Add a comprehensive specification document for the render‑pipeline refactor, detailing the problem statement, target architecture, intentional behavior changes, stage‑by‑stage plan, and review notes. This serves as the guiding blueprint for the upcoming refactor work.
Closes#34
Implementation-ready specification for the cache overhaul, accepted after
4 rounds of adversarial review (1 blocker and 3 majors found and fixed).
Work is tracked in gitea issues #23 (packages A+B+F), #24 (C, depends
on #23), #25 (D), #26 (E).
Detailed 7-stage plan covering: RPC timeouts under the global throttle gate,
background worker task_done/queue fixes, atomic large-video downloads,
FloodWait-to-429 mapping, FileResponse migration, event-loop hygiene for feed
rendering, SQLite write batching, and a lightweight /ping healthcheck.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
Add queue-based background download system to improve performance and reliability:
- Introduce DOWNLOAD_SEMAPHORE to limit concurrent downloads to 3
- Add asyncio.Queue (maxsize 100) with dedicated worker for background processing
- Implement safe_get_messages and safe_download_media wrappers with timeout protection (30s and 120s)
- Add retry logic for KeyError auth failures with 5s backoff
- Replace synchronous sequential downloads with asynchronous queued processing
- Prevent event loop blocking by queuing files instead of immediate download
vvzvlad