# Chat Backend

Django + Channels API for AIML Operations chat (`chatbackend.aimloperations.com`).
Packaging via `uv`; production deploy via `server-infra`.

Companion frontend: [`chat_web_app`](https://git.aimloperations.com/ai_ml_operations/chat_web_app)
(node-static, not Docker).

Ticket: [chat_backend#6](https://git.aimloperations.com/ai_ml_operations/chat_backend/issues/6)

## Layout

```text
chat_backend/                 ← repo root (Dockerfile, compose, pyproject, .gitea)
├── llm_be/                   ← Django project root (manage.py)
│   ├── manage.py
│   ├── llm_be/               ← settings, urls, asgi/wsgi
│   └── chat_backend/         ← app (models, consumers, services, storage)
├── scripts/
│   ├── docker-entrypoint.sh
│   └── validate-env.sh
├── docker-compose.yml        ← local/CI (bundled Postgres)
└── docker-compose.prod.yml   ← server-infra (external DATABASE_URL)
```

## Local development

### Prerequisites

- Python 3.12+
- [uv](https://docs.astral.sh/uv/)
- Docker + Docker Compose (optional, recommended)
- Ollama reachable at `OLLAMA_BASE_URL` for LLM features

### uv (host)

```bash
cp .env.example .env
uv sync
cd llm_be
uv run python manage.py migrate
uv run python manage.py runserver 0.0.0.0:8003
```

Without `DATABASE_URL` / `DB_HOST`, settings fall back to SQLite (`llm_be/db.sqlite3`).

Tests (skip live-Ollama classifier cases):

```bash
cd llm_be
SKIP_RAG_INIT=1 uv run python manage.py test
```

### Docker (dev, bundled Postgres)

```bash
docker compose up --build
```

App: http://localhost:8003 — Postgres via bundled `db`
(`postgres://chat_backend:chat_backend@db:5432/chat_backend`).
Compose does **not** read host `DATABASE_URL` (avoids CI/prod leaks); override
with `COMPOSE_DATABASE_URL` if needed.

## Environment variables

| Variable | Dev default | Prod required | Notes |
|----------|-------------|---------------|-------|
| `DJANGO_ENV` | `dev` | `prod` / `beta` | |
| `DJANGO_SECRET_KEY` | insecure default | yes | Must be real in prod/beta |
| `DJANGO_DEBUG` | true when `dev` | `false` | |
| `DJANGO_ALLOWED_HOSTS` | localhost + chat hosts | yes | Comma-separated |
| `DJANGO_CSRF_TRUSTED_ORIGINS` | derived from hosts | optional | Full origins |
| `DATABASE_URL` | SQLite fallback | yes | Shared Postgres in prod |
| `WEB_PORT` | n/a (compose maps 8003) | `8003` | Host port for prod compose |
| `OLLAMA_BASE_URL` | `http://127.0.0.1:11434` | yes | GPU host in prod: `http://10.0.0.128:11434` |
| `OLLAMA_MODEL` / `OLLAMA_EMBED_MODEL` | from `DEBUG` | optional | Override model names |
| `EMAIL_HOST_*` | empty | yes (prod/beta) | SMTP2GO |
| `CAPTCHA_SECRET_KEY` | empty | recommended | |
| `CORS_ALLOWED_ORIGINS` | local + chat FE | set in prod | Frontend origin |
| `USE_TLS_PROXY` | false (dev) | true behind NPM | Sets `SECURE_PROXY_SSL_HEADER` |
| `GUNICORN_WORKERS` / `GUNICORN_BIND` | 2 / `0.0.0.0:8000` | optional | Entrypoint |
| `SKIP_RAG_INIT` | unset | CI/migrate often `1` | Skip Chroma/Ollama boot work |

Templates: `.env.example` (local), `.env.prod.example` (control-node secret).

Control-node secret path (server-infra on ai-server-4080):

```text
~/Documents/secrets/chat_backend/chat_backend_prod.env
```

Validate with:

```bash
./scripts/validate-env.sh ~/Documents/secrets/chat_backend/chat_backend_prod.env
```

If `DATABASE_URL` password contains `$`, escape each as `$$` for Compose.

## Ollama

All clients (`ollama.Client`, `OllamaLLM`, `OllamaEmbeddings`, `ChatOllama`) use
`OLLAMA_BASE_URL` — never hardcoded localhost in deployed code.

| Env | Typical URL |
|-----|-------------|
| Local (Ollama on same machine) | `http://127.0.0.1:11434` |
| prod / beta (containers on adama/roslin/ai-server) | `http://10.0.0.128:11434` |

Firewall / Ollama listen on ai-server-4080 must allow `10.0.0.0/24` → `:11434`.

## File storage

Prompt attachments and workspace documents use **`DatabaseStorage`**
(`chat_backend.StoredFile` BinaryField in Postgres). Blobs are **not** written
to the container filesystem under `media/`.

RAG loaders that need a path materialize a short-lived temp file, then delete it.
Chroma’s vector index may still use a volume (`chroma_db`); that is embeddings
metadata, not the original upload.

## Production (docker-compose.prod.yml)

- Single `web` service; **no** bundled DB — `DATABASE_URL` → shared Postgres (`10.0.0.230`).
- Host port from `WEB_PORT` (catalog: **8003**; beta reserved **8013**).
- Entrypoint: wait DB → migrate → collectstatic → `gunicorn` + `UvicornWorker`
  (ASGI for HTTP **and** WebSockets).
- Active/active on **adama + roslin + ai-server-4080**; NPM balances upstreams.
- Deployed by:

```bash
~/Documents/repos/server-infra/scripts/deploy.sh \
  --app chat_backend --env prod --ref <sha>
```

## CI / CD (Gitea Actions)

| Workflow | Trigger | Action |
|----------|---------|--------|
| `unittests.yml` | push + PR → `master` | `uv sync` + `manage.py test` |
| `ci.yml` | PR → `master` | same unit tests |
| `deploy.yml` | after Unit Tests succeeds on `master` **push** | docker build + tests on **ephemeral compose Postgres** → `deploy.sh` |

Deploy never runs on PRs.

## Security note

Secrets previously hardcoded in `settings.py` (email password, captcha, Django
secret) must live only in the control-node env file. Rotate anything that was
ever committed; never commit `.env` or `~/Documents/secrets/`.