wip(inventory-agent): local presence advertisement and discovery using mdns almost working

adr/agent_discovery/mdns/src/advertise.rs

@@ -0,0 +1,52 @@
+// harmony-agent/src/main.rs
+
+use log::info;
+use mdns_sd::{ServiceDaemon, ServiceInfo};
+use std::collections::HashMap;
+
+use crate::SERVICE_TYPE;
+
+// The service we are advertising.
+const SERVICE_PORT: u16 = 43210; // A port for the service. It needs one, even if unused.
+
+pub async fn advertise() {
+
+    info!("Starting Harmony Agent...");
+
+    // Get a unique ID for this machine.
+    let motherboard_id = "some motherboard id";    
+    let instance_name = format!("harmony-agent-{}", motherboard_id);
+    info!("This agent's instance name: {}", instance_name);
+    info!("Advertising with ID: {}", motherboard_id);
+
+    // Create a new mDNS daemon.
+    let mdns = ServiceDaemon::new().expect("Failed to create mDNS daemon");
+
+    // Create a TXT record HashMap to hold our metadata.
+    let mut properties = HashMap::new();
+    properties.insert("id".to_string(), motherboard_id.to_string());
+    properties.insert("version".to_string(), "1.0".to_string());
+
+    // Create the service information.
+    // The instance name should be unique on the network.
+    let service_info = ServiceInfo::new(
+        SERVICE_TYPE,
+        &instance_name,
+        "harmony-host.local.", // A hostname for the service
+        (), // No specific IP addresses, let the daemon figure it out
+        SERVICE_PORT,
+        Some(properties),
+    )
+    .expect("Failed to create service info");
+
+    // Register our service with the daemon.
+    mdns.register(service_info)
+        .expect("Failed to register service");
+
+    info!("Service '{}' registered and now being advertised.", instance_name);
+    info!("Agent is running. Press Ctrl+C to exit.");
+
+    // Keep the agent running indefinitely.
+    tokio::signal::ctrl_c().await.unwrap();
+    info!("Shutting down agent.");
+}