multi: make forwarding history limit configurable

db.go

@@ -96,7 +96,7 @@ type Db struct {
 	fwdHistoryLimit int
 }
 
-func NewDb(dbPath string, opts ...func(*Db)) (*Db, error) {
+func NewDb(dbPath string, fwdHistoryLimit int) (*Db, error) {
 	const busyTimeoutMs = 5000
 
 	dsn := dbPath + fmt.Sprintf("?_pragma=busy_timeout=%d", busyTimeoutMs)
@@ -116,10 +116,7 @@ func NewDb(dbPath string, opts ...func(*Db)) (*Db, error) {
 
 	database := &Db{
 		db:              db,
-		fwdHistoryLimit: defaultFwdHistoryLimit,
-	}
-	for _, opt := range opts {
-		opt(database)
+		fwdHistoryLimit: fwdHistoryLimit,
 	}
 
 	return database, nil
@@ -244,6 +241,12 @@ type HtlcInfo struct {
 func (d *Db) RecordHtlcResolution(ctx context.Context,
 	htlc *HtlcInfo) error {
 
+	// If the database is configured to not store any records, save the hassle of
+	// writing and deleting a record by returning early.
+	if d.fwdHistoryLimit == 0 {
+		return nil
+	}
+
 	if err := d.insertHtlcResolution(ctx, htlc); err != nil {
 		return err
 	}

db_test.go

@@ -10,11 +10,11 @@ import (
 	"github.com/stretchr/testify/require"
 )
 
-func setupTestDb(t *testing.T, dbOpts ...func(*Db)) (*Db, func()) {
+func setupTestDb(t *testing.T, fwdingHistoryLimit int) (*Db, func()) {
 	file, err := os.CreateTemp("", "test_db_")
 	require.NoError(t, err)
 
-	db, err := NewDb(file.Name(), dbOpts...)
+	db, err := NewDb(file.Name(), fwdingHistoryLimit)
 	require.NoError(t, err)
 
 	return db, func() {
@@ -24,7 +24,7 @@ func setupTestDb(t *testing.T, dbOpts ...func(*Db)) (*Db, func()) {
 
 func TestDb(t *testing.T) {
 	ctx := context.Background()
-	db, cleanup := setupTestDb(t)
+	db, cleanup := setupTestDb(t, defaultFwdHistoryLimit)
 	defer cleanup()
 
 	expectedDefaultLimit := Limit{
@@ -68,18 +68,12 @@ func TestDb(t *testing.T) {
 	defer db.Close()
 }
 
-func dbWithCustomForwardingHistoryLimit(limit int) func(d *Db) {
-	return func(d *Db) {
-		d.fwdHistoryLimit = limit
-	}
-}
-
 func TestDbForwardingHistory(t *testing.T) {
 	limit := 20
 
 	// Create a test DB that will limit to 10 forwarding history records.
 	ctx := context.Background()
-	db, cleanup := setupTestDb(t, dbWithCustomForwardingHistoryLimit(limit))
+	db, cleanup := setupTestDb(t, limit)
 	defer cleanup()
 
 	// Insert HTLCs just up until our limit.
@@ -122,3 +116,16 @@ func testHtlc(i uint64) *HtlcInfo {
 		},
 	}
 }
+
+func TestDbNoForwardingHistory(t *testing.T) {
+	ctx := context.Background()
+	db, cleanup := setupTestDb(t, 0)
+	defer cleanup()
+
+	htlc := testHtlc(1)
+	require.NoError(t, db.RecordHtlcResolution(ctx, htlc))
+
+	fwds, err := db.ListForwardingHistory(ctx, time.Time{}, time.Unix(1000000, 0))
+	require.NoError(t, err)
+	require.Len(t, fwds, 0)
+}

main.go

@@ -129,6 +129,11 @@ func main() {
 			Value: "127.0.0.1:9234",
 			Usage: "grpc server listen address",
 		},
+		cli.Uint64Flag{
+			Name:  "fwdhistorylimit",
+			Usage: "limit the number of htlc forwards that are persisted",
+			Value: defaultFwdHistoryLimit,
+		},
 		httpListenFlag,
 		stubFlag,
 	}

process_test.go

@@ -37,7 +37,7 @@ func testProcess(t *testing.T, event resolveEvent) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	db, cleanup := setupTestDb(t)
+	db, cleanup := setupTestDb(t, defaultFwdHistoryLimit)
 	defer cleanup()
 
 	log := zaptest.NewLogger(t).Sugar()
@@ -114,7 +114,7 @@ func TestLimits(t *testing.T) {
 func testRateLimit(t *testing.T, mode Mode) {
 	defer Timeout()()
 
-	db, cleanup := setupTestDb(t)
+	db, cleanup := setupTestDb(t, defaultFwdHistoryLimit)
 	defer cleanup()
 
 	cfg := &Limits{
@@ -204,7 +204,7 @@ func testRateLimit(t *testing.T, mode Mode) {
 func testMaxPending(t *testing.T, mode Mode) {
 	defer Timeout()()
 
-	db, cleanup := setupTestDb(t)
+	db, cleanup := setupTestDb(t, defaultFwdHistoryLimit)
 	defer cleanup()
 
 	cfg := &Limits{
@@ -283,7 +283,7 @@ func TestNewPeer(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	db, cleanup := setupTestDb(t)
+	db, cleanup := setupTestDb(t, defaultFwdHistoryLimit)
 	defer cleanup()
 
 	log := zaptest.NewLogger(t).Sugar()
@@ -323,7 +323,7 @@ func TestNewPeer(t *testing.T) {
 func TestBlocked(t *testing.T) {
 	defer Timeout()()
 
-	db, cleanup := setupTestDb(t)
+	db, cleanup := setupTestDb(t, defaultFwdHistoryLimit)
 	defer cleanup()
 
 	cfg := &Limits{
@@ -375,7 +375,7 @@ func TestChannelNotFound(t *testing.T) {
 	ctx, cancel := context.WithCancel(context.Background())
 	defer cancel()
 
-	db, cleanup := setupTestDb(t)
+	db, cleanup := setupTestDb(t, defaultFwdHistoryLimit)
 	defer cleanup()
 
 	log := zaptest.NewLogger(t).Sugar()

run.go

@@ -43,7 +43,7 @@ func run(c *cli.Context) error {
 	log.Infow("Opening database", "path", dbPath)
 
 	// Open database.
-	db, err := NewDb(dbPath)
+	db, err := NewDb(dbPath, c.Int("fwdhistorylimit"))
 	if err != nil {
 		return err
 	}