Merge pull request #507 from telefonicaid/task/use_mqtt_retain_from_c…

…ommand

check first and use mqtt {retain, qos} properties from command in command execution

CHANGES_NEXT_RELEASE

@@ -1,3 +1,4 @@
+Add: use mqtt.qos and mqtt.retain values from command for command execution (#504)
 Add: log in info level command and configuration MQTT
 FIX: check ngsi version in configuration handler (#500)
 Add missed global config env vars (IOTA_CONFIG_RETRIEVAL, IOTA_DEFAULT_KEY, IOTA_DEFAULT_TRANSPORT)

docs/usermanual.md

@@ -85,7 +85,7 @@ following query parameters:
 -   **k (API Key)**: API Key for the service the device is registered on.
 -   **t (timestamp)**: Timestamp of the measure. Will override the automatic IoTAgent timestamp (optional).
 
-#### Commands
+#### Sending Commands
 
 MQTT devices commands are always push. For HTTP Devices commands to be push they **must** be provisioned with the
 `endpoint` attribute, that will contain the URL where the IoT Agent will send the received commands. Otherwise the
@@ -111,6 +111,26 @@ Some additional remarks regarding polling commands:
 -   Commands can be also retrieved without needed of sending a mesaure. In other words, the device is not forced to send
     a measure in order to get the accumulated commands. However, in this case note that `GET` method is used to carry
     the `getCmd=1` query parameter (as they are no actual payload for measures, `POST` wouldn't make too much sense).
+-   MQTT devices can configure (at provisioning and updating time) each command with different values of MQTT QoS and MQTT retain values, which will be used only by a command. Moreover, in the same MQTT device different commands can be configured to use different MQTT options related with QoS level and Retain message policy. I.E:
+
+```json
+{
+
+  "commands": [
+    {
+      "type": "command",
+      "name": "a_command_name_A",
+      "mqtt": { "qos": 2, "retain": true }
+    },
+    {
+      "type": "command",
+      "name": "a_command_name_B",
+      "mqtt": { "qos": 1, "retain": false }
+    }
+  ]
+
+}
+```
 
 #### Configuration retrieval
 

lib/bindings/MQTTBinding.js

@@ -329,16 +329,37 @@ function stop(callback) {
  */
 function executeCommand(apiKey, device, serializedPayload, callback) {
     const options = {};
-    if (config.getConfig().mqtt.qos) {
-        options.qos = parseInt(config.getConfig().mqtt.qos) || 0;
-    }
-    if (config.getConfig().mqtt.retain === true) {
-        options.retain = config.getConfig().mqtt.retain;
-    }
-    config.getLogger().debug(context, 'Sending cmd to the device:\n %j', serializedPayload);
+    // retrieve command mqtt options from device
+    var cmdName = Object.keys(JSON.parse(serializedPayload))[0];
+    var commands = Object.assign({}, ...device.commands.map((c) => ({[c.name]: c})));
+
+    options.qos =
+        commands[cmdName].mqtt && commands[cmdName].mqtt.qos
+            ? commands[cmdName].mqtt.qos
+            : config.getConfig().mqtt.qos
+            ? parseInt(config.getConfig().mqtt.qos)
+            : 0;
+    options.retain =
+        commands[cmdName].mqtt && commands[cmdName].mqtt.retain
+            ? commands[cmdName].mqtt.retain
+            : config.getConfig().mqtt.retain
+            ? config.getConfig().mqtt.retain
+            : false;
+
     const commandTopic = '/' + apiKey + '/' + device.id + '/cmd';
+    config.getLogger().debug(
+        context,
+        'Sending command execution to [%s] with payload [%s] and with mqtt options [%j]',
+        commandTopic,
+        serializedPayload,
+        options);
     mqttClient.publish(commandTopic, serializedPayload, options);
-    config.getLogger().info(context, 'Cmd:\n %j was sent to the device %s', serializedPayload, commandTopic);
+    config.getLogger().info(
+        context,
+        'Cmd:\n %j was sent to the device %s with mqtt options %j',
+        serializedPayload,
+        commandTopic,
+        options);
     callback();
 }