Adds late-fusion hybrid search to Turnstone's log retrieval layer:
hybrid_score = 0.6 * bm25_normalized + 0.4 * cosine_similarity
Implementation:
- _bm25_search() extracts the existing FTS5 BM25 path as a named helper
- _hybrid_search() fetches an oversized BM25 candidate pool (5x limit,
min 100), embeds the query and each candidate text in-process via the
existing embeddings service, normalizes BM25 rank to [0,1], combines
with cosine similarity, and re-ranks
- search() gets semantic=False param that dispatches to _hybrid_search()
when True; pure BM25 remains the default for all existing call sites
- diagnose_stream() enables semantic=True so symptom-based queries
("database connection failed") surface semantically equivalent entries
("ECONNREFUSED", "backend gone away", "max retries exceeded")
- /api/search REST endpoint exposes ?semantic=true query param
Graceful degradation: falls back silently to pure BM25 when the embedding
backend is unavailable (EMBEDDING_AVAILABLE=False) or when embed_batch
raises an exception. No new infra — in-process numpy cosine, no vector DB.
11 new tests: BM25 helper, hybrid re-ranking, fallback paths, dispatcher.
372 + 11 = 383 tests passing.
Closes: #15
context_facts, context_documents, and context_chunks now live in
turnstone-context.db (sibling of turnstone.db). The glean scheduler
held write locks on the main DB long enough to cause 5-second timeout
failures on context fact inserts; separate files have independent WAL
write locks so they never contend.
Changes:
- pipeline.py: extract _CONTEXT_SCHEMA + ensure_context_schema()
- rest.py: CONTEXT_DB_PATH (TURNSTONE_CONTEXT_DB env var, defaults to
sibling file); init via ensure_context_schema(); all context routes
pass CONTEXT_DB_PATH; diagnose_stream receives context_db_path kwarg
- diagnose/__init__.py: diagnose_stream() accepts context_db_path
(falls back to db_path for backward compat); retrieve_context uses it
- store.py: sqlite3.connect() timeout=30.0 — Python driver retry loop
is independent of PRAGMA busy_timeout; needed for any remaining
contention during test or single-file deployments
Closes: #42
- #33: Wrap ClassifiedTimeline.cluster_severities in MappingProxyType for
true immutability (frozen=True only blocks field reassignment, not dict
mutation).
- #34: Remove dead suppression branch in synthesizer._build_hypothesis_block.
active[] is already filtered to not rh.suppress, so the 'Yes — suppressed'
branch was unreachable. Now shows novelty score only.
- #35: Extract shared _llm_client.py with call_llm() + extract_content() +
strip_json_fences(). Both RootCauseHypothesizer and SummarySynthesizer
now import from one source. Also strips JSON fences from LLM output before
parsing in hypothesizer._parse_response.
- #36: Add per-stage try/except in pipeline.run_pipeline(). Unhandled
stage exceptions now emit {type: 'error'} + {type: 'done'} SSE events
instead of silently closing the stream.
- #37: Move format_context_block() call inside the legacy LLM branch in
diagnose/__init__.py — it was being computed unconditionally but only
used in the non-pipeline path.
- #38: Coerce supporting_cluster_ids items to str() in hypothesizer
_parse_response to guard against LLMs returning integers instead of
string cluster IDs.
- Move app/services/diagnose.py verbatim to app/services/diagnose/legacy.py
- Create app/services/diagnose/__init__.py with full implementation so that
patch('app.services.diagnose._HAS_DATEPARSER') targets the correct namespace
and all 303 existing tests continue to pass without modification
- Add app/services/diagnose/models.py with 5 pipeline dataclasses:
EventCluster, TimelineResult, ClassifiedTimeline, Hypothesis, RankedHypothesis
- Add app/services/diagnose/pipeline.py with run_pipeline() stub (Task 6)
- Add MULTI_AGENT_ENABLED feature flag (off by default via env var)
- Zero behavior change; ruff clean
Closes: #29
