feat(agent): transport UDP fire-and-forget + test loopback

agent/src/transport/udp.rs

@@ -1,9 +1,42 @@
-pub struct UdpSender;
+use std::net::UdpSocket;
+
+pub struct UdpSender {
+    socket: UdpSocket,
+    addr: String,
+}
 
 impl UdpSender {
-    pub fn new(_ip: &str, _port: u16) -> Self {
-        UdpSender
+    pub fn new(ip: &str, port: u16) -> Self {
+        let socket = UdpSocket::bind("0.0.0.0:0")
+            .expect("Impossible de créer le socket UDP");
+        UdpSender {
+            socket,
+            addr: format!("{}:{}", ip, port),
+        }
     }
 
-    pub fn send(&self, _json: &str) {}
+    pub fn send(&self, json: &str) {
+        let _ = self.socket.send_to(json.as_bytes(), &self.addr);
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use std::net::UdpSocket;
+
+    #[test]
+    fn test_udp_envoi_loopback() {
+        let recv = UdpSocket::bind("127.0.0.1:0").unwrap();
+        let port = recv.local_addr().unwrap().port();
+        recv.set_read_timeout(Some(std::time::Duration::from_millis(500))).unwrap();
+
+        let sender = UdpSender::new("127.0.0.1", port);
+        sender.send(r#"{"status":"ok"}"#);
+
+        let mut buf = [0u8; 1024];
+        let (n, _) = recv.recv_from(&mut buf).unwrap();
+        let msg = std::str::from_utf8(&buf[..n]).unwrap();
+        assert_eq!(msg, r#"{"status":"ok"}"#);
+    }
 }