loopd: instruct REST proxy to print default values

loopd/daemon.go

@@ -97,11 +97,22 @@ func daemon(config *config, lisCfg *listenerCfg) error {
 	}
 	defer grpcListener.Close()
 
+	// The default JSON marshaler of the REST proxy only sets OrigName to
+	// true, which instructs it to use the same field names as specified in
+	// the proto file and not switch to camel case. What we also want is
+	// that the marshaler prints all values, even if they are falsey.
+	customMarshalerOption := proxy.WithMarshalerOption(
+		proxy.MIMEWildcard, &proxy.JSONPb{
+			OrigName:     true,
+			EmitDefaults: true,
+		},
+	)
+
 	// We'll also create and start an accompanying proxy to serve clients
 	// through REST.
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
-	mux := proxy.NewServeMux()
+	mux := proxy.NewServeMux(customMarshalerOption)
 	proxyOpts := []grpc.DialOption{grpc.WithInsecure()}
 	err = looprpc.RegisterSwapClientHandlerFromEndpoint(
 		ctx, mux, config.RPCListen, proxyOpts,