# Scaling Setup

This codebase now supports optional Redis, BullMQ, S3-compatible storage, structured JSON logging, and feed caching.

## What was added

- Redis-backed cache and rate limiting fallback to in-memory
- Optional Socket.IO Redis adapter
- Optional BullMQ queue for outbox processing
- Pluggable storage layer with:
  - `local`
  - `s3` compatible providers such as AWS S3 or Cloudflare R2
- Feed response caching with versioned invalidation
- Fast refresh-token fingerprinting to reduce bcrypt load
- JSON request logging

## Feature flags

### Redis

```env
REDIS_ENABLED=true
REDIS_URL=redis://127.0.0.1:6379
REDIS_KEY_PREFIX=oudelaa
REDIS_SOCKET_ADAPTER_ENABLED=true
```

### Queue

```env
QUEUE_ENABLED=true
QUEUE_NAME=app-jobs
QUEUE_DEFAULT_ATTEMPTS=3
QUEUE_DEFAULT_BACKOFF_MS=1000
QUEUE_WORKER_CONCURRENCY=5
```

Queue processing falls back to in-process execution when Redis/queue is disabled.

### S3 / R2

```env
STORAGE_PROVIDER=s3
STORAGE_BASE_PATH=uploads
STORAGE_PUBLIC_BASE_URL=https://cdn.example.com
S3_BUCKET=oudelaa
S3_REGION=auto
S3_ENDPOINT=https://<account-or-endpoint>
S3_ACCESS_KEY_ID=...
S3_SECRET_ACCESS_KEY=...
S3_FORCE_PATH_STYLE=false
```

For Cloudflare R2, `S3_REGION=auto` is acceptable and `STORAGE_PUBLIC_BASE_URL` should usually point to the CDN/custom domain.

### Logging

```env
LOG_LEVEL=log
REQUEST_LOGGING_ENABLED=true
```

### Feed cache

```env
FEED_CACHE_ENABLED=true
FEED_CACHE_USER_TTL_SECONDS=15
FEED_CACHE_TRENDING_TTL_SECONDS=30
```

## Practical rollout order

1. Enable JSON logging in staging
2. Enable Redis cache and Redis rate limiting
3. Enable BullMQ queue for outbox jobs
4. Move uploads to S3/R2
5. Enable Socket.IO Redis adapter when running multiple instances
6. Run authenticated load tests against `auth`, `feed`, `posts`, `chat`, and `notifications`

## Current limitations

- The app is still a modular monolith, not separate microservices yet
- Feed caching is versioned invalidation plus TTL, not full fan-out precomputation
- Marketplace images are still URL-based data, not binary upload pipelines
- Local tests do not replace full production benchmarking
