ledger

Documentation

Index

• type HistoryQueryExecutor
• type PeerLedger
• type PeerLedgerProvider
• type QueryExecutor
• type TxSimulator
• type ValidatedLedger

Types

type HistoryQueryExecutor

type HistoryQueryExecutor interface {
	// GetHistoryForKey retrieves the history of values for a key.
	// The returned ResultsIterator contains results of type *KeyModification which is defined in protos/ledger/queryresult.
	// 获取key的变动历史
	GetHistoryForKey(namespace string, key string) (commonledger.ResultsIterator, error)
}

HistoryQueryExecutor executes the history queries

type PeerLedger

type PeerLedger interface {
	commonledger.Ledger // 账本的文件存储
	// GetTransactionByID retrieves a transaction by id
	GetTransactionByID(txID string) (*peer.ProcessedTransaction, error)
	// GetBlockByHash returns a block given it's hash
	GetBlockByHash(blockHash []byte) (*common.Block, error)
	// GetBlockByTxID returns a block which contains a transaction
	GetBlockByTxID(txID string) (*common.Block, error)
	// GetTxValidationCodeByTxID returns reason code of transaction validation
	GetTxValidationCodeByTxID(txID string) (peer.TxValidationCode, error)

	// NewTxSimulator gives handle to a transaction simulator.
	// A client can obtain more than one 'TxSimulator's for parallel execution.
	// Any snapshoting/synchronization should be performed at the implementation level if required
	// 交易模拟器
	NewTxSimulator() (TxSimulator, error)
	// NewQueryExecutor gives handle to a query executor.
	// A client can obtain more than one 'QueryExecutor's for parallel execution.
	// Any synchronization should be performed at the implementation level if required
	NewQueryExecutor() (QueryExecutor, error)
	// NewHistoryQueryExecutor gives handle to a history query executor.
	// A client can obtain more than one 'HistoryQueryExecutor's for parallel execution.
	// Any synchronization should be performed at the implementation level if required
	NewHistoryQueryExecutor() (HistoryQueryExecutor, error)
	// 两个查询接口
	//Prune prunes the blocks/transactions that satisfy the given policy
	Prune(policy commonledger.PrunePolicy) error
}

PeerLedger differs from the OrdererLedger in that PeerLedger locally maintain a bitmask that tells apart valid transactions from invalid ones

type PeerLedgerProvider

type PeerLedgerProvider interface {
	// Create creates a new ledger with the given genesis block.
	// This function guarantees that the creation of ledger and committing the genesis block would an atomic action
	// The chain id retrieved from the genesis block is treated as a ledger id
	// 创建账本
	Create(genesisBlock *common.Block) (PeerLedger, error)
	// Open opens an already created ledger
	// 打开账本
	Open(ledgerID string) (PeerLedger, error)
	// Exists tells whether the ledger with given id exists
	// 账本是否存在
	Exists(ledgerID string) (bool, error)
	// List lists the ids of the existing ledgers
	// peer节点有哪些账本
	List() ([]string, error)
	// Close closes the PeerLedgerProvider
	Close()
}

PeerLedgerProvider provides handle to ledger instances

type QueryExecutor

type QueryExecutor interface {
	// GetState gets the value for given namespace and key. For a chaincode, the namespace corresponds to the chaincodeId
	// 获取一个状态
	GetState(namespace string, key string) ([]byte, error)
	// GetStateMultipleKeys gets the values for multiple keys in a single call
	// 获取多个状态
	GetStateMultipleKeys(namespace string, keys []string) ([][]byte, error)
	// GetStateRangeScanIterator returns an iterator that contains all the key-values between given key ranges.
	// startKey is included in the results and endKey is excluded. An empty startKey refers to the first available key
	// and an empty endKey refers to the last available key. For scanning all the keys, both the startKey and the endKey
	// can be supplied as empty strings. However, a full scan shuold be used judiciously for performance reasons.
	// The returned ResultsIterator contains results of type *KV which is defined in protos/ledger/queryresult.
	// 获取状态区间
	GetStateRangeScanIterator(namespace string, startKey string, endKey string) (commonledger.ResultsIterator, error)
	// ExecuteQuery executes the given query and returns an iterator that contains results of type specific to the underlying data store.
	// Only used for state databases that support query
	// For a chaincode, the namespace corresponds to the chaincodeId
	// The returned ResultsIterator contains results of type *KV which is defined in protos/ledger/queryresult.
	// 模糊查询
	ExecuteQuery(namespace, query string) (commonledger.ResultsIterator, error)
	// Done releases resources occupied by the QueryExecutor
	Done()
}

QueryExecutor executes the queries Get* methods are for supporting KV-based data model. ExecuteQuery method is for supporting a rich datamodel and query support

ExecuteQuery method in the case of a rich data model is expected to support queries on latest state, historical state and on the intersection of state and transactions

type TxSimulator

type TxSimulator interface {
	QueryExecutor
	// SetState sets the given value for the given namespace and key. For a chaincode, the namespace corresponds to the chaincodeId
	SetState(namespace string, key string, value []byte) error
	// DeleteState deletes the given namespace and key
	DeleteState(namespace string, key string) error
	// SetMultipleKeys sets the values for multiple keys in a single call
	SetStateMultipleKeys(namespace string, kvs map[string][]byte) error
	// ExecuteUpdate for supporting rich data model (see comments on QueryExecutor above)
	ExecuteUpdate(query string) error
	// GetTxSimulationResults encapsulates the results of the transaction simulation.
	// This should contain enough detail for
	// - The update in the state that would be caused if the transaction is to be committed
	// - The environment in which the transaction is executed so as to be able to decide the validity of the environment
	//   (at a later time on a different peer) during committing the transactions
	// Different ledger implementation (or configurations of a single implementation) may want to represent the above two pieces
	// of information in different way in order to support different data-models or optimize the information representations.
	GetTxSimulationResults() ([]byte, error)
}

TxSimulator simulates a transaction on a consistent snapshot of the 'as recent state as possible' Set* methods are for supporting KV-based data model. ExecuteUpdate method is for supporting a rich datamodel and query support

type ValidatedLedger

type ValidatedLedger interface {
	commonledger.Ledger // 指代账本文件存储
}

ValidatedLedger represents the 'final ledger' after filtering out invalid transactions from PeerLedger. Post-v1