From 7076fef5fef81cce47dbfbab3d7257cc7d3776bc Mon Sep 17 00:00:00 2001
From: Alex Hong <9397363+hongalex@users.noreply.github.com>
Date: Mon, 28 Jun 2021 18:18:24 -0700
Subject: [PATCH] fix(pubsub): retry GOAWAY errors (#4313)

The frontend server for Pub/Sub might occasionally emit GOAWAY errors which are currently not retried. This is not unique to the Go client, though the categorization as `UNKNOWN` vs `UNVAILABLE` is a golang-GRPC issue. Although UNKNOWN [should not generally be retried](https://google.aip.dev/194), this will unblock users of `Receive` until the grpc library can be changed. See internal cl/377393940 for a similar fix in another Go library.

Fixes #4257.
---
 pubsub/service.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/pubsub/service.go b/pubsub/service.go
index d9a00021eb0..0c24be25a69 100644
--- a/pubsub/service.go
+++ b/pubsub/service.go
@@ -62,6 +62,14 @@ func (r *defaultRetryer) Retry(err error) (pause time.Duration, shouldRetry bool
 			return r.bo.Pause(), true
 		}
 		return 0, false
+	case codes.Unknown:
+		// Retry GOAWAY, see https://github.com/googleapis/google-cloud-go/issues/4257.
+		isGoaway := strings.Contains(s.Message(), "error reading from server: EOF") &&
+			strings.Contains(s.Message(), "received prior goaway")
+		if isGoaway {
+			return r.bo.Pause(), true
+		}
+		return 0, false
 	default:
 		return 0, false
 	}