Fix issue #1627 - stats usage

CHANGES_NEXT_RELEASE

@@ -1,3 +1,5 @@
+- Add: openmetrics-compatible `/metrics` endpoint in nortbound API (#1627)
+- Remove: push-based stats (including stats section in config file)
 - Fix: service header to use uppercase in case of update and delete (#1528)
 - Fix: Allow to send to CB batch update for multimeasures for NGSI-LD (#1623)
 - Add: new JEXL transformations for including into an array keys that have a certain value: valuePicker and valuePickerMulti

doc/admin.md

@@ -5,7 +5,6 @@
         -   [loglevel](#loglevel)
         -   [contextBroker](#contextbroker)
         -   [server](#server)
-        -   [stats](#stats)
         -   [authentication](#authentication)
         -   [deviceRegistry](#deviceregistry)
         -   [mongodb](#mongodb)
@@ -159,17 +158,6 @@ support nulls or multi-attribute requests if they are encountered.
 }
 ```
 
-#### `stats`
-
-It configures the periodic collection of statistics. Use `interval` in milliseconds to set the time between stats
-writings.
-
-```javascript
-stats: {
-    interval: 100;
-}
-```
-
 #### `authentication`
 
 Stores the authentication data, for use in retrieving tokens for devices with a trust token (required in scenarios with

doc/api.md

@@ -69,6 +69,8 @@
             -   [Retrieve log level `GET /admin/log`](#retrieve-log-level-get-adminlog)
         -   [About operations](#about-operations)
             -   [List IoTA Information `GET /iot/about`](#list-iota-information-get-iotabout)
+        -   [Metrics](#metrics)
+            -   [Retrieve metrics `GET /metrics`](#retrieve-metrics-get-metrics)
 
 <!-- /TOC -->
 
@@ -2224,6 +2226,57 @@ Example:
 }
 ```
 
+### Metrics
+
+The IoT Agent Library exposes a [openmetrics-compatible](https://github.com/OpenObservability/OpenMetrics) endpoint for
+telemetry collectors to gather application statistics.
+
+#### Retrieve metrics `GET /metrics`
+
+_**Response code**_
+
+-   `200` `OK` if successful.
+-   `406` `Wrong Accept Header` If accept format is not supported.
+-   `500` `SERVER ERROR` if there was any error not contemplated above.
+
+_**Response body**_
+
+Returns the current value of the server stats,
+
+-   If `Accept` header contains `application/openmetrics-text`, the response has content-type
+    `application/openmetrics-text; version=1.0.0; charset=utf-8`
+-   Else, If `Accept` header is missing or supports `text/plain` (explicitly or by `*/*`) , the response has
+    content-type `text/plain; version=0.0.4; charset=utf-8` (legacy format for [prometheus](https://prometheus.io))
+-   In any other case, returns an error message with `406` status.
+
+For the kind of metrics exposed by the application, the actual payload itself is completely the same for both
+content-types, and follows the openmetrics specification, e.g:
+
+```
+# HELP deviceCreationRequests global metric for deviceCreationRequests
+# TYPE deviceCreationRequests counter
+deviceCreationRequests 0
+# HELP deviceRemovalRequests global metric for deviceRemovalRequests
+# TYPE deviceRemovalRequests counter
+deviceRemovalRequests 0
+# HELP measureRequests global metric for measureRequests
+# TYPE measureRequests counter
+measureRequests 0
+# HELP raiseAlarm global metric for raiseAlarm
+# TYPE raiseAlarm counter
+raiseAlarm 0
+# HELP releaseAlarm global metric for releaseAlarm
+# TYPE releaseAlarm counter
+releaseAlarm 0
+# HELP updateEntityRequestsOk global metric for updateEntityRequestsOk
+# TYPE updateEntityRequestsOk counter
+updateEntityRequestsOk 2
+# HELP updateEntityRequestsError global metric for updateEntityRequestsError
+# TYPE updateEntityRequestsError counter
+updateEntityRequestsError 5
+# EOF
+```
+
 [1]:
     https://czosel.github.io/jexl-playground/#/?context=%7B%0A%20%20%22longitude%22%3A%205%2C%0A%20%20%22latitude%22%3A%2037%2C%0A%20%20%22level%22%3A223%0A%7D&input=%7Bcoordinates%3A%20%5Blongitude%2Clatitude%5D%2C%20type%3A%20'Point'%7D&transforms=%7B%0A%7D
 [2]:

doc/deprecated.md

@@ -25,6 +25,7 @@ A list of deprecated features and the version in which they were deprecated foll
 -   Support to legacy expressions (finally removed in 3.2.0)
 -   Bidirectinal pluging (finally removed in 3.4.0)
 -   appendMode configuration (`IOTA_APPEND_MODE` env var) (finally removed in 3.4.0)
+-   `config.stats` section, and push-mode statistics.
 
 The use of Node.js v14 is highly recommended.
 
@@ -57,3 +58,4 @@ The following table provides information about the last iotagent-node-lib versio
 | Support to Legacy Expressions                         | 3.1.0                                                 | April 25th, 2023              |
 | bidirectional plugin                                  | 3.3.0                                                 | August 24th, 2023             |
 | appendMode configuration (`IOTA_APPEND_MODE` env var) | 3.3.0                                                 | August 24th, 2023             |
+| push-mode stats                                       | 4.5.0                                                 | June 11th, 2024               |

doc/devel/development.md

@@ -226,18 +226,20 @@ npm run prettier:text
 
 ### Stats Registry
 
-The library provides a mechanism for the periodic reporting of stats related to the library's work. In order to activate
-the use of the periodic stats, it must be configured in the config file, as described in the
-[Configuration](../admin.md#configuration) section.
-
-The Stats Registry holds two dictionaries, with the same set of stats. For each stat, one of the dictionaries holds the
-historical global value and the other one stores the value since the last value reporting (or current value).
+The library provides a mechanism for the collection of stats related to the library's work. The Stats Registry holds a
+dictionary with the historical global value of each stat.
 
 The stats library currently stores only the following values:
 
 -   **deviceCreationRequests**: number of Device Creation Requests that arrived to the API (no matter the result).
 -   **deviceRemovalRequests**: number of Removal Device Requests that arrived to the API (no matter the result).
 -   **measureRequests**: number of times the ngsiService.update() function has been invoked (no matter the result).
+-   **raiseAlarm**: number of times the alarmManagement.raise() function has been invoked.
+-   **releaseAlarm**: number of times the alarmManagement.release() function has been invoked.
+-   **updateEntityRequestsOk**: number of times the ngsiService.sendUpdateValue() function has been invoked
+    successfully.
+-   **updateEntityRequestsError**: number of times the ngsiService.sendUpdateValue() function has been invoked and
+    failed.
 
 More values will be added in the future to the library. The applications using the library can add values to the Stats
 Registry just by using the following function:
@@ -247,7 +249,7 @@ iotagentLib.statsRegistry.add('statName', statIncrementalValue, callback);
 ```
 
 The first time this function is invoked, it will add the new stat to the registry. Subsequent calls will add the value
-to the specified stat both to the current and global measures. The stat will be cleared in each interval as usual.
+to the specified stat.
 
 ### Alarm module
 

lib/fiware-iotagent-lib.js

@@ -45,22 +45,19 @@ const context = {
     op: 'IoTAgentNGSI.Global'
 };
 
+/* eslint-disable-next-line  no-unused-vars */
 function activateStatLogs(newConfig, callback) {
-    if (newConfig.stats && newConfig.stats.interval) {
-        async.series(
-            [
-                apply(statsRegistry.globalLoad, {
-                    deviceCreationRequests: 0,
-                    deviceRemovalRequests: 0,
-                    measureRequests: 0
-                }),
-                apply(statsRegistry.addTimerAction, statsRegistry.logStats)
-            ],
-            callback
-        );
-    } else {
-        callback();
-    }
+    async.series([
+        apply(statsRegistry.globalLoad, {
+            deviceCreationRequests: 0,
+            deviceRemovalRequests: 0,
+            measureRequests: 0,
+            raiseAlarm: 0,
+            releaseAlarm: 0,
+            updateEntityRequestsOk: 0,
+            updateEntityRequestsError: 0
+        })
+    ], callback);
 }
 
 /**

lib/model/dbConn.js

@@ -190,10 +190,7 @@ function configureDb(callback) {
     /*jshint camelcase:false, validthis:true */
     const currentConfig = config.getConfig();
 
-    if (
-        (currentConfig.deviceRegistry && currentConfig.deviceRegistry.type === 'mongodb') ||
-        (currentConfig.stats && currentConfig.stats.persistence === true)
-    ) {
+    if (currentConfig.deviceRegistry && currentConfig.deviceRegistry.type === 'mongodb') {
         if (!currentConfig.mongodb || !currentConfig.mongodb.host) {
             logger.fatal(context, 'MONGODB-003: No host found for MongoDB driver.');
             callback(new errors.BadConfiguration('No host found for MongoDB driver'));

lib/services/common/alarmManagement.js

@@ -22,6 +22,7 @@
  */
 
 let alarmRepository = {};
+const statsRegistry = require('../stats/statsRegistry');
 const logger = require('logops');
 const context = {
     op: 'IoTAgentNGSI.Alarms'
@@ -41,6 +42,7 @@ function raise(alarmName, description) {
         };
 
         logger.error(context, 'Raising [%s]: %j', alarmName, description);
+        statsRegistry.add('raiseAlarm', 1, function () {});
     }
 }
 
@@ -53,6 +55,7 @@ function release(alarmName) {
     if (alarmRepository[alarmName]) {
         delete alarmRepository[alarmName];
         logger.error(context, 'Releasing [%s]', alarmName);
+        statsRegistry.add('releaseAlarm', 1, function () {});
     }
 }
 

lib/services/ngsi/ngsiService.js

@@ -26,6 +26,7 @@
 
 const async = require('async');
 const apply = async.apply;
+const statsRegistry = require('../stats/statsRegistry');
 const intoTrans = require('../common/domain').intoTrans;
 const fillService = require('./../common/domain').fillService;
 const errors = require('../../errors');
@@ -67,7 +68,8 @@ function init() {
  * @param {String} token            User token to identify against the PEP Proxies (optional).
  */
 function sendUpdateValue(entityName, attributes, typeInformation, token, callback) {
-    entityHandler.sendUpdateValue(entityName, attributes, typeInformation, token, callback);
+    const newCallback = statsRegistry.withStats('updateEntityRequestsOk', 'updateEntityRequestsError', callback);
+    entityHandler.sendUpdateValue(entityName, attributes, typeInformation, token, newCallback);
 }
 
 /**

lib/services/northBound/northboundServer.js

@@ -33,6 +33,7 @@ const intoTrans = domainUtils.intoTrans;
 const deviceProvisioning = require('./deviceProvisioningServer');
 const deviceUpdating = require('./deviceProvisioningServer');
 const groupProvisioning = require('./deviceGroupAdministrationServer');
+const statsRegistry = require('../stats/statsRegistry');
 const logger = require('logops');
 const context = {
     op: 'IoTAgentNGSI.NorthboundServer'
@@ -83,6 +84,7 @@ function start(config, callback) {
     northboundServer.router.get('/version', middlewares.retrieveVersion);
     northboundServer.router.put('/admin/log', middlewares.changeLogLevel);
     northboundServer.router.get('/admin/log', middlewares.getLogLevel);
+    northboundServer.router.get('/metrics', statsRegistry.openmetricsHandler);
 
     northboundServer.app.use(baseRoot, northboundServer.router);
     contextServer.loadContextRoutes(northboundServer.router);