Pass StateDB constructor parameters as Config type

- KVDB/StateDB
        - Pass config parameters in a Config type instead of using many
          arguments in constructor.
	- Add new parameter `NoLast` which disables having an opened DB with a
	  checkpoint to the last batchNum for thread-safe reads.  Last will be
	  disabled in the StateDB used by the TxSelector and BatchBuilder.
	- Add new parameter `NoGapsCheck` which skips checking gaps in the list
	  of checkpoints and returning errors if there are gaps.  Gaps check
	  will be disabled in the StateDB used by the TxSelector and
	  BatchBuilder, because we expect to have gaps when there are multiple
	  coordinators forging (slots not forged by our coordinator will leave
	  gaps).

db/statedb/statedb.go

@@ -52,19 +52,40 @@ const (
 	// TypeBatchBuilder defines a StateDB used by the BatchBuilder, that
 	// generates the ExitTree and the ZKInput when processing the txs
 	TypeBatchBuilder = "batchbuilder"
+	// MaxNLevels is the maximum value of NLevels for the merkle tree,
+	// which comes from the fact that AccountIdx has 48 bits.
+	MaxNLevels = 48
 )
 
 // TypeStateDB determines the type of StateDB
 type TypeStateDB string
 
+// Config of the StateDB
+type Config struct {
+	// Path where the checkpoints will be stored
+	Path string
+	// Keep is the number of old checkpoints to keep.  If 0, all
+	// checkpoints are kept.
+	Keep int
+	// NoLast skips having an opened DB with a checkpoint to the last
+	// batchNum for thread-safe reads.
+	NoLast bool
+	// Type of StateDB (
+	Type TypeStateDB
+	// NLevels is the number of merkle tree levels in case the Type uses a
+	// merkle tree.  If the Type doesn't use a merkle tree, NLevels should
+	// be 0.
+	NLevels int
+	// At every checkpoint, check that there are no gaps between the
+	// checkpoints
+	noGapsCheck bool
+}
+
 // StateDB represents the StateDB object
 type StateDB struct {
-	path    string
-	Typ     TypeStateDB
-	db      *kvdb.KVDB
-	nLevels int
-	MT      *merkletree.MerkleTree
-	keep    int
+	cfg Config
+	db  *kvdb.KVDB
+	MT  *merkletree.MerkleTree
 }
 
 // Last offers a subset of view methods of the StateDB that can be
@@ -104,36 +125,40 @@ func (s *Last) GetAccounts() ([]common.Account, error) {
 // NewStateDB creates a new StateDB, allowing to use an in-memory or in-disk
 // storage.  Checkpoints older than the value defined by `keep` will be
 // deleted.
-func NewStateDB(pathDB string, keep int, typ TypeStateDB, nLevels int) (*StateDB, error) {
+// func NewStateDB(pathDB string, keep int, typ TypeStateDB, nLevels int) (*StateDB, error) {
+func NewStateDB(cfg Config) (*StateDB, error) {
 	var kv *kvdb.KVDB
 	var err error
 
-	kv, err = kvdb.NewKVDB(pathDB, keep)
+	kv, err = kvdb.NewKVDB(kvdb.Config{Path: cfg.Path, Keep: cfg.Keep,
+		NoGapsCheck: cfg.noGapsCheck, NoLast: cfg.NoLast})
 	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}
 
 	var mt *merkletree.MerkleTree = nil
-	if typ == TypeSynchronizer || typ == TypeBatchBuilder {
-		mt, err = merkletree.NewMerkleTree(kv.StorageWithPrefix(PrefixKeyMT), nLevels)
+	if cfg.Type == TypeSynchronizer || cfg.Type == TypeBatchBuilder {
+		mt, err = merkletree.NewMerkleTree(kv.StorageWithPrefix(PrefixKeyMT), cfg.NLevels)
 		if err != nil {
 			return nil, tracerr.Wrap(err)
 		}
 	}
-	if typ == TypeTxSelector && nLevels != 0 {
+	if cfg.Type == TypeTxSelector && cfg.NLevels != 0 {
 		return nil, tracerr.Wrap(fmt.Errorf("invalid StateDB parameters: StateDB type==TypeStateDB can not have nLevels!=0"))
 	}
 
 	return &StateDB{
-		path:    pathDB,
-		db:      kv,
-		nLevels: nLevels,
-		MT:      mt,
-		Typ:     typ,
-		keep:    keep,
+		cfg: cfg,
+		db:  kv,
+		MT:  mt,
 	}, nil
 }
 
+// Type returns the StateDB configured Type
+func (s *StateDB) Type() TypeStateDB {
+	return s.cfg.Type
+}
+
 // LastRead is a thread-safe method to query the last checkpoint of the StateDB
 // via the Last type methods
 func (s *StateDB) LastRead(fn func(sdbLast *Last) error) error {
@@ -179,7 +204,7 @@ func (s *StateDB) LastGetCurrentBatch() (common.BatchNum, error) {
 func (s *StateDB) LastMTGetRoot() (*big.Int, error) {
 	var root *big.Int
 	if err := s.LastRead(func(sdb *Last) error {
-		mt, err := merkletree.NewMerkleTree(sdb.DB().WithPrefix(PrefixKeyMT), s.nLevels)
+		mt, err := merkletree.NewMerkleTree(sdb.DB().WithPrefix(PrefixKeyMT), s.cfg.NLevels)
 		if err != nil {
 			return tracerr.Wrap(err)
 		}
@@ -195,7 +220,7 @@ func (s *StateDB) LastMTGetRoot() (*big.Int, error) {
 // Internally this advances & stores the current BatchNum, and then stores a
 // Checkpoint of the current state of the StateDB.
 func (s *StateDB) MakeCheckpoint() error {
-	log.Debugw("Making StateDB checkpoint", "batch", s.CurrentBatch()+1, "type", s.Typ)
+	log.Debugw("Making StateDB checkpoint", "batch", s.CurrentBatch()+1, "type", s.cfg.Type)
 	return s.db.MakeCheckpoint()
 }
 
@@ -230,7 +255,7 @@ func (s *StateDB) SetCurrentIdx(idx common.Idx) error {
 // those checkpoints will remain in the storage, and eventually will be
 // deleted when MakeCheckpoint overwrites them.
 func (s *StateDB) Reset(batchNum common.BatchNum) error {
-	log.Debugw("Making StateDB Reset", "batch", batchNum, "type", s.Typ)
+	log.Debugw("Making StateDB Reset", "batch", batchNum, "type", s.cfg.Type)
 	if err := s.db.Reset(batchNum); err != nil {
 		return tracerr.Wrap(err)
 	}
@@ -460,9 +485,10 @@ type LocalStateDB struct {
 // NewLocalStateDB returns a new LocalStateDB connected to the given
 // synchronizerDB.  Checkpoints older than the value defined by `keep` will be
 // deleted.
-func NewLocalStateDB(path string, keep int, synchronizerDB *StateDB, typ TypeStateDB,
-	nLevels int) (*LocalStateDB, error) {
-	s, err := NewStateDB(path, keep, typ, nLevels)
+func NewLocalStateDB(cfg Config, synchronizerDB *StateDB) (*LocalStateDB, error) {
+	cfg.noGapsCheck = true
+	cfg.NoLast = true
+	s, err := NewStateDB(cfg)
 	if err != nil {
 		return nil, tracerr.Wrap(err)
 	}

db/statedb/statedb_test.go

@@ -45,7 +45,7 @@ func TestNewStateDBIntermediateState(t *testing.T) {
 	require.NoError(t, err)
 	defer require.NoError(t, os.RemoveAll(dir))
 
-	sdb, err := NewStateDB(dir, 128, TypeTxSelector, 0)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: 128, Type: TypeTxSelector, NLevels: 0})
 	require.NoError(t, err)
 
 	// test values
@@ -78,7 +78,7 @@ func TestNewStateDBIntermediateState(t *testing.T) {
 
 	// call NewStateDB which should get the db at the last checkpoint state
 	// executing a Reset (discarding the last 'testkey0'&'testvalue0' data)
-	sdb, err = NewStateDB(dir, 128, TypeTxSelector, 0)
+	sdb, err = NewStateDB(Config{Path: dir, Keep: 128, Type: TypeTxSelector, NLevels: 0})
 	require.NoError(t, err)
 	v, err = sdb.db.DB().Get(k0)
 	assert.NotNil(t, err)
@@ -158,7 +158,7 @@ func TestNewStateDBIntermediateState(t *testing.T) {
 
 	// call NewStateDB which should get the db at the last checkpoint state
 	// executing a Reset (discarding the last 'testkey1'&'testvalue1' data)
-	sdb, err = NewStateDB(dir, 128, TypeTxSelector, 0)
+	sdb, err = NewStateDB(Config{Path: dir, Keep: 128, Type: TypeTxSelector, NLevels: 0})
 	require.NoError(t, err)
 
 	bn, err = sdb.getCurrentBatch()
@@ -182,7 +182,7 @@ func TestStateDBWithoutMT(t *testing.T) {
 	require.NoError(t, err)
 	defer require.NoError(t, os.RemoveAll(dir))
 
-	sdb, err := NewStateDB(dir, 128, TypeTxSelector, 0)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: 128, Type: TypeTxSelector, NLevels: 0})
 	require.NoError(t, err)
 
 	// create test accounts
@@ -236,7 +236,7 @@ func TestStateDBWithMT(t *testing.T) {
 	require.NoError(t, err)
 	defer require.NoError(t, os.RemoveAll(dir))
 
-	sdb, err := NewStateDB(dir, 128, TypeSynchronizer, 32)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: 128, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	// create test accounts
@@ -290,7 +290,7 @@ func TestCheckpoints(t *testing.T) {
 	require.NoError(t, err)
 	defer require.NoError(t, os.RemoveAll(dir))
 
-	sdb, err := NewStateDB(dir, 128, TypeSynchronizer, 32)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: 128, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	err = sdb.Reset(0)
@@ -335,7 +335,7 @@ func TestCheckpoints(t *testing.T) {
 		assert.Equal(t, common.BatchNum(i+1), cb)
 	}
 
-	// printCheckpoints(t, sdb.path)
+	// printCheckpoints(t, sdb.cfg.Path)
 
 	// reset checkpoint
 	err = sdb.Reset(3)
@@ -371,7 +371,7 @@ func TestCheckpoints(t *testing.T) {
 	dirLocal, err := ioutil.TempDir("", "ldb")
 	require.NoError(t, err)
 	defer require.NoError(t, os.RemoveAll(dirLocal))
-	ldb, err := NewLocalStateDB(dirLocal, 128, sdb, TypeBatchBuilder, 32)
+	ldb, err := NewLocalStateDB(Config{Path: dirLocal, Keep: 128, Type: TypeBatchBuilder, NLevels: 32}, sdb)
 	require.NoError(t, err)
 
 	// get checkpoint 4 from sdb (StateDB) to ldb (LocalStateDB)
@@ -392,7 +392,7 @@ func TestCheckpoints(t *testing.T) {
 	dirLocal2, err := ioutil.TempDir("", "ldb2")
 	require.NoError(t, err)
 	defer require.NoError(t, os.RemoveAll(dirLocal2))
-	ldb2, err := NewLocalStateDB(dirLocal2, 128, sdb, TypeBatchBuilder, 32)
+	ldb2, err := NewLocalStateDB(Config{Path: dirLocal2, Keep: 128, Type: TypeBatchBuilder, NLevels: 32}, sdb)
 	require.NoError(t, err)
 
 	// get checkpoint 4 from sdb (StateDB) to ldb (LocalStateDB)
@@ -409,9 +409,9 @@ func TestCheckpoints(t *testing.T) {
 
 	debug := false
 	if debug {
-		printCheckpoints(t, sdb.path)
-		printCheckpoints(t, ldb.path)
-		printCheckpoints(t, ldb2.path)
+		printCheckpoints(t, sdb.cfg.Path)
+		printCheckpoints(t, ldb.cfg.Path)
+		printCheckpoints(t, ldb2.cfg.Path)
 	}
 }
 
@@ -419,7 +419,7 @@ func TestStateDBGetAccounts(t *testing.T) {
 	dir, err := ioutil.TempDir("", "tmpdb")
 	require.NoError(t, err)
 
-	sdb, err := NewStateDB(dir, 128, TypeTxSelector, 0)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: 128, Type: TypeTxSelector, NLevels: 0})
 	require.NoError(t, err)
 
 	// create test accounts
@@ -466,7 +466,7 @@ func TestCheckAccountsTreeTestVectors(t *testing.T) {
 	require.NoError(t, err)
 	defer require.NoError(t, os.RemoveAll(dir))
 
-	sdb, err := NewStateDB(dir, 128, TypeSynchronizer, 32)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: 128, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	ay0 := new(big.Int).Sub(new(big.Int).Exp(big.NewInt(2), big.NewInt(253), nil), big.NewInt(1))
@@ -540,7 +540,7 @@ func TestListCheckpoints(t *testing.T) {
 	require.NoError(t, err)
 	defer require.NoError(t, os.RemoveAll(dir))
 
-	sdb, err := NewStateDB(dir, 128, TypeSynchronizer, 32)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: 128, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	numCheckpoints := 16
@@ -573,7 +573,7 @@ func TestDeleteOldCheckpoints(t *testing.T) {
 	defer require.NoError(t, os.RemoveAll(dir))
 
 	keep := 16
-	sdb, err := NewStateDB(dir, keep, TypeSynchronizer, 32)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: keep, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	numCheckpoints := 32
@@ -594,7 +594,7 @@ func TestCurrentIdx(t *testing.T) {
 	defer require.NoError(t, os.RemoveAll(dir))
 
 	keep := 16
-	sdb, err := NewStateDB(dir, keep, TypeSynchronizer, 32)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: keep, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	idx := sdb.CurrentIdx()
@@ -602,7 +602,7 @@ func TestCurrentIdx(t *testing.T) {
 
 	sdb.Close()
 
-	sdb, err = NewStateDB(dir, keep, TypeSynchronizer, 32)
+	sdb, err = NewStateDB(Config{Path: dir, Keep: keep, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	idx = sdb.CurrentIdx()
@@ -616,7 +616,7 @@ func TestCurrentIdx(t *testing.T) {
 
 	sdb.Close()
 
-	sdb, err = NewStateDB(dir, keep, TypeSynchronizer, 32)
+	sdb, err = NewStateDB(Config{Path: dir, Keep: keep, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	idx = sdb.CurrentIdx()
@@ -629,7 +629,7 @@ func TestResetFromBadCheckpoint(t *testing.T) {
 	defer require.NoError(t, os.RemoveAll(dir))
 
 	keep := 16
-	sdb, err := NewStateDB(dir, keep, TypeSynchronizer, 32)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: keep, Type: TypeSynchronizer, NLevels: 32})
 	require.NoError(t, err)
 
 	err = sdb.MakeCheckpoint()

db/statedb/utils_test.go

@@ -18,7 +18,7 @@ func TestGetIdx(t *testing.T) {
 	require.NoError(t, err)
 	defer assert.NoError(t, os.RemoveAll(dir))
 
-	sdb, err := NewStateDB(dir, 128, TypeTxSelector, 0)
+	sdb, err := NewStateDB(Config{Path: dir, Keep: 128, Type: TypeTxSelector, NLevels: 0})
 	assert.NoError(t, err)
 
 	var sk babyjub.PrivateKey