add websocket timeout

src/slot_latency_tester.rs

@@ -13,8 +13,11 @@ use std::collections::{HashMap, HashSet};
 use std::env;
 use std::pin::pin;
 use std::time::Duration;
-use tokio::time::Instant;
+use tokio::sync::broadcast::error::RecvError;
+use tokio::time::{Instant, sleep, timeout, Timeout};
+use tokio::time::error::Elapsed;
 use tokio_stream::StreamExt;
+use tracing::{error, warn};
 use url::Url;
 use websocket_tungstenite_retry::websocket_stable::{StableWebSocket, WsMessage};
 use yellowstone_grpc_proto::geyser::subscribe_update::UpdateOneof;
@@ -110,6 +113,7 @@ async fn main() {
     ));
 
     let mut latest_slot_per_source: HashMap<SlotSource, Slot> = HashMap::new();
+
     while let Some(SlotDatapoint { slot, source, .. }) = slots_rx.recv().await {
         // println!("Slot from {:?}: {}", source, slot);
         latest_slot_per_source.insert(source, slot);
@@ -173,8 +177,10 @@ async fn websocket_source(
 
     let mut channel = ws1.subscribe_message_channel();
 
-    while let Ok(msg) = channel.recv().await {
+    // the timeout is a workaround as we see the websocket source starving with no data
-        if let WsMessage::Text(payload) = msg {
+    loop {
+        match timeout(Duration::from_millis(5000), channel.recv()).await {
+            Ok(Ok(WsMessage::Text(payload))) => {
                 let ws_result: jsonrpsee_types::SubscriptionResponse<SlotInfo> =
                     serde_json::from_str(&payload).unwrap();
                 let slot_info = ws_result.params.result;
@@ -186,9 +192,24 @@ async fn websocket_source(
                     Err(_) => panic!("downstream error"),
                 }
             }
+            Ok(Ok(WsMessage::Binary(_))) => {
+                panic!("Unexpected binary message from websocket source");
+            }
+            Err(_elapsed) => {
+                warn!("Websocket source timeout unexpectedly; continue waiting but there's little hope");
+                // throttle a bit
+                sleep(Duration::from_millis(500)).await;
+            }
+            Ok(Err(RecvError::Lagged(_))) => {
+                warn!("Websocket broadcast channel lagged - continue");
+            }
+            Ok(Err(RecvError::Closed)) => {
+                panic!("Websocket broadcast channel closed - should never happen");
+            }
+        }
     }
 
-    panic!("Websocket source ended unexpectedly");
+    // unreachable code
 }
 
 // note: this might fail if the yellowstone plugin does not allow "any broadcast filter"