Reestablish conn with mixnode if err occurs (#501)

nomos-services/network/src/backends/libp2p/mixnet.rs

@@ -1,6 +1,6 @@
 use std::{ops::Range, time::Duration};
 
-use mixnet_client::MixnetClient;
+use mixnet_client::{MessageStream, MixnetClient};
 use nomos_core::wire;
 use rand::{rngs::OsRng, thread_rng, Rng};
 use serde::{Deserialize, Serialize};
@@ -47,11 +47,26 @@ impl MixnetHandler {
     }
 
     pub async fn run(&mut self) {
-        let Ok(mut stream) = self.client.run().await else {
-            tracing::error!("Could not quickstart mixnet stream");
-            return;
-        };
+        const BASE_DELAY: Duration = Duration::from_secs(5);
+        // we need this loop to help us reestablish the connection in case
+        // the mixnet client fails for whatever reason
+        let mut backoff = 0;
+        loop {
+            match self.client.run().await {
+                Ok(stream) => {
+                    backoff = 0;
+                    self.handle_stream(stream).await;
+                }
+                Err(e) => {
+                    tracing::error!("mixnet client error: {e}");
+                    backoff += 1;
+                    tokio::time::sleep(BASE_DELAY * backoff).await;
+                }
+            }
+        }
+    }
 
+    async fn handle_stream(&mut self, mut stream: MessageStream) {
         while let Some(result) = stream.next().await {
             match result {
                 Ok(msg) => {
@@ -72,7 +87,8 @@ impl MixnetHandler {
                         .unwrap_or_else(|_| tracing::error!("could not schedule broadcast"));
                 }
                 Err(e) => {
-                    todo!("Handle mixclient error: {e}");
+                    tracing::error!("mixnet client stream error: {e}");
+                    return;
                 }
             }
         }