区块链教程Fabric1.0源代码分析Ledger historydb历史数据库
1、historydb概述 historydb，用于存储所有块读写集中写集的内容。代码分布在core/ledger/kvledger/history/historydb目录下，目录结构如下： historydb.go，定义核心接口HistoryDBProvider和HistoryDB。 histmgr_helper.go，historydb工具函数。 historyleveldb目录，historydb基于leveldb的实现。* historyleveldb.go，HistoryDBProvider和HistoryDB接口实现，即historyleveldb.HistoryDBProvider和historyleveldb.historyDB结构体及方法。 * historyleveldb_query_executer.go，定义LevelHistoryDBQueryExecutor和historyScanner结构体及方法。 2、核心接口定义 HistoryDBProvider接口定义： type HistoryDBProvider interface { GetDBHandle(id string) (HistoryDB, error) //获取HistoryDB Close() //关闭所有HistoryDB } //代码在core/ledger/kvledger/history/historydb/historydb.go HistoryDB接口定义： type HistoryDB interface { //构造 LevelHistoryDBQueryExecutor NewHistoryQueryExecutor(blockStore blkstorage.BlockStore) (ledger.HistoryQueryExecutor, error) //提交Block入historyDB Commit(block *common.Block) error //获取savePointKey，即version.Height GetLastSavepoint() (*version.Height, error) //是否应该恢复，比较lastAvailableBlock和Savepoint ShouldRecover(lastAvailableBlock uint64) (bool, uint64, error) //提交丢失的块 CommitLostBlock(block *common.Block) error } //代码在core/ledger/kvledger/history/historydb/historydb.go 补充ledger.HistoryQueryExecutor接口定义：执行历史记录查询。 type HistoryQueryExecutor interface { GetHistoryForKey(namespace string, key string) (commonledger.ResultsIterator, error) //按key查历史记录 } //代码在core/ledger/ledger_interface.go 3、historydb工具函数 //构造复合HistoryKey，ns 0x00 key 0x00 blocknum trannum func ConstructCompositeHistoryKey(ns string, key string, blocknum uint64, trannum uint64) []byte //构造部分复合HistoryKey，ns 0x00 key 0x00 0xff func ConstructPartialCompositeHistoryKey(ns string, key string, endkey bool) []byte //按分隔符separator，分割bytesToSplit func SplitCompositeHistoryKey(bytesToSplit []byte, separator []byte) ([]byte, []byte) //代码在core/ledger/kvledger/history/historydb/histmgr_helper.go 4、HistoryDB接口实现 HistoryDB接口实现，即historyleveldb.historyDB结构体及方法。historyDB结构体定义如下： type historyDB struct { db *leveldbhelper.DBHandle //leveldb dbName string //dbName } //代码在core/ledger/kvledger/history/historydb/historyleveldb/historyleveldb.go 涉及方法如下： //构造historyDB func newHistoryDB(db *leveldbhelper.DBHandle, dbName string) *historyDB //do nothing func (historyDB *historyDB) Open() error //do nothing func (historyDB *historyDB) Close() //提交Block入historyDB，将读写集中写集入库，并更新savePointKey func (historyDB *historyDB) Commit(block *common.Block) error //构造 LevelHistoryDBQueryExecutor func (historyDB *historyDB) NewHistoryQueryExecutor(blockStore blkstorage.BlockStore) (ledger.HistoryQueryExecutor, error) 获取savePointKey，即version.Height func (historyDB *historyDB) GetLastSavepoint() (*version.Height, error) //是否应该恢复，比较lastAvailableBlock和Savepoint func (historyDB *historyDB) ShouldRecover(lastAvailableBlock uint64) (bool, uint64, error) //提交丢失的块，即调用historyDB.Commit(block) func (historyDB *historyDB) CommitLostBlock(block *common.Block) error //代码在core/ledger/kvledger/history/historydb/historyleveldb/historyleveldb.go func (historyDB historyDB) Commit(block common.Block) error代码如下： blockNo := block.Header.Number //区块编号 var tranNo uint64 //交易编号，初始化值为0 dbBatch := leveldbhelper.NewUpdateBatch() //leveldb批量更新 //交易验证代码，type TxValidationFlags []uint8 //交易筛选器 txsFilter := util.TxValidationFlags(block.Metadata.Metadata[common.BlockMetadataIndex_TRANSACTIONS_FILTER]) if len(txsFilter) == 0 { txsFilter = util.NewTxValidationFlags(len(block.Data.Data)) block.Metadata.Metadata[common.BlockMetadataIndex_TRANSACTIONS_FILTER] = txsFilter } for _, envBytes := range block.Data.Data { if txsFilter.IsInvalid(int(tranNo)) { //检查指定的交易是否有效 tranNo++ continue } //[]byte反序列化为Envelope env, err := putils.GetEnvelopeFromBlock(envBytes) payload, err := putils.GetPayload(env) //e.Payload反序列化为Payload //[]byte反序列化为ChannelHeader chdr, err := putils.UnmarshalChannelHeader(payload.Header.ChannelHeader) if common.HeaderType(chdr.Type) == common.HeaderType_ENDORSER_TRANSACTION { //背书交易，type HeaderType int32 respPayload, err := putils.GetActionFromEnvelope(envBytes) //获取ChaincodeAction txRWSet := &rwsetutil.TxRwSet{} err = txRWSet.FromProtoBytes(respPayload.Results) //[]byte反序列化后构造NsRwSet，加入txRWSet.NsRwSets for _, nsRWSet := range txRWSet.NsRwSets { ns := nsRWSet.NameSpace for _, kvWrite := range nsRWSet.KvRwSet.Writes { writeKey := kvWrite.Key //txRWSet中写集入库 compositeHistoryKey := historydb.ConstructCompositeHistoryKey(ns, writeKey, blockNo, tranNo) dbBatch.Put(compositeHistoryKey, emptyValue) } } } else { logger.Debugf("Skipping transaction [%d] since it is not an endorsement transaction\n", tranNo) } tranNo++ } height := version.NewHeight(blockNo, tranNo) dbBatch.Put(savePointKey, height.ToBytes()) err := historyDB.db.WriteBatch(dbBatch, true) //代码在core/ledger/kvledger/history/historydb/historyleveldb/historyleveldb.go Tx（Transaction 交易）相关更详细内容，参考：Fabric 1.0源代码笔记 之 Tx（Transaction 交易） 5、HistoryDBProvider接口实现 HistoryDBProvider接口实现，即historyleveldb.HistoryDBProvider结构体和方法。 type HistoryDBProvider struct { dbProvider *leveldbhelper.Provider } //构造HistoryDBProvider func NewHistoryDBProvider() *HistoryDBProvider //获取HistoryDB func (provider *HistoryDBProvider) GetDBHandle(dbName string) (historydb.HistoryDB, error) //关闭所有HistoryDB句柄，调取provider.dbProvider.Close() func (provider *HistoryDBProvider) Close() //代码在core/ledger/kvledger/history/historydb/historyleveldb/historyleveldb.go 6、LevelHistoryDBQueryExecutor和historyScanner结构体及方法 LevelHistoryDBQueryExecutor结构体及方法：实现ledger.HistoryQueryExecutor接口。 type LevelHistoryDBQueryExecutor struct { historyDB *historyDB blockStore blkstorage.BlockStore //用于传递给historyScanner } //按key查historyDB，调用q.historyDB.db.GetIterator(compositeStartKey, compositeEndKey) func (q *LevelHistoryDBQueryExecutor) GetHistoryForKey(namespace string, key string) (commonledger.ResultsIterator, error) //代码在core/ledger/kvledger/history/historydb/historyleveldb/historyleveldb_query_executer.go historyScanner结构体及方法：实现ledger.ResultsIterator接口。 type historyScanner struct { compositePartialKey []byte //ns 0x00 key 0x00 namespace string key string dbItr iterator.Iterator //leveldb迭代器 blockStore blkstorage.BlockStore } //构造historyScanner func newHistoryScanner(compositePartialKey []byte, namespace string, key string, dbItr iterator.Iterator, blockStore blkstorage.BlockStore) *historyScanner //按迭代器中key取blockNum和tranNum，再按blockNum和tranNum从blockStore中取Envelope，然后从Envelope的txRWSet.NsRwSets中按key查找并构造queryresult.KeyModification func (scanner *historyScanner) Next() (commonledger.QueryResult, error) func (scanner *historyScanner) Close() //scanner.dbItr.Release() 从Envelope的txRWSet.NsRwSets中按key查找并构造queryresult.KeyModification func getKeyModificationFromTran(tranEnvelope *common.Envelope, namespace string, key string) (commonledger.QueryResult, error) //代码在core/ledger/kvledger/history/historydb/historyleveldb/historyleveldb_query_executer.go 补充queryresult.KeyModification： type KeyModification struct { TxId string //交易ID，ChannelHeader.TxId Value []byte //读写集中Value，KVWrite.Value Timestamp *google_protobuf.Timestamp //ChannelHeader.Timestamp IsDelete bool //KVWrite.IsDelete } //代码在protos/ledger/queryresult/kv_query_result.pb.go 感谢关注兄弟连区块链教程分享！
