Abstract KVDB from StateDB

- KVDB contains the Checkpoint & Resets system
- StateDB uses KVDB and adds all the StateDB related methods

db/kvdb/kvdb_test.go

@@ -0,0 +1,195 @@
+package kvdb
+
+import (
+	"fmt"
+	"io/ioutil"
+	"os"
+	"testing"
+
+	"github.com/hermeznetwork/hermez-node/common"
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func addTestKV(t *testing.T, db *KVDB, k, v []byte) {
+	tx, err := db.db.NewTx()
+	require.NoError(t, err)
+
+	err = tx.Put(k, v)
+	require.NoError(t, err)
+
+	err = tx.Commit()
+	require.NoError(t, err)
+}
+
+func printCheckpoints(t *testing.T, path string) {
+	files, err := ioutil.ReadDir(path)
+	assert.NoError(t, err)
+
+	fmt.Println(path)
+	for _, f := range files {
+		fmt.Println("	" + f.Name())
+	}
+}
+
+func TestCheckpoints(t *testing.T) {
+	dir, err := ioutil.TempDir("", "sdb")
+	require.NoError(t, err)
+	defer assert.NoError(t, os.RemoveAll(dir))
+
+	db, err := NewKVDB(dir, 128)
+	assert.NoError(t, err)
+
+	// add test key-values
+	for i := 0; i < 10; i++ {
+		addTestKV(t, db, []byte{byte(i), byte(i)}, []byte{byte(i * 2), byte(i * 2)})
+	}
+
+	// do checkpoints and check that currentBatch is correct
+	err = db.MakeCheckpoint()
+	assert.NoError(t, err)
+	cb, err := db.GetCurrentBatch()
+	assert.NoError(t, err)
+	assert.Equal(t, common.BatchNum(1), cb)
+
+	for i := 1; i < 10; i++ {
+		err = db.MakeCheckpoint()
+		assert.NoError(t, err)
+
+		cb, err = db.GetCurrentBatch()
+		assert.NoError(t, err)
+		assert.Equal(t, common.BatchNum(i+1), cb)
+	}
+
+	// printCheckpoints(t, sdb.path)
+
+	// reset checkpoint
+	err = db.Reset(3)
+	assert.NoError(t, err)
+
+	// check that reset can be repeated (as there exist the 'current' and
+	// 'BatchNum3', from where the 'current' is a copy)
+	err = db.Reset(3)
+	require.NoError(t, err)
+
+	// check that currentBatch is as expected after Reset
+	cb, err = db.GetCurrentBatch()
+	assert.NoError(t, err)
+	assert.Equal(t, common.BatchNum(3), cb)
+
+	// advance one checkpoint and check that currentBatch is fine
+	err = db.MakeCheckpoint()
+	assert.NoError(t, err)
+	cb, err = db.GetCurrentBatch()
+	assert.NoError(t, err)
+	assert.Equal(t, common.BatchNum(4), cb)
+
+	err = db.DeleteCheckpoint(common.BatchNum(1))
+	assert.NoError(t, err)
+	err = db.DeleteCheckpoint(common.BatchNum(2))
+	assert.NoError(t, err)
+	err = db.DeleteCheckpoint(common.BatchNum(1)) // does not exist, should return err
+	assert.NotNil(t, err)
+	err = db.DeleteCheckpoint(common.BatchNum(2)) // does not exist, should return err
+	assert.NotNil(t, err)
+
+	// Create a new KVDB which will get Reset from the initial KVDB
+	dirLocal, err := ioutil.TempDir("", "ldb")
+	require.NoError(t, err)
+	defer assert.NoError(t, os.RemoveAll(dirLocal))
+	ldb, err := NewKVDB(dirLocal, 128)
+	assert.NoError(t, err)
+
+	// get checkpoint 4 from sdb (StateDB) to ldb (LocalStateDB)
+	err = ldb.ResetFromSynchronizer(4, db)
+	assert.NoError(t, err)
+	// check that currentBatch is 4 after the Reset
+	cb, err = ldb.GetCurrentBatch()
+	assert.NoError(t, err)
+	assert.Equal(t, common.BatchNum(4), cb)
+	// advance one checkpoint in ldb
+	err = ldb.MakeCheckpoint()
+	assert.NoError(t, err)
+	cb, err = ldb.GetCurrentBatch()
+	assert.NoError(t, err)
+	assert.Equal(t, common.BatchNum(5), cb)
+
+	// Create a 3rd KVDB which will get Reset from the initial KVDB
+	dirLocal2, err := ioutil.TempDir("", "ldb2")
+	require.NoError(t, err)
+	defer assert.NoError(t, os.RemoveAll(dirLocal2))
+	ldb2, err := NewKVDB(dirLocal2, 128)
+	assert.NoError(t, err)
+
+	// get checkpoint 4 from sdb (StateDB) to ldb (LocalStateDB)
+	err = ldb2.ResetFromSynchronizer(4, db)
+	assert.NoError(t, err)
+	// check that currentBatch is 4 after the Reset
+	cb, err = ldb2.GetCurrentBatch()
+	assert.NoError(t, err)
+	assert.Equal(t, common.BatchNum(4), cb)
+	// advance one checkpoint in ldb2
+	err = ldb2.MakeCheckpoint()
+	assert.NoError(t, err)
+	cb, err = ldb2.GetCurrentBatch()
+	assert.NoError(t, err)
+	assert.Equal(t, common.BatchNum(5), cb)
+
+	debug := false
+	if debug {
+		printCheckpoints(t, db.path)
+		printCheckpoints(t, ldb.path)
+		printCheckpoints(t, ldb2.path)
+	}
+}
+
+func TestListCheckpoints(t *testing.T) {
+	dir, err := ioutil.TempDir("", "tmpdb")
+	require.NoError(t, err)
+	defer assert.NoError(t, os.RemoveAll(dir))
+
+	db, err := NewKVDB(dir, 128)
+	require.NoError(t, err)
+
+	numCheckpoints := 16
+	// do checkpoints
+	for i := 0; i < numCheckpoints; i++ {
+		err = db.MakeCheckpoint()
+		require.NoError(t, err)
+	}
+	list, err := db.ListCheckpoints()
+	require.NoError(t, err)
+	assert.Equal(t, numCheckpoints, len(list))
+	assert.Equal(t, 1, list[0])
+	assert.Equal(t, numCheckpoints, list[len(list)-1])
+
+	numReset := 10
+	err = db.Reset(common.BatchNum(numReset))
+	require.NoError(t, err)
+	list, err = db.ListCheckpoints()
+	require.NoError(t, err)
+	assert.Equal(t, numReset, len(list))
+	assert.Equal(t, 1, list[0])
+	assert.Equal(t, numReset, list[len(list)-1])
+}
+
+func TestDeleteOldCheckpoints(t *testing.T) {
+	dir, err := ioutil.TempDir("", "tmpdb")
+	require.NoError(t, err)
+	defer assert.NoError(t, os.RemoveAll(dir))
+
+	keep := 16
+	db, err := NewKVDB(dir, keep)
+	require.NoError(t, err)
+
+	numCheckpoints := 32
+	// do checkpoints and check that we never have more than `keep`
+	// checkpoints
+	for i := 0; i < numCheckpoints; i++ {
+		err = db.MakeCheckpoint()
+		require.NoError(t, err)
+		checkpoints, err := db.ListCheckpoints()
+		require.NoError(t, err)
+		assert.LessOrEqual(t, len(checkpoints), keep)
+	}
+}