From 7261ddedccb63f6e4dc42807b74a629133c1e80c Mon Sep 17 00:00:00 2001
From: Tolga Ceylan <tolga.ceylan@gmail.com>
Date: Mon, 4 Jun 2018 12:10:00 -0700
Subject: [PATCH] fn: LB agent: EOF from runner is normal in nack cases (#1032)

---
 api/agent/runner_client.go | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

diff --git a/api/agent/runner_client.go b/api/agent/runner_client.go
index 1b8c56008..6c567305b 100644
--- a/api/agent/runner_client.go
+++ b/api/agent/runner_client.go
@@ -181,7 +181,11 @@ func sendToRunner(protocolClient pb.RunnerProtocol_EngageClient, call pool.Runne
 			},
 		})
 		if sendErr != nil {
-			logrus.WithError(sendErr).Errorf("Failed to send data frame size=%d isEOF=%v", n, isEOF)
+			// It's often normal to receive an EOF here as we optimistically start sending body until a NACK
+			// from the runner. Let's ignore EOF and rely on recv side to catch premature EOF.
+			if sendErr != io.EOF {
+				logrus.WithError(sendErr).Errorf("Failed to send data frame size=%d isEOF=%v", n, isEOF)
+			}
 			return
 		}
 		if isEOF {