Fix issues in MQTT integration samples

integrator-default-profile/connectors/mqtt_connector_sample/automation.bal

@@ -3,7 +3,13 @@ import ballerina/mqtt;
 
 public function main() returns error? {
     do {
-        mqtt:DeliveryToken mqttDeliverytoken = check mqttClient->publish(mqttTopic, {payload: "Hello World".toBytes()});
+        mqtt:DeliveryToken _ = check mqttClient->publish(mqttTopic, {
+            payload: "25.5".toBytes(),
+            qos: 2,
+            retained: true
+        });
+        log:printInfo("Temperature published to MQTT broker", topic = mqttTopic, value = "25.5");
+
     } on fail error e {
         log:printError("Error occurred", 'error = e);
         return e;

integrator-default-profile/connectors/mqtt_connector_sample/config.bal

@@ -1,4 +1,5 @@
+import ballerina/mqtt;
 
-configurable string mqttServerUri = ?;
-configurable string mqttClientId = ?;
-configurable string mqttTopic = "test/topic";
+configurable string mqttServerUri = mqtt:DEFAULT_URL;
+configurable string mqttClientId = "ballerina-mqtt-client";
+configurable string mqttTopic = "sensors/temperature";

integrator-default-profile/connectors/mqtt_trigger_sample/main.bal

@@ -1,16 +1,34 @@
 import ballerina/log;
 import ballerina/mqtt;
+import ballerina/uuid;
 
-listener mqtt:Listener mqttListener = new (string `${mqttBrokerUrl}mqtt://localhost:1883`, string `${mqttClientId}unique_client_001`, string `${mqttTopic}topic1`);
+configurable string broker = mqtt:DEFAULT_URL;
+const TOPIC = "sensors/temperature";
 
-service mqtt:Service on mqttListener {
-    remote function onMessage(mqtt:Message message) returns error? {
-        do {
-            log:printInfo(message.toJsonString());
-        } on fail error err {
-            // handle error
-            return error("unhandled error", err);
+listener mqtt:Listener mqttListener = new (
+    broker,
+    uuid:createType1AsString(),
+    TOPIC,
+    {manualAcks: true}
+);
+
+service on mqttListener {
+    remote function onMessage(mqtt:Message message, mqtt:Caller caller) returns error? {
+        string payload = check string:fromBytes(message.payload);
+        log:printInfo("Temperature message received from MQTT broker", topic = message.topic, payload = payload);
+        float temperature = check float:fromString(payload);
+
+        if temperature > 30.0 {
+            log:printWarn("High temperature alert!", temp = temperature);
+        } else {
+            log:printInfo("Temperature normal", temp = temperature);
         }
+
+        // Acknowledge the message
+        check caller->complete();
     }
 
-}
+    remote function onError(mqtt:Error err) returns error? {
+        log:printError("Error processing message", 'error = err);
+    }
+}