Task/add health check to /about

CHANGES_NEXT_RELEASE

@@ -1 +1,5 @@
-- Upgrade express dep from 4.21.2 to 4.22.1
+<<<<<<< task/add_health_middleware
+- Add to endpoint /about  info about status of CB, IotaM, Mongo and MQTT broker (#1763)
+=======
+- Upgrade express dep from 4.21.2 to 4.22.1
+>>>>>>> master

doc/admin.md

@@ -458,6 +458,20 @@ values are:
 
 Have a look to [this document](devel/northboundinteractions.md) for more detail on how this modes work.
 
+#### `healthCheckInterval`
+
+Time interval (in milliseconds) between consecutive health checks. Default: 20000 (20 seconds)
+
+#### `healthCheckTimeout`
+
+Maximum time (in milliseconds) to wait for a single health check operation (HTTP request, MongoDB ping, MQTT connect)
+before considering it failed. Default: 1500 (1.5 seconds)
+
+#### `healthCheckDownAfterFails`
+
+Number of consecutive failed checks required before marking a connection as DOWN (ok: false). Until this threshold is
+reached, transient failures are tolerated. Default: 3
+
 ### Configuration using environment variables
 
 Some of the configuration parameters can be overriden with environment variables, to ease the use of those parameters
@@ -514,6 +528,9 @@ overrides.
 | IOTA_STORE_LAST_MEASURE              | `storeLastMeasure`              |
 | IOTA_CB_FLOW_CONTROL                 | `useCBflowControl`              |
 | IOTA_CMD_MODE                        | `cmdMode`                       |
+| IOTA_HEALTH_CHECK_INTERVAL           | `healthCheckInterval`           |
+| IOTA_HEALTH_CHECK_TIMEOUT            | `healthCheckTimeout`            |
+| IOTA_HEALTH_CHECK_DOWN_AFTER_FAILS   | `healthCheckDownAfterFails`     |
 
 Note:
 

lib/commonConfig.js

@@ -161,7 +161,10 @@ function processEnvironmentVariables() {
         'IOTA_EXPRESS_LIMIT',
         'IOTA_USE_CB_FLOW_CONTROL',
         'IOTA_STORE_LAST_MEASURE',
-        'IOTA_CMD_MODE'
+        'IOTA_CMD_MODE',
+        'IOTA_HEALTH_CHECK_INTERVAL',
+        'IOTA_HEALTH_CHECK_TIMEOUT',
+        'IOTA_HEALTH_CHECK_DOWN_AFTER_FAILS'
     ];
     const iotamVariables = [
         'IOTA_IOTAM_URL',
@@ -517,6 +520,22 @@ function processEnvironmentVariables() {
     if (process.env.IOTA_CMD_MODE) {
         config.cmdMode = process.env.IOTA_CMD_MODE;
     }
+
+    if (process.env.IOTA_HEALTH_CHECK_INTERVAL) {
+        config.healthCheckInterval = process.env.IOTA_HEALTH_CHECK_INTERVAL;
+    } else {
+        config.healthCheckInterval = config.healthCheckInterval ? config.healthCheckInterval : 20000;
+    }
+    if (process.env.IOTA_HEALTH_CHECK_TIMEOUT) {
+        config.healthCheckTimeout = process.env.IOTA_HEALTH_CHECK_TIMEOUT;
+    } else {
+        config.healthCheckTimeout = config.healthCheckTimeout ? config.healthCheckTimeout : 1500;
+    }
+    if (process.env.IOTA_HEALTH_CHECK_DOWN_AFTER_FAILS) {
+        config.healthCheckDownAfterFails = process.env.IOTA_HEALTH_CHECK_DOWN_AFTER_FAILS;
+    } else {
+        config.healthCheckDownAfterFails = config.healthCheckDownAfterFails ? config.healthCheckDownAfterFails : 3;
+    }
 }
 
 function setConfig(newConfig) {

lib/request-shim.js

@@ -53,7 +53,8 @@ function getOptions(options) {
         headers: options.headers,
         throwHttpErrors: options.throwHttpErrors || false,
         retry: options.retry || 0,
-        responseType: options.responseType || 'json'
+        responseType: options.responseType || 'json',
+        timeout: options.timeout || undefined
     };
 
     // got library is not properly documented, so it is not clear which takes precedence

lib/services/common/genericMiddleware.js

@@ -29,6 +29,7 @@ let iotaInformation;
 let context = {
     op: 'IoTAgentNGSI.GenericMiddlewares'
 };
+const { getHealthState } = require('./health');
 
 /**
  * Express middleware for handling errors in the IoTAs. It extracts the code information to return from the error itself
@@ -156,7 +157,10 @@ function validateJson(template) {
 
 /* eslint-disable-next-line  no-unused-vars */
 function retrieveVersion(req, res, next) {
-    res.status(200).json(iotaInformation);
+    res.status(200).json({
+        ...iotaInformation,
+        connections: getHealthState()
+    });
 }
 
 /**