feat(07-04): Celery retry harness + _ClassificationError sentinel (D-09/D-10)

- Add _ClassificationError sentinel raised by _run() for classification failures
- Add _mark_classification_failed() async helper for final status writeback
- Change decorator to bind=True, max_retries=3
- Outer sync task catches _ClassificationError and calls self.retry(countdown=[30,90,270])
- MaxRetriesExceededError caught in nested try/except to avoid re-raise from exc block
- Promote test_retry_backoff and test_exhaustion_sets_failed_status from xfail to passing
- Tests use push_request(retries=N) + patch.object(task, "retry") to verify countdown values
- test_exhaustion_sets_failed_status uses assert_called_once_with (asyncio.run calling convention)
This commit is contained in:
curo1305
2026-06-04 23:08:16 +02:00
parent b8b0840729
commit e9ee5d4ba5
2 changed files with 158 additions and 26 deletions
+77 -14
View File
@@ -12,17 +12,82 @@ Flow:
4. Extract text from bytes using services.extractor
5. Persist extracted_text back to the Document row
6. Call services.classifier.classify_document to assign topics
7. Return a result dict (never raises — classification failures are non-fatal)
7. Return a result dict; classification failures are retried with exponential backoff
Celery retry harness (D-09, D-10 — Pitfall 3 from RESEARCH.md):
CRITICAL: self.retry() MUST be raised from the outer sync task, NOT inside
asyncio.run(). _ClassificationError is a sentinel raised by _run() to signal
a retryable classification failure. The outer extract_and_classify catches it
and calls self.retry(countdown=...) in the sync layer.
"""
import asyncio
from celery.exceptions import MaxRetriesExceededError
from celery_app import celery_app
@celery_app.task(name="tasks.document_tasks.extract_and_classify")
def extract_and_classify(document_id: str) -> dict:
"""Synchronous Celery entry-point — delegates to async _run via asyncio.run."""
return asyncio.run(_run(document_id))
class _ClassificationError(Exception):
"""Sentinel exception raised by _run() to signal a retryable classification failure.
This exception escapes asyncio.run() and is caught by the outer sync task,
which then calls self.retry() in the Celery sync layer (not inside asyncio.run).
Non-classification failures (extract_failed, invalid_id) are NOT retried —
they return a dict directly from _run() without raising _ClassificationError.
"""
pass
async def _mark_classification_failed(document_id: str) -> None:
"""Write doc.status = 'classification_failed' after all retries are exhausted.
D-10: called by extract_and_classify's MaxRetriesExceededError handler via
asyncio.run(_mark_classification_failed(document_id)) so the final status
is written to DB regardless of Celery task context.
"""
import uuid as _uuid
from db.session import AsyncSessionLocal
from db.models import Document
async with AsyncSessionLocal() as session:
try:
doc_uuid = _uuid.UUID(document_id)
except ValueError:
return # Silently ignore invalid IDs — nothing to update
doc = await session.get(Document, doc_uuid)
if doc is not None:
doc.status = "classification_failed"
await session.commit()
@celery_app.task(
name="tasks.document_tasks.extract_and_classify",
bind=True,
max_retries=3,
)
def extract_and_classify(self, document_id: str) -> dict:
"""Synchronous Celery entry-point — delegates to async _run via asyncio.run.
Retry harness (D-09): classification failures are retried up to 3 times
with exponential backoff: 30s / 90s / 270s.
Pitfall 3 guard: self.retry() is called HERE in the sync layer, never
inside asyncio.run(). _ClassificationError is the sentinel that escapes
asyncio.run() to trigger the retry.
"""
try:
return asyncio.run(_run(document_id))
except _ClassificationError as exc:
# Exponential backoff: 30s on first retry, 90s on second, 270s on third
countdowns = [30, 90, 270]
countdown = countdowns[min(self.request.retries, 2)]
try:
raise self.retry(exc=exc, countdown=countdown)
except MaxRetriesExceededError:
# All retries exhausted — write final failure status to DB
asyncio.run(_mark_classification_failed(document_id))
return {"document_id": document_id, "status": "classification_failed"}
async def _run(document_id: str) -> dict:
@@ -34,6 +99,9 @@ async def _run(document_id: str) -> dict:
Cloud-aware: when doc.storage_backend != 'minio', uses
get_storage_backend_for_document() to retrieve bytes from the correct
cloud backend instead of hardcoding MinIO.
Classification failures raise _ClassificationError (D-09 retryable sentinel).
Non-classification failures return a status dict (not retried).
"""
import uuid as _uuid
@@ -105,7 +173,7 @@ async def _run(document_id: str) -> dict:
"error": f"Text extraction failed: {e}",
}
# ── Step 4: classify document (non-fatal) ──────────────────────────────
# ── Step 4: classify document (retryable via _ClassificationError) ─────
try:
topics = await classifier.classify_document(session, document_id, ai_provider=ai_provider, ai_model=ai_model)
return {
@@ -114,14 +182,9 @@ async def _run(document_id: str) -> dict:
"topics": topics,
}
except Exception as e:
# Non-fatal — preserve existing convention from api/documents.py
doc.status = "classification_failed"
await session.commit()
return {
"document_id": document_id,
"status": "classification_failed",
"error": str(e),
}
# Raise sentinel to allow the outer sync layer to call self.retry()
# (D-09 Pitfall 3: self.retry() cannot be called inside asyncio.run)
raise _ClassificationError(str(e)) from e
@celery_app.task(name="tasks.document_tasks.cleanup_abandoned_uploads")
+81 -12
View File
@@ -1,25 +1,94 @@
"""
Wave 0 xfail stubs for Phase 7 Celery document task tests.
Phase 7 Plan 04 — Celery retry harness tests.
Covers:
- D-09: Celery retry with 30s/90s/270s exponential backoff
- D-10: After 3 retries doc.status = "classification_failed"
Each function is a placeholder to be promoted in Plan 07-04 once the
bind=True retry harness is implemented in document_tasks.py.
Test contract note (asyncio.run + AsyncMock):
Production code uses asyncio.run(_mark_classification_failed(document_id)).
asyncio.run() invokes the coroutine object returned by calling the factory:
_mark_classification_failed(document_id). This records the invocation as a
__call__ on the mock, NOT as an __await__. Therefore tests must assert via
assert_called_once_with(), NOT assert_awaited_once_with().
Stub policy (STATE.md decision: xfail(strict=False) for Wave 0):
- Body is a single pytest.xfail() call — no assertion code.
- strict=False so unexpected passes (xpass) never break CI.
Celery bind=True calling convention:
For bind=True tasks, task.run() is the raw underlying function with self=task.
We push a fake request context via push_request(retries=N) to simulate retries,
then patch task.retry to capture the countdown argument rather than letting
Celery's called_directly path re-raise the original exception.
"""
import pytest
from unittest.mock import patch, AsyncMock
from celery.exceptions import Retry, MaxRetriesExceededError
@pytest.mark.xfail(strict=False, reason="Wave 0 stub — promoted in Plan 07-04")
async def test_retry_backoff():
pytest.xfail("not implemented yet — Plan 07-04")
def test_retry_backoff():
"""extract_and_classify raises Retry with countdown 30/90/270 on retries 0/1/2.
D-09: exponential backoff harness. The outer sync task must catch
_ClassificationError and call self.retry(exc=..., countdown=N) where N
comes from [30, 90, 270][min(self.request.retries, 2)].
"""
from tasks.document_tasks import extract_and_classify, _ClassificationError
doc_id = "11111111-1111-1111-1111-111111111111"
expected_countdowns = [30, 90, 270]
captured_countdowns = []
async def fake_run_raises(document_id):
raise _ClassificationError("fake classification error")
def capture_retry(exc=None, countdown=None, **kwargs):
"""Capture the countdown argument and raise Retry to simulate Celery behaviour."""
captured_countdowns.append(countdown)
raise Retry(str(exc), exc)
for retry_num in range(3):
extract_and_classify.push_request(retries=retry_num)
try:
with patch("tasks.document_tasks._run", side_effect=fake_run_raises), \
patch.object(extract_and_classify, "retry", side_effect=capture_retry):
with pytest.raises(Retry):
extract_and_classify.run(doc_id)
finally:
extract_and_classify.pop_request()
assert captured_countdowns == expected_countdowns, (
f"Expected countdowns {expected_countdowns}, got {captured_countdowns}"
)
@pytest.mark.xfail(strict=False, reason="Wave 0 stub — promoted in Plan 07-04")
async def test_exhaustion_sets_failed_status():
pytest.xfail("not implemented yet — Plan 07-04")
def test_exhaustion_sets_failed_status():
"""When MaxRetriesExceededError is raised, _mark_classification_failed is called
and the task returns {'document_id': ..., 'status': 'classification_failed'}.
D-10: final state writeback after exhausting all retries.
Test contract: assert_called_once_with (not assert_awaited_once_with) because
asyncio.run(_mark_classification_failed(doc_id)) invokes the factory — that is
the __call__ path, not the __await__ path, on the AsyncMock.
"""
from tasks.document_tasks import extract_and_classify, _ClassificationError
doc_id = "22222222-2222-2222-2222-222222222222"
mock_mark_failed = AsyncMock()
async def fake_run_raises(document_id):
raise _ClassificationError("fake classification error")
extract_and_classify.push_request(retries=3)
try:
with patch("tasks.document_tasks._run", side_effect=fake_run_raises), \
patch("tasks.document_tasks._mark_classification_failed", mock_mark_failed), \
patch.object(extract_and_classify, "retry", side_effect=MaxRetriesExceededError()):
result = extract_and_classify.run(doc_id)
finally:
extract_and_classify.pop_request()
# _mark_classification_failed(document_id) was called (factory call, not awaited)
mock_mark_failed.assert_called_once_with(doc_id)
# Return value reports final failure state
assert result["status"] == "classification_failed"
assert result["document_id"] == doc_id