Architecture & infra design doc (Channels + Mongo + Redis + Workers)

[mehalyna]

Task 1 — Architecture & infra design doc (Channels + Mongo + Redis + Workers)

Title: design: Messaging architecture doc (Django Channels + MongoDB + Redis + worker)

Deliverables

• Short design document covering:

  • Why MongoDB for message store (fast append, BSON, flexible metadata) and Postgres for relational data (users, notifications).
  • Channel layer: Redis (requirements and config).
  • Websocket routing & authentication approach (JWT or session cookie).
  • Message lifecycle: send → persist → publish to channel → create notification via background worker.
  • Scaling & retention strategy (sharding, TTL indexes in Mongo, archiving).
  • Security (auth checks, sanitize message content, limit attachments).
  • Backpressure & rate limiting approach.

• Diagrams (sequence for send/receive, flow for offline notifications).

Acceptance

• Doc committed to docs/architecture/messaging.md.
• Team sign-off (one reviewer).

Dependencies

• Existing auth & user model.
• Infrastructure: Redis, MongoDB, Celery (or chosen worker), channels.

Notes

• Provide recommended Redis and Mongo versions and sample docker-compose service definitions for local dev.