detections/_docs/03_implementation/implementation_report_distributed_architecture.md

Final Implementation Report — Distributed Architecture

Date: 2026-03-31 Epic: AZ-172 (Distributed Architecture Adaptation) Tasks: 4 implemented, 0 blocked

Summary

All 4 tasks from the distributed architecture epic have been successfully implemented across 3 batches. The detection service now operates in a distributed architecture where media is received as byte streams rather than local file paths, AI configuration is fetched from the database via the annotations service, and media records are managed with proper status lifecycle tracking.

Batch Summary

Batch	Tasks	Complexity	Verdict	Commit
1 (sequential)	AZ-173, AZ-174	5 pts	PASS_WITH_WARNINGS	6c24d09
2	AZ-175	2 pts	PASS_WITH_WARNINGS	40be55a
3	AZ-176	1 pt	PASS	9411103

Total: 8 complexity points, 3 batches, 0 blockers

Key Changes

AZ-173: Stream-Based Detection API

• New run_detect_video and run_detect_image methods accept bytes instead of file paths
• PyAV library for video stream decoding from memory buffers
• Simultaneous disk write and frame processing via background thread
• Image decoding via cv2.imdecode from bytes buffer

AZ-174: DB-Driven AI Configuration

• AIRecognitionConfig.paths field removed
• Configuration fetched from annotations service GET /api/users/{userId}/ai-settings
• JWT userId extraction via TokenManager.decode_user_id
• Multi-format field name mapping (snake_case, camelCase, PascalCase)
• Fallback to sensible defaults if service unreachable

AZ-175: Media Table Integration

• XxHash64 content hashing with sampling algorithm
• Media record creation via annotations service POST /api/media
• Persistent file storage at configurable directories
• MediaStatus lifecycle: New(1) → AIProcessing(2) → AIProcessed(3) / Error(6)

AZ-176: Cleanup Obsolete Path-Based Code

• Removed is_video, run_detect, _process_video (cv2.VideoCapture), _process_images (cv2.imread)
• Cleaned up dead imports (mimetypes, pathlib.Path)

Test Results

• Unit tests: 14/14 passed
• New dependencies: av==14.2.0, xxhash==3.5.0

Files Modified

File	Changes
src/inference.pyx	Stream-based methods, removed path-based methods
src/main.py	Media lifecycle, DB config, upload handling
src/ai_config.pxd	Removed paths field
src/ai_config.pyx	Removed paths from init/from_dict
src/loader_http_client.pyx	fetch_user_ai_settings, fetch_media_path
src/loader_http_client.pxd	Method declarations
src/media_hash.py	New — XxHash64 content hashing
requirements.txt	Added av, xxhash
e2e/mocks/annotations/app.py	New mock endpoints
e2e/tests/test_async_sse.py	Adapted for new API
e2e/tests/test_video.py	Adapted for new API