# Scan Bridge Phase 2 Implementation - COMPLETE

**Date:** 2026-03-24  
**Phase:** 2 - Prefect Integration  
**Status:** ✅ IMPLEMENTATION COMPLETE

---

## Deliverables Created

| File | Purpose | Lines |
|------|---------|-------|
| `scan_bridge_prefect_daemon.py` | Prefect-managed daemon with health monitoring | 397 |
| `scan_bridge_deploy.py` | Deployment and management script | 152 |
| `prefect.yaml` | Prefect deployment configuration | 65 |
| `SCAN_BRIDGE_PHASE2_COMPLETE.md` | This completion document | - |

---

## Architecture

```
┌─────────────────────────────────────────────────────────────────┐
│                    PREFECT ORCHESTRATION                        │
│                     (localhost:4200)                            │
├─────────────────────────────────────────────────────────────────┤
│  ┌─────────────────────┐     ┌─────────────────────────────┐   │
│  │ Health Check Task   │────▶│ scan-bridge-daemon Flow     │   │
│  │ (every 30s)         │     │ (long-running)              │   │
│  └─────────────────────┘     └─────────────────────────────┘   │
│                                         │                       │
│                                         │ manages               │
│                                         ▼                       │
│  ┌─────────────────────────────────────────────────────────┐   │
│  │         Scan Bridge Subprocess                          │   │
│  │         (scan_bridge_service.py)                        │   │
│  │                                                         │   │
│  │  • Watches Arrow files                                  │   │
│  │  • Pushes to Hazelcast                                  │   │
│  │  • Logs forwarded to Prefect                            │   │
│  └─────────────────────────────────────────────────────────┘   │
│                                         │                       │
└─────────────────────────────────────────┼───────────────────────┘
                                          │
                                          ▼
                              ┌─────────────────────┐
                              │    Hazelcast        │
                              │  (DOLPHIN_FEATURES) │
                              │  latest_eigen_scan  │
                              └─────────────────────┘
```

---

## Key Features

### 1. Automatic Restart
- Restarts bridge on crash
- Max 3 restart attempts
- 5-second delay between attempts

### 2. Health Monitoring
```python
HEALTH_CHECK_INTERVAL = 30  # seconds
DATA_STALE_THRESHOLD = 60   # Critical - triggers restart
DATA_WARNING_THRESHOLD = 30  # Warning only
```

### 3. Centralized Logging
All bridge output appears in Prefect UI:
```
[Bridge] [OK] Pushed 200 scans. Latest: #4228
[Bridge] Connected to Hazelcast
```

### 4. Hazelcast Integration
Checks data freshness:
- Verifies `latest_eigen_scan` exists
- Monitors data age
- Alerts on staleness

---

## Usage

### Deploy to Prefect
```bash
cd /mnt/dolphinng5_predict/prod
source /home/dolphin/siloqy_env/bin/activate

# Create deployment
python scan_bridge_deploy.py create

# Or manually:
prefect deployment build scan_bridge_prefect_daemon.py:scan_bridge_daemon_flow \
    --name scan-bridge-daemon --pool dolphin-daemon-pool
prefect deployment apply scan-bridge-daemon-deployment.yaml
```

### Start Worker
```bash
python scan_bridge_deploy.py start
# Or:
prefect worker start --pool dolphin-daemon-pool
```

### Check Status
```bash
python scan_bridge_deploy.py status
python scan_bridge_deploy.py health
```

---

## Health Check States

| Status | Condition | Action |
|--------|-----------|--------|
| ✅ Healthy | Data age < 30s | Continue monitoring |
| ⚠️ Warning | Data age 30-60s | Log warning |
| ❌ Stale | Data age > 60s | Restart bridge |
| ❌ Down | Process not running | Restart bridge |
| ❌ Error | Hazelcast unavailable | Alert, retry |

---

## Monitoring Metrics

The daemon tracks:
- Process uptime
- Data freshness (seconds)
- Scan number progression
- Asset count
- Restart count

---

## Files Modified

- `SYSTEM_BIBLE.md` - Updated v4 with Prefect daemon info

---

## Next Steps (Phase 3)

1. **Deploy to production**
   ```bash
   python scan_bridge_deploy.py create
   prefect worker start --pool dolphin-daemon-pool
   ```

2. **Configure alerting**
   - Add Slack/Discord webhooks
   - Set up PagerDuty for critical alerts

3. **Dashboard**
   - Create Prefect dashboard
   - Monitor health over time

4. **Integration with main flows**
   - Ensure `paper_trade_flow` waits for bridge
   - Add dependency checks

---

## Testing

```bash
# Test health check
python -c "
from scan_bridge_prefect_daemon import check_hazelcast_data_freshness
result = check_hazelcast_data_freshness()
print(f\"Status: {result}\")
"

# Run standalone health check
python scan_bridge_prefect_daemon.py
# Then: Ctrl+C to stop
```

---

**Phase 2 Status:** ✅ COMPLETE  
**Ready for:** Production deployment  
**Next Review:** After 7 days of production running

---

*Document: SCAN_BRIDGE_PHASE2_COMPLETE.md*  
*Version: 1.0*  
*Date: 2026-03-24*