Method GarbageCollect

core/metadata/db.go:383–489

GarbageCollect removes resources (snapshots, contents, ...) that are no longer used.

(ctx context.Context)

// GarbageCollect removes resources (snapshots, contents, ...) that are no longer used.
func (m *DB) GarbageCollect(ctx context.Context) (gc.Stats, error) {
	m.wlock.Lock()
	t1 := time.Now()
	c := startGCContext(ctx, m.collectors)

	marked, err := m.getMarked(ctx, c) // Pass in gc context
	if err != nil {
		m.wlock.Unlock()
		c.cancel(ctx)
		return nil, err
	}

	events := []namespacedEvent{}
	if err := m.db.Update(func(tx *bolt.Tx) error {
		ctx, cancel := context.WithCancel(ctx)
		defer cancel()

		rm := func(ctx context.Context, n gc.Node) error {
			if _, ok := marked[n]; ok {
				return nil
			}

			switch n.Type {
			case ResourceSnapshot:
				if idx := strings.IndexRune(n.Key, '/'); idx > 0 {
					m.dirtySS[n.Key[:idx]] = struct{}{}
				}
				// queue event to publish after successful commit
			case ResourceContent, ResourceIngest:
				m.dirtyCS = true
			}

			event, err := c.remove(ctx, tx, n)
			if event != nil && err == nil {
				events = append(events,
					namespacedEvent{
						namespace: n.Namespace,
						event:     event,
					})
			}
			return err
		}

		if err := c.scanAll(ctx, tx, rm); err != nil { // From gc context
			return fmt.Errorf("failed to scan and remove: %w", err)
		}

		return nil
	}); err != nil {
		m.wlock.Unlock()
		c.cancel(ctx)
		return nil, err
	}

	var stats GCStats
	var wg sync.WaitGroup

	// Flush events asynchronously after commit