From 05a8399769df61962b73f606b80c232f1f4f2e47 Mon Sep 17 00:00:00 2001
From: Adam Szkoda <adaszko@gmail.com>
Date: Thu, 13 Aug 2020 06:12:18 +0000
Subject: [PATCH] Wind down the SSE thread when the client disconnects (#1514)

These started to appear when I `^C` `curl -N http://localhost:5052/beacon/fork/stream`: `Aug 12 13:00:01.539 ERRO Couldn't stream piece hyper::Error(ChannelClosed), service: http`

Something must have changed in hyper since SSE has been implemented because I'm sure I haven't seen those errors before.

This PR properly detects a closed SSE stream and cleans up.
---
 beacon_node/rest_api/src/beacon.rs | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/beacon_node/rest_api/src/beacon.rs b/beacon_node/rest_api/src/beacon.rs
index 73c6bd1ea..f7887c48f 100644
--- a/beacon_node/rest_api/src/beacon.rs
+++ b/beacon_node/rest_api/src/beacon.rs
@@ -155,8 +155,10 @@ pub fn stream_forks<T: BeaconChainTypes>(
                     break;
                 }
             };
-            if let Err(bytes) = block_on(sender.send_data(chunk)) {
-                error!(log, "Couldn't stream piece {:?}", bytes);
+            match block_on(sender.send_data(chunk)) {
+                Err(e) if e.is_closed() => break,
+                Err(e) => error!(log, "Couldn't stream piece {:?}", e),
+                Ok(_) => (),
             }
         }
     });