logs

type DB ¶

type DB struct {
	// contains filtered or unexported fields
}

DB implements an append only database for log data and cross-chain dependencies.

To keep the append-only format, reduce data size, and support reorg detection and registering of executing-messages:

Use a fixed 24 bytes per entry.

Data is an append-only log, that can be binary searched for any necessary event data.

Rules: if entry_index % 256 == 0: must be type 0. For easy binary search. type 1 always adjacent to type 0 type 2 "diff" values are offsets from type 0 values (always within 256 entries range) type 3 always after type 2 type 4 always after type 3

Types (<type> = 1 byte): type 0: "search checkpoint" <type><uint64 block number: 8 bytes><uint32 event index offset: 4 bytes><uint64 timestamp: 8 bytes> = 20 bytes type 1: "canonical hash" <type><parent blockhash truncated: 20 bytes> = 21 bytes type 2: "initiating event" <type><blocknum diff: 1 byte><event flags: 1 byte><event-hash: 20 bytes> = 23 bytes type 3: "executing link" <type><chain: 4 bytes><blocknum: 8 bytes><event index: 3 bytes><uint64 timestamp: 8 bytes> = 24 bytes type 4: "executing check" <type><event-hash: 20 bytes> = 21 bytes other types: future compat. E.g. for linking to L1, registering block-headers as a kind of initiating-event, tracking safe-head progression, etc.

Right-pad each entry that is not 24 bytes.

event-flags: each bit represents a boolean value, currently only two are defined * event-flags & 0x01 - true if the log index should increment. Should only be false when the event is immediately after a search checkpoint and canonical hash * event-flags & 0x02 - true if the initiating event has an executing link that should follow. Allows detecting when the executing link failed to write. event-hash: H(origin, timestamp, payloadhash); enough to check identifier matches & payload matches.

func NewFromEntryStore(logger log.Logger, m Metrics, store EntryStore) (*DB, error)

func NewFromFile(logger log.Logger, m Metrics, path string) (*DB, error)

func (db *DB) AddLog(logHash types.TruncatedHash, block eth.BlockID, timestamp uint64, logIdx uint32, execMsg *types.ExecutingMessage) error

func (db *DB) Close() error

func (db *DB) ClosestBlockInfo(blockNum uint64) (uint64, types.TruncatedHash, error)

func (db *DB) Contains(blockNum uint64, logIdx uint32, logHash types.TruncatedHash) (bool, error)

func (db *DB) Executes(blockNum uint64, logIdx uint32) (types.ExecutingMessage, error)

func (db *DB) LatestBlockNum() uint64

func (db *DB) Rewind(headBlockNum uint64) error

type EntryStore ¶

type EntryStore interface {
	Size() int64
	LastEntryIdx() entrydb.EntryIdx
	Read(idx entrydb.EntryIdx) (entrydb.Entry, error)
	Append(entries ...entrydb.Entry) error
	Truncate(idx entrydb.EntryIdx) error
	Close() error
}

type Metrics ¶

type Metrics interface {
	RecordDBEntryCount(count int64)
	RecordDBSearchEntriesRead(count int64)
}