# DLQ Quick Start Guide

**Navigation:** [📖 Index](DLQ_INDEX.md) | [🚀 Quick Start](DLQ_QUICKSTART.md) | [📚 API Reference](DLQ_API_REFERENCE.md) | [🔧 Operations](DLQ_OPERATIONS.md) | [🏗️ System Guide](DLQ_SYSTEM_GUIDE.md)

---

Get started with Dead Letter Queue (DLQ) management in minutes.

## What is the DLQ System?

The DLQ system provides queue-native tools for monitoring and managing failed tasks across **all queue types** (partner_tasks, jobs, etc.) without MongoDB coupling, supporting multiple queue types.

---

## Quick Access

### 1. Web Dashboard

```
https://localhost:4100/dlq-monitor.html
```

- Real-time DLQ statistics
- View failed messages
- One-click retry operations
- Queue-native operations

### 2. API Access

View DLQ statistics:

```bash
curl http://localhost:4100/api/dlq/partner_tasks/stats \
  -H "Authorization: Bearer $TOKEN"
```

Retry all messages:

```bash
curl -X POST http://localhost:4100/api/dlq/partner_tasks/retryAll \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"maxMessages": 100}'
```

### 3. Message Operations

```bash
curl http://localhost:4100/api/dlq/partner_tasks/stats \
  -H "Authorization: Bearer $TOKEN"
```

---

## Common Operations

### View DLQ Messages

```bash
curl -X GET "http://localhost:4100/api/dlq/partner_tasks/messages?limit=20" \
  -H "Authorization: Bearer $TOKEN"
```

### Retry All Messages

```bash
curl -X POST http://localhost:4100/api/dlq/partner_tasks/retryAll \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"maxMessages": 50}'
```

### Retry by Position Range

```bash
curl -X POST http://localhost:4100/api/dlq/partner_tasks/retryByPosition \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"startPosition": 0, "endPosition": 10}'
```

### Retry by Header Match

```bash
curl -X POST http://localhost:4100/api/dlq/partner_tasks/retryByHeader \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"headerKey": "x-retry-count", "headerValue": "1"}'
```

---

## API Endpoints Summary

| Endpoint | Method | Purpose |
|----------|--------|---------|
| `/api/dlq/:queueName/messages` | GET | View DLQ messages (peek mode) |
| `/api/dlq/:queueName/stats` | GET | Get DLQ statistics |
| `/api/dlq/:queueName/retryAll` | POST | Retry all messages (queue-native) |
| `/api/dlq/:queueName/retryByPosition` | POST | Retry by position range (queue-native) |
| `/api/dlq/:queueName/retryByHeader` | POST | Retry by header match (queue-native) |
| `/api/dlq/:queueName/purge` | DELETE | Purge all DLQ messages ⚠️ |

---

## Multiple Queue Support

### Partner Queue
```bash
curl -X POST http://localhost:4100/api/dlq/partner_tasks/retryAll ...
```

### Job Queue
```bash
curl -X POST http://localhost:4100/api/dlq/dev_jobs/retryAll ...
```

### Any Future Queue
```bash
curl -X POST http://localhost:4100/api/dlq/notifications/retryAll ...
```

No code changes needed - just use the queue name!

---

## Monitoring Workflow

### 1. Check DLQ Health

```bash
curl -s http://localhost:4100/api/dlq/partner_tasks/stats \
  -H "Authorization: Bearer $TOKEN" | jq '.dlq.messageCount'
```

### 2. View Failed Messages

```bash
curl -s http://localhost:4100/api/dlq/partner_tasks/messages?limit=5 \
  -H "Authorization: Bearer $TOKEN" | jq '.messages[].errorMessage'
```

### 3. Retry Failed Messages

```bash
# Retry all (up to 100)
curl -X POST http://localhost:4100/api/dlq/partner_tasks/retryAll \
  -H "Authorization: Bearer $TOKEN" \
  -H "Content-Type: application/json" \
  -d '{"maxMessages": 100}'
```

---

## Troubleshooting

### High DLQ Count

1. Check recent error messages:
   ```bash
   curl http://localhost:4100/api/dlq/partner_tasks/messages?limit=10 \
     -H "Authorization: Bearer $TOKEN"
   ```

2. Review error patterns in logs:
   ```bash
   grep "DLQ" agm_server.rlog
   ```

3. Retry transient errors:
   ```bash
   curl -X POST http://localhost:4100/api/dlq/partner_tasks/retryAll \
     -H "Authorization: Bearer $TOKEN" \
     -d '{"maxMessages": 50}'
   ```

### Authentication Errors

Ensure your token is valid:
```bash
export TOKEN=$(curl -X POST http://localhost:4100/api/auth/login \
  -H "Content-Type: application/json" \
  -d '{"username":"admin","password":"***"}' | jq -r '.token')
```

### Queue Not Found

Verify queue name matches environment config:
- Development: `dev_partner_tasks`, `dev_jobs`
- Production: `partner_tasks`, `jobs`

---

## Best Practices

1. **Monitor Regularly**: Check DLQ counts daily
2. **Retry Transient Errors**: Network timeouts often succeed on retry
3. **Investigate Patterns**: Multiple failures of same type indicate systemic issues
4. **Use Position Retry**: For targeted retry of specific message ranges
5. **Archive Non-Recoverable**: Purge after investigation (with confirm=true)

---

## Next Steps

### 📚 Complete Documentation

- **[📖 DLQ Index](DLQ_INDEX.md)** - Documentation overview and navigation
- **[📚 API Reference](DLQ_API_REFERENCE.md)** - Complete API with examples
- **[🔧 Operations Guide](DLQ_OPERATIONS.md)** - Advanced operations and troubleshooting
- **[🏗️ System Guide](DLQ_SYSTEM_GUIDE.md)** - Architecture and internals

### 🔗 Related Resources

- [Global DLQ Refactoring](../GLOBAL_DLQ_REFACTORING_COMPLETE.md) - Architecture changes
- [Partner Integration Guide](../README_PARTNER_INTEGRATION.md) - Partner system overview
- [Main README](../README.md) - Server documentation