From aded90b92de3fa3bed079af1aa4879d00572e8ae Mon Sep 17 00:00:00 2001
From: Nicole Zhu <69952136+nicoleczhu@users.noreply.github.com>
Date: Sun, 2 May 2021 20:01:07 -0700
Subject: [PATCH] fix(logging): allow nil or custom zones in resource detection
 (#3997)

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

diff --git a/logging/logging.go b/logging/logging.go
index 7ae47598879..656b379cd37 100644
--- a/logging/logging.go
+++ b/logging/logging.go
@@ -404,7 +404,11 @@ func monitoredResource(parent string) *mrpb.MonitoredResource {
 }
 
 func regionFromZone(zone string) string {
-	return zone[:strings.LastIndex(zone, "-")]
+	cutoff := strings.LastIndex(zone, "-")
+	if cutoff > 0 {
+		return zone[:cutoff]
+	}
+	return zone
 }
 
 func globalResource(projectID string) *mrpb.MonitoredResource {