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package db |
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import ( |
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"context" |
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"database/sql" |
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"errors" |
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"fmt" |
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"time" |
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) |
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// IndexStamp records which revision of a space's approved branch the global |
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// bleve index currently reflects. |
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// |
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// It is the reconciler's staleness comparison, and it is why a crash between |
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// merge and reindex is a defined repair rather than a bespoke one: stamp rev |
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// != approved head means reindex. The index is a pure cache, so a missing or |
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// wrong stamp costs a rebuild, never data. |
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type IndexStamp struct { |
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SpaceID int |
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Rev string |
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IndexedAt time.Time |
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} |
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// GetIndexStamp returns the space's index stamp. Returns ErrNotFound when the |
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// space has never been indexed — which the reconciler must treat as "stale", |
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// not as "up to date"; that is exactly why this is an error rather than a zero |
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// value. |
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func (s *Store) GetIndexStamp(ctx context.Context, spaceID int) (*IndexStamp, error) { |
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const q = `SELECT space_id, rev, indexed_at FROM index_stamp WHERE space_id = $1` |
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var st IndexStamp |
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err := s.q.QueryRowContext(ctx, q, spaceID).Scan(&st.SpaceID, &st.Rev, &st.IndexedAt) |
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if errors.Is(err, sql.ErrNoRows) { |
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return nil, ErrNotFound |
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} |
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if err != nil { |
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return nil, fmt.Errorf("get index stamp space=%d: %w", spaceID, err) |
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} |
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return &st, nil |
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} |
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// SetIndexStamp records that the index now reflects rev for this space. Called |
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// after a rebuild completes, never before: a stamp written ahead of the rebuild |
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// would make a crash look like a fresh index. |
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func (s *Store) SetIndexStamp(ctx context.Context, spaceID int, rev string) (*IndexStamp, error) { |
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if rev == "" { |
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return nil, fmt.Errorf("set index stamp space=%d: rev is required", spaceID) |
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} |
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const q = ` |
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INSERT INTO index_stamp (space_id, rev, indexed_at) |
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VALUES ($1, $2, $3) |
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ON CONFLICT (space_id) DO UPDATE |
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SET rev = EXCLUDED.rev, indexed_at = EXCLUDED.indexed_at |
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RETURNING space_id, rev, indexed_at` |
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var st IndexStamp |
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err := s.q.QueryRowContext(ctx, q, spaceID, rev, time.Now().UTC()). |
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Scan(&st.SpaceID, &st.Rev, &st.IndexedAt) |
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if err != nil { |
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return nil, fmt.Errorf("set index stamp space=%d: %w", spaceID, err) |
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} |
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return &st, nil |
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} |
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// GetDigestMark returns when the owner last looked at the digest of |
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// policy-merged content. Returns ErrNotFound if they never have. |
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// |
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// Auto-merged content that never appears in any view is write-only and rots |
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// invisibly — the exact failure this service exists to prevent, just relocated. |
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// This one timestamp is the whole of "what landed since you last looked". |
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func (s *Store) GetDigestMark(ctx context.Context, owner string) (time.Time, error) { |
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const q = `SELECT seen_at FROM digest_mark WHERE owner = $1` |
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var seen time.Time |
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err := s.q.QueryRowContext(ctx, q, owner).Scan(&seen) |
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if errors.Is(err, sql.ErrNoRows) { |
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return time.Time{}, ErrNotFound |
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} |
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if err != nil { |
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return time.Time{}, fmt.Errorf("get digest mark %q: %w", owner, err) |
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} |
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return seen, nil |
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} |
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// SetDigestMark moves the owner's "last looked at" timestamp. seenAt is passed |
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// in rather than defaulted to now() so the caller can mark the digest as of the |
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// moment it rendered the page, not the moment the write happened — anything |
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// that lands in between must still show up next time. |
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func (s *Store) SetDigestMark(ctx context.Context, owner string, seenAt time.Time) error { |
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if owner == "" { |
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return fmt.Errorf("set digest mark: owner is required") |
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} |
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if seenAt.IsZero() { |
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return fmt.Errorf("set digest mark %q: seen_at is required", owner) |
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} |
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const q = ` |
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INSERT INTO digest_mark (owner, seen_at) |
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VALUES ($1, $2) |
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ON CONFLICT (owner) DO UPDATE SET seen_at = EXCLUDED.seen_at` |
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if _, err := s.q.ExecContext(ctx, q, owner, seenAt.UTC()); err != nil { |
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return fmt.Errorf("set digest mark %q: %w", owner, err) |
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} |
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return nil |
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} |