routing: add color to node update

routing/notifications.go

@@ -2,6 +2,7 @@ package routing
 
 import (
 	"fmt"
+	"image/color"
 	"net"
 	"sync"
 	"sync/atomic"
@@ -246,6 +247,9 @@ type NetworkNodeUpdate struct {
 
 	// Alias is the alias or nick name of the node.
 	Alias string
+
+	// Color is the node's color in hex code format.
+	Color string
 }
 
 // ChannelEdgeUpdate is an update for a new channel within the ChannelGraph.
@@ -321,6 +325,7 @@ func addToTopologyChange(graph *channeldb.ChannelGraph, update *TopologyChange,
 			Addresses:   m.Addresses,
 			IdentityKey: pubKey,
 			Alias:       m.Alias,
+			Color:       EncodeHexColor(m.Color),
 		}
 		nodeUpdate.IdentityKey.Curve = nil
 
@@ -388,3 +393,8 @@ func addToTopologyChange(graph *channeldb.ChannelGraph, update *TopologyChange,
 			"unknown message type %T", msg)
 	}
 }
+
+// EncodeHexColor takes a color and returns it in hex code format.
+func EncodeHexColor(color color.RGBA) string {
+	return fmt.Sprintf("#%02x%02x%02x", color.R, color.G, color.B)
+}

routing/notifications_test.go

@@ -628,6 +628,10 @@ func TestNodeUpdateNotification(t *testing.T) {
 			t.Fatalf("node alias doesn't match: expected %v, got %v",
 				ann.Alias, nodeUpdate.Alias)
 		}
+		if nodeUpdate.Color != EncodeHexColor(ann.Color) {
+			t.Fatalf("node color doesn't match: expected %v, got %v",
+				EncodeHexColor(ann.Color), nodeUpdate.Color)
+		}
 	}
 
 	// Create lookup map for notifications we are intending to receive. Entries
@@ -926,3 +930,30 @@ func TestChannelCloseNotification(t *testing.T) {
 		t.Fatal("notification not sent")
 	}
 }
+
+// TestEncodeHexColor tests that the string used to represent a node color is
+// correctly encoded.
+func TestEncodeHexColor(t *testing.T) {
+	var colorTestCases = []struct {
+		R       uint8
+		G       uint8
+		B       uint8
+		encoded string
+		isValid bool
+	}{
+		{0, 0, 0, "#000000", true},
+		{255, 255, 255, "#ffffff", true},
+		{255, 117, 215, "#ff75d7", true},
+		{0, 0, 0, "000000", false},
+		{1, 2, 3, "", false},
+		{1, 2, 3, "#", false},
+	}
+
+	for _, tc := range colorTestCases {
+		encoded := EncodeHexColor(color.RGBA{tc.R, tc.G, tc.B, 0})
+		if (encoded == tc.encoded) != tc.isValid {
+			t.Fatalf("incorrect color encoding, "+
+				"want: %v, got: %v", tc.encoded, encoded)
+		}
+	}
+}