From 1bc42d345d9a277212404919168fcd39c086fcba Mon Sep 17 00:00:00 2001
From: Luis Rascao <luis.rascao@gmail.com>
Date: Wed, 21 May 2025 13:23:14 +0100
Subject: [PATCH] Enable gRPC keep-alive by default

Ensures intermediary proxies/gateways (AWS NLB notably) don't silently
close connections after a configurable inactivity timeout expires.
---
 client/client.go | 47 +++++++++++++++++++++++++++++++++++++++--------
 1 file changed, 39 insertions(+), 8 deletions(-)

diff --git a/client/client.go b/client/client.go
index 4b8215ec..545a1444 100644
--- a/client/client.go
+++ b/client/client.go
@@ -35,6 +35,7 @@ import (
 	"google.golang.org/grpc"
 	"google.golang.org/grpc/credentials"
 	"google.golang.org/grpc/credentials/insecure"
+	"google.golang.org/grpc/keepalive"
 	"google.golang.org/grpc/metadata"
 
 	pb "github.com/dapr/dapr/pkg/proto/runtime/v1"
@@ -44,14 +45,16 @@ import (
 )
 
 const (
-	daprPortDefault                = "50001"
-	daprPortEnvVarName             = "DAPR_GRPC_PORT" /* #nosec */
-	daprGRPCEndpointEnvVarName     = "DAPR_GRPC_ENDPOINT"
-	traceparentKey                 = "traceparent"
-	apiTokenKey                    = "dapr-api-token" /* #nosec */
-	apiTokenEnvVarName             = "DAPR_API_TOKEN" /* #nosec */
-	clientDefaultTimeoutSeconds    = 5
-	clientTimeoutSecondsEnvVarName = "DAPR_CLIENT_TIMEOUT_SECONDS"
+	daprPortDefault                  = "50001"
+	daprPortEnvVarName               = "DAPR_GRPC_PORT" /* #nosec */
+	daprGRPCEndpointEnvVarName       = "DAPR_GRPC_ENDPOINT"
+	traceparentKey                   = "traceparent"
+	apiTokenKey                      = "dapr-api-token" /* #nosec */
+	apiTokenEnvVarName               = "DAPR_API_TOKEN" /* #nosec */
+	clientDefaultTimeoutSeconds      = 5
+	clientDefaultKeepaliveSeconds    = 10
+	clientTimeoutSecondsEnvVarName   = "DAPR_CLIENT_TIMEOUT_SECONDS"
+	clientKeepAliveSecondsEnvVarName = "DAPR_CLIENT_KEEP_ALIVE_SECONDS"
 )
 
 var (
@@ -350,6 +353,11 @@ func NewClientWithAddressContext(ctx context.Context, address string) (client Cl
 		return nil, err
 	}
 
+	keepAliveSeconds, err := getClientKeepaliveSeconds()
+	if err != nil {
+		return nil, err
+	}
+
 	parsedAddress, err := internal.ParseGRPCEndpoint(address)
 	if err != nil {
 		return nil, fmt.Errorf("error parsing address '%s': %w", address, err)
@@ -362,6 +370,13 @@ func NewClientWithAddressContext(ctx context.Context, address string) (client Cl
 		grpc.WithBlock(), //nolint:staticcheck
 		authTokenUnaryInterceptor(at),
 		authTokenStreamInterceptor(at),
+		grpc.WithKeepaliveParams(
+			keepalive.ClientParameters{
+				Time:                time.Duration(keepAliveSeconds),
+				Timeout:             time.Second,
+				PermitWithoutStream: true,
+			},
+		),
 	}
 
 	if parsedAddress.TLS {
@@ -399,6 +414,22 @@ func getClientTimeoutSeconds() (int, error) {
 	return timeoutVar, nil
 }
 
+func getClientKeepaliveSeconds() (int, error) {
+	tStr := os.Getenv(clientKeepAliveSecondsEnvVarName)
+	if len(tStr) == 0 {
+		return clientDefaultKeepaliveSeconds, nil
+	}
+	keepAlive, err := strconv.Atoi(tStr)
+	if err != nil {
+		return 0, fmt.Errorf("error parsing keep alive value (%s): %w",
+			tStr, err)
+	}
+	if keepAlive <= 0 {
+		return 0, errors.New("incorrect value")
+	}
+	return keepAlive, nil
+}
+
 // NewClientWithSocket instantiates Dapr using specific socket.
 func NewClientWithSocket(socket string) (client Client, err error) {
 	if socket == "" {