Oleksandr Kozachuk
46 lines
1.8 KiB
Markdown
46 lines
1.8 KiB
Markdown
# SPEC-009 — Persistence
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One SQLite database per deployment (`<history-directory>/bot.db`),
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replacing the per-channel pickle files (`<channel>.dat`,
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`<channel>.memory`). Stdlib `sqlite3` via worker threads — no new
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dependency (D-010). Without `history-directory` in config the bot
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runs memory-only, as before.
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### PER-01 — History survives restarts (coverage: test)
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History entries written through the store are returned, in order and
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per channel, by a fresh store instance on the same database file.
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### PER-02 — Memory survives restarts (coverage: test)
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The per-channel memory string written through the store is returned
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by a fresh store instance on the same database file.
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### PER-03 — Existing pickles migrate exactly once (coverage: test)
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On responder start, when the database holds no rows for the channel
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and legacy pickle files exist, their content is imported and the
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pickle files are renamed to `*.migrated` (kept for rollback). A
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second start does not re-import. Users keep their history through
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the cutover (review consensus: migration is a decision, not an
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accident).
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### PER-04 — Database hygiene (coverage: test)
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The database runs in WAL journal mode, carries `PRAGMA user_version`
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= the store's current schema version for the migration/rollback
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policy, and the file is chmod 0600 (it stores conversation data).
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### PER-06 — Schema migrations run forward automatically (coverage: test)
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Opening a database with an older `user_version` applies the missing
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migration steps in order (v1 → v2 adds the usage table) and preserves
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existing rows. Deploy rollback policy: never roll binaries back past
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a schema bump without restoring the pre-deploy backup.
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### PER-05 — Writes run off the event loop (coverage: test)
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History and memory persistence happen in a worker thread
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(`asyncio.to_thread`) — a slow disk cannot stall Discord event
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handling (D6).
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