cleaup code

common/src/lib.rs

@@ -1,2 +1,37 @@
+use chrono::{DateTime, Utc};
+use serde::{Deserialize, Serialize};
+use serde_json::Error;
+use crate::metrics::Metrics;
+
 pub mod metrics;
-pub mod mqtt;
+
+pub const MQTT_TOPIC: &str = "system/metrics";
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct StatusMessage<'a> {
+    pub agent: &'a str,
+    pub metrics: Metrics,
+    pub timestamp: DateTime<Utc>,
+}
+
+impl<'a> StatusMessage<'a> {
+    pub fn new(agent: &'a str, metrics: Metrics) -> Self {
+        Self {
+            agent,
+            metrics,
+            timestamp: Utc::now(),
+        }
+    }
+
+    pub fn to_string(&self) -> Result<String, Error> {
+        serde_json::to_string_pretty(&self)
+    }
+}
+
+impl<'a> TryFrom<&'a [u8]> for StatusMessage<'a> {
+    type Error = serde_json::Error;
+
+    fn try_from(value: &'a [u8]) -> Result<Self, Self::Error> {
+        serde_json::from_slice(value)
+    }
+}