routing+routerrpc+lnrpc: add option to use mc in queryroutes

A boolean flag is added to the QueryRoutes rpc that allows feeding
mission control probabilities into path finding.

lnrpc/routerrpc/router_backend.go

@@ -167,7 +167,13 @@ func (r *RouterBackend) QueryRoutes(ctx context.Context,
 				return 0
 			}
 
-			return 1
+			if !in.UseMissionControl {
+				return 1
+			}
+
+			return r.MissionControl.GetEdgeProbability(
+				node, edge, amt,
+			)
 		},
 	}
 

lnrpc/routerrpc/router_backend_test.go

@@ -17,6 +17,8 @@ import (
 const (
 	destKey       = "0286098b97bc843372b4426d4b276cea9aa2f48f0428d6f5b66ae101befc14f8b4"
 	ignoreNodeKey = "02f274f48f3c0d590449a6776e3ce8825076ac376e470e992246eebc565ef8bb2a"
+
+	testMissionControlProb = 0.5
 )
 
 var (
@@ -26,6 +28,15 @@ var (
 // TestQueryRoutes asserts that query routes rpc parameters are properly parsed
 // and passed onto path finding.
 func TestQueryRoutes(t *testing.T) {
+	t.Run("no mission control", func(t *testing.T) {
+		testQueryRoutes(t, false)
+	})
+	t.Run("with mission control", func(t *testing.T) {
+		testQueryRoutes(t, true)
+	})
+}
+
+func testQueryRoutes(t *testing.T, useMissionControl bool) {
 	ignoreNodeBytes, err := hex.DecodeString(ignoreNodeKey)
 	if err != nil {
 		t.Fatal(err)
@@ -58,6 +69,7 @@ func TestQueryRoutes(t *testing.T) {
 			ChannelId:        555,
 			DirectionReverse: true,
 		}},
+		UseMissionControl: useMissionControl,
 	}
 
 	findRoute := func(source, target route.Vertex,
@@ -92,9 +104,13 @@ func TestQueryRoutes(t *testing.T) {
 			t.Fatal("expecting 0% probability for ignored node")
 		}
 
+		expectedProb := 1.0
+		if useMissionControl {
+			expectedProb = testMissionControlProb
+		}
 		if restrictions.ProbabilitySource(route.Vertex{},
 			routing.EdgeLocator{}, 0,
-		) != 1 {
+		) != expectedProb {
 			t.Fatal("expecting 100% probability")
 		}
 
@@ -111,6 +127,7 @@ func TestQueryRoutes(t *testing.T) {
 
 			return 1, nil
 		},
+		MissionControl: &mockMissionControl{},
 	}
 
 	resp, err := backend.QueryRoutes(context.Background(), request)
@@ -121,3 +138,17 @@ func TestQueryRoutes(t *testing.T) {
 		t.Fatal("expected a single route response")
 	}
 }
+
+type mockMissionControl struct {
+}
+
+func (m *mockMissionControl) GetEdgeProbability(fromNode route.Vertex,
+	edge routing.EdgeLocator, amt lnwire.MilliSatoshi) float64 {
+	return testMissionControlProb
+}
+
+func (m *mockMissionControl) ResetHistory() {}
+
+func (m *mockMissionControl) GetHistorySnapshot() *routing.MissionControlSnapshot {
+	return nil
+}

lnrpc/rpc.proto

@@ -1651,6 +1651,12 @@ message QueryRoutesRequest {
     self is assumed.
     */
     string source_pub_key = 8;
+
+    /**
+    If set to true, edge probabilities from mission control will be used to get
+    the optimal route.
+    */
+    bool use_mission_control = 9;
 }
 
 message EdgeLocator {

lnrpc/rpc.swagger.json

@@ -722,6 +722,14 @@
             "in": "query",
             "required": false,
             "type": "string"
+          },
+          {
+            "name": "use_mission_control",
+            "description": "*\nIf set to true, edge probabilities from mission control will be used to get\nthe optimal route.",
+            "in": "query",
+            "required": false,
+            "type": "boolean",
+            "format": "boolean"
           }
         ],
         "tags": [