multi: add health check for remote signer

lnwallet/rpcwallet/healthcheck.go

@@ -0,0 +1,24 @@
+package rpcwallet
+
+import (
+	"fmt"
+	"time"
+
+	"github.com/lightningnetwork/lnd/lncfg"
+)
+
+// HealthCheck returns a health check function for the given remote signing
+// configuration.
+func HealthCheck(cfg *lncfg.RemoteSigner, timeout time.Duration) func() error {
+	return func() error {
+		_, err := connectRPC(
+			cfg.RPCHost, cfg.TLSCertPath, cfg.MacaroonPath, timeout,
+		)
+		if err != nil {
+			return fmt.Errorf("error connecting to the remote "+
+				"signing node through RPC: %v", err)
+		}
+
+		return nil
+	}
+}