/
database_backend.go
271 lines (233 loc) · 8.38 KB
/
database_backend.go
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package ledgerbackend
import (
"context"
"database/sql"
"sort"
"time"
"github.com/TosinShada/stellar-core/network"
"github.com/TosinShada/stellar-core/support/db"
"github.com/TosinShada/stellar-core/support/errors"
"github.com/TosinShada/stellar-core/xdr"
)
const (
latestLedgerSeqQuery = "select ledgerseq, closetime from ledgerheaders order by ledgerseq desc limit 1"
txHistoryQuery = "select txbody, txresult, txmeta, txindex from txhistory where ledgerseq = ? "
ledgerHeaderQuery = "select ledgerhash, data from ledgerheaders where ledgerseq = ? "
ledgerSequenceAfterQuery = "select ledgerseq from ledgerheaders where ledgerseq > ? "
txFeeHistoryQuery = "select txchanges, txindex from txfeehistory where ledgerseq = ? "
upgradeHistoryQuery = "select ledgerseq, upgradeindex, upgrade, changes from upgradehistory where ledgerseq = ? order by upgradeindex asc"
orderBy = "order by txindex asc"
dbDriver = "postgres"
)
// Ensure DatabaseBackend implements LedgerBackend
var _ LedgerBackend = (*DatabaseBackend)(nil)
// DatabaseBackend implements a database data store.
type DatabaseBackend struct {
networkPassphrase string
session session
}
func NewDatabaseBackend(dataSourceName, networkPassphrase string) (*DatabaseBackend, error) {
session, err := createSession(dataSourceName)
if err != nil {
return nil, err
}
return NewDatabaseBackendFromSession(session, networkPassphrase)
}
func NewDatabaseBackendFromSession(session db.SessionInterface, networkPassphrase string) (*DatabaseBackend, error) {
return &DatabaseBackend{
session: session,
networkPassphrase: networkPassphrase,
}, nil
}
func (dbb *DatabaseBackend) PrepareRange(ctx context.Context, ledgerRange Range) error {
_, err := dbb.GetLedger(ctx, ledgerRange.from)
if err != nil {
return errors.Wrap(err, "error getting ledger")
}
if ledgerRange.bounded {
_, err := dbb.GetLedger(ctx, ledgerRange.to)
if err != nil {
return errors.Wrap(err, "error getting ledger")
}
}
return nil
}
// IsPrepared returns true if a given ledgerRange is prepared.
func (*DatabaseBackend) IsPrepared(ctx context.Context, ledgerRange Range) (bool, error) {
return true, nil
}
// GetLatestLedgerSequence returns the most recent ledger sequence number present in the database.
func (dbb *DatabaseBackend) GetLatestLedgerSequence(ctx context.Context) (uint32, error) {
var ledger []ledgerHeader
err := dbb.session.SelectRaw(ctx, &ledger, latestLedgerSeqQuery)
if err != nil {
return 0, errors.Wrap(err, "couldn't select ledger sequence")
}
if len(ledger) == 0 {
return 0, errors.New("no ledgers exist in ledgerheaders table")
}
return ledger[0].LedgerSeq, nil
}
func sortByHash(transactions []xdr.TransactionEnvelope, passphrase string) error {
hashes := make([]xdr.Hash, len(transactions))
txByHash := map[xdr.Hash]xdr.TransactionEnvelope{}
for i, tx := range transactions {
hash, err := network.HashTransactionInEnvelope(tx, passphrase)
if err != nil {
return errors.Wrap(err, "cannot hash transaction")
}
hashes[i] = hash
txByHash[hash] = tx
}
sort.Slice(hashes, func(i, j int) bool {
a := hashes[i]
b := hashes[j]
for k := range a {
if a[k] < b[k] {
return true
}
if a[k] > b[k] {
return false
}
}
return false
})
for i, hash := range hashes {
transactions[i] = txByHash[hash]
}
return nil
}
// GetLedger will block until the ledger is
// available in the backend (even for UnaboundedRange).
// Please note that requesting a ledger sequence far after current ledger will
// block the execution for a long time.
func (dbb *DatabaseBackend) GetLedger(ctx context.Context, sequence uint32) (xdr.LedgerCloseMeta, error) {
for {
exists, meta, err := dbb.getLedgerQuery(ctx, sequence)
if err != nil {
return xdr.LedgerCloseMeta{}, err
}
if exists {
return meta, nil
} else {
// Check if there are ledgers after `sequence`. If so, it's likely
// the requested sequence was removed during maintenance so return
// error.
ledgerAfterExist, oldestSequenceAfter, err := dbb.getLedgerAfterExist(ctx, sequence)
if err != nil {
return xdr.LedgerCloseMeta{}, err
}
if ledgerAfterExist {
return xdr.LedgerCloseMeta{}, errors.Errorf("requested ledger already removed (oldest sequence after %d is %d)", sequence, oldestSequenceAfter)
}
time.Sleep(time.Second)
}
}
}
// getLedgerAfterExist returns true (and sequence number) if there's a ledger in
// the Stellar-Core DB with the sequence number higher than sequence.
func (dbb *DatabaseBackend) getLedgerAfterExist(ctx context.Context, sequence uint32) (bool, uint32, error) {
var fetchedSequence uint32
err := dbb.session.GetRaw(ctx, &fetchedSequence, ledgerSequenceAfterQuery, sequence)
// Return errors...
if err != nil {
switch err {
case sql.ErrNoRows:
// Ledger was not found
return false, fetchedSequence, nil
default:
return false, fetchedSequence, errors.Wrapf(err, "Error getting ledger after %d", sequence)
}
}
return true, fetchedSequence, nil
}
// getLedgerQuery returns the LedgerCloseMeta for the given ledger sequence number.
// The first returned value is false when the ledger does not exist in the database.
func (dbb *DatabaseBackend) getLedgerQuery(ctx context.Context, sequence uint32) (bool, xdr.LedgerCloseMeta, error) {
lcm := xdr.LedgerCloseMeta{
V0: &xdr.LedgerCloseMetaV0{},
}
// Query - ledgerheader
var lRow ledgerHeaderHistory
err := dbb.session.GetRaw(ctx, &lRow, ledgerHeaderQuery, sequence)
// Return errors...
if err != nil {
switch err {
case sql.ErrNoRows:
// Ledger was not found
return false, xdr.LedgerCloseMeta{}, nil
default:
return false, xdr.LedgerCloseMeta{}, errors.Wrap(err, "Error getting ledger header")
}
}
// ...otherwise store the header
lcm.V0.LedgerHeader = xdr.LedgerHeaderHistoryEntry{
Hash: lRow.Hash,
Header: lRow.Header,
Ext: xdr.LedgerHeaderHistoryEntryExt{},
}
// Query - txhistory
var txhRows []txHistory
err = dbb.session.SelectRaw(ctx, &txhRows, txHistoryQuery+orderBy, sequence)
// Return errors...
if err != nil {
return false, lcm, errors.Wrap(err, "Error getting txHistory")
}
// ...otherwise store the data
for i, tx := range txhRows {
// Sanity check index. Note that first TXIndex in a ledger is 1
if i != int(tx.TXIndex)-1 {
return false, xdr.LedgerCloseMeta{}, errors.New("transactions read from DB history table are misordered")
}
lcm.V0.TxSet.Txs = append(lcm.V0.TxSet.Txs, tx.TXBody)
lcm.V0.TxProcessing = append(lcm.V0.TxProcessing, xdr.TransactionResultMeta{
Result: tx.TXResult,
TxApplyProcessing: tx.TXMeta,
})
}
if err = sortByHash(lcm.V0.TxSet.Txs, dbb.networkPassphrase); err != nil {
return false, xdr.LedgerCloseMeta{}, errors.Wrap(err, "could not sort txset")
}
// Query - txfeehistory
var txfhRows []txFeeHistory
err = dbb.session.SelectRaw(ctx, &txfhRows, txFeeHistoryQuery+orderBy, sequence)
// Return errors...
if err != nil {
return false, lcm, errors.Wrap(err, "Error getting txFeeHistory")
}
// ...otherwise store the data
for i, tx := range txfhRows {
// Sanity check index. Note that first TXIndex in a ledger is 1
if i != int(tx.TXIndex)-1 {
return false, xdr.LedgerCloseMeta{}, errors.New("transactions read from DB fee history table are misordered")
}
lcm.V0.TxProcessing[i].FeeProcessing = tx.TXChanges
}
// Query - upgradehistory
var upgradeHistoryRows []upgradeHistory
err = dbb.session.SelectRaw(ctx, &upgradeHistoryRows, upgradeHistoryQuery, sequence)
// Return errors...
if err != nil {
return false, lcm, errors.Wrap(err, "Error getting upgradeHistoryRows")
}
// ...otherwise store the data
lcm.V0.UpgradesProcessing = make([]xdr.UpgradeEntryMeta, len(upgradeHistoryRows))
for i, upgradeHistoryRow := range upgradeHistoryRows {
lcm.V0.UpgradesProcessing[i] = xdr.UpgradeEntryMeta{
Upgrade: upgradeHistoryRow.Upgrade,
Changes: upgradeHistoryRow.Changes,
}
}
return true, lcm, nil
}
// CreateSession returns a new db.Session that connects to the given DB settings.
func createSession(dataSourceName string) (*db.Session, error) {
if dataSourceName == "" {
return nil, errors.New("missing DatabaseBackend.DataSourceName (e.g. \"postgres://stellar:postgres@localhost:8002/core\")")
}
return db.Open(dbDriver, dataSourceName)
}
// Close disconnects an active database session.
func (dbb *DatabaseBackend) Close() error {
return dbb.session.Close()
}