fix(rpc): add keepalive enforcement policy to server

Without an explicit KeepaliveEnforcementPolicy, the gRPC transport
applies a default MinTime of 5 minutes and PermitWithoutStream=false.
Any client that pings more frequently than every 5 minutes — or pings
while idle — accumulates ping strikes and gets disconnected with a
GOAWAY (too_many_pings) after three strikes.

Author: UnderTreeTech

pkg/server/rpc/server/server.go

@@ -69,6 +69,22 @@ func New(cfg *config.ServerConfig) *Server {
 		MaxConnectionAge:      cfg.MaxLifeTime,
 	})
 
+	// KeepaliveEnforcementPolicy limits how aggressively clients may send
+	// keepalive pings. Without it, the transport applies a default MinTime of
+	// 5 minutes and PermitWithoutStream=false, which rejects clients that ping
+	// more frequently (e.g. every 60s) or ping while idle — sending GOAWAY
+	// (too_many_pings) and breaking the connection.
+	// Setting MinTime to KeepAliveInterval (60s) matches the client ping rate,
+	// and PermitWithoutStream=true allows idle keepalive pings so clients can
+	// proactively detect dead connections. This keeps both old and new clients
+	// working: an old client (PermitWithoutStream=false) never pings while idle
+	// and so never triggers a strike; a new client (PermitWithoutStream=true)
+	// pings at 60s, within the allowed MinTime.
+	keepaliveEnforcementOpts := grpc.KeepaliveEnforcementPolicy(keepalive.EnforcementPolicy{
+		MinTime:             cfg.KeepAliveInterval,
+		PermitWithoutStream: true,
+	})
+
 	if cfg.MaxReceiveMessageSize > 0 {
 		srv.serverOptions = append(srv.serverOptions, grpc.MaxRecvMsgSize(cfg.MaxReceiveMessageSize))
 	}
@@ -79,7 +95,7 @@ func New(cfg *config.ServerConfig) *Server {
 		interceptors.LoggerForUnaryServer(srv.config),
 		interceptors.Metric(),
 	)
-	srv.serverOptions = append(srv.serverOptions, keepaliveOpts, srv.WithUnaryServerChain())
+	srv.serverOptions = append(srv.serverOptions, keepaliveOpts, keepaliveEnforcementOpts, srv.WithUnaryServerChain())
 	srv.server = grpc.NewServer(srv.serverOptions...)
 	return srv
 }