channeldb+routing: htlcs are pruned on settle

channeldb/payment_control.go

@@ -223,6 +223,19 @@ func (p *PaymentControl) InitPayment(paymentHash lntypes.Hash,
 	return updateErr
 }
 
+// DeleteFailedAttempts deletes all failed htlcs for a payment if configured
+// by the PaymentControl db.
+func (p *PaymentControl) DeleteFailedAttempts(hash lntypes.Hash) error {
+	if !p.db.keepFailedPaymentAttempts {
+		const failedHtlcsOnly = true
+		err := p.db.DeletePayment(hash, failedHtlcsOnly)
+		if err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
 // paymentIndexTypeHash is a payment index type which indicates that we have
 // created an index of payment sequence number to payment hash.
 type paymentIndexType uint8

channeldb/payment_control_test.go

@@ -308,7 +308,7 @@ func TestPaymentControlFailsWithoutInFlight(t *testing.T) {
 
 // TestPaymentControlDeleteNonInFlight checks that calling DeletePayments only
 // deletes payments from the database that are not in-flight.
-func TestPaymentControlDeleteNonInFligt(t *testing.T) {
+func TestPaymentControlDeleteNonInFlight(t *testing.T) {
 	t.Parallel()
 
 	db, cleanup, err := MakeTestDB()
@@ -528,7 +528,7 @@ func TestPaymentControlDeletePayments(t *testing.T) {
 
 	// Register three payments:
 	// 1. A payment with two failed attempts.
-	// 2. A Payment with one failed and one settled attempt.
+	// 2. A payment with one failed and one settled attempt.
 	// 3. A payment with one failed and one in-flight attempt.
 	payments := []*payment{
 		{status: StatusFailed},
@@ -585,7 +585,7 @@ func TestPaymentControlDeleteSinglePayment(t *testing.T) {
 	// according to its final status.
 	// 1. A payment with two failed attempts.
 	// 2. Another payment with two failed attempts.
-	// 3. A Payment with one failed and one settled attempt.
+	// 3. A payment with one failed and one settled attempt.
 	// 4. A payment with one failed and one in-flight attempt.
 
 	// Initiate payments, which is a slice of payment that is used as
@@ -1003,6 +1003,96 @@ func TestPaymentControlMPPRecordValidation(t *testing.T) {
 	}
 }
 
+// TestDeleteFailedAttempts checks that DeleteFailedAttempts properly removes
+// failed HTLCs from finished payments.
+func TestDeleteFailedAttempts(t *testing.T) {
+	t.Parallel()
+
+	t.Run("keep failed payment attempts", func(t *testing.T) {
+		testDeleteFailedAttempts(t, true)
+	})
+	t.Run("remove failed payment attempts", func(t *testing.T) {
+		testDeleteFailedAttempts(t, false)
+	})
+}
+
+func testDeleteFailedAttempts(t *testing.T, keepFailedPaymentAttempts bool) {
+	db, cleanup, err := MakeTestDB()
+	defer cleanup()
+
+	require.NoError(t, err, "unable to init db")
+	db.keepFailedPaymentAttempts = keepFailedPaymentAttempts
+
+	pControl := NewPaymentControl(db)
+
+	// Register three payments:
+	// All payments will have one failed HTLC attempt and one HTLC attempt
+	// according to its final status.
+	// 1. A payment with two failed attempts.
+	// 2. A payment with one failed and one in-flight attempt.
+	// 3. A payment with one failed and one settled attempt.
+
+	// Initiate payments, which is a slice of payment that is used as
+	// template to create the corresponding test payments in the database.
+	//
+	// Note: The payment id and number of htlc attempts of each payment will
+	// be added to this slice when creating the payments below.
+	// This allows the slice to be used directly for testing purposes.
+	payments := []*payment{
+		{status: StatusFailed},
+		{status: StatusInFlight},
+		{status: StatusSucceeded},
+	}
+
+	// Use helper function to register the test payments in the data and
+	// populate the data to the payments slice.
+	createTestPayments(t, pControl, payments)
+
+	// Check that all payments are there as we added them.
+	assertPayments(t, db, payments)
+
+	// Calling DeleteFailedAttempts on a failed payment should delete all
+	// HTLCs.
+	require.NoError(t, pControl.DeleteFailedAttempts(payments[0].id))
+
+	// Expect all HTLCs to be deleted if the config is set to delete them.
+	if !keepFailedPaymentAttempts {
+		payments[0].htlcs = 0
+	}
+	assertPayments(t, db, payments)
+
+	// Calling DeleteFailedAttempts on an in-flight payment should return
+	// an error.
+	if keepFailedPaymentAttempts {
+		require.NoError(t, pControl.DeleteFailedAttempts(payments[1].id))
+	} else {
+		require.Error(t, pControl.DeleteFailedAttempts(payments[1].id))
+	}
+
+	// Since DeleteFailedAttempts returned an error, we should expect the
+	// payment to be unchanged.
+	assertPayments(t, db, payments)
+
+	// Cleaning up a successful payment should remove failed htlcs.
+	require.NoError(t, pControl.DeleteFailedAttempts(payments[2].id))
+	// Expect all HTLCs except for the settled one to be deleted if the
+	// config is set to delete them.
+	if !keepFailedPaymentAttempts {
+		payments[2].htlcs = 1
+	}
+	assertPayments(t, db, payments)
+
+	if keepFailedPaymentAttempts {
+		// DeleteFailedAttempts is ignored, even for non-existent
+		// payments, if the control tower is configured to keep failed
+		// HTLCs.
+		require.NoError(t, pControl.DeleteFailedAttempts(lntypes.ZeroHash))
+	} else {
+		// Attempting to cleanup a non-existent payment returns an error.
+		require.Error(t, pControl.DeleteFailedAttempts(lntypes.ZeroHash))
+	}
+}
+
 // assertPaymentStatus retrieves the status of the payment referred to by hash
 // and compares it with the expected state.
 func assertPaymentStatus(t *testing.T, p *PaymentControl,

routing/control_tower.go

@@ -19,6 +19,11 @@ type ControlTower interface {
 	// hash.
 	InitPayment(lntypes.Hash, *channeldb.PaymentCreationInfo) error
 
+	// DeleteFailedAttempts removes all failed HTLCs from the db. It should
+	// be called for a given payment whenever all inflight htlcs are
+	// completed, and the payment has reached a final settled state.
+	DeleteFailedAttempts(lntypes.Hash) error
+
 	// RegisterAttempt atomically records the provided HTLCAttemptInfo.
 	RegisterAttempt(lntypes.Hash, *channeldb.HTLCAttemptInfo) error
 
@@ -125,6 +130,12 @@ func (p *controlTower) InitPayment(paymentHash lntypes.Hash,
 	return p.db.InitPayment(paymentHash, info)
 }
 
+// DeleteFailedAttempts deletes all failed htlcs if the payment was
+// successfully settled.
+func (p *controlTower) DeleteFailedAttempts(paymentHash lntypes.Hash) error {
+	return p.db.DeleteFailedAttempts(paymentHash)
+}
+
 // RegisterAttempt atomically records the provided HTLCAttemptInfo to the
 // DB.
 func (p *controlTower) RegisterAttempt(paymentHash lntypes.Hash,

routing/mock_test.go

@@ -309,6 +309,32 @@ func (m *mockControlTowerOld) InitPayment(phash lntypes.Hash,
 	return nil
 }
 
+func (m *mockControlTowerOld) DeleteFailedAttempts(phash lntypes.Hash) error {
+	p, ok := m.payments[phash]
+	if !ok {
+		return channeldb.ErrPaymentNotInitiated
+	}
+
+	var inFlight bool
+	for _, a := range p.attempts {
+		if a.Settle != nil {
+			continue
+		}
+
+		if a.Failure != nil {
+			continue
+		}
+
+		inFlight = true
+	}
+
+	if inFlight {
+		return channeldb.ErrPaymentInFlight
+	}
+
+	return nil
+}
+
 func (m *mockControlTowerOld) RegisterAttempt(phash lntypes.Hash,
 	a *channeldb.HTLCAttemptInfo) error {
 
@@ -665,6 +691,11 @@ func (m *mockControlTower) InitPayment(phash lntypes.Hash,
 	return args.Error(0)
 }
 
+func (m *mockControlTower) DeleteFailedAttempts(phash lntypes.Hash) error {
+	args := m.Called(phash)
+	return args.Error(0)
+}
+
 func (m *mockControlTower) RegisterAttempt(phash lntypes.Hash,
 	a *channeldb.HTLCAttemptInfo) error {
 

routing/payment_lifecycle.go

@@ -186,9 +186,21 @@ lifecycle:
 			// Find the first successful shard and return
 			// the preimage and route.
 			for _, a := range payment.HTLCs {
-				if a.Settle != nil {
-					return a.Settle.Preimage, &a.Route, nil
+				if a.Settle == nil {
+					continue
 				}
+
+				err := p.router.cfg.Control.
+					DeleteFailedAttempts(
+						p.identifier)
+				if err != nil {
+					log.Errorf("Error deleting failed "+
+						"payment attempts for "+
+						"payment %v: %v", p.identifier,
+						err)
+				}
+
+				return a.Settle.Preimage, &a.Route, nil
 			}
 
 			// Payment failed.

routing/router_test.go

@@ -3571,6 +3571,7 @@ func TestSendMPPaymentSucceed(t *testing.T) {
 			}
 		}
 	})
+	controlTower.On("DeleteFailedAttempts", identifier).Return(nil)
 
 	// Call the actual method SendPayment on router. This is place inside a
 	// goroutine so we can set a timeout for the whole test, in case
@@ -3782,6 +3783,7 @@ func TestSendMPPaymentSucceedOnExtraShards(t *testing.T) {
 			return
 		}
 	})
+	controlTower.On("DeleteFailedAttempts", identifier).Return(nil)
 
 	// Call the actual method SendPayment on router. This is place inside a
 	// goroutine so we can set a timeout for the whole test, in case