feat: timout connections to observers

Without a timout for these connections, the node can get stuck here and
it is not obvious what is happening. With this timeout, we will see log
messages that will point to the problem.

Author: obycode

testnet/stacks-node/src/event_dispatcher.rs

@@ -318,6 +318,7 @@ impl EventObserver {
         };
 
         let backoff = Duration::from_millis((1.0 * 1_000.0) as u64);
+        let connection_timeout = Duration::from_secs(5);
 
         loop {
             let body = body.clone();
@@ -326,19 +327,26 @@ impl EventObserver {
             req.set_body(body);
 
             let response = async_std::task::block_on(async {
-                let stream = match TcpStream::connect(self.endpoint.clone()).await {
-                    Ok(stream) => stream,
-                    Err(err) => {
+                match async_std::future::timeout(
+                    connection_timeout,
+                    TcpStream::connect(self.endpoint.clone()),
+                )
+                .await
+                {
+                    Ok(Ok(stream)) => match client::connect(stream, req).await {
+                        Ok(response) => Some(response),
+                        Err(err) => {
+                            warn!("Event dispatcher: rpc invocation failed  - {:?}", err);
+                            None
+                        }
+                    },
+                    Ok(Err(err)) => {
                         warn!("Event dispatcher: connection failed  - {:?}", err);
-                        return None;
+                        None
                     }
-                };
-
-                match client::connect(stream, req).await {
-                    Ok(response) => Some(response),
-                    Err(err) => {
-                        warn!("Event dispatcher: rpc invocation failed  - {:?}", err);
-                        return None;
+                    Err(_) => {
+                        error!("Event dispatcher: connection attempt timed out");
+                        None
                     }
                 }
             });