From 136984fb14ca80bd7cef6da1a765f861d7e77d65 Mon Sep 17 00:00:00 2001
From: Kenneth Jenkins <51246568+kenjenkins@users.noreply.github.com>
Date: Tue, 9 Jan 2024 15:53:03 -0800
Subject: [PATCH] match Go default TCP keepalive settings

---
 config/envoyconfig/clusters.go            |  8 ++++++--
 config/envoyconfig/testdata/clusters.json | 25 ++++++++++++++++++-----
 2 files changed, 26 insertions(+), 7 deletions(-)

diff --git a/config/envoyconfig/clusters.go b/config/envoyconfig/clusters.go
index 273d075c4..1a04f6bbe 100644
--- a/config/envoyconfig/clusters.go
+++ b/config/envoyconfig/clusters.go
@@ -142,9 +142,13 @@ func (b *Builder) buildInternalCluster(
 ) (*envoy_config_cluster_v3.Cluster, error) {
 	cluster := newDefaultEnvoyClusterConfig()
 	cluster.DnsLookupFamily = config.GetEnvoyDNSLookupFamily(cfg.Options.DNSLookupFamily)
+	// Match the Go standard library default TCP keepalive settings.
+	const keepaliveTimeSeconds = 15
 	cluster.UpstreamConnectionOptions = &envoy_config_cluster_v3.UpstreamConnectionOptions{
-		// Enable TCP keepalive with OS default settings.
-		TcpKeepalive: &envoy_config_core_v3.TcpKeepalive{},
+		TcpKeepalive: &envoy_config_core_v3.TcpKeepalive{
+			KeepaliveTime:     wrapperspb.UInt32(keepaliveTimeSeconds),
+			KeepaliveInterval: wrapperspb.UInt32(keepaliveTimeSeconds),
+		},
 	}
 	var endpoints []Endpoint
 	for _, dst := range dsts {
diff --git a/config/envoyconfig/testdata/clusters.json b/config/envoyconfig/testdata/clusters.json
index f92dc3587..d9b2a82cc 100644
--- a/config/envoyconfig/testdata/clusters.json
+++ b/config/envoyconfig/testdata/clusters.json
@@ -62,7 +62,10 @@
       }
     },
     "upstreamConnectionOptions": {
-      "tcpKeepalive": {}
+      "tcpKeepalive": {
+        "keepaliveInterval": 15,
+        "keepaliveTime": 15
+      }
     }
   },
   {
@@ -110,7 +113,10 @@
       }
     },
     "upstreamConnectionOptions": {
-      "tcpKeepalive": {}
+      "tcpKeepalive": {
+        "keepaliveInterval": 15,
+        "keepaliveTime": 15
+      }
     }
   },
   {
@@ -158,7 +164,10 @@
       }
     },
     "upstreamConnectionOptions": {
-      "tcpKeepalive": {}
+      "tcpKeepalive": {
+        "keepaliveInterval": 15,
+        "keepaliveTime": 15
+      }
     }
   },
   {
@@ -202,7 +211,10 @@
       }
     },
     "upstreamConnectionOptions": {
-      "tcpKeepalive": {}
+      "tcpKeepalive": {
+        "keepaliveInterval": 15,
+        "keepaliveTime": 15
+      }
     }
   },
   {
@@ -246,7 +258,10 @@
       }
     },
     "upstreamConnectionOptions": {
-      "tcpKeepalive": {}
+      "tcpKeepalive": {
+        "keepaliveInterval": 15,
+        "keepaliveTime": 15
+      }
     }
   },
   {