Add Last db view in kvdb and statedb

Last db view is an opened pebble db which always contains a checkpoint from the
last batch.  Methods to access this last batch are thread safe so that views of
the last checkpoint can be made anywhere and with a consistent view of the
state.

api/account.go

@@ -6,6 +6,8 @@ import (
 	"github.com/gin-gonic/gin"
 	"github.com/hermeznetwork/hermez-node/apitypes"
 	"github.com/hermeznetwork/hermez-node/db/historydb"
+	"github.com/hermeznetwork/hermez-node/db/statedb"
+	"github.com/hermeznetwork/tracerr"
 )
 
 func (a *API) getAccount(c *gin.Context) {
@@ -22,7 +24,7 @@ func (a *API) getAccount(c *gin.Context) {
 	}
 
 	// Get balance from stateDB
-	account, err := a.s.GetAccount(*idx)
+	account, err := a.s.LastGetAccount(*idx)
 	if err != nil {
 		retSQLErr(err, c)
 		return
@@ -56,19 +58,23 @@ func (a *API) getAccounts(c *gin.Context) {
 	}
 
 	// Get balances from stateDB
-	for x, apiAccount := range apiAccounts {
-		idx, err := stringToIdx(string(apiAccount.Idx), "Account Idx")
-		if err != nil {
-			retSQLErr(err, c)
-			return
+	if err := a.s.LastRead(func(sdb *statedb.Last) error {
+		for x, apiAccount := range apiAccounts {
+			idx, err := stringToIdx(string(apiAccount.Idx), "Account Idx")
+			if err != nil {
+				return tracerr.Wrap(err)
+			}
+			account, err := sdb.GetAccount(*idx)
+			if err != nil {
+				return tracerr.Wrap(err)
+			}
+			apiAccounts[x].Balance = apitypes.NewBigIntStr(account.Balance)
+			apiAccounts[x].Nonce = account.Nonce
 		}
-		account, err := a.s.GetAccount(*idx)
-		if err != nil {
-			retSQLErr(err, c)
-			return
-		}
-		apiAccounts[x].Balance = apitypes.NewBigIntStr(account.Balance)
-		apiAccounts[x].Nonce = account.Nonce
+		return nil
+	}); err != nil {
+		retSQLErr(err, c)
+		return
 	}
 
 	// Build succesfull response

api/account_test.go

@@ -10,6 +10,7 @@ import (
 	"github.com/hermeznetwork/hermez-node/db/historydb"
 	"github.com/mitchellh/copystructure"
 	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
 )
 
 type testAccount struct {
@@ -76,40 +77,40 @@ func TestGetAccounts(t *testing.T) {
 	// Filter by BJJ
 	path := fmt.Sprintf("%s?BJJ=%s&limit=%d", endpoint, tc.accounts[0].PublicKey, limit)
 	err := doGoodReqPaginated(path, historydb.OrderAsc, &testAccountsResponse{}, appendIter)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	assert.Greater(t, len(fetchedAccounts), 0)
 	assert.LessOrEqual(t, len(fetchedAccounts), len(tc.accounts))
 	fetchedAccounts = []testAccount{}
 	// Filter by ethAddr
 	path = fmt.Sprintf("%s?hezEthereumAddress=%s&limit=%d", endpoint, tc.accounts[3].EthAddr, limit)
 	err = doGoodReqPaginated(path, historydb.OrderAsc, &testAccountsResponse{}, appendIter)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	assert.Greater(t, len(fetchedAccounts), 0)
 	assert.LessOrEqual(t, len(fetchedAccounts), len(tc.accounts))
 	fetchedAccounts = []testAccount{}
 	// both filters (incompatible)
 	path = fmt.Sprintf("%s?hezEthereumAddress=%s&BJJ=%s&limit=%d", endpoint, tc.accounts[0].EthAddr, tc.accounts[0].PublicKey, limit)
 	err = doBadReq("GET", path, nil, 400)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	fetchedAccounts = []testAccount{}
 	// Filter by token IDs
 	path = fmt.Sprintf("%s?tokenIds=%s&limit=%d", endpoint, stringIds, limit)
 	err = doGoodReqPaginated(path, historydb.OrderAsc, &testAccountsResponse{}, appendIter)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	assert.Greater(t, len(fetchedAccounts), 0)
 	assert.LessOrEqual(t, len(fetchedAccounts), len(tc.accounts))
 	fetchedAccounts = []testAccount{}
 	// Token Ids + bjj
 	path = fmt.Sprintf("%s?tokenIds=%s&BJJ=%s&limit=%d", endpoint, stringIds, tc.accounts[10].PublicKey, limit)
 	err = doGoodReqPaginated(path, historydb.OrderAsc, &testAccountsResponse{}, appendIter)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	assert.Greater(t, len(fetchedAccounts), 0)
 	assert.LessOrEqual(t, len(fetchedAccounts), len(tc.accounts))
 	fetchedAccounts = []testAccount{}
 	// No filters (checks response content)
 	path = fmt.Sprintf("%s?limit=%d", endpoint, limit)
 	err = doGoodReqPaginated(path, historydb.OrderAsc, &testAccountsResponse{}, appendIter)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	assert.Equal(t, len(tc.accounts), len(fetchedAccounts))
 	for i := 0; i < len(fetchedAccounts); i++ {
 		fetchedAccounts[i].Token.ItemID = 0
@@ -132,7 +133,7 @@ func TestGetAccounts(t *testing.T) {
 		}
 	}
 	err = doGoodReqPaginated(path, historydb.OrderDesc, &testAccountsResponse{}, appendIter)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	assert.Equal(t, len(reversedAccounts), len(fetchedAccounts))
 	for i := 0; i < len(fetchedAccounts); i++ {
 		reversedAccounts[i].Token.ItemID = 0
@@ -147,21 +148,21 @@ func TestGetAccounts(t *testing.T) {
 	// 400
 	path = fmt.Sprintf("%s?hezEthereumAddress=hez:0x123456", endpoint)
 	err = doBadReq("GET", path, nil, 400)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 
 	// Test GetAccount
 	path = fmt.Sprintf("%s/%s", endpoint, fetchedAccounts[2].Idx)
 	account := testAccount{}
-	assert.NoError(t, doGoodReq("GET", path, nil, &account))
+	require.NoError(t, doGoodReq("GET", path, nil, &account))
 	account.Token.ItemID = 0
 	assert.Equal(t, fetchedAccounts[2], account)
 
 	// 400
 	path = fmt.Sprintf("%s/hez:12345", endpoint)
 	err = doBadReq("GET", path, nil, 400)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 	// 404
 	path = fmt.Sprintf("%s/hez:10:12345", endpoint)
 	err = doBadReq("GET", path, nil, 404)
-	assert.NoError(t, err)
+	require.NoError(t, err)
 }

api/api_test.go

@@ -355,6 +355,10 @@ func TestMain(m *testing.M) {
 			panic(err)
 		}
 	}
+	// Make a checkpoint to make the accounts available in Last
+	if err := api.s.MakeCheckpoint(); err != nil {
+		panic(err)
+	}
 
 	// Generate Coordinators and add them to HistoryDB
 	const nCoords = 10

api/txspool.go

@@ -170,7 +170,7 @@ func (a *API) verifyPoolL2TxWrite(txw *l2db.PoolL2TxWrite) error {
 		return tracerr.Wrap(err)
 	}
 	// Get public key
-	account, err := a.s.GetAccount(poolTx.FromIdx)
+	account, err := a.s.LastGetAccount(poolTx.FromIdx)
 	if err != nil {
 		return tracerr.Wrap(err)
 	}