Add getLedgers implementation

cmd/soroban-rpc/internal/config/main.go

@@ -26,6 +26,7 @@ type Config struct {
 	CoreRequestTimeout                             time.Duration
 	DefaultEventsLimit                             uint
 	DefaultTransactionsLimit                       uint
+	DefaultLedgersLimit                            uint
 	FriendbotURL                                   string
 	HistoryArchiveURLs                             []string
 	HistoryArchiveUserAgent                        string
@@ -34,6 +35,7 @@ type Config struct {
 	LogLevel                                       logrus.Level
 	MaxEventsLimit                                 uint
 	MaxTransactionsLimit                           uint
+	MaxLedgersLimit                                uint
 	MaxHealthyLedgerLatency                        time.Duration
 	NetworkPassphrase                              string
 	PreflightWorkerCount                           uint
@@ -52,6 +54,7 @@ type Config struct {
 	RequestBacklogGetLedgerEntriesQueueLimit       uint
 	RequestBacklogGetTransactionQueueLimit         uint
 	RequestBacklogGetTransactionsQueueLimit        uint
+	RequestBacklogGetLedgersQueueLimit             uint
 	RequestBacklogSendTransactionQueueLimit        uint
 	RequestBacklogSimulateTransactionQueueLimit    uint
 	RequestBacklogGetFeeStatsTransactionQueueLimit uint
@@ -65,6 +68,7 @@ type Config struct {
 	MaxGetLedgerEntriesExecutionDuration           time.Duration
 	MaxGetTransactionExecutionDuration             time.Duration
 	MaxGetTransactionsExecutionDuration            time.Duration
+	MaxGetLedgersExecutionDuration                 time.Duration
 	MaxSendTransactionExecutionDuration            time.Duration
 	MaxSimulateTransactionExecutionDuration        time.Duration
 	MaxGetFeeStatsExecutionDuration                time.Duration

cmd/soroban-rpc/internal/config/options.go

@@ -282,6 +282,28 @@ func (cfg *Config) options() Options {
 				return nil
 			},
 		},
+		{
+			Name:         "max-ledgers-limit",
+			Usage:        "Maximum amount of ledgers allowed in a single getLedgers response",
+			ConfigKey:    &cfg.MaxLedgersLimit,
+			DefaultValue: uint(200),
+		},
+		{
+			Name:         "default-ledgers-limit",
+			Usage:        "Default cap on the amount of ledgers included in a single getLedgers response",
+			ConfigKey:    &cfg.DefaultLedgersLimit,
+			DefaultValue: uint(50),
+			Validate: func(_ *Option) error {
+				if cfg.DefaultLedgersLimit > cfg.MaxLedgersLimit {
+					return fmt.Errorf(
+						"default-ledgers-limit (%v) cannot exceed max-ledgers-limit (%v)",
+						cfg.DefaultLedgersLimit,
+						cfg.MaxLedgersLimit,
+					)
+				}
+				return nil
+			},
+		},
 		{
 			Name: "max-healthy-ledger-latency",
 			Usage: "maximum ledger latency (i.e. time elapsed since the last known ledger closing time) considered to be healthy" +
@@ -372,6 +394,13 @@ func (cfg *Config) options() Options {
 			DefaultValue: uint(1000),
 			Validate:     positive,
 		},
+		{
+			TomlKey:      strutils.KebabToConstantCase("request-backlog-get-ledgers-queue-limit"),
+			Usage:        "Maximum number of outstanding getLedgers requests",
+			ConfigKey:    &cfg.RequestBacklogGetLedgersQueueLimit,
+			DefaultValue: uint(1000),
+			Validate:     positive,
+		},
 		{
 			TomlKey:      strutils.KebabToConstantCase("request-backlog-send-transaction-queue-limit"),
 			Usage:        "Maximum number of outstanding SendTransaction requests",
@@ -453,6 +482,12 @@ func (cfg *Config) options() Options {
 			ConfigKey:    &cfg.MaxGetTransactionsExecutionDuration,
 			DefaultValue: 5 * time.Second,
 		},
+		{
+			TomlKey:      strutils.KebabToConstantCase("max-get-ledgers-execution-duration"),
+			Usage:        "The maximum duration of time allowed for processing a getLedgers request. When that time elapses, the rpc server would return -32001 and abort the request's execution",
+			ConfigKey:    &cfg.MaxGetLedgersExecutionDuration,
+			DefaultValue: 5 * time.Second,
+		},
 		{
 			TomlKey:      strutils.KebabToConstantCase("max-send-transaction-execution-duration"),
 			Usage:        "The maximum duration of time allowed for processing a sendTransaction request. When that time elapses, the rpc server would return -32001 and abort the request's execution",

cmd/soroban-rpc/internal/db/ledger.go

@@ -2,10 +2,12 @@ package db
 
 import (
 	"context"
+	"database/sql"
 	"fmt"
 
 	sq "github.com/Masterminds/squirrel"
 
+	"github.com/stellar/go/support/db"
 	"github.com/stellar/go/xdr"
 
 	"github.com/stellar/soroban-rpc/cmd/soroban-rpc/internal/ledgerbucketwindow"
@@ -22,20 +24,82 @@ type LedgerReader interface {
 	StreamAllLedgers(ctx context.Context, f StreamLedgerFn) error
 	GetLedgerRange(ctx context.Context) (ledgerbucketwindow.LedgerRange, error)
 	StreamLedgerRange(ctx context.Context, startLedger uint32, endLedger uint32, f StreamLedgerFn) error
+	NewTx(ctx context.Context) (LedgerReaderTx, error)
+}
+
+type LedgerReaderTx interface {
+	GetLedgerRange(ctx context.Context) (ledgerbucketwindow.LedgerRange, error)
+	BatchGetLedgers(ctx context.Context, sequence uint32, batchSize uint) ([]xdr.LedgerCloseMeta, error)
+	Done() error
 }
 
 type LedgerWriter interface {
 	InsertLedger(ledger xdr.LedgerCloseMeta) error
 }
 
+type readDB interface {
+	Select(ctx context.Context, dest interface{}, query sq.Sqlizer) error
+}
+
 type ledgerReader struct {
 	db *DB
 }
 
+type ledgerReaderTx struct {
+	tx                    db.SessionInterface
+	latestLedgerSeq       uint32
+	latestLedgerCloseTime int64
+}
+
+func (l ledgerReaderTx) GetLedgerRange(ctx context.Context) (ledgerbucketwindow.LedgerRange, error) {
+	if l.latestLedgerSeq != 0 {
+		return getLedgerRangeWithCache(ctx, l.tx, l.latestLedgerSeq, l.latestLedgerCloseTime)
+	}
+	return getLedgerRangeWithoutCache(ctx, l.tx)
+}
+
+// BatchGetLedgers fetches ledgers in batches from the db.
+func (l ledgerReaderTx) BatchGetLedgers(ctx context.Context, sequence uint32,
+	batchSize uint,
+) ([]xdr.LedgerCloseMeta, error) {
+	sql := sq.Select("meta").
+		From(ledgerCloseMetaTableName).
+		Where(sq.And{
+			sq.GtOrEq{"sequence": sequence},
+			sq.LtOrEq{"sequence": sequence + uint32(batchSize) - 1},
+		})
+
+	results := make([]xdr.LedgerCloseMeta, 0, batchSize)
+	if err := l.tx.Select(ctx, &results, sql); err != nil {
+		return nil, err
+	}
+
+	return results, nil
+}
+
+func (l ledgerReaderTx) Done() error {
+	return l.tx.Rollback()
+}
+
 func NewLedgerReader(db *DB) LedgerReader {
 	return ledgerReader{db: db}
 }
 
+func (r ledgerReader) NewTx(ctx context.Context) (LedgerReaderTx, error) {
+	r.db.cache.RLock()
+	defer r.db.cache.RUnlock()
+	txSession := r.db.Clone()
+	if err := txSession.BeginTx(ctx, &sql.TxOptions{ReadOnly: true}); err != nil {
+		return nil, fmt.Errorf("failed to begin read transaction: %w", err)
+	}
+	tx := ledgerReaderTx{
+		tx:                    txSession,
+		latestLedgerSeq:       r.db.cache.latestLedgerSeq,
+		latestLedgerCloseTime: r.db.cache.latestLedgerCloseTime,
+	}
+	return tx, nil
+}
+
 // StreamAllLedgers runs f over all the ledgers in the database (until f errors or signals it's done).
 func (r ledgerReader) StreamAllLedgers(ctx context.Context, f StreamLedgerFn) error {
 	sql := sq.Select("meta").From(ledgerCloseMetaTableName).OrderBy("sequence asc")
@@ -112,32 +176,44 @@ func (r ledgerReader) GetLedgerRange(ctx context.Context) (ledgerbucketwindow.Le
 
 	// Make use of the cached latest ledger seq and close time to query only the oldest ledger details.
 	if latestLedgerSeqCache != 0 {
-		query := sq.Select("meta").
-			From(ledgerCloseMetaTableName).
-			Where(
-				fmt.Sprintf("sequence = (SELECT MIN(sequence) FROM %s)", ledgerCloseMetaTableName),
-			)
-		var lcm []xdr.LedgerCloseMeta
-		if err := r.db.Select(ctx, &lcm, query); err != nil {
-			return ledgerbucketwindow.LedgerRange{}, fmt.Errorf("couldn't query ledger range: %w", err)
-		}
+		return getLedgerRangeWithCache(ctx, r.db, latestLedgerSeqCache, latestLedgerCloseTimeCache)
+	}
+	return getLedgerRangeWithoutCache(ctx, r.db)
+}
 
-		if len(lcm) == 0 {
-			return ledgerbucketwindow.LedgerRange{}, ErrEmptyDB
-		}
+// getLedgerRangeWithCache uses the latest ledger cache to optimize the query.
+// It only needs to look up the first ledger since we have the latest cached.
+func getLedgerRangeWithCache(ctx context.Context, db readDB,
+	latestSeq uint32, latestTime int64,
+) (ledgerbucketwindow.LedgerRange, error) {
+	query := sq.Select("meta").
+		From(ledgerCloseMetaTableName).
+		Where(
+			fmt.Sprintf("sequence = (SELECT MIN(sequence) FROM %s)", ledgerCloseMetaTableName),
+		)
+	var lcm []xdr.LedgerCloseMeta
+	if err := db.Select(ctx, &lcm, query); err != nil {
+		return ledgerbucketwindow.LedgerRange{}, fmt.Errorf("couldn't query ledger range: %w", err)
+	}
 
-		return ledgerbucketwindow.LedgerRange{
-			FirstLedger: ledgerbucketwindow.LedgerInfo{
-				Sequence:  lcm[0].LedgerSequence(),
-				CloseTime: lcm[0].LedgerCloseTime(),
-			},
-			LastLedger: ledgerbucketwindow.LedgerInfo{
-				Sequence:  latestLedgerSeqCache,
-				CloseTime: latestLedgerCloseTimeCache,
-			},
-		}, nil
+	if len(lcm) == 0 {
+		return ledgerbucketwindow.LedgerRange{}, ErrEmptyDB
 	}
 
+	return ledgerbucketwindow.LedgerRange{
+		FirstLedger: ledgerbucketwindow.LedgerInfo{
+			Sequence:  lcm[0].LedgerSequence(),
+			CloseTime: lcm[0].LedgerCloseTime(),
+		},
+		LastLedger: ledgerbucketwindow.LedgerInfo{
+			Sequence:  latestSeq,
+			CloseTime: latestTime,
+		},
+	}, nil
+}
+
+// getLedgerRangeWithoutCache queries both the first and last ledger when cache isn't available
+func getLedgerRangeWithoutCache(ctx context.Context, db readDB) (ledgerbucketwindow.LedgerRange, error) {
 	query := sq.Select("lcm.meta").
 		From(ledgerCloseMetaTableName + " as lcm").
 		Where(sq.Or{
@@ -146,7 +222,7 @@ func (r ledgerReader) GetLedgerRange(ctx context.Context) (ledgerbucketwindow.Le
 		}).OrderBy("lcm.sequence ASC")
 
 	var lcms []xdr.LedgerCloseMeta
-	if err := r.db.Select(ctx, &lcms, query); err != nil {
+	if err := db.Select(ctx, &lcms, query); err != nil {
 		return ledgerbucketwindow.LedgerRange{}, fmt.Errorf("couldn't query ledger range: %w", err)
 	}
 

cmd/soroban-rpc/internal/db/ledger_test.go

@@ -183,25 +183,8 @@ func TestGetLedgerRange_EmptyDB(t *testing.T) {
 }
 
 func BenchmarkGetLedgerRange(b *testing.B) {
-	db := NewTestDB(b)
-	logger := log.DefaultLogger
-	writer := NewReadWriter(logger, db, interfaces.MakeNoOpDeamon(), 100, 1_000_000, passphrase)
-	write, err := writer.NewTx(context.TODO())
-	require.NoError(b, err)
-
-	// create 100k tx rows
-	lcms := make([]xdr.LedgerCloseMeta, 0, 100_000)
-	for i := range cap(lcms) {
-		lcms = append(lcms, txMeta(uint32(1234+i), i%2 == 0))
-	}
-
-	ledgerW, txW := write.LedgerWriter(), write.TransactionWriter()
-	for _, lcm := range lcms {
-		require.NoError(b, ledgerW.InsertLedger(lcm))
-		require.NoError(b, txW.InsertTransactions(lcm))
-	}
-	require.NoError(b, write.Commit(lcms[len(lcms)-1]))
-	reader := NewLedgerReader(db)
+	testDB, lcms := setupBenchmarkingDB(b)
+	reader := NewLedgerReader(testDB)
 
 	b.ResetTimer()
 	for range b.N {
@@ -212,6 +195,22 @@ func BenchmarkGetLedgerRange(b *testing.B) {
 	}
 }
 
+func BenchmarkBatchGetLedgers(b *testing.B) {
+	testDB, lcms := setupBenchmarkingDB(b)
+	reader := NewLedgerReader(testDB)
+	readTx, err := reader.NewTx(context.Background())
+	require.NoError(b, err)
+	batchSize := uint(200) // using the current maximum value for getLedgers endpoint
+
+	b.ResetTimer()
+	for range b.N {
+		ledgers, err := readTx.BatchGetLedgers(context.TODO(), 1334, batchSize)
+		require.NoError(b, err)
+		assert.Equal(b, lcms[0].LedgerSequence(), ledgers[0].LedgerSequence())
+		assert.Equal(b, lcms[batchSize-1].LedgerSequence(), ledgers[batchSize-1].LedgerSequence())
+	}
+}
+
 func NewTestDB(tb testing.TB) *DB {
 	tmp := tb.TempDir()
 	dbPath := path.Join(tmp, "db.sqlite")
@@ -222,3 +221,25 @@ func NewTestDB(tb testing.TB) *DB {
 	})
 	return db
 }
+
+func setupBenchmarkingDB(b *testing.B) (*DB, []xdr.LedgerCloseMeta) {
+	testDB := NewTestDB(b)
+	logger := log.DefaultLogger
+	writer := NewReadWriter(logger, testDB, interfaces.MakeNoOpDeamon(),
+		100, 1_000_000, passphrase)
+	write, err := writer.NewTx(context.TODO())
+	require.NoError(b, err)
+
+	lcms := make([]xdr.LedgerCloseMeta, 0, 100_000)
+	for i := range cap(lcms) {
+		lcms = append(lcms, txMeta(uint32(1234+i), i%2 == 0))
+	}
+
+	ledgerW, txW := write.LedgerWriter(), write.TransactionWriter()
+	for _, lcm := range lcms {
+		require.NoError(b, ledgerW.InsertLedger(lcm))
+		require.NoError(b, txW.InsertTransactions(lcm))
+	}
+	require.NoError(b, write.Commit(lcms[len(lcms)-1]))
+	return testDB, lcms
+}

cmd/soroban-rpc/internal/db/mocks.go

@@ -109,6 +109,10 @@ func (m *MockLedgerReader) GetLedgerRange(_ context.Context) (ledgerbucketwindow
 	return m.txn.ledgerRange, nil
 }
 
+func (m *MockLedgerReader) NewTx(_ context.Context) (LedgerReaderTx, error) {
+	return nil, errors.New("mock NewTx error")
+}
+
 var (
 	_ TransactionReader = &MockTransactionHandler{}
 	_ TransactionWriter = &MockTransactionHandler{}