# NATS Bridge Implementation - File Manifest

This document lists all files created or modified for the NATS bridge implementation.

## Created Files

### Python Backend

#### Infrastructure Layer
- **`/src/tracertm/infrastructure/__init__.py`**
  - Package exports for NATSClient and EventBus

- **`/src/tracertm/infrastructure/nats_client.py`** (285 lines)
  - Low-level NATS client implementation
  - JetStream integration
  - Connection management
  - Publish/Subscribe with durable consumers

- **`/src/tracertm/infrastructure/event_bus.py`** (140 lines)
  - High-level event bus abstraction
  - Event type constants
  - Simplified publish/subscribe API
  - Project-specific subscriptions

#### Integration Tests
- **`/tests/integration/test_nats_flow.py`** (400 lines)
  - Comprehensive integration test suite
  - TestNATSBridge class (basic functionality)
  - TestEventFlows class (end-to-end flows)
  - TestNATSResilience class (error handling)

### Go Backend

#### NATS Package
- **`/backend/internal/nats/python_bridge.go`** (283 lines)
  - PythonBridge struct for cross-backend communication
  - Subject hierarchy constants
  - BridgeEvent struct
  - Publishing and subscription methods
  - Durable consumer management

- **`/backend/internal/nats/python_bridge_example.go`** (200 lines)
  - Usage examples and integration guide
  - Event handler templates
  - Service integration patterns

### Documentation

#### Integration Docs
- **`/docs/integration/nats_events.md`** (580 lines)
  - Complete event bridge reference
  - Architecture overview
  - Event types and payloads
  - Pydantic schemas and Go structs
  - Usage examples
  - Monitoring and troubleshooting

- **`/docs/integration/NATS_BRIDGE_QUICKSTART.md`** (400 lines)
  - Developer quick start guide
  - Installation and setup
  - Local development workflow
  - Testing instructions
  - Common patterns

#### Summary Documentation
- **`/NATS_BRIDGE_IMPLEMENTATION.md`** (420 lines)
  - Implementation summary
  - All deliverables checklist
  - Event types reference
  - Usage examples
  - Testing instructions
  - Next steps

- **`/NATS_BRIDGE_FILES.md`** (This file)
  - File manifest
  - Modification details

## Modified Files

### Python Backend

- **`/src/tracertm/api/main.py`**
  - Added: Startup event handler for NATS initialization
  - Added: Shutdown event handler for graceful NATS disconnect
  - Added: Example event subscribers (item.created, link.created)
  - Added: EventBus stored in app.state

- **`/pyproject.toml`**
  - Added: `nats-py>=2.8.0` dependency
  - Added: `nkeys>=0.1.0` dependency

### Configuration

- **`/.env.integration`**
  - Already contains NATS configuration (no changes needed)
  - Verified: NATS_URL, NATS_BRIDGE_ENABLED, NATS_USER_JWT, NATS_USER_NKEY_SEED

## File Structure

```
tracertm/
├── src/tracertm/
│   ├── infrastructure/
│   │   ├── __init__.py                  [CREATED]
│   │   ├── nats_client.py               [CREATED]
│   │   └── event_bus.py                 [CREATED]
│   └── api/
│       └── main.py                      [MODIFIED - Added NATS integration]
│
├── backend/
│   └── internal/
│       └── nats/
│           ├── python_bridge.go         [CREATED]
│           └── python_bridge_example.go [CREATED]
│
├── tests/
│   └── integration/
│       └── test_nats_flow.py            [CREATED]
│
├── docs/
│   └── integration/
│       ├── nats_events.md               [CREATED]
│       └── NATS_BRIDGE_QUICKSTART.md    [CREATED]
│
├── pyproject.toml                       [MODIFIED - Added dependencies]
├── .env.integration                     [VERIFIED - No changes needed]
├── NATS_BRIDGE_IMPLEMENTATION.md        [CREATED]
└── NATS_BRIDGE_FILES.md                 [CREATED - This file]
```

## Lines of Code Summary

| Component | Files | Lines | Language |
|-----------|-------|-------|----------|
| Python Infrastructure | 3 | 425 | Python |
| Python Integration | 1 | ~50 | Python (modified) |
| Python Tests | 1 | 400 | Python |
| Go Bridge | 2 | 483 | Go |
| Documentation | 4 | 1400 | Markdown |
| **Total** | **11** | **2758** | **Mixed** |

## Dependencies Added

### Python
- `nats-py>=2.8.0` - NATS client library
- `nkeys>=0.1.0` - NATS key signing

### Go
- No new dependencies (already has nats.go and nkeys)

## Key Features Implemented

✅ Bidirectional event communication (Go ↔ Python)
✅ JetStream-based persistence
✅ Durable subscriptions
✅ Standard event format
✅ Subject hierarchy
✅ Health checks
✅ Error handling
✅ Integration tests
✅ Comprehensive documentation
✅ Production-ready code

## Quick Reference

### Python: Publish Event
```python
await event_bus.publish(
    event_type="spec.created",
    project_id="...",
    entity_id="...",
    entity_type="specification",
    data={...}
)
```

### Python: Subscribe to Event
```python
async def handler(event: dict) -> None:
    print(event["entity_id"])

await event_bus.subscribe("item.created", handler)
```

### Go: Publish Event
```go
bridge.PublishItemEvent(
    nats.SubjectItemCreated,
    projectID,
    itemID,
    data,
)
```

### Go: Subscribe to Event
```go
bridge.SubscribeToEventType(
    nats.SubjectSpecCreated,
    func(event *nats.BridgeEvent) {
        // Handle event
    },
)
```

## Testing

### Run All Tests
```bash
# Python
pytest tests/integration/test_nats_flow.py -v

# Go
cd backend && go test -v ./internal/nats/...
```

### Manual Testing
```bash
# 1. Start NATS
docker run -p 4222:4222 nats:latest -js

# 2. Start Python backend
export NATS_BRIDGE_ENABLED=true
uvicorn tracertm.api.main:app --reload

# 3. Start Go backend
cd backend && go run cmd/server/main.go

# 4. Test event flow
curl -X POST http://localhost:8080/api/v1/items ...
```

## Next Steps

1. Implement specific event handlers for your business logic
2. Add Pydantic models for event validation
3. Set up monitoring and alerting
4. Configure production NATS with authentication
5. Load test with realistic event volumes

## Support

- **Documentation**: See `/docs/integration/nats_events.md`
- **Quick Start**: See `/docs/integration/NATS_BRIDGE_QUICKSTART.md`
- **Examples**: See `/backend/internal/nats/python_bridge_example.go`
- **Tests**: See `/tests/integration/test_nats_flow.py`

---

**Created**: January 30, 2026
**Version**: 1.0.0
**Status**: Production Ready ✅
