lnrpc: Add metadata field to AddInvoice and DecodePayReq

itest/lnd_single_hop_invoice_test.go

@@ -137,5 +137,16 @@ func testSingleHopInvoice(ht *lntest.HarnessTest) {
 	require.EqualValues(ht, 20, hopHint.CltvExpiryDelta,
 		"wrong CltvExpiryDelta")
 
+	// Now create an invoice and specify some random metadata.
+	invoice = &lnrpc.Invoice{
+		Memo:     "metadata",
+		Value:    paymentAmt,
+		Metadata: []byte("Here's some fancy metadata :)"),
+	}
+	invoiceResp = bob.RPC.AddInvoice(invoice)
+	payreq = bob.RPC.DecodePayReq(invoiceResp.PaymentRequest)
+	require.Equal(ht, payreq.Metadata,
+		[]byte("Here's some fancy metadata :)"), "wrong metadata")
+
 	ht.CloseChannel(alice, cp)
 }

lnrpc/invoicesrpc/addinvoice.go

@@ -137,6 +137,10 @@ type AddInvoiceData struct {
 	// RouteHints are optional route hints that can each be individually
 	// used to assist in reaching the invoice's destination.
 	RouteHints [][]zpay32.HopHint
+
+	// Metadata is additional data that is sent along with the payment to
+	// the payee.
+	Metadata []byte
 }
 
 // paymentHashAndPreimage returns the payment hash and preimage for this invoice
@@ -439,6 +443,10 @@ func AddInvoice(ctx context.Context, cfg *AddInvoiceConfig,
 	}
 	options = append(options, zpay32.PaymentAddr(paymentAddr))
 
+	if len(invoice.Metadata) > 0 {
+		options = append(options, zpay32.Metadata(invoice.Metadata))
+	}
+
 	// Create and encode the payment request as a bech32 (zpay32) string.
 	creationDate := time.Now()
 	payReq, err := zpay32.NewInvoice(

lnrpc/invoicesrpc/invoices.swagger.json

@@ -578,6 +578,11 @@
           },
           "description": "Maps a 32-byte hex-encoded set ID to the sub-invoice AMP state for the\ngiven set ID. This field is always populated for AMP invoices, and can be\nused along side LookupInvoice to obtain the HTLC information related to a\ngiven sub-invoice.\nNote: Output only, don't specify for creating an invoice.",
           "title": "[EXPERIMENTAL]:"
+        },
+        "metadata": {
+          "type": "string",
+          "format": "byte",
+          "description": "Metadata to send along to the payee in the invoice."
         }
       }
     },

lnrpc/lightning.proto

@@ -3836,6 +3836,11 @@ message Invoice {
     Note: Output only, don't specify for creating an invoice.
     */
     map<string, AMPInvoiceState> amp_invoice_state = 28;
+
+    /*
+    Metadata to send along to the payee in the invoice.
+    */
+    bytes metadata = 29;
 }
 
 enum InvoiceHTLCState {
@@ -4289,6 +4294,7 @@ message PayReq {
     bytes payment_addr = 11;
     int64 num_msat = 12;
     map<uint32, Feature> features = 13;
+    bytes metadata = 14;
 }
 
 enum FeatureBit {

lnrpc/lightning.swagger.json

@@ -5490,6 +5490,11 @@
           },
           "description": "Maps a 32-byte hex-encoded set ID to the sub-invoice AMP state for the\ngiven set ID. This field is always populated for AMP invoices, and can be\nused along side LookupInvoice to obtain the HTLC information related to a\ngiven sub-invoice.\nNote: Output only, don't specify for creating an invoice.",
           "title": "[EXPERIMENTAL]:"
+        },
+        "metadata": {
+          "type": "string",
+          "format": "byte",
+          "description": "Metadata to send along to the payee in the invoice."
         }
       }
     },
@@ -6299,6 +6304,10 @@
           "additionalProperties": {
             "$ref": "#/definitions/lnrpcFeature"
           }
+        },
+        "metadata": {
+          "type": "string",
+          "format": "byte"
         }
       }
     },

rpcserver.go

@@ -5791,6 +5791,7 @@ func (r *rpcServer) AddInvoice(ctx context.Context,
 		Private:         invoice.Private,
 		RouteHints:      routeHints,
 		Amp:             invoice.IsAmp,
+		Metadata:        invoice.Metadata,
 	}
 
 	if invoice.RPreimage != nil {
@@ -6998,6 +6999,7 @@ func (r *rpcServer) DecodePayReq(ctx context.Context,
 		RouteHints:      routeHints,
 		PaymentAddr:     paymentAddr,
 		Features:        invoicesrpc.CreateRPCFeatures(payReq.Features),
+		Metadata:        payReq.Metadata,
 	}, nil
 }