attune/work-summary/sessions/2026-01-12-authentication.md

# Work Summary: Phase 2.2 - Authentication & Authorization
**Date:** 2026-01-12
**Status:** ✅ Complete (Core Authentication)

## Overview
Implemented a comprehensive JWT-based authentication system for the Attune API service, including user registration, login, token management, and password security.

## Completed Tasks

### 1. Database Migration
- ✅ Created migration `20240102000001_add_identity_password.sql`
- Added `password_hash` column to `identity` table
- Column is nullable to support external auth providers and service accounts
- Added index for faster password hash lookups

### 2. Authentication Dependencies
- ✅ Added `jsonwebtoken` 9.3 for JWT handling
- ✅ Added `argon2` 0.5 for password hashing
- ✅ Added `rand` 0.8 for secure random generation

### 3. Core Authentication Modules

#### Password Module (`auth/password.rs`)
- ✅ Implemented Argon2id password hashing
- ✅ Implemented password verification
- ✅ Custom error types (`PasswordError`)
- ✅ Comprehensive unit tests
- Features:
  - Secure salt generation using OS RNG
  - Memory-hard algorithm (Argon2id)
  - PHC string format for hashes

#### JWT Module (`auth/jwt.rs`)
- ✅ JWT token generation (access & refresh tokens)
- ✅ JWT token validation and decoding
- ✅ Claims structure with identity info
- ✅ Token type differentiation (access vs refresh)
- ✅ Configurable expiration times
- ✅ Header extraction utilities
- ✅ Custom error types (`JwtError`)
- ✅ Comprehensive unit tests

#### Middleware Module (`auth/middleware.rs`)
- ✅ Authentication middleware (`require_auth`)
- ✅ Request extractor (`RequireAuth`)
- ✅ Authenticated user context
- ✅ Custom error types with proper HTTP responses
- Features:
  - Validates JWT tokens from Authorization header
  - Extracts claims and adds to request extensions
  - Provides convenient access to identity ID and login

### 4. Authentication DTOs (`dto/auth.rs`)
- ✅ `LoginRequest` - User login credentials
- ✅ `RegisterRequest` - New user registration
- ✅ `TokenResponse` - JWT token response
- ✅ `RefreshTokenRequest` - Token refresh
- ✅ `ChangePasswordRequest` - Password change
- ✅ `CurrentUserResponse` - Current user info
- All DTOs include validation constraints

### 5. Authentication Routes (`routes/auth.rs`)
- ✅ POST `/auth/register` - Register new user
- ✅ POST `/auth/login` - User login
- ✅ POST `/auth/refresh` - Refresh access token
- ✅ GET `/auth/me` - Get current user (protected)
- ✅ POST `/auth/change-password` - Change password (protected)

### 6. Application Integration
- ✅ Added JWT config to `AppState`
- ✅ Updated `main.rs` to initialize JWT configuration
- ✅ Added auth routes to server router
- ✅ Added error conversions for auth errors
- ✅ Environment variable configuration:
  - `JWT_SECRET` - Secret key for token signing
  - `JWT_ACCESS_EXPIRATION` - Access token lifetime (default: 3600s)
  - `JWT_REFRESH_EXPIRATION` - Refresh token lifetime (default: 604800s)

### 7. Error Handling
- ✅ Added `From` implementations for `JwtError` → `ApiError`
- ✅ Added `From` implementations for `PasswordError` → `ApiError`
- ✅ Added `From` implementations for `ParseIntError` → `ApiError`
- Proper HTTP status codes for all auth errors (401, 403, 409)

### 8. Documentation
- ✅ Created comprehensive authentication documentation (`docs/authentication.md`)
- Includes:
  - Architecture overview
  - Configuration guide
  - API endpoint documentation
  - Security best practices
  - Usage examples with cURL
  - Troubleshooting guide
  - Future enhancements roadmap

## Technical Details

### Security Features
1. **Password Hashing**
   - Algorithm: Argon2id (memory-hard, resistant to GPU attacks)
   - Unique salt per password
   - PHC string format for storage

2. **JWT Tokens**
   - HS256 algorithm (HMAC-SHA256)
   - Configurable secret key
   - Separate access and refresh tokens
   - Token type validation
   - Expiration checking

3. **Authentication Middleware**
   - Bearer token extraction
   - Token validation before route handling
   - Claims injection into request context
   - Automatic error responses

### Data Storage
- Password hashes stored in `identity.attributes` JSONB field
- Format: `{"password_hash": "$argon2id$v=19$m=19456,t=2,p=1$..."}`
- Nullable password_hash supports external auth providers

### Token Structure
```json
{
  "sub": "123",              // Identity ID
  "login": "username",        // Username
  "iat": 1234567890,         // Issued at
  "exp": 1234571490,         // Expiration
  "token_type": "access"     // Token type
}
```

## Code Quality
- ✅ All code compiles without errors
- ✅ Comprehensive unit tests for password and JWT modules
- ✅ Proper error handling throughout
- ✅ Type-safe API with Rust's type system
- ✅ Request validation using `validator` crate
- ✅ Follows established project patterns

## Testing
- Unit tests for password hashing (hash generation, verification, salts)
- Unit tests for JWT tokens (generation, validation, expiration)
- Unit tests for middleware helpers
- Manual testing pending database availability

## Deferred Features
The following features were deferred to **Phase 2.13** to focus on core authentication:
- RBAC permission checking middleware
- Identity management CRUD endpoints
- Permission assignment endpoints
- Permission set management
- Advanced authorization rules

These will be implemented after core CRUD APIs are complete.

## Configuration Example

```bash
# .env file
JWT_SECRET=your-super-secret-key-min-256-bits
JWT_ACCESS_EXPIRATION=3600
JWT_REFRESH_EXPIRATION=604800
DATABASE_URL=postgresql://svc_attune:password@localhost:5432/attune
```

## Usage Examples

### Registration
```bash
curl -X POST http://localhost:8080/auth/register \
  -H "Content-Type: application/json" \
  -d '{"login":"alice","password":"secure123","display_name":"Alice"}'
```

### Login
```bash
curl -X POST http://localhost:8080/auth/login \
  -H "Content-Type: application/json" \
  -d '{"login":"alice","password":"secure123"}'
```

### Protected Endpoint
```bash
curl http://localhost:8080/auth/me \
  -H "Authorization: Bearer eyJhbGciOiJIUzI1NiIs..."
```

## Dependencies Added
```toml
jsonwebtoken = "9.3"
argon2 = "0.5"
rand = "0.8"
```

## Files Created/Modified

### New Files
- `migrations/20240102000001_add_identity_password.sql`
- `crates/api/src/auth/mod.rs`
- `crates/api/src/auth/password.rs`
- `crates/api/src/auth/jwt.rs`
- `crates/api/src/auth/middleware.rs`
- `crates/api/src/dto/auth.rs`
- `crates/api/src/routes/auth.rs`
- `docs/authentication.md`

### Modified Files
- `crates/api/Cargo.toml` - Added auth dependencies
- `crates/api/src/main.rs` - Added auth module, JWT config
- `crates/api/src/state.rs` - Added JWT config to AppState
- `crates/api/src/server.rs` - Added auth routes
- `crates/api/src/dto/mod.rs` - Exported auth DTOs
- `crates/api/src/routes/mod.rs` - Added auth routes module
- `crates/api/src/middleware/error.rs` - Added auth error conversions
- `work-summary/TODO.md` - Marked Phase 2.2 complete

## Next Steps
1. Start database and run migration
2. Test authentication endpoints manually
3. Proceed to **Phase 2.4: Action Management API**
4. Continue with other CRUD APIs
5. Return to RBAC implementation in Phase 2.13

## Notes
- JWT secret defaults to insecure value for development
- Production deployments MUST set a strong JWT_SECRET
- Password requirements: minimum 8 characters (can be enhanced)
- Tokens are stateless (no server-side session storage)
- Token revocation will be added in future enhancement

## Build Status
✅ Successfully compiles with warnings (unused imports to be cleaned up)
✅ All authentication tests pass
✅ Ready for integration testing once database is available

## Security Considerations
- Always use HTTPS in production
- Rotate JWT secrets periodically
- Consider implementing rate limiting on auth endpoints
- Add MFA support in future releases
- Implement token blacklisting for logout functionality