|
| 1 | +package boltstore |
| 2 | + |
| 3 | +import ( |
| 4 | + "context" |
| 5 | + "encoding/binary" |
| 6 | + "encoding/json" |
| 7 | + "errors" |
| 8 | + "fmt" |
| 9 | + "iter" |
| 10 | + "strconv" |
| 11 | + "time" |
| 12 | + |
| 13 | + agentledger "github.com/compforge/agent-ledger/go" |
| 14 | + bolt "go.etcd.io/bbolt" |
| 15 | +) |
| 16 | + |
| 17 | +var ( |
| 18 | + streamsBucket = []byte("streams") |
| 19 | + sessionsBucket = []byte("sessions") |
| 20 | + receiptsBucket = []byte("receipts") |
| 21 | + eventIDsBucket = []byte("event_ids") |
| 22 | +) |
| 23 | + |
| 24 | +// Store persists Agent Ledger streams in one Bolt database. Bolt serializes |
| 25 | +// writers, so the EventStore append contract and its optimistic version check |
| 26 | +// are committed in the same transaction. |
| 27 | +type Store struct { |
| 28 | + db *bolt.DB |
| 29 | +} |
| 30 | + |
| 31 | +func Open(path string, timeout time.Duration) (*Store, error) { |
| 32 | + if timeout <= 0 { |
| 33 | + return nil, errors.New("open bolt event store: timeout must be positive") |
| 34 | + } |
| 35 | + db, err := bolt.Open(path, 0o600, &bolt.Options{Timeout: timeout}) |
| 36 | + if err != nil { |
| 37 | + return nil, fmt.Errorf("open bolt event store %q: %w", path, err) |
| 38 | + } |
| 39 | + return &Store{db: db}, nil |
| 40 | +} |
| 41 | + |
| 42 | +func (s *Store) Close() error { |
| 43 | + if err := s.db.Close(); err != nil { |
| 44 | + return fmt.Errorf("close bolt event store: %w", err) |
| 45 | + } |
| 46 | + return nil |
| 47 | +} |
| 48 | + |
| 49 | +func (s *Store) Append( |
| 50 | + ctx context.Context, |
| 51 | + stream agentledger.EventStream, |
| 52 | + expectedVersion int64, |
| 53 | + appendID string, |
| 54 | + events ...agentledger.ProposedEvent, |
| 55 | +) (agentledger.CommitReceipt, error) { |
| 56 | + if err := ctx.Err(); err != nil { |
| 57 | + return agentledger.CommitReceipt{}, err |
| 58 | + } |
| 59 | + if len(events) == 0 { |
| 60 | + return agentledger.CommitReceipt{}, errors.New("append requires at least one event") |
| 61 | + } |
| 62 | + batch, err := clone(events) |
| 63 | + if err != nil { |
| 64 | + return agentledger.CommitReceipt{}, fmt.Errorf("snapshot append batch: %w", err) |
| 65 | + } |
| 66 | + seen := make(map[string]struct{}, len(batch)) |
| 67 | + for _, event := range batch { |
| 68 | + if event.SessionID != stream.SessionID { |
| 69 | + return agentledger.CommitReceipt{}, errors.New("all events must belong to the target stream's session") |
| 70 | + } |
| 71 | + if _, duplicate := seen[event.EventID]; duplicate { |
| 72 | + return agentledger.CommitReceipt{}, fmt.Errorf("%w: %s", agentledger.ErrDuplicateEvent, event.EventID) |
| 73 | + } |
| 74 | + seen[event.EventID] = struct{}{} |
| 75 | + } |
| 76 | + digest, err := agentledger.CanonicalAppendDigest(batch) |
| 77 | + if err != nil { |
| 78 | + return agentledger.CommitReceipt{}, err |
| 79 | + } |
| 80 | + |
| 81 | + var receipt agentledger.CommitReceipt |
| 82 | + err = s.db.Update(func(tx *bolt.Tx) error { |
| 83 | + if err := ctx.Err(); err != nil { |
| 84 | + return err |
| 85 | + } |
| 86 | + streams, err := tx.CreateBucketIfNotExists(streamsBucket) |
| 87 | + if err != nil { |
| 88 | + return err |
| 89 | + } |
| 90 | + sessions, err := tx.CreateBucketIfNotExists(sessionsBucket) |
| 91 | + if err != nil { |
| 92 | + return err |
| 93 | + } |
| 94 | + receipts, err := tx.CreateBucketIfNotExists(receiptsBucket) |
| 95 | + if err != nil { |
| 96 | + return err |
| 97 | + } |
| 98 | + eventIDs, err := tx.CreateBucketIfNotExists(eventIDsBucket) |
| 99 | + if err != nil { |
| 100 | + return err |
| 101 | + } |
| 102 | + |
| 103 | + receiptKey := composite(stream.SessionID, stream.StreamID, appendID) |
| 104 | + if encoded := receipts.Get(receiptKey); encoded != nil { |
| 105 | + if err := json.Unmarshal(encoded, &receipt); err != nil { |
| 106 | + return fmt.Errorf("decode append receipt: %w", err) |
| 107 | + } |
| 108 | + if receipt.Digest != digest { |
| 109 | + return agentledger.ErrIdempotencyViolation |
| 110 | + } |
| 111 | + return nil |
| 112 | + } |
| 113 | + |
| 114 | + streamBucket, err := streams.CreateBucketIfNotExists(composite(stream.SessionID, stream.StreamID)) |
| 115 | + if err != nil { |
| 116 | + return err |
| 117 | + } |
| 118 | + currentVersion := int64(streamBucket.Sequence()) - 1 |
| 119 | + if currentVersion != expectedVersion { |
| 120 | + return fmt.Errorf("%w: expected %d, actual %d", agentledger.ErrStreamConflict, expectedVersion, currentVersion) |
| 121 | + } |
| 122 | + for _, event := range batch { |
| 123 | + key := composite(stream.SessionID, event.EventID) |
| 124 | + if eventIDs.Get(key) != nil { |
| 125 | + return fmt.Errorf("%w: %s", agentledger.ErrDuplicateEvent, event.EventID) |
| 126 | + } |
| 127 | + } |
| 128 | + |
| 129 | + sessionBucket, err := sessions.CreateBucketIfNotExists([]byte(stream.SessionID)) |
| 130 | + if err != nil { |
| 131 | + return err |
| 132 | + } |
| 133 | + committedAt := time.Now().UTC().Format(time.RFC3339Nano) |
| 134 | + stored := make([]agentledger.StoredEvent, 0, len(batch)) |
| 135 | + for _, event := range batch { |
| 136 | + streamSequence, err := streamBucket.NextSequence() |
| 137 | + if err != nil { |
| 138 | + return err |
| 139 | + } |
| 140 | + sessionSequence, err := sessionBucket.NextSequence() |
| 141 | + if err != nil { |
| 142 | + return err |
| 143 | + } |
| 144 | + item := agentledger.StoredEvent{ |
| 145 | + ProposedEvent: event, |
| 146 | + StreamID: stream.StreamID, |
| 147 | + StreamVersion: int64(streamSequence) - 1, |
| 148 | + CommitCursor: strconv.FormatUint(sessionSequence-1, 10), |
| 149 | + CommittedAt: committedAt, |
| 150 | + } |
| 151 | + encoded, err := json.Marshal(item) |
| 152 | + if err != nil { |
| 153 | + return fmt.Errorf("encode stored event: %w", err) |
| 154 | + } |
| 155 | + if err := streamBucket.Put(sequenceKey(streamSequence-1), encoded); err != nil { |
| 156 | + return err |
| 157 | + } |
| 158 | + if err := sessionBucket.Put(sequenceKey(sessionSequence-1), encoded); err != nil { |
| 159 | + return err |
| 160 | + } |
| 161 | + if err := eventIDs.Put(composite(stream.SessionID, event.EventID), []byte{1}); err != nil { |
| 162 | + return err |
| 163 | + } |
| 164 | + stored = append(stored, item) |
| 165 | + } |
| 166 | + |
| 167 | + receipt = agentledger.CommitReceipt{ |
| 168 | + Stream: stream, |
| 169 | + AppendID: appendID, |
| 170 | + Digest: digest, |
| 171 | + FirstVersion: stored[0].StreamVersion, |
| 172 | + LastVersion: stored[len(stored)-1].StreamVersion, |
| 173 | + FirstCursor: stored[0].CommitCursor, |
| 174 | + LastCursor: stored[len(stored)-1].CommitCursor, |
| 175 | + CommittedAt: committedAt, |
| 176 | + } |
| 177 | + for _, event := range stored { |
| 178 | + receipt.EventIDs = append(receipt.EventIDs, event.EventID) |
| 179 | + } |
| 180 | + encoded, err := json.Marshal(receipt) |
| 181 | + if err != nil { |
| 182 | + return fmt.Errorf("encode append receipt: %w", err) |
| 183 | + } |
| 184 | + return receipts.Put(receiptKey, encoded) |
| 185 | + }) |
| 186 | + if err != nil { |
| 187 | + return agentledger.CommitReceipt{}, fmt.Errorf("append bolt event batch: %w", err) |
| 188 | + } |
| 189 | + return clone(receipt) |
| 190 | +} |
| 191 | + |
| 192 | +func (s *Store) Load(ctx context.Context, stream agentledger.EventStream, afterVersion int64) iter.Seq2[agentledger.StoredEvent, error] { |
| 193 | + return s.read(ctx, streamsBucket, composite(stream.SessionID, stream.StreamID), afterVersion) |
| 194 | +} |
| 195 | + |
| 196 | +func (s *Store) ScanSession(ctx context.Context, sessionID, afterCursor string) iter.Seq2[agentledger.StoredEvent, error] { |
| 197 | + after := int64(-1) |
| 198 | + if afterCursor != "" { |
| 199 | + value, err := strconv.ParseInt(afterCursor, 10, 64) |
| 200 | + if err != nil || value < 0 { |
| 201 | + return errorSequence(fmt.Errorf("invalid cursor %q", afterCursor)) |
| 202 | + } |
| 203 | + after = value |
| 204 | + } |
| 205 | + return s.read(ctx, sessionsBucket, []byte(sessionID), after) |
| 206 | +} |
| 207 | + |
| 208 | +func (s *Store) read(ctx context.Context, rootName, childName []byte, after int64) iter.Seq2[agentledger.StoredEvent, error] { |
| 209 | + return func(yield func(agentledger.StoredEvent, error) bool) { |
| 210 | + var encodedEvents [][]byte |
| 211 | + err := s.db.View(func(tx *bolt.Tx) error { |
| 212 | + root := tx.Bucket(rootName) |
| 213 | + if root == nil { |
| 214 | + return nil |
| 215 | + } |
| 216 | + child := root.Bucket(childName) |
| 217 | + if child == nil { |
| 218 | + return nil |
| 219 | + } |
| 220 | + cursor := child.Cursor() |
| 221 | + for key, value := cursor.Seek(sequenceKey(uint64(after + 1))); key != nil; key, value = cursor.Next() { |
| 222 | + encodedEvents = append(encodedEvents, append([]byte(nil), value...)) |
| 223 | + } |
| 224 | + return nil |
| 225 | + }) |
| 226 | + if err != nil { |
| 227 | + yield(agentledger.StoredEvent{}, fmt.Errorf("read bolt event stream: %w", err)) |
| 228 | + return |
| 229 | + } |
| 230 | + for _, encoded := range encodedEvents { |
| 231 | + if err := ctx.Err(); err != nil { |
| 232 | + yield(agentledger.StoredEvent{}, err) |
| 233 | + return |
| 234 | + } |
| 235 | + var event agentledger.StoredEvent |
| 236 | + if err := json.Unmarshal(encoded, &event); err != nil { |
| 237 | + yield(agentledger.StoredEvent{}, fmt.Errorf("decode stored event: %w", err)) |
| 238 | + return |
| 239 | + } |
| 240 | + if !yield(event, nil) { |
| 241 | + return |
| 242 | + } |
| 243 | + } |
| 244 | + } |
| 245 | +} |
| 246 | + |
| 247 | +func composite(parts ...string) []byte { |
| 248 | + var result []byte |
| 249 | + for index, part := range parts { |
| 250 | + if index > 0 { |
| 251 | + result = append(result, 0) |
| 252 | + } |
| 253 | + result = append(result, part...) |
| 254 | + } |
| 255 | + return result |
| 256 | +} |
| 257 | + |
| 258 | +func sequenceKey(value uint64) []byte { |
| 259 | + key := make([]byte, 8) |
| 260 | + binary.BigEndian.PutUint64(key, value) |
| 261 | + return key |
| 262 | +} |
| 263 | + |
| 264 | +func clone[T any](value T) (T, error) { |
| 265 | + var result T |
| 266 | + encoded, err := json.Marshal(value) |
| 267 | + if err != nil { |
| 268 | + return result, err |
| 269 | + } |
| 270 | + if err := json.Unmarshal(encoded, &result); err != nil { |
| 271 | + return result, err |
| 272 | + } |
| 273 | + return result, nil |
| 274 | +} |
| 275 | + |
| 276 | +func errorSequence(err error) iter.Seq2[agentledger.StoredEvent, error] { |
| 277 | + return func(yield func(agentledger.StoredEvent, error) bool) { |
| 278 | + yield(agentledger.StoredEvent{}, err) |
| 279 | + } |
| 280 | +} |
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