| Dimension | Shared | Only in A | Only in B | Overlap |
|---|---|---|---|---|
| Sections | 0 | 1 | 6 | 0% |
| Commands | 0 | 0 | 0 | — |
| Section tags | 0 | 1 | 1 | 0% |
What each file covers
Sections
0 shared · 1 only in A · 6 only in B- − Claude Code
- + Background Task Lifecycle
- + Drain vs. cancel on `stop()` (a correctness decision)
- + Loop invariants
- + ✅ wakes immediately on stop
- + ❌ asyncio.sleep(self._interval) # ignores the stop signal
- + Shutdown ordering in `app/main.py` lifespan
Commands
neither file has anySection tags
0 shared · 1 only in A · 1 only in B- − agent-behaviour
- + monorepo
Line diff
jleist-clemson/acheron · CLAUDE.md
@@ −1 @@
1@AGENTS.md
2
3@.claude/rules/python-standards.md
4@.claude/rules/api-routes.md
5@.claude/rules/testing.md
6@.claude/rules/elasticsearch-mapping.md
7@.claude/rules/background-tasks.md
8
9## Claude Code
10
11Shared, vendor-neutral project context lives in `AGENTS.md` (imported above).
12Project conventions live in `.claude/rules/` and are **imported above** so they
13load every session — Claude Code has no glob-scoped rules directory, so each
14file simply names the paths it applies to in an "Applies to" line. They mirror
15the Cursor rules in `.cursor/rules/` (which *are* glob-scoped via `globs:`); if
16you change a convention, update **both** mirrors and the relevant section of
17`ARCHITECTURE.md` so the tools and docs don't drift.
18
jleist-clemson/acheron · .cursor/rules/background-tasks.mdc
@@ +1 @@
1---
2description: Background task lifecycle, shutdown ordering, and loop invariants
3globs: app/worker/**/*.py,app/main.py
4alwaysApply: false
5---
6
7# Background Task Lifecycle
8
9Background tasks (`WorkerPool`, `EsIndexer`, `RollupScheduler`) follow a
10`start()` / `stop()` shape with an `asyncio.Event` stop signal and a single
11`asyncio.create_task(..., name=...)`. The skeleton matters less than the
12decisions below — get these wrong and you lose data or hang a deploy.
13
14## Drain vs. cancel on `stop()` (a correctness decision)
15
16- If the task holds **un-acked, un-persisted work**, drain it before cancelling.
17 `WorkerPool.stop()` does `await queue.join()` with a timeout, *then* cancels.
18- If the task's work is **idempotent / replayable** (the outbox re-indexes, the
19 next tick re-aggregates), set the stop event and cancel directly —
20 `EsIndexer` / `RollupScheduler`.
21
22When adding a task, ask: would cancelling mid-flight lose anything? That answer
23picks the variant.
24
25## Loop invariants
26
27- Idle interruptibly — never block shutdown for a full interval:
28
29```python
30# ✅ wakes immediately on stop
31try:
32 await asyncio.wait_for(self._stop_event.wait(), timeout=self._interval)
33except asyncio.TimeoutError:
34 pass # interval elapsed
35# ❌ asyncio.sleep(self._interval) # ignores the stop signal
36```
37
38- The loop body **catches and logs**, never lets an exception kill the task.
39- Consumers must call `task_done()` for every `get()`, even on error.
40
41## Shutdown ordering in `app/main.py` lifespan
42
43`ingestion.stop_accepting()` → `worker.stop()` (drain) → `es_indexer.stop()` →
44`rollup.stop()` → **then** close Mongo/ES/Redis clients. Never close a client a
45running task still uses.
46
@@ −1 +1 @@
1−@AGENTS.md
1+---
2+description: Background task lifecycle, shutdown ordering, and loop invariants
3+globs: app/worker/**/*.py,app/main.py
4+alwaysApply: false
5+---
26
3−@.claude/rules/python-standards.md
4−@.claude/rules/api-routes.md
5−@.claude/rules/testing.md
6−@.claude/rules/elasticsearch-mapping.md
7−@.claude/rules/background-tasks.md
7+# Background Task Lifecycle
88
9−## Claude Code
9+Background tasks (`WorkerPool`, `EsIndexer`, `RollupScheduler`) follow a
10+`start()` / `stop()` shape with an `asyncio.Event` stop signal and a single
11+`asyncio.create_task(..., name=...)`. The skeleton matters less than the
12+decisions below — get these wrong and you lose data or hang a deploy.
1013
11−Shared, vendor-neutral project context lives in `AGENTS.md` (imported above).
12−Project conventions live in `.claude/rules/` and are **imported above** so they
13−load every session — Claude Code has no glob-scoped rules directory, so each
14−file simply names the paths it applies to in an "Applies to" line. They mirror
15−the Cursor rules in `.cursor/rules/` (which *are* glob-scoped via `globs:`); if
16−you change a convention, update **both** mirrors and the relevant section of
17−`ARCHITECTURE.md` so the tools and docs don't drift.
14+## Drain vs. cancel on `stop()` (a correctness decision)
15+
16+- If the task holds **un-acked, un-persisted work**, drain it before cancelling.
17+ `WorkerPool.stop()` does `await queue.join()` with a timeout, *then* cancels.
18+- If the task's work is **idempotent / replayable** (the outbox re-indexes, the
19+ next tick re-aggregates), set the stop event and cancel directly —
20+ `EsIndexer` / `RollupScheduler`.
21+
22+When adding a task, ask: would cancelling mid-flight lose anything? That answer
23+picks the variant.
24+
25+## Loop invariants
26+
27+- Idle interruptibly — never block shutdown for a full interval:
28+
29+```python
30+# ✅ wakes immediately on stop
31+try:
32+ await asyncio.wait_for(self._stop_event.wait(), timeout=self._interval)
33+except asyncio.TimeoutError:
34+ pass # interval elapsed
35+# ❌ asyncio.sleep(self._interval) # ignores the stop signal
36+```
37+
38+- The loop body **catches and logs**, never lets an exception kill the task.
39+- Consumers must call `task_done()` for every `get()`, even on error.
40+
41+## Shutdown ordering in `app/main.py` lifespan
42+
43+`ingestion.stop_accepting()` → `worker.stop()` (drain) → `es_indexer.stop()` →
44+`rollup.stop()` → **then** close Mongo/ES/Redis clients. Never close a client a
45+running task still uses.
1846
