmeasure). False by default.                                                                                                    |
-| `lastMeasure`         | ✓        | `object` |             | last measure stored on device when `storeLastMeasure` is enabled. See more info [in this section](admin.md#storelastmeasure). This field can be cleared using `{}` in a device update request. In that case, `lastMeasure` is removed from device (until a next measure is received and `lastMesuare` gets created again).                                                                            |
-| `useCBflowControl`    | ✓        | `boolean` |            | Use Context Broker flow control. See more info [in this section](admin.md#useCBflowControl). False by default.                                                                                                          |
+| `payloadType`         | ✓        | `string`  |            | optional string value used to switch between **IoTAgent**, **NGSI-v2** and **NGSI-LD** measure payloads types. Possible values are: `iotagent`, `ngsiv2` or `ngsild`. The default is `iotagent`.                                                                                                                                                                                                                           |
+| `storeLastMeasure`    | ✓        | `boolean` |            | Store in device last measure received. Useful just for debugging purpose. See more info [in this section](admin.md#storelastmeasure). False by default.                                                                                                                                                                                                                                                                    |
+| `lastMeasure`         | ✓        | `object`  |            | last measure stored on device when `storeLastMeasure` is enabled. See more info [in this section](admin.md#storelastmeasure). This field can be cleared using `{}` in a device update request. In that case, `lastMeasure` is removed from device (until a next measure is received and `lastMesuare` gets created again).                                                                                                 |
+| `useCBflowControl`    | ✓        | `boolean` |            | Use Context Broker flow control. See more info [in this section](admin.md#useCBflowControl). False by default.                                                                                                                                                                                                                                                                                                             |
+
 ### Device operations
 
 #### Retrieve devices /iot/devices `GET /iot/devices`

lib/model/Device.js

@@ -56,7 +56,8 @@ const Device = new Schema({
     payloadType: String,
     useCBflowControl: Boolean,
     storeLastMeasure: Boolean,
-    lastMeasure: Object
+    lastMeasure: Object,
+    oldCtxt: Object
 });
 
 function load() {

lib/services/devices/deviceRegistryMemory.js

@@ -210,7 +210,7 @@ function getDevicesByAttribute(name, value, service, subservice, callback) {
     }
 }
 
-function storeLastMeasure(measure, typeInformation, callback) {
+function storeDeviceField(fieldName, fieldValue, typeInformation, callback) {
     if (
         typeInformation &&
         typeInformation.id &&
@@ -226,7 +226,11 @@ function storeLastMeasure(measure, typeInformation, callback) {
             function (error, data) {
                 if (!error) {
                     if (data) {
-                        data.lastMeasure = measure;
+                        if (fieldName === 'lastMeasure') {
+                            data.lastMeasure = { timestamp: new Date().toISOString(), measure: fieldValue };
+                        } else {
+                            data[fieldName] = fieldValue;
+                        }
                     }
                     if (callback) {
                         callback(null, data);
@@ -243,7 +247,7 @@ function storeLastMeasure(measure, typeInformation, callback) {
 
 exports.getDevicesByAttribute = getDevicesByAttribute;
 exports.store = storeDevice;
-exports.storeLastMeasure = storeLastMeasure;
+exports.storeDeviceField = storeDeviceField;
 exports.update = update;
 exports.remove = removeDevice;
 exports.list = listDevices;

lib/services/devices/deviceRegistryMongoDB.js

@@ -397,7 +397,7 @@ function getDevicesByAttribute(name, value, service, subservice, callback) {
         });
 }
 
-function storeLastMeasure(measure, typeInformation, callback) {
+function storeDeviceField(fieldName, fieldValue, typeInformation, callback) {
     if (
         typeInformation &&
         typeInformation.id &&
@@ -414,7 +414,11 @@ function storeLastMeasure(measure, typeInformation, callback) {
                 if (error) {
                     callback(error);
                 } else {
-                    data.lastMeasure = { timestamp: new Date().toISOString(), measure };
+                    if (fieldName === 'lastMeasure') {
+                        data.lastMeasure = { timestamp: new Date().toISOString(), measure: fieldValue };
+                    } else {
+                        data[fieldName] = fieldValue;
+                    }
                     /* eslint-disable-next-line  new-cap */
                     const deviceObj = new Device.model(data);
                     deviceObj.isNew = false;
@@ -441,7 +445,7 @@ function storeLastMeasure(measure, typeInformation, callback) {
 
 exports.getDevicesByAttribute = alarmsInt(constants.MONGO_ALARM, getDevicesByAttribute);
 exports.store = alarmsInt(constants.MONGO_ALARM, storeDevice);
-exports.storeLastMeasure = alarmsInt(constants.MONGO_ALARM, storeLastMeasure);
+exports.storeDeviceField = alarmsInt(constants.MONGO_ALARM, storeDeviceField);
 exports.update = alarmsInt(constants.MONGO_ALARM, update);
 exports.remove = alarmsInt(constants.MONGO_ALARM, removeDevice);
 exports.list = alarmsInt(constants.MONGO_ALARM, listDevices);

lib/services/devices/deviceService.js

@@ -717,8 +717,8 @@ function retrieveDevice(deviceId, apiKey, callback) {
     }
 }
 
-function storeLastMeasure(measure, typeInformation, callback) {
-    config.getRegistry().storeLastMeasure(measure, typeInformation, callback);
+function storeDeviceField(fieldName, fieldValue, typeInformation, callback) {
+    config.getRegistry().storeDeviceField(fieldName, fieldValue, typeInformation, callback);
 }
 
 exports.listDevices = intoTrans(context, checkRegistry)(listDevices);
@@ -737,5 +737,5 @@ exports.retrieveDevice = intoTrans(context, checkRegistry)(retrieveDevice);
 exports.mergeDeviceWithConfiguration = mergeDeviceWithConfiguration;
 exports.findOrCreate = findOrCreate;
 exports.findConfigurationGroup = findConfigurationGroup;
-exports.storeLastMeasure = storeLastMeasure;
+exports.storeDeviceField = storeDeviceField;
 exports.init = init;

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

@@ -347,6 +347,10 @@ function sendUpdateValueNgsi2(entityName, originMeasures, originTypeInformation,
         //metadata static attributes
         jexlctxt = reduceMetadataAttrToPlainObject(typeInformation.staticAttributes, jexlctxt);
 
+        //recover oldctxt
+        if (typeInformation.oldCtxt) {
+            jexlctxt.oldCtxt = typeInformation.oldCtxt;
+        }
         logger.debug(
             context,
             'sendUpdateValueNgsi2 loop with: entityName=%s,  measures=%j,  typeInformation=%j, initial jexlContext=%j, timestamp=%j',
@@ -652,6 +656,10 @@ function sendUpdateValueNgsi2(entityName, originMeasures, originTypeInformation,
                 }
             }
         }
+        //Add jexlctxt to typeInformation without oldCtxt
+        const oldCJexlctxt = { ...jexlctxt };
+        delete oldCJexlctxt.oldCtxt;
+        originTypeInformation['oldCtxt'] = oldCJexlctxt;
     } // end for (let measures of originMeasures)
     let url = '/v2/op/update';
     if (originTypeInformation.useCBflowControl) {

lib/services/ngsi/ngsiService.js

@@ -69,15 +69,37 @@ function init() {
  * @param {String} token            User token to identify against the PEP Proxies (optional).
  */
 function sendUpdateValue(entityName, attributes, typeInformation, token, callback) {
-    // check config about store last measure
     const newCallback = statsRegistry.withStats('updateEntityRequestsOk', 'updateEntityRequestsError', callback);
+    const additionalCallback = (data, next) => {
+        if (typeInformation.oldCtxt) {
+            logger.debug(context, 'StoreOldCtxt %j', typeInformation.oldCtxt);
+            deviceService.storeDeviceField('oldCtxt', typeInformation.oldCtxt, typeInformation, function () {
+                next(null, data);
+            });
+        } else {
+            next(null, data);
+        }
+    };
+    const wrappedNewCallback = (err, result) => {
+        if (err) {
+            newCallback(err);
+        } else {
+            additionalCallback(result, (additionalErr, modifiedResult) => {
+                if (additionalErr) {
+                    newCallback(additionalErr);
+                }
+                newCallback(null, modifiedResult || result);
+            });
+        }
+    };
+    // check config about store last measure
     if (typeInformation.storeLastMeasure) {
         logger.debug(context, 'StoreLastMeasure for %j', typeInformation);
-        deviceService.storeLastMeasure(attributes, typeInformation, function () {
-            return entityHandler.sendUpdateValue(entityName, attributes, typeInformation, token, newCallback);
+        deviceService.storeDeviceField('lastMeasure', attributes, typeInformation, function () {
+            return entityHandler.sendUpdateValue(entityName, attributes, typeInformation, token, wrappedNewCallback);
         });
     } else {
-        entityHandler.sendUpdateValue(entityName, attributes, typeInformation, token, newCallback);
+        entityHandler.sendUpdateValue(entityName, attributes, typeInformation, token, wrappedNewCallback);
     }
 }