NexaPG/README.md

# NexaPG - PostgreSQL Monitoring Stack

NexaPG is a Docker-based PostgreSQL monitoring platform for multiple remote targets, built with FastAPI + React.

## PostgreSQL Version Support

NexaPG targets PostgreSQL versions **14, 15, 16, 17, and 18**.

- Compatibility is verified with an automated CI matrix.
- Collector and overview queries include fallbacks for stats view differences between versions (for example `pg_stat_bgwriter` vs `pg_stat_checkpointer` fields).

## What it includes

- Multi-target PostgreSQL monitoring (remote instances)
- Polling collector for:
  - `pg_stat_database`
  - `pg_stat_activity`
  - `pg_stat_bgwriter`
  - `pg_locks`
  - `pg_stat_statements` (if enabled on target)
- Core metadata database for:
  - Authentication and RBAC (`admin`, `operator`, `viewer`)
  - Monitored target configuration (encrypted credentials)
  - Metrics and query stats
  - Audit logs
- JWT auth (access + refresh)
- FastAPI + SQLAlchemy async + Alembic migrations
- React (Vite) frontend with:
  - Login/logout
  - Dashboard overview
  - Target detail with charts and database overview
  - Query insights
  - Admin user management
- Health endpoints:
  - `/api/v1/healthz`
  - `/api/v1/readyz`

## Repository structure

- `backend/` FastAPI application
- `frontend/` React (Vite) application
- `ops/` helper scripts and env template copy
- `docker-compose.yml` full stack definition
- `.env.example` environment template

## Prerequisites

Install these before starting:

- Docker Engine 24+
- Docker Compose v2+
- GNU Make (optional, for `make up/down/logs/migrate`)
- Open ports on your host:
  - frontend: `5173` (default)
  - backend: `8000` (or your `BACKEND_PORT`)
  - core DB: `5433` (or your `DB_PORT`)

Optional but recommended:

- `psql` client for troubleshooting target connectivity

## Quick start

1. Create local env file:

```bash
cp .env.example .env
```

2. Generate an encryption key and set `ENCRYPTION_KEY` in `.env`:

```bash
python -c "from cryptography.fernet import Fernet; print(Fernet.generate_key().decode())"
```

3. Start services:

```bash
make up
```

4. Open:

- Frontend: `http://<SERVER_IP>:5173` (or `https://<your-domain>`)
- Backend API: `http://<SERVER_IP>:8000/api/v1` (or `https://<your-domain>/api/v1`)
- OpenAPI docs: `http://<SERVER_IP>:8000/docs` (or `https://<your-domain>/docs`)

Default initial admin (from `.env`):

- Email: `admin@example.com`
- Password: `ChangeMe123!`

## Common commands

```bash
make up        # build + start all services
make down      # stop all services
make logs      # follow logs
make migrate   # run Alembic migrations in backend container
```

PostgreSQL compatibility smoke check script:

```bash
PG_DSN='postgresql://postgres:postgres@127.0.0.1:5432/compatdb?sslmode=disable' \
python backend/scripts/pg_compat_smoke.py
```

## Environment variables reference

All variables are defined in `.env.example`.

### Application

- `APP_NAME`: Display name used by backend/docs
- `ENVIRONMENT`: `dev | staging | prod | test`
- `LOG_LEVEL`: `DEBUG | INFO | WARNING | ERROR`

### Core database (internal)

- `DB_NAME`: Internal metadata DB name
- `DB_USER`: Internal metadata DB user
- `DB_PASSWORD`: Internal metadata DB password
- `DB_PORT`: Host port mapped to internal PostgreSQL `5432`

### Backend API

- `BACKEND_PORT`: Host port mapped to backend container `8000`
- `JWT_SECRET_KEY`: JWT signing key (must be changed)
- `JWT_ALGORITHM`: JWT algorithm (default `HS256`)
- `JWT_ACCESS_TOKEN_MINUTES`: access token lifetime
- `JWT_REFRESH_TOKEN_MINUTES`: refresh token lifetime
- `ENCRYPTION_KEY`: Fernet key for encrypting target passwords at rest
- `CORS_ORIGINS`: comma-separated allowed origins or `*` (dev-only)
- `POLL_INTERVAL_SECONDS`: collector polling interval
- `INIT_ADMIN_EMAIL`: bootstrap admin email
- `INIT_ADMIN_PASSWORD`: bootstrap admin password

### Frontend

- `FRONTEND_PORT`: Host port mapped to frontend container `80`
- `VITE_API_URL`: API base URL baked into frontend build
  - Proxy/SSL setup: use `/api/v1`
  - Direct server setup: use `http://<SERVER_IP>:<BACKEND_PORT>/api/v1`

## API overview (minimum)

- Auth:
  - `POST /api/v1/auth/login`
  - `POST /api/v1/auth/refresh`
  - `POST /api/v1/auth/logout`
  - `GET /api/v1/me`
- Targets:
  - `GET/POST /api/v1/targets`
  - `GET/PUT/DELETE /api/v1/targets/{id}`
  - `GET /api/v1/targets/{id}/metrics?from=&to=&metric=`
  - `GET /api/v1/targets/{id}/locks`
  - `GET /api/v1/targets/{id}/activity`
  - `GET /api/v1/targets/{id}/top-queries`
  - `GET /api/v1/targets/{id}/overview`
- Admin users (admin-only):
  - `GET /api/v1/admin/users`
  - `POST /api/v1/admin/users`
  - `PUT /api/v1/admin/users/{user_id}`
  - `DELETE /api/v1/admin/users/{user_id}`

## Security notes

- No secrets are hardcoded in source
- Passwords are hashed with Argon2
- Target credentials are encrypted with Fernet
- CORS is environment-configurable
- Audit logs include auth, target, and user management events
- Rate limiting is currently a placeholder for future middleware integration

## Important: `pg_stat_statements`

Query Insights requires `pg_stat_statements` on each monitored target.

```sql
CREATE EXTENSION IF NOT EXISTS pg_stat_statements;
```

## Reverse proxy and SSL

For production-like deployments behind HTTPS:

- Set frontend API to relative path: `VITE_API_URL=/api/v1`
- Route `/api/` from proxy to backend service
- Keep frontend and API on the same public origin to avoid CORS/mixed-content problems

## CI Compatibility Matrix

GitHub Actions workflow:

- `.github/workflows/pg-compat-matrix.yml`

It runs smoke checks against PostgreSQL `14`, `15`, `16`, `17`, and `18`.