channeldb+routing: expose HTLCs in payment subscriptions

This commit modifies the FetchPayment method to return MPPayment structs
converted from the legacy on-disk format. This allows us to attach the
HTLCs to the events given to clients subscribing to the outcome of an
HTLC.

This commit also bubbles up to the routerrpc/router_server, by
populating HTLCAttempts in the response and extracting the legacy route
field from the HTLCAttempts.

channeldb/payment_control.go

@@ -8,7 +8,6 @@ import (
 
 	"github.com/coreos/bbolt"
 	"github.com/lightningnetwork/lnd/lntypes"
-	"github.com/lightningnetwork/lnd/routing/route"
 )
 
 var (
@@ -192,16 +191,17 @@ func (p *PaymentControl) RegisterAttempt(paymentHash lntypes.Hash,
 // duplicate payments to the same payment hash. The provided preimage is
 // atomically saved to the DB for record keeping.
 func (p *PaymentControl) Success(paymentHash lntypes.Hash,
-	preimage lntypes.Preimage) (*route.Route, error) {
+	preimage lntypes.Preimage) (*MPPayment, error) {
 
 	var (
 		updateErr error
-		route     *route.Route
+		payment   *MPPayment
 	)
 	err := p.db.Batch(func(tx *bbolt.Tx) error {
 		// Reset the update error, to avoid carrying over an error
 		// from a previous execution of the batched db transaction.
 		updateErr = nil
+		payment = nil
 
 		bucket, err := fetchPaymentBucket(tx, paymentHash)
 		if err == ErrPaymentNotInitiated {
@@ -225,20 +225,14 @@ func (p *PaymentControl) Success(paymentHash lntypes.Hash,
 		}
 
 		// Retrieve attempt info for the notification.
-		attempt, err := fetchPaymentAttempt(bucket)
-		if err != nil {
-			return err
-		}
-
-		route = &attempt.Route
-
-		return nil
+		payment, err = fetchPayment(bucket)
+		return err
 	})
 	if err != nil {
 		return nil, err
 	}
 
-	return route, updateErr
+	return payment, updateErr
 }
 
 // Fail transitions a payment into the Failed state, and records the reason the
@@ -246,16 +240,17 @@ func (p *PaymentControl) Success(paymentHash lntypes.Hash,
 // its next call for this payment hash, allowing the switch to make a
 // subsequent payment.
 func (p *PaymentControl) Fail(paymentHash lntypes.Hash,
-	reason FailureReason) (*route.Route, error) {
+	reason FailureReason) (*MPPayment, error) {
 
 	var (
 		updateErr error
-		route     *route.Route
+		payment   *MPPayment
 	)
 	err := p.db.Batch(func(tx *bbolt.Tx) error {
 		// Reset the update error, to avoid carrying over an error
 		// from a previous execution of the batched db transaction.
 		updateErr = nil
+		payment = nil
 
 		bucket, err := fetchPaymentBucket(tx, paymentHash)
 		if err == ErrPaymentNotInitiated {
@@ -279,28 +274,21 @@ func (p *PaymentControl) Fail(paymentHash lntypes.Hash,
 		}
 
 		// Retrieve attempt info for the notification, if available.
-		attempt, err := fetchPaymentAttempt(bucket)
-		if err != nil && err != errNoAttemptInfo {
-			return err
-		}
-		if err != errNoAttemptInfo {
-			route = &attempt.Route
-		}
-
-		return nil
+		payment, err = fetchPayment(bucket)
+		return err
 	})
 	if err != nil {
 		return nil, err
 	}
 
-	return route, updateErr
+	return payment, updateErr
 }
 
 // FetchPayment returns information about a payment from the database.
 func (p *PaymentControl) FetchPayment(paymentHash lntypes.Hash) (
-	*Payment, error) {
+	*MPPayment, error) {
 
-	var payment *Payment
+	var payment *MPPayment
 	err := p.db.View(func(tx *bbolt.Tx) error {
 		bucket, err := fetchPaymentBucket(tx, paymentHash)
 		if err != nil {

channeldb/payment_control_test.go

@@ -14,7 +14,6 @@ import (
 	"github.com/coreos/bbolt"
 	"github.com/davecgh/go-spew/spew"
 	"github.com/lightningnetwork/lnd/lntypes"
-	"github.com/lightningnetwork/lnd/routing/route"
 )
 
 func initDB() (*DB, error) {
@@ -132,16 +131,22 @@ func TestPaymentControlSwitchFail(t *testing.T) {
 	)
 
 	// Verifies that status was changed to StatusSucceeded.
-	var route *route.Route
-	route, err = pControl.Success(info.PaymentHash, preimg)
+	var payment *MPPayment
+	payment, err = pControl.Success(info.PaymentHash, preimg)
 	if err != nil {
 		t.Fatalf("error shouldn't have been received, got: %v", err)
 	}
 
-	err = assertRouteEqual(route, &attempt.Route)
+	if len(payment.HTLCs) != 1 {
+		t.Fatalf("payment should have one htlc, got: %d",
+			len(payment.HTLCs))
+	}
+
+	err = assertRouteEqual(&payment.HTLCs[0].Route, &attempt.Route)
 	if err != nil {
 		t.Fatalf("unexpected route returned: %v vs %v: %v",
-			spew.Sdump(attempt.Route), spew.Sdump(*route), err)
+			spew.Sdump(attempt.Route),
+			spew.Sdump(payment.HTLCs[0].Route), err)
 	}
 
 	assertPaymentStatus(t, db, info.PaymentHash, StatusSucceeded)

channeldb/payments.go

@@ -337,7 +337,7 @@ func (db *DB) FetchPayments() ([]*MPPayment, error) {
 				return err
 			}
 
-			payments = append(payments, p.ToMPPayment())
+			payments = append(payments, p)
 
 			// For older versions of lnd, duplicate payments to a
 			// payment has was possible. These will be found in a
@@ -362,7 +362,7 @@ func (db *DB) FetchPayments() ([]*MPPayment, error) {
 					return err
 				}
 
-				payments = append(payments, p.ToMPPayment())
+				payments = append(payments, p)
 				return nil
 			})
 		})
@@ -379,7 +379,7 @@ func (db *DB) FetchPayments() ([]*MPPayment, error) {
 	return payments, nil
 }
 
-func fetchPayment(bucket *bbolt.Bucket) (*Payment, error) {
+func fetchPayment(bucket *bbolt.Bucket) (*MPPayment, error) {
 	var (
 		err error
 		p   = &Payment{}
@@ -434,7 +434,7 @@ func fetchPayment(bucket *bbolt.Bucket) (*Payment, error) {
 		p.Failure = &reason
 	}
 
-	return p, nil
+	return p.ToMPPayment(), nil
 }
 
 // DeletePayments deletes all completed and failed payments from the DB.