Ingest signers change from pre-auth transactions

es/ledger_serializer.go

@@ -41,6 +41,11 @@ func (s *ledgerSerializer) serialize() {
 		if transaction.Successful {
 			changes := s.feeRows[transaction.Index-1].Changes
 			s.serializeBalances(changes, transaction, nil, BalanceSourceFee)
+
+			h := ProduceSignerHistoryFromTxMeta(transaction)
+			if h != nil {
+				SerializeForBulk(h, s.buffer)
+			}
 		}
 
 		s.serializeOperations(transactionRow, transaction)
@@ -64,7 +69,7 @@ func (s *ledgerSerializer) serializeOperations(transactionRow db.TxHistoryRow, t
 
 			s.serializeTrades(result, transaction, operation, effectsCount)
 
-			h := ProduceSignerHistory(operation)
+			h := ProduceSignerHistoryFromOperation(operation)
 			if h != nil {
 				SerializeForBulk(h, s.buffer)
 			}

es/signer_history.go

@@ -1,6 +1,7 @@
 package es
 
 import (
+	"github.com/stellar/go/xdr"
 	"time"
 )
 
@@ -17,8 +18,86 @@ type SignerHistory struct {
 	LedgerCloseTime time.Time   `json:"ledger_close_time"`
 }
 
-// ProduceSignerHistory creates new signer history entry
-func ProduceSignerHistory(o *Operation) (h *SignerHistory) {
+// ProduceSignerHistoryFromTxMeta handles pre-authorized transactions
+//
+// Stellar allows user to create pre-authorized transactions, which
+// can be submitted later by other users. This mechanism is implemented
+// using multi-sig. When such pre-authorized transaction is executed, the "signer"
+// for this transaction is deleted. We should ingest this change too
+//
+// You can read about pre-authorized transactions process here:
+// https://medium.com/@katopz/stellar-pre-signed-transaction-d93e91191c15
+func ProduceSignerHistoryFromTxMeta(tx *Transaction) (h *SignerHistory) {
+	currentSigners := make(map[string][]xdr.Signer)
+
+	for _, change := range tx.meta.TxChanges {
+		if change.EntryType() != xdr.LedgerEntryTypeAccount {
+			continue
+		}
+
+		switch t := change.Type; t {
+		case xdr.LedgerEntryChangeTypeLedgerEntryState:
+			accountData := change.MustState().Data.MustAccount()
+			accountId := accountData.AccountId.Address()
+
+			currentSigners[accountId] = accountData.Signers
+
+		case xdr.LedgerEntryChangeTypeLedgerEntryUpdated:
+			accountData := change.MustUpdated().Data.MustAccount()
+			accountId := accountData.AccountId.Address()
+
+			if len(currentSigners[accountId]) == len(accountData.Signers) {
+				continue
+			}
+
+			for _, signer := range currentSigners[accountId] {
+				if contains(accountData.Signers, signer) {
+					continue
+				}
+
+				s := NewSigner(&signer)
+
+				token := PagingToken{
+					LedgerSeq:        tx.Seq,
+					TransactionOrder: tx.Index,
+				}
+
+				entry := &SignerHistory{
+					PagingToken:     token,
+					AccountID:       accountId,
+					Signer:          s.ID,
+					Type:            s.Type,
+					Weight:          0,
+					TxIndex:         tx.Index,
+					Index:           0,
+					Seq:             tx.Seq,
+					LedgerCloseTime: tx.CloseTime,
+				}
+
+				// we can return quickly, because there can be only one
+				// signer change in pre-auth tx
+				return entry
+			}
+		}
+	}
+
+	return nil
+}
+
+// contains checks, whether given array of signers contains given
+// particular signer or nor
+func contains(array []xdr.Signer, signer xdr.Signer) bool {
+	for _, s := range array {
+		if s.Key.Address() == signer.Key.Address() && s.Weight == signer.Weight {
+			return true
+		}
+	}
+
+	return false
+}
+
+// ProduceSignerHistoryFromOperation creates new signer history entry
+func ProduceSignerHistoryFromOperation(o *Operation) (h *SignerHistory) {
 	s := o.Signer
 
 	if s == nil {

es/transaction.go

@@ -21,6 +21,8 @@ type Transaction struct {
 	ResultCode      int         `json:"result_code"`
 	SourceAccountID string      `json:"source_account_id"`
 
+	meta xdr.TransactionMetaV1
+
 	*TimeBounds `json:"time_bounds,omitempty"`
 	*Memo       `json:"memo,omitempty"`
 }
@@ -41,6 +43,7 @@ func NewTransaction(row *db.TxHistoryRow, t time.Time) *Transaction {
 		Successful:      resultCode == xdr.TransactionResultCodeTxSuccess,
 		ResultCode:      int(resultCode),
 		SourceAccountID: row.Envelope.Tx.SourceAccount.Address(),
+		meta:            row.Meta.MustV1(),
 	}
 
 	if row.Envelope.Tx.Memo.Type != xdr.MemoTypeMemoNone {