Native staking committee (#141)

* native_committee_server

* enable getBucketsByCandidate

* slow down to prevent rate limit

* bundle servers and add native staking into vote sync

committee/bucketarchive.go

@@ -0,0 +1,122 @@
+// Copyright (c) 2019 IoTeX
+// This program is free software: you can redistribute it and/or modify it under the terms of the
+// GNU General Public License as published by the Free Software Foundation, either version 3 of
+// the License, or (at your option) any later version.
+// This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY;
+// without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+// the GNU General Public License for more details.
+// You should have received a copy of the GNU General Public License along with this program. If
+// not, see <http://www.gnu.org/licenses/>.
+
+package committee
+
+import (
+	"context"
+	"database/sql"
+	"reflect"
+	"sync"
+	"time"
+
+	// require sqlite3 driver
+	_ "github.com/mattn/go-sqlite3"
+	"github.com/pkg/errors"
+
+	"github.com/iotexproject/iotex-election/types"
+)
+
+type BucketArchive struct {
+	startHeight         uint64
+	interval            uint64
+	db                  *sql.DB
+	bucketTableOperator Operator
+	timeTableOperator   Operator
+
+	// Put (native) polls are synchronized to get rid of the risk of reading uncommitted changes from other tx on the
+	// same connection.
+	mutex sync.Mutex
+}
+
+// NewBucketArchive creates a new archive of bucket
+func NewBucketArchive(dbPath string, numOfRetries uint8, startHeight uint64, interval uint64) (*BucketArchive, error) {
+	sqlDB, err := sql.Open("sqlite3", dbPath)
+	if err != nil {
+		return nil, err
+	}
+	bucketTableOperator, err := NewDeltaBucketTableOperator("buckets", SQLITE)
+	if err != nil {
+		return nil, err
+	}
+	return &BucketArchive{
+		db:                  sqlDB,
+		startHeight:         startHeight,
+		interval:            interval,
+		timeTableOperator:   NewTimeTableOperator("mint_time", SQLITE),
+		bucketTableOperator: bucketTableOperator,
+	}, nil
+}
+
+func (arch *BucketArchive) TipHeight() (uint64, error) {
+	return arch.timeTableOperator.TipHeight(arch.db, nil)
+}
+
+func (arch *BucketArchive) MintTime(height uint64) (time.Time, error) {
+	value, err := arch.timeTableOperator.Get(height, arch.db, nil)
+	if err != nil {
+		return time.Time{}, err
+	}
+	mintTime, ok := value.(time.Time)
+	if !ok {
+		return time.Time{}, errors.Errorf("Unexpected type %s", reflect.TypeOf(value))
+	}
+	return mintTime, nil
+}
+
+func (arch *BucketArchive) Buckets(height uint64) ([]*types.Bucket, error) {
+	value, err := arch.bucketTableOperator.Get(height, arch.db, nil)
+	if err != nil {
+		return nil, err
+	}
+	records, ok := value.([]*types.Bucket)
+	if !ok {
+		return nil, errors.Errorf("Unexpected type %s", reflect.TypeOf(value))
+	}
+	return records, nil
+}
+
+func (arch *BucketArchive) PutDelta(height uint64, ts time.Time, updatedBuckets []*pyggBucket) (err error) {
+	arch.mutex.Lock()
+	defer arch.mutex.Unlock()
+
+	tx, err := arch.db.Begin()
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback()
+	if err := arch.timeTableOperator.Put(height, ts, tx); err != nil {
+		return err
+	}
+	if err := arch.bucketTableOperator.Put(height, updatedBuckets, tx); err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+func (arch *BucketArchive) Start(ctx context.Context) (err error) {
+	var tx *sql.Tx
+	tx, err = arch.db.Begin()
+	if err != nil {
+		return err
+	}
+	defer tx.Rollback()
+	if err = arch.timeTableOperator.CreateTables(tx); err != nil {
+		return err
+	}
+	if err = arch.bucketTableOperator.CreateTables(tx); err != nil {
+		return err
+	}
+	return tx.Commit()
+}
+
+func (arch *BucketArchive) Stop(_ context.Context) (err error) {
+	return arch.db.Close()
+}