Refactor Mqtt Sync client (#5)

Co-authored-by: Felipe Diniello <felipediniello@pm.me>
Reviewed-on: #5

kairo-common/src/mqtt.rs

@@ -62,39 +62,51 @@ pub mod for_sync {
     use paho_mqtt as mqtt;
     use std::{process, time::Duration};
 
-    pub fn get_mqtt_cli() -> mqtt::Client {
-        let host = dotenv::var("MQTT_BROKER").unwrap_or_else(|_| {
+    pub struct MqttClient {
+        cli: mqtt::Client,
+    }
+
+    impl MqttClient {
+        pub fn new(client_id: Option<&str>) -> MqttClient {
+            let host = dotenv::var("MQTT_BROKER").unwrap_or_else(|_| {
             println! {"MQTT_BROKER not found in .evn file, using default: tcp://localhost:1883"};
             "tcp://localhost:1883".to_string()
         });
 
-        let mut cli = mqtt::Client::new(host).unwrap_or_else(|e| {
-            println!("Error creating the client: {:?}", e);
-            process::exit(1);
-        });
+            let mut cli = if let Some(client_id) = client_id {
+                mqtt::Client::new((host, String::from(client_id))).unwrap_or_else(|e| {
+                    println!("Error creating the client: {:?}", e);
+                    process::exit(1);
+                })
+            } else {
+                mqtt::Client::new(host).unwrap_or_else(|e| {
+                    println!("Error creating the client: {:?}", e);
+                    process::exit(1);
+                })
+            };
 
-        // Use 5sec timeouts for sync calls.
-        cli.set_timeout(Duration::from_secs(5));
+            // Use 5sec timeouts for sync calls.
+            cli.set_timeout(Duration::from_secs(5));
 
-        // Connect and wait for it to complete or fail
-        if let Err(e) = cli.connect(None) {
-            println!("Unable to connect: {:?}", e);
-            process::exit(1);
+            // Connect and wait for it to complete or fail
+            if let Err(e) = cli.connect(None) {
+                println!("Unable to connect: {:?}", e);
+                process::exit(1);
+            }
+
+            MqttClient { cli }
+        }
+        pub fn publish(&self, topic: &str, payload: Option<&str>) -> Result<(), paho_mqtt::Error> {
+            let msg = if let Some(payload) = payload {
+                mqtt::MessageBuilder::new()
+                    .topic(topic)
+                    .qos(0)
+                    .payload(payload)
+                    .finalize()
+            } else {
+                mqtt::MessageBuilder::new().topic(topic).qos(0).finalize()
+            };
+            self.cli.publish(msg)
         }
-        cli
-    }
-
-    pub fn mqtt_pub(
-        client: &mqtt::Client,
-        topic: &str,
-        payload: &str,
-    ) -> Result<(), paho_mqtt::Error> {
-        let msg = mqtt::MessageBuilder::new()
-            .topic(topic)
-            .payload(payload)
-            .qos(0)
-            .finalize();
-
-        client.publish(msg)
     }
 }