broker2http - increase tokio::broadcast::channel capacity to try hand…

…ling receiver lags

Signed-off-by: Lance-Drane <[email protected]>

broker-2-http/src/broadcaster.rs

@@ -17,8 +17,8 @@ impl Broadcaster {
     /// Create the broadcaster. Note that it automatically wraps it in an Arc.
     /// The broadcaster manages its producer but does not manage its consumers
     pub fn new() -> Arc<Self> {
-        // TODO may be able to get away with smaller capacity
-        let (tx, _) = broadcast::channel(1);
+        // use a fairly large channel capacity to account for potential receiver lags
+        let (tx, _) = broadcast::channel(256);
         Arc::new(Broadcaster { fanout: tx })
     }
 

broker-2-http/src/routes/subscribe.rs

@@ -27,6 +27,7 @@ fn sse_response(
                     break;
                 },
                 // send the broadcast message to the client, and continue listening for more messages
+                // TODO figure out more robust mechanism to handle "lagged" errors from the receiver.
                 resp = rx.recv() => {
                     match resp {
                         Ok(event) => {