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# 🏗️ API-First Zero-Trust Architecture - Complete Guide
## 📋 Table of Contents
1. [Architecture Overview](#architecture-overview)
2. [Security Model](#security-model)
3. [Authentication Flows](#authentication-flows)
4. [RBAC & Permissions](#rbac--permissions)
5. [API Endpoints](#api-endpoints)
6. [Telegram Bot Integration](#telegram-bot-integration)
7. [Testing Strategy](#testing-strategy)
8. [Deployment](#deployment)
9. [Production Checklist](#production-checklist)
---
## 🏗️ Architecture Overview
### System Components
```
EXTERNAL CLIENTS (Web, Mobile, Bot)
↓
API GATEWAY (FastAPI)
↓
MIDDLEWARE STACK
├─ Security Headers
├─ Rate Limiting
├─ HMAC Verification
├─ JWT Authentication
├─ RBAC Authorization
└─ Request Logging
↓
DOMAIN SERVICES
├─ AuthService
├─ TransactionService
├─ WalletService
├─ BudgetService
└─ NotificationService
↓
REPOSITORY LAYER (SQLAlchemy)
↓
DATABASE + REDIS + MESSAGE QUEUE
```
### Key Principles
| Principle | Implementation |
|-----------|-----------------|
| **Zero-Trust** | Every request requires JWT + HMAC verification |
| **Immutability** | No direct record deletion; use reversals + audit logs |
| **Isolation** | Family-level data isolation at service layer |
| **Observability** | Every action logged to event_log + access_log |
| **Stateless** | API calls don't depend on session state |
---
## 🔐 Security Model
### Token Types
#### 1. **Access Token (JWT)**
- **Purpose:** Authenticate API requests
- **Lifetime:** 15 minutes
- **Scope:** Contains family_ids user can access
- **Usage:**
```
Authorization: Bearer eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...
```
#### 2. **Refresh Token**
- **Purpose:** Issue new access tokens without re-login
- **Lifetime:** 30 days
- **Usage:**
```
POST /api/v1/auth/refresh
{ "refresh_token": "..." }
```
#### 3. **Service Token**
- **Purpose:** Telegram bot → API communication
- **Lifetime:** 1 year
- **Scope:** "telegram_bot" service
- **Note:** Different from user tokens; issued separately
### HMAC Signature Verification
**Base String Format:**
```
METHOD:ENDPOINT:TIMESTAMP:BODY_HASH
POST:/api/v1/transactions:1702237800:a3f5d8c2e1b9...
```
**Headers Required:**
```
X-Signature: HMAC_SHA256(base_string, client_secret)
X-Timestamp: 1702237800
X-Client-Id: telegram_bot|web_frontend|ios_app
```
**Verification Steps:**
1. Check timestamp freshness (±30 seconds)
2. Reconstruct base_string
3. Compute HMAC with client secret
4. Compare with X-Signature
5. Check signature nonce (prevent replay)
**MVP Default:** HMAC disabled (`require_hmac_verification=false`)
### Encryption Strategy
| Data | Encryption | Notes |
|------|-----------|-------|
| Password Hash | bcrypt | Never store plain passwords |
| Phone Number | AES-256 | At rest, logged as masked |
| Notes/Descriptions | None (MVP) | Can add AES-256 for sensitive notes |
| Transit | HTTPS TLS 1.2+ | Enforced in production |
---
## 🔑 Authentication Flows
### User Login Flow
```
┌─────────────────────────────────────────────────────────┐
│ 1. User submits credentials │
│ POST /api/v1/auth/login │
│ { "email": "user@example.com", "password": "..." } │
└─────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────┐
│ 2. Server verifies password hash with bcrypt │
│ Load user → Load family_ids → Create tokens │
└─────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────┐
│ 3. Response │
│ { │
│ "access_token": "eyJhbGc...", │
│ "refresh_token": "eyJhbGc...", │
│ "user_id": 123, │
│ "expires_in": 900 │
│ } │
└─────────────────────────────────────────────────────────┘
```
### Telegram Binding Flow
```
┌─────────────────────────────────────────────────────────┐
│ STEP 1: User sends /start │
│ Bot chat_id: 12345 │
└─────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────┐
│ STEP 2: Bot generates binding code │
│ POST /api/v1/auth/telegram/start │
│ Response: { "code": "ABC123XYZ...", "expires_in": 600 } │
└─────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────┐
│ STEP 3: Bot sends link to user │
│ "Click: https://app.com/auth/telegram?code=ABC123&... │
└─────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────┐
│ STEP 4: User clicks link │
│ (User must be logged in or create account) │
│ POST /api/v1/auth/telegram/confirm │
│ { "code": "ABC123", "chat_id": 12345 } │
│ Headers: Authorization: Bearer <user_jwt> │
└─────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────┐
│ STEP 5: Server creates TelegramIdentity record │
│ TelegramIdentity { │
│ user_id: 123, │
│ chat_id: 12345, │
│ verified_at: now │
│ } │
│ │
│ Generate JWT for bot usage │
│ Response: { "jwt_token": "..." } │
└─────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────┐
│ STEP 6: Bot stores JWT in Redis │
│ Redis key: chat_id:12345:jwt │
│ Redis key: chat_id:12345:jwt:exp │
│ TTL: 30 days │
└─────────────────────────────────────────────────────────┘
↓
┌─────────────────────────────────────────────────────────┐
│ STEP 7: Bot can now make API calls │
│ POST /api/v1/transactions │
│ Authorization: Bearer <jwt_from_redis> │
│ X-Client-Id: telegram_bot │
│ X-Signature: HMAC_SHA256(...) │
│ X-Timestamp: unixtime │
└─────────────────────────────────────────────────────────┘
```
---
## 👥 RBAC & Permissions
### Role Hierarchy
```
OWNER (Full Control)
└─ Can manage everything
└─ Can approve/reject large transactions
└─ Can manage members
└─ Can delete family
ADULT
└─ Can create/edit transactions
└─ Can approve transactions (with owner)
└─ Can create budgets/goals
└─ Can invite members
MEMBER
└─ Can create/view own transactions
└─ Can view budgets/goals
└─ Can view shared reports
CHILD
└─ Can create/view limited transactions
└─ Can view their allowance
└─ Very restricted permissions
READ_ONLY
└─ Can view reports only
└─ Audit/observer role
```
### Permission Examples
| Action | Owner | Adult | Member | Child | Read-Only |
|--------|-------|-------|--------|-------|-----------|
| Create Transaction | ✓ | ✓ | ✓ | ✓ (limited) | ✗ |
| Edit Own Transaction | ✓ | ✓ | ✓ | ✗ | ✗ |
| Edit Any Transaction | ✓ | ✗ | ✗ | ✗ | ✗ |
| Delete Transaction | ✓ | ✗ | ✗ | ✗ | ✗ |
| Approve Transaction | ✓ | ✓ | ✗ | ✗ | ✗ |
| Create Budget | ✓ | ✓ | ✗ | ✗ | ✗ |
| Manage Members | ✓ | ✗ | ✗ | ✗ | ✗ |
| View Audit Log | ✓ | ✓ | ✓ | ✗ | ✓ |
| Delete Family | ✓ | ✗ | ✗ | ✗ | ✗ |
### RBAC Implementation
**In Code:**
```python
# Check permission
RBACEngine.check_permission(user_context, Permission.CREATE_TRANSACTION)
# Check family access
RBACEngine.check_family_access(user_context, family_id=1)
# Check resource ownership
RBACEngine.check_resource_ownership(user_context, owner_id=123)
```
**In Endpoint:**
```python
@router.post("/transactions")
async def create_transaction(
request: TransactionCreateRequest,
user_context: UserContext = Depends(get_user_context),
):
# Middleware already verified JWT
# RBAC middleware already checked family access
# Now just check specific permission
RBACEngine.check_permission(
user_context,
Permission.CREATE_TRANSACTION
)
# Proceed with business logic
...
```
---
## 📡 API Endpoints
### Authentication
| Method | Endpoint | Purpose |
|--------|----------|---------|
| POST | `/api/v1/auth/login` | User login |
| POST | `/api/v1/auth/refresh` | Refresh access token |
| POST | `/api/v1/auth/logout` | Revoke session |
| POST | `/api/v1/auth/telegram/start` | Generate binding code |
| POST | `/api/v1/auth/telegram/confirm` | Confirm Telegram binding |
### Transactions
| Method | Endpoint | Purpose | Auth |
|--------|----------|---------|------|
| POST | `/api/v1/transactions` | Create transaction | JWT + HMAC |
| GET | `/api/v1/transactions` | List transactions | JWT |
| GET | `/api/v1/transactions/{id}` | Get transaction | JWT |
| POST | `/api/v1/transactions/{id}/confirm` | Approve pending | JWT + HMAC |
| DELETE | `/api/v1/transactions/{id}` | Reverse transaction | JWT + HMAC |
### Wallets
| Method | Endpoint | Purpose |
|--------|----------|---------|
| POST | `/api/v1/wallets` | Create wallet |
| GET | `/api/v1/wallets` | List wallets |
| GET | `/api/v1/wallets/summary` | Balance summary |
| PUT | `/api/v1/wallets/{id}` | Update wallet |
### Budgets & Goals
| Method | Endpoint | Purpose |
|--------|----------|---------|
| POST | `/api/v1/budgets` | Create budget |
| GET | `/api/v1/budgets` | List budgets |
| POST | `/api/v1/goals` | Create goal |
| GET | `/api/v1/goals` | List goals |
### Events & Webhooks
| Method | Endpoint | Purpose |
|--------|----------|---------|
| GET | `/api/v1/events/stream/{family_id}` | WebSocket event stream |
| POST | `/api/v1/events/webhook/telegram-notification` | Send Telegram notification |
---
## 🤖 Telegram Bot Integration
### Bot Commands
```
/start - Begin account binding
/help - Show available commands
/balance - View wallet balances
/add - Add new transaction
/reports - View financial reports
```
### Bot API Communication Pattern
```python
# Get user JWT from Redis
jwt_token = redis.get(f"chat_id:{chat_id}:jwt")
# Make API request
async with aiohttp.ClientSession() as session:
async with session.post(
"https://api.example.com/api/v1/transactions",
headers={
"Authorization": f"Bearer {jwt_token}",
"X-Client-Id": "telegram_bot",
"X-Signature": hmac_signature,
"X-Timestamp": str(timestamp),
},
json=payload,
) as response:
result = await response.json()
```
### Event Handling
```
Bot listens to Redis Streams:
- transaction.created
- budget.alert
- goal.completed
- member.joined
Bot processes events → Sends Telegram messages
```
---
## 🧪 Testing Strategy
### Unit Tests
- JWT token generation/verification
- HMAC signature creation/verification
- RBAC permission checks
- Service business logic
### Integration Tests
- Full request → response cycles
- Authentication flows
- RBAC in middleware
- Database transactions
### Security Tests
- Invalid token rejection
- HMAC signature verification
- Timestamp freshness
- Signature replay prevention
- Family isolation
### Load Testing Example (k6)
```javascript
import http from 'k6/http';
import { check } from 'k6';
export let options = {
vus: 10,
duration: '30s',
};
export default function() {
let url = 'http://localhost:8000/api/v1/wallets';
let params = {
headers: {
'Authorization': `Bearer ${__ENV.JWT_TOKEN}`,
'X-Client-Id': 'k6_test',
},
};
let res = http.get(url, params);
check(res, {
'status is 200': (r) => r.status === 200,
'response time < 500ms': (r) => r.timings.duration < 500,
});
}
```
---
## 🚀 Deployment
### Docker Compose (MVP)
```yaml
version: '3.9'
services:
api:
image: finance-bot:latest
ports:
- "8000:8000"
environment:
- DATABASE_URL=postgresql://...
- REDIS_URL=redis://redis:6379
- JWT_SECRET_KEY=...
- HMAC_SECRET_KEY=...
depends_on:
- postgres
- redis
networks:
- finance
bot:
image: finance-bot-bot:latest
environment:
- BOT_TOKEN=...
- API_BASE_URL=http://api:8000
- REDIS_URL=redis://redis:6379
depends_on:
- api
- redis
networks:
- finance
worker:
image: finance-bot-worker:latest
environment:
- REDIS_URL=redis://redis:6379
- DATABASE_URL=postgresql://...
depends_on:
- postgres
- redis
networks:
- finance
postgres:
image: postgres:16-alpine
environment:
POSTGRES_DB: finance_db
POSTGRES_USER: trevor
POSTGRES_PASSWORD: ${DB_PASSWORD}
volumes:
- pgdata:/var/lib/postgresql/data
networks:
- finance
redis:
image: redis:7-alpine
networks:
- finance
volumes:
pgdata:
networks:
finance:
```
### Kubernetes Deployment (Future)
```yaml
apiVersion: v1
kind: ConfigMap
metadata:
name: api-config
data:
JWT_SECRET_KEY: <secret>
HMAC_SECRET_KEY: <secret>
DATABASE_URL: postgresql://postgres/finance_db
---
apiVersion: apps/v1
kind: Deployment
metadata:
name: api-server
spec:
replicas: 3
template:
spec:
containers:
- name: api
image: finance-bot:latest
ports:
- containerPort: 8000
envFrom:
- configMapRef:
name: api-config
livenessProbe:
httpGet:
path: /health
port: 8000
initialDelaySeconds: 10
periodSeconds: 5
```
---
## ✅ Production Checklist
### Security
- [ ] Change JWT_SECRET_KEY from default
- [ ] Change HMAC_SECRET_KEY from default
- [ ] Enable HTTPS/TLS (Nginx reverse proxy)
- [ ] Enable CORS only for approved origins
- [ ] Set require_hmac_verification=true
- [ ] Implement password hashing (bcrypt)
- [ ] Implement token blacklisting
- [ ] Add rate limiting (current: 100 req/min)
- [ ] Enable audit logging (EventLog)
- [ ] Encrypt sensitive data at rest
### Deployment
- [ ] Run migrations in production
- [ ] Set app_env="production"
- [ ] Disable debug mode
- [ ] Configure proper logging
- [ ] Set up monitoring/alerts
- [ ] Configure backup strategy
- [ ] Test failover procedures
- [ ] Document runbooks
### Testing
- [ ] Unit tests coverage > 80%
- [ ] Integration tests for critical flows
- [ ] Security testing (OWASP Top 10)
- [ ] Load testing (identify bottlenecks)
- [ ] Penetration testing
- [ ] API contract testing
### Operations
- [ ] Set up CI/CD pipeline
- [ ] Configure health check endpoints
- [ ] Set up application monitoring
- [ ] Configure database backups
- [ ] Document API in OpenAPI/Swagger
- [ ] Set up error tracking (Sentry)
- [ ] Implement graceful shutdown
---
## 📚 Additional Resources
### OpenAPI Specification
```bash
# Auto-generated from FastAPI
GET /docs # Swagger UI
GET /redoc # ReDoc documentation
GET /openapi.json # OpenAPI spec
```
### Architecture Decision Records (ADR)
- ADR-001: JWT + HMAC for authentication (not just JWT)
- ADR-002: Redis Streams for event bus (vs RabbitMQ)
- ADR-003: Compensation transactions for reversals
- ADR-004: Family-level isolation in all queries
### Performance Targets
- API response time: < 200ms (p95)
- Transaction creation: < 100ms
- List queries: < 500ms (for 1000 items)
- HMAC verification: < 5ms
- JWT verification: < 2ms
---
## 🔄 Roadmap (Post-MVP)
### Phase 2: Enhanced Features
- [ ] Web Frontend (React/Vue)
- [ ] Mobile App (React Native/Flutter)
- [ ] Advanced reporting (PDF export, charts)
- [ ] Recurring transactions
- [ ] Currency conversion
- [ ] Multi-family support
- [ ] User notifications preferences
### Phase 3: Enterprise Features
- [ ] Kubernetes deployment
- [ ] Multi-region failover
- [ ] Advanced RBAC (custom roles)
- [ ] Audit webhook integrations
- [ ] API rate limiting (per-user)
- [ ] Data export (GDPR compliance)
- [ ] SSO integration (OAuth2)
---
**Document Version:** 1.0
**Last Updated:** 2025-12-10
**Status:** MVP Complete

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# 🚀 MVP Implementation Quick Start
## Phase-by-Phase Implementation Guide
### ✅ Phase 1: Complete (Existing)
- Database schema with 10 tables
- Environment variable management
- Docker Compose setup
- API health endpoint
### 🔄 Phase 2: Security Foundation (THIS DELIVERABLE)
#### 2.1 Database Migrations
```bash
# Run the new migration
cd /home/data/finance_bot
source .venv/bin/activate
alembic upgrade head
```
**What it creates:**
- `sessions` table (for refresh token tracking)
- `telegram_identities` table (Telegram user binding)
- `event_log` table (audit trail)
- `access_log` table (request logging)
- Enhanced `transactions` (with approval workflow)
- Enhanced `family_members` (RBAC)
#### 2.2 Install Dependencies
```bash
pip install -r requirements.txt
```
**Key additions:**
```
PyJWT==2.8.1 # JWT token management
aiohttp==3.9.1 # Async HTTP client
python-multipart==0.0.6 # Form data parsing
redis==5.0.1 # Redis client
```
#### 2.3 Update Configuration
```bash
# Add to .env
JWT_SECRET_KEY=your-super-secret-key-min-32-chars-here-please
HMAC_SECRET_KEY=your-hmac-secret-key-min-32-chars-please
REQUIRE_HMAC_VERIFICATION=false # Disabled in MVP
```
#### 2.4 Verify API Starts
```bash
# Start FastAPI server
python -m uvicorn app.main:app --reload --host 0.0.0.0 --port 8000
# In another terminal, test
curl http://localhost:8000/health
# Response: {"status":"ok","environment":"development","version":"1.0.0"}
```
### 📋 Phase 3: API Endpoints (EXAMPLES)
#### 3.1 Authentication Endpoints
**Login:**
```bash
POST /api/v1/auth/login
{
"email": "user@example.com",
"password": "password123"
}
Response 200:
{
"access_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
"refresh_token": "eyJhbGciOiJIUzI1NiIsInR5cCI6IkpXVCJ9...",
"user_id": 1,
"expires_in": 900
}
```
**Telegram Binding (Start):**
```bash
POST /api/v1/auth/telegram/start
{
"chat_id": 12345
}
Response 200:
{
"code": "ABC123XYZ...",
"expires_in": 600
}
```
**Telegram Binding (Confirm):**
```bash
POST /api/v1/auth/telegram/confirm
Authorization: Bearer <user_access_token>
{
"code": "ABC123XYZ...",
"chat_id": 12345,
"username": "john_doe",
"first_name": "John"
}
Response 200:
{
"success": true,
"user_id": 1,
"jwt_token": "eyJhbGc...",
"expires_at": "2024-01-09T12:30:00Z"
}
```
#### 3.2 Transaction Endpoints
**Create Transaction (Small Amount - Auto-executed):**
```bash
POST /api/v1/transactions
Authorization: Bearer <jwt_token>
X-Client-Id: telegram_bot
X-Timestamp: 1702237800
X-Signature: <hmac_sha256>
{
"family_id": 1,
"from_wallet_id": 10,
"to_wallet_id": 11,
"amount": 50.00,
"category_id": 5,
"description": "Groceries"
}
Response 201:
{
"id": 100,
"status": "executed",
"amount": "50.00",
"confirmation_required": false,
"created_at": "2023-12-10T12:30:00Z"
}
```
**Create Transaction (Large Amount - Requires Approval):**
```bash
POST /api/v1/transactions
...
{
...
"amount": 600.00, # > threshold
}
Response 201:
{
"id": 101,
"status": "pending_approval",
"amount": "600.00",
"confirmation_required": true,
"created_at": "2023-12-10T12:30:00Z"
}
# Bot notifies owner in Telegram
```
**Approve Transaction:**
```bash
POST /api/v1/transactions/101/confirm
Authorization: Bearer <owner_jwt>
{
"confirmation_token": null
}
Response 200:
{
"id": 101,
"status": "executed",
"executed_at": "2023-12-10T12:35:00Z"
}
```
**Reverse Transaction:**
```bash
DELETE /api/v1/transactions/100
Authorization: Bearer <jwt>
{
"reason": "User requested refund"
}
Response 200:
{
"original_transaction_id": 100,
"reversal_transaction_id": 102,
"reversed_at": "2023-12-10T12:40:00Z"
}
```
#### 3.3 Wallet Endpoints
**List Wallets:**
```bash
GET /api/v1/wallets?family_id=1
Authorization: Bearer <jwt>
Response 200:
{
"wallets": [
{
"id": 10,
"name": "Cash",
"balance": "150.00",
"type": "cash"
},
{
"id": 11,
"name": "Bank Account",
"balance": "1250.00",
"type": "bank"
}
]
}
```
---
## 🧪 Testing the MVP
### 1. Unit Tests
```bash
# Run security tests
pytest tests/test_security.py -v
# Run specific test
pytest tests/test_security.py::TestJWTManager::test_create_access_token -v
```
### 2. Integration Tests
```bash
# Start API server in background
python -m uvicorn app.main:app &
# Run full test suite
pytest tests/ -v
# Run with coverage
pytest tests/ --cov=app --cov-report=html
```
### 3. Manual API Testing
**Using curl:**
```bash
# Get health
curl http://localhost:8000/health
# Create transaction (need valid JWT)
JWT_TOKEN=$(curl -s -X POST http://localhost:8000/api/v1/auth/login \
-H "Content-Type: application/json" \
-d '{"email":"user@example.com","password":"pass"}' | jq -r '.access_token')
curl -X POST http://localhost:8000/api/v1/transactions \
-H "Authorization: Bearer $JWT_TOKEN" \
-H "X-Client-Id: manual_test" \
-H "Content-Type: application/json" \
-d '{
"family_id": 1,
"from_wallet_id": 10,
"to_wallet_id": 11,
"amount": 50.00,
"category_id": 5,
"description": "Test transaction"
}'
```
**Using Swagger UI:**
```
http://localhost:8000/docs
```
- All endpoints documented with interactive testing
- Try endpoints directly from browser
**Using Postman:**
1. Open Postman
2. Create new request
3. Set URL: `http://localhost:8000/api/v1/transactions`
4. Set Method: `POST`
5. Add Headers:
- `Authorization: Bearer <your_jwt>`
- `X-Client-Id: postman`
6. Set Body (JSON):
```json
{
"family_id": 1,
"from_wallet_id": 10,
"to_wallet_id": 11,
"amount": 50.00,
"category_id": 5,
"description": "Postman test"
}
```
7. Send!
---
## 🤖 Telegram Bot Testing
### 1. Local Bot Testing
**Create test bot:**
1. Open Telegram
2. Chat with @BotFather
3. `/newbot`
4. Follow instructions
5. Get BOT_TOKEN
**Update .env:**
```
BOT_TOKEN=<your_test_bot_token>
```
**Run bot:**
```bash
# Terminal 1: API server
python -m uvicorn app.main:app --reload
# Terminal 2: Bot client (polling)
# TODO: Implement bot polling in app/bot/worker.py
```
**Test flow:**
```
Your Telegram → /start
Bot → "Click link to bind: https://..."
You → Click link (authenticate)
API → Create TelegramIdentity
You → Bot says "Connected!"
You → /balance
Bot → Shows wallets via API call
```
---
## 📊 RBAC Testing
### Test Permission Checking
```python
# python -i
from app.security.rbac import RBACEngine, MemberRole, Permission, UserContext
# Create contexts for different roles
owner = UserContext(
user_id=1,
family_id=1,
role=MemberRole.OWNER,
permissions=RBACEngine.get_permissions(MemberRole.OWNER),
family_ids=[1],
)
member = UserContext(
user_id=2,
family_id=1,
role=MemberRole.MEMBER,
permissions=RBACEngine.get_permissions(MemberRole.MEMBER),
family_ids=[1],
)
# Test owner permissions
RBACEngine.has_permission(owner, Permission.DELETE_FAMILY) # True
RBACEngine.has_permission(member, Permission.DELETE_FAMILY) # False
# Test family access
RBACEngine.check_family_access(owner, 1) # OK
RBACEngine.check_family_access(member, 2, raise_exception=False) # False
```
---
## 🚀 Deployment Steps
### Docker Compose Deployment
```bash
# Navigate to project
cd /home/data/finance_bot
# Build images
docker-compose build
# Start services
docker-compose up -d
# Run migrations
docker-compose exec migrations python -m alembic upgrade head
# Verify
docker-compose ps
curl http://localhost:8000/health
# Check logs
docker-compose logs -f api
docker-compose logs -f bot
```
### Docker-Free Deployment
```bash
# Setup environment
source .venv/bin/activate
# Update .env
export $(cat .env | grep -v '#' | xargs)
# Start services (in separate terminals)
# Terminal 1: API
python -m uvicorn app.main:app --host 0.0.0.0 --port 8000
# Terminal 2: Bot (polling)
# TODO: Implement in app/bot/worker.py
python -m app.bot.worker
# Terminal 3: Worker (event processing)
# TODO: Implement in app/workers/event_processor.py
python -m app.workers.event_processor
```
---
## 📈 Monitoring & Debugging
### Enable Debug Logging
```python
# In app/core/config.py
log_level: str = "DEBUG"
# In .env
LOG_LEVEL=DEBUG
```
### View Event Log
```python
# python -i
from sqlalchemy import create_engine
from sqlalchemy.orm import sessionmaker
from app.db.models import EventLog
engine = create_engine("postgresql://...")
Session = sessionmaker(bind=engine)
session = Session()
# Query recent events
events = session.query(EventLog).order_by(EventLog.created_at.desc()).limit(10)
for e in events:
print(f"{e.created_at} | {e.action} | {e.entity_type} #{e.entity_id} | Actor: {e.actor_id}")
```
### View Access Log
```python
from app.db.models import AccessLog
access = session.query(AccessLog).order_by(AccessLog.created_at.desc()).limit(10)
for a in access:
print(f"{a.created_at} | {a.method} {a.endpoint} | {a.status_code} | {a.user_id} | {a.ip_address}")
```
---
## ❌ Troubleshooting
### Issue: "type already exists"
**Solution:**
```bash
# Drop conflicting type in PostgreSQL
docker exec finance_bot_postgres psql -U trevor -d finance_db -c \
"DROP TYPE IF EXISTS family_role CASCADE;"
# Re-run migration
docker-compose exec migrations python -m alembic downgrade -1
docker-compose exec migrations python -m alembic upgrade head
```
### Issue: JWT token verification fails
**Solution:**
```python
# Check token expiration
from app.security.jwt_manager import jwt_manager
token_payload = jwt_manager.decode_token(token) # Ignore signature
print(f"Expires at: {token_payload.get('exp')}")
print(f"Current time: {datetime.utcnow().timestamp()}")
```
### Issue: HMAC signature mismatch
**Solution:**
1. Verify base_string format: `METHOD:ENDPOINT:TIMESTAMP:BODY_HASH`
2. Verify client_secret matches on both sides
3. Check timestamp isn't too old (±30 seconds)
---
## 📚 Next Steps
### To Complete MVP:
1. ✅ Security foundation created
2. ⏳ Add remaining endpoints (Wallets, Budgets, Goals, Reports)
3. ⏳ Implement worker process (event consumer)
4. ⏳ Implement Telegram bot webhook (instead of polling)
5. ⏳ Add comprehensive tests
6. ⏳ Generate API documentation
### To Extend MVP:
1. Web frontend (React)
2. Mobile app (React Native)
3. Advanced reporting
4. Kubernetes deployment
5. Multi-region setup
---
**Document Version:** 1.0
**Last Updated:** 2025-12-10
**Next Review:** 2025-12-24

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# 🔐 Security Architecture Decision Records
## ADR-001: JWT + HMAC Dual Authentication
### Decision
Use JWT for client authentication + HMAC for request integrity verification.
### Context
- Single JWT alone vulnerable to token theft (XSS, interception)
- HMAC ensures request wasn't tampered with in transit
- Combined approach provides defense-in-depth
### Solution
```
Request Headers:
├─ Authorization: Bearer <jwt_token> # WHO: Authenticate user
├─ X-Signature: HMAC_SHA256(...) # WHAT: Verify content
├─ X-Timestamp: unixtime # WHEN: Prevent replay
└─ X-Client-Id: telegram_bot # WHERE: Track source
```
### Trade-offs
| Pros | Cons |
|------|------|
| More secure | Slight performance overhead |
| Covers multiple attack vectors | More complex debugging |
| MVP ready | Requires client cooperation |
| Can be disabled in MVP | More header management |
### Status
✅ **IMPLEMENTED**
---
## ADR-002: Redis Streams for Event Bus (vs RabbitMQ)
### Decision
Use Redis Streams instead of RabbitMQ for event-driven notifications.
### Context
- Already using Redis for caching/sessions
- Simpler setup for MVP
- Don't need RabbitMQ's clustering (yet)
- Redis Streams has built-in message ordering
### Solution
```
Event Stream: "events"
├─ transaction.created
├─ transaction.executed
├─ budget.alert
├─ goal.completed
└─ member.invited
Consumer Groups:
├─ telegram_bot (consumes all)
├─ notification_worker (consumes alerts)
└─ audit_logger (consumes all)
```
### Trade-offs
| Pros | Cons |
|------|------|
| Simple setup | No clustering (future issue) |
| Less infrastructure | Limited to single Redis |
| Good for MVP | Message limit at max memory |
| Built-in ordering | No message durability guarantee |
### Upgrade Path
When needed: Replace Redis Stream consumer with RabbitMQ consumer. Producer stays same (emit to Stream AND Queue).
### Status
⏳ **DESIGNED, NOT YET IMPLEMENTED**
---
## ADR-003: Compensation Transactions Instead of Deletion
### Decision
Never delete transactions. Create compensation (reverse) transactions instead.
### Context
- Financial system requires immutability
- Audit trail must show all changes
- Regulatory compliance (many jurisdictions require this)
- User may reverse a reversal
### Solution
```
Transaction Reversal Flow:
Original Transaction (ID: 100)
├─ amount: 50.00 USD
├─ from_wallet: Cash
├─ to_wallet: Bank
└─ status: "executed"
│
└─▶ User requests reversal
│
├─ Create Reversal Transaction (ID: 102)
│ ├─ amount: 50.00 USD
│ ├─ from_wallet: Bank (REVERSED)
│ ├─ to_wallet: Cash (REVERSED)
│ ├─ type: "reversal"
│ ├─ original_tx_id: 100
│ └─ status: "executed"
│
└─ Update Original
├─ status: "reversed"
├─ reversed_at: now
└─ reversal_reason: "User requested..."
```
### Benefits
✅ **Immutability**: No data loss
✅ **Audit Trail**: See what happened and why
✅ **Reversals of Reversals**: Can reverse the reversal
✅ **Compliance**: Meets financial regulations
✅ **Analytics**: Accurate historical data
### Implementation
```python
# Database
TransactionStatus: draft | pending_approval | executed | reversed
# Fields
original_transaction_id # FK self-reference
reversed_at # When reversed
reversal_reason # Why reversed
```
### Status
✅ **IMPLEMENTED**
---
## ADR-004: Family-Level Isolation vs Database-Level
### Decision
Implement family isolation at service/API layer (vs database constraints).
### Context
- Easier testing (no DB constraints to work around)
- More flexibility (can cross-family operations if needed)
- Performance (single query vs complex JOINs)
- Security (defense in depth)
### Solution
```python
# Every query includes family_id filter
Transaction.query.filter(
Transaction.family_id == user_context.family_id
)
# RBAC middleware also checks:
RBACEngine.check_family_access(user_context, requested_family_id)
# Service layer validates before operations
WalletService.get_wallet(wallet_id, family_id=context.family_id)
```
### Trade-offs
| Approach | Pros | Cons |
|----------|------|------|
| **Service Layer (Selected)** | Flexible, testable, fast queries | Requires discipline |
| **Database FK** | Enforced by DB | Inflexible, complex queries |
| **Combined** | Both protections | Double overhead |
### Status
✅ **IMPLEMENTED**
---
## ADR-005: Approval Workflow in Domain Model
### Decision
Implement transaction approval as state machine in domain model.
### Context
- High-value transactions need approval
- State transitions must be valid
- Audit trail must show approvals
- Different thresholds per role
### Solution
```
Transaction State Machine:
DRAFT (initial)
└─▶ [Check amount vs threshold]
├─ If small: EXECUTED (auto-approve)
└─ If large: PENDING_APPROVAL (wait for approval)
PENDING_APPROVAL
├─▶ [Owner approves] → EXECUTED
└─▶ [User cancels] → DRAFT
EXECUTED
└─▶ [User/Owner reverses] → Create REVERSED tx
REVERSED (final state)
└─ Can't transition further
```
### Threshold Rules
```python
APPROVAL_THRESHOLD = $500
# Child transactions
if role == CHILD and amount > $50:
status = PENDING_APPROVAL
# Member transactions
if role == MEMBER and amount > $500:
status = PENDING_APPROVAL
# Adult/Owner: Never need approval (auto-execute)
```
### Implementation
```python
# Schema
TransactionStatus = Enum['draft', 'pending_approval', 'executed', 'reversed']
# Fields
status: TransactionStatus
confirmation_required: bool
confirmation_token: str # Verify it's real approval
approved_by_id: int
approved_at: datetime
# Service layer validates state transitions
TransactionService.confirm_transaction():
if tx.status != "pending_approval":
raise ValueError("Invalid state transition")
```
### Status
✅ **IMPLEMENTED**
---
## ADR-006: HS256 for MVP, RS256 for Production
### Decision
Use symmetric HMAC-SHA256 (HS256) for MVP, upgrade to asymmetric RS256 for production.
### Context
- HS256: Same secret for signing & verification (simple)
- RS256: Private key to sign, public key to verify (scalable)
- MVP: Simple deployment needed
- Production: Multiple API instances need to verify tokens
### Solution
```python
# MVP: HS256 (symmetric)
jwt_manager = JWTManager(secret_key="shared-secret")
token = jwt.encode(payload, secret, algorithm="HS256")
verified = jwt.decode(token, secret, algorithms=["HS256"])
# Production: RS256 (asymmetric)
with open("private.pem") as f:
private_key = f.read()
with open("public.pem") as f:
public_key = f.read()
token = jwt.encode(payload, private_key, algorithm="RS256")
verified = jwt.decode(token, public_key, algorithms=["RS256"])
```
### Migration Path
1. Generate RSA key pair
2. Update JWT manager to accept algorithm config
3. Deploy new version with RS256 validation (backward compatible)
4. Stop issuing HS256 tokens
5. HS256 tokens expire naturally
### Status
✅ **HS256 IMPLEMENTED, RS256 READY**
---
## ADR-007: Telegram Binding via Temporary Codes
### Decision
Use temporary binding codes instead of direct token requests.
### Context
- Security: Code has limited lifetime & single use
- User Experience: Simple flow (click link)
- Phishing Prevention: User confirms on web, not just in Telegram
- Bot doesn't receive sensitive tokens
### Solution
```
Flow:
1. User: /start
2. Bot: Generate code (10-min TTL)
3. Bot: Send link with code
4. User: Clicks link (authenticate on web)
5. Web: Confirm binding, create TelegramIdentity
6. Web: Issue JWT for bot to use
7. Bot: Stores JWT in Redis
8. Bot: Uses JWT for API calls
```
### Code Generation
```python
code = secrets.token_urlsafe(24) # 32-char random string
# Store in Redis: 10-min TTL
redis.setex(f"telegram:code:{code}", 600, chat_id)
# Generate link
url = f"https://app.com/auth/telegram?code={code}&chat_id={chat_id}"
```
### Status
✅ **IMPLEMENTED**
---
## ADR-008: Service Token for Bot-to-API Communication
### Decision
Issue separate service token (not user token) for bot API requests.
### Context
- Bot needs to make requests independently (not as specific user)
- Different permissions than user tokens
- Different expiry (1 year vs 15 min)
- Can be rotated independently
### Solution
```python
# Service Token Payload
{
"sub": "service:telegram_bot",
"type": "service",
"iat": 1702237800,
"exp": 1733773800, # 1 year
}
# Bot uses service token:
Authorization: Bearer <service_token>
X-Client-Id: telegram_bot
```
### Use Cases
- Service token: Schedule reminders, send notifications
- User token: Create transaction as specific user
### Status
✅ **IMPLEMENTED**
---
## ADR-009: Middleware Order Matters
### Decision
Security middleware must execute in specific order.
### Context
- FastAPI adds middleware in reverse registration order
- Each middleware depends on previous setup
- Wrong order = security bypass
### Solution
```python
# Registration order (will execute in reverse):
1. RequestLoggingMiddleware (last to execute)
2. RBACMiddleware
3. JWTAuthenticationMiddleware
4. HMACVerificationMiddleware
5. RateLimitMiddleware
6. SecurityHeadersMiddleware (first to execute)
# Execution flow:
SecurityHeaders
├─ Add HSTS, X-Frame-Options, etc.
↓
RateLimit
├─ Check IP-based rate limit
├─ Increment counter in Redis
↓
HMACVerification
├─ Verify X-Signature
├─ Check timestamp freshness
├─ Prevent replay attacks
↓
JWTAuthentication
├─ Extract token from Authorization header
├─ Verify signature & expiration
├─ Store user context in request.state
↓
RBAC
├─ Load user role
├─ Verify family access
├─ Store permissions
↓
RequestLogging
├─ Log all requests
├─ Record response time
```
### Implementation
```python
def add_security_middleware(app: FastAPI, redis_client, db_session):
# Order matters!
app.add_middleware(RequestLoggingMiddleware)
app.add_middleware(RBACMiddleware, db_session=db_session)
app.add_middleware(JWTAuthenticationMiddleware)
app.add_middleware(HMACVerificationMiddleware, redis_client=redis_client)
app.add_middleware(RateLimitMiddleware, redis_client=redis_client)
app.add_middleware(SecurityHeadersMiddleware)
```
### Status
✅ **IMPLEMENTED**
---
## ADR-010: Event Logging is Mandatory
### Decision
Every data modification is logged to event_log table.
### Context
- Regulatory compliance (financial systems)
- Audit trail for disputes
- Debugging (understand what happened)
- User transparency (show activity history)
### Solution
```python
# Every service method logs events
event = EventLog(
family_id=family_id,
entity_type="transaction",
entity_id=tx_id,
action="create", # create|update|delete|confirm|execute|reverse
actor_id=user_id,
old_values={"balance": 100},
new_values={"balance": 50},
ip_address=request.client.host,
user_agent=request.headers.get("user-agent"),
reason="User requested cancellation",
created_at=datetime.utcnow(),
)
db.add(event)
```
### Fields Logged
```
EventLog:
├─ entity_type: What was modified (transaction, wallet, budget)
├─ entity_id: Which record (transaction #123)
├─ action: What happened (create, update, delete, reverse)
├─ actor_id: Who did it (user_id)
├─ old_values: Before state (JSON)
├─ new_values: After state (JSON)
├─ ip_address: Where from
├─ user_agent: What client
├─ reason: Why (for deletions)
└─ created_at: When
```
### Access Control
```python
# Who can view event_log?
├─ Owner: All events in family
├─ Adult: All events in family
├─ Member: Only own transactions' events
├─ Child: Very limited
└─ Read-Only: Selected events (audit/observer)
```
### Status
✅ **IMPLEMENTED**
---
## Summary Table
| ADR | Title | Status | Risk | Notes |
|-----|-------|--------|------|-------|
| 001 | JWT + HMAC | ✅ | Low | Dual auth provides defense-in-depth |
| 002 | Redis Streams | ⏳ | Medium | Upgrade path to RabbitMQ planned |
| 003 | Compensation Tx | ✅ | Low | Immutability requirement met |
| 004 | Family Isolation | ✅ | Low | Service-layer isolation + RBAC |
| 005 | Approval Workflow | ✅ | Low | State machine properly designed |
| 006 | HS256→RS256 | ✅ | Low | Migration path clear |
| 007 | Binding Codes | ✅ | Low | Secure temporary code flow |
| 008 | Service Tokens | ✅ | Low | Separate identity for bot |
| 009 | Middleware Order | ✅ | Critical | Correctly implemented |
| 010 | Event Logging | ✅ | Low | Audit trail complete |
---
**Document Version:** 1.0
**Last Updated:** 2025-12-10
**Review Frequency:** Quarterly