Implement the UKOIndexer service that produces UKO triples from resources
using pluggable domain-specific analyzers, wraps each triple with provenance
metadata, and simultaneously indexes into text, vector, and graph backends.
Key design decisions and components:
- UKOIndexer orchestrates the full index lifecycle: add_resource,
update_resource (remove-then-add), remove_resource, and maintenance
triggers. Each operation fires lifecycle hooks (on_indexed, on_removed,
on_error) so callers can observe progress.
- Analyzer selection is pluggable via ContentAnalyzer protocol. The indexer
accepts a registry mapping resource types to analyzers. PythonAnalyzer
and MarkdownAnalyzer are provided as built-in implementations.
- LocationContentReader protocol abstracts file I/O with a base_dir
parameter for path-traversal prevention (post-resolve validation rejects
paths escaping the base directory and non-regular files).
- UKOTriple model includes a @model_validator ensuring at least one of
object_uri or object_value is populated, preventing empty triples at
construction time.
- Triple removal uses scoped deletion via uko:sourceResource predicate to
avoid shared-subject collision — only triples originating from the
specific resource are removed, not all triples for a shared subject.
- _resource_subjects.pop is deferred until after all backend removal
operations succeed, preventing inconsistent state on partial failure.
- analyzer.analyze() is wrapped in try/except so that analyzer errors
produce an IndexResult with error details rather than propagating
exceptions to callers.
- All lifecycle hook calls are guarded via _fire_on_indexed,
_fire_on_removed, and _fire_on_error helpers that catch and log hook
exceptions without disrupting the indexing pipeline.
- max_triples parameter (default 50,000) bounds analyzer output size to
prevent runaway resource consumption.
- ResourceFileWatcher monitors filesystem paths via watchdog and triggers
re-indexing callbacks on file changes with configurable debouncing.
Emits RESOURCE_MODIFIED domain events via EventBus when file changes
are detected. Debounce timers coalesce rapid edits into a single
callback invocation. Thread-safe design with daemon threads for clean
shutdown.
- SearchResult.__post_init__ validates score is in [0.0, 1.0], correctly
rejecting NaN values.
- Placeholder embedding uses [1.0] instead of [float(len(content))] to
avoid leaking content size information.
- isinstance check on graph_backend ensures GraphIndexBackend protocol
compliance at runtime.
- Test doubles extracted to features/mocks/uko_indexer_mocks.py for reuse
across BDD steps and Robot helpers.
Spec reference: Architecture > ACMS > Real-time Index Synchronization
(specification.md lines ~43205-43300).
ISSUES CLOSED: #578
hamza.khyari