Add PoolL2Tx.Info about the status of the tx

PoolL2Tx.Info contains information about the status & State of the
transaction. As for example, if the Tx has not been selected in the last
batch due not enough Balance at the Sender account, this reason would
appear at this parameter.
This will help the client (wallet, batchexplorer, etc) to reason why a
L2Tx is not selected in the forged batches.

db/l2db/l2db.go

@@ -94,6 +94,37 @@ func (l2db *L2DB) AddTx(tx *PoolL2TxWrite) error {
 	return tracerr.Wrap(meddler.Insert(l2db.db, "tx_pool", tx))
 }
 
+// UpdateTxsInfo updates the parameter Info of the pool transactions
+func (l2db *L2DB) UpdateTxsInfo(txs []common.PoolL2Tx) error {
+	if len(txs) == 0 {
+		return nil
+	}
+	type txUpdate struct {
+		ID   common.TxID `db:"id"`
+		Info string      `db:"info"`
+	}
+	txUpdates := make([]txUpdate, len(txs))
+	for i := range txs {
+		txUpdates[i] = txUpdate{ID: txs[i].TxID, Info: txs[i].Info}
+	}
+	const query string = `
+		UPDATE tx_pool SET
+			info = tx_update.info
+		FROM (VALUES
+			(NULL::::BYTEA, NULL::::VARCHAR),
+			(:id, :info)
+		) as tx_update (id, info)
+		WHERE tx_pool.tx_id = tx_update.id;
+	`
+	if len(txUpdates) > 0 {
+		if _, err := sqlx.NamedExec(l2db.db, query, txUpdates); err != nil {
+			return tracerr.Wrap(err)
+		}
+	}
+
+	return nil
+}
+
 // AddTxTest inserts a tx into the L2DB. This is useful for test purposes,
 // but in production txs will only be inserted through the API
 func (l2db *L2DB) AddTxTest(tx *common.PoolL2Tx) error {
@@ -146,7 +177,7 @@ func (l2db *L2DB) AddTxTest(tx *common.PoolL2Tx) error {
 const selectPoolTxAPI = `SELECT  tx_pool.tx_id, hez_idx(tx_pool.from_idx, token.symbol) AS from_idx, tx_pool.effective_from_eth_addr, 
 tx_pool.effective_from_bjj, hez_idx(tx_pool.to_idx, token.symbol) AS to_idx, tx_pool.effective_to_eth_addr, 
 tx_pool.effective_to_bjj, tx_pool.token_id, tx_pool.amount, tx_pool.fee, tx_pool.nonce, 
-tx_pool.state, tx_pool.signature, tx_pool.timestamp, tx_pool.batch_num, hez_idx(tx_pool.rq_from_idx, token.symbol) AS rq_from_idx, 
+tx_pool.state, tx_pool.info, tx_pool.signature, tx_pool.timestamp, tx_pool.batch_num, hez_idx(tx_pool.rq_from_idx, token.symbol) AS rq_from_idx, 
 hez_idx(tx_pool.rq_to_idx, token.symbol) AS rq_to_idx, tx_pool.rq_to_eth_addr, tx_pool.rq_to_bjj, tx_pool.rq_token_id, tx_pool.rq_amount, 
 tx_pool.rq_fee, tx_pool.rq_nonce, tx_pool.tx_type, 
 token.item_id AS token_item_id, token.eth_block_num, token.eth_addr, token.name, token.symbol, token.decimals, token.usd, token.usd_update 
@@ -155,7 +186,7 @@ FROM tx_pool INNER JOIN token ON tx_pool.token_id = token.token_id `
 // selectPoolTxCommon select part of queries to get common.PoolL2Tx
 const selectPoolTxCommon = `SELECT  tx_pool.tx_id, from_idx, to_idx, tx_pool.to_eth_addr, 
 tx_pool.to_bjj, tx_pool.token_id, tx_pool.amount, tx_pool.fee, tx_pool.nonce, 
-tx_pool.state, tx_pool.signature, tx_pool.timestamp, rq_from_idx, 
+tx_pool.state, tx_pool.info, tx_pool.signature, tx_pool.timestamp, rq_from_idx, 
 rq_to_idx, tx_pool.rq_to_eth_addr, tx_pool.rq_to_bjj, tx_pool.rq_token_id, tx_pool.rq_amount, 
 tx_pool.rq_fee, tx_pool.rq_nonce, tx_pool.tx_type, 
 fee_percentage(tx_pool.fee::NUMERIC) * token.usd * tx_pool.amount_f AS fee_usd, token.usd_update  

db/l2db/l2db_test.go

@@ -162,6 +162,30 @@ func TestAddTxTest(t *testing.T) {
 		assert.Equal(t, 0, offset)
 	}
 }
+func TestUpdateTxsInfo(t *testing.T) {
+	err := prepareHistoryDB(historyDB)
+	if err != nil {
+		log.Error("Error prepare historyDB", err)
+	}
+	poolL2Txs, err := generatePoolL2Txs()
+	assert.NoError(t, err)
+	for i := range poolL2Txs {
+		err := l2DB.AddTxTest(&poolL2Txs[i])
+		require.NoError(t, err)
+
+		// once added, change the Info parameter
+		poolL2Txs[i].Info = "test"
+	}
+	// update the txs
+	err = l2DB.UpdateTxsInfo(poolL2Txs)
+	require.NoError(t, err)
+
+	for i := range poolL2Txs {
+		fetchedTx, err := l2DB.GetTx(poolL2Txs[i].TxID)
+		assert.NoError(t, err)
+		assert.Equal(t, "test", fetchedTx.Info)
+	}
+}
 
 func assertTx(t *testing.T, expected, actual *common.PoolL2Tx) {
 	// Check that timestamp has been set within the last 3 seconds

db/l2db/views.go

@@ -49,6 +49,7 @@ type PoolTxAPI struct {
 	Fee                  common.FeeSelector    `meddler:"fee"`
 	Nonce                common.Nonce          `meddler:"nonce"`
 	State                common.PoolL2TxState  `meddler:"state"`
+	Info                 *string               `meddler:"info"`
 	Signature            babyjub.SignatureComp `meddler:"signature"`
 	RqFromIdx            *apitypes.HezIdx      `meddler:"rq_from_idx"`
 	RqToIdx              *apitypes.HezIdx      `meddler:"rq_to_idx"`
@@ -90,6 +91,7 @@ func (tx PoolTxAPI) MarshalJSON() ([]byte, error) {
 		"fee":                         tx.Fee,
 		"nonce":                       tx.Nonce,
 		"state":                       tx.State,
+		"info":                        tx.Info,
 		"signature":                   tx.Signature,
 		"timestamp":                   tx.Timestamp,
 		"batchNum":                    tx.BatchNum,