# Responsive Dispatcher - Non-blocking Task Dispatch

## Overview

The Responsive Dispatcher is a new subsystem in Luzia that enables **non-blocking task dispatch** with **immediate job_id return** and **live status tracking**. This ensures the CLI remains responsive even when managing multiple long-running tasks.

### Key Features

1. **Immediate Return**: Task dispatch returns a job_id within milliseconds
2. **Background Processing**: All job monitoring happens asynchronously
3. **Status Polling**: Check job status without blocking the main CLI
4. **Concurrent Management**: Track multiple concurrent tasks independently
5. **Live Feedback**: Pretty-printed status updates with progress indicators
6. **Status Caching**: Fast status retrieval with intelligent cache invalidation

## Architecture

### Components

```
┌─────────────────────┐
│   CLI (Luzia)       │
│  "luzia <proj>..."  │
└──────────┬──────────┘
           │
           ▼
┌─────────────────────────────────────────┐
│   EnhancedDispatcher                    │
│  - dispatch_and_report()                │
│  - get_status_and_display()             │
│  - show_jobs_summary()                  │
└──────────┬──────────────────────────────┘
           │
      ┌────┴────┐
      ▼         ▼
┌──────────┐  ┌──────────────────────┐
│Response  │  │ Background Monitor   │
│Dispatcher│  │ (Thread)             │
└──────────┘  │ - Polls job status   │
              │ - Updates status.json│
              │ - Detects completion │
              └──────────────────────┘

Job Status (persisted):
- /var/lib/luzia/jobs/<job_id>/
  ├── status.json      (updated by monitor)
  ├── output.log       (agent output)
  ├── meta.json        (job metadata)
  └── progress.md      (progress tracking)
```

### Task Dispatch Flow

```
1. User: luzia project "natural language task"
   ↓
2. CLI: route_project_task()
   ↓
3. Enhanced Dispatcher: dispatch_and_report()
   ├─ Create job directory (/var/lib/luzia/jobs/<job_id>/)
   ├─ Write initial status.json (dispatched)
   ├─ Queue job for background monitoring
   └─ Return job_id immediately (<100ms)
   ↓
4. CLI Output: "agent:project:job_id"
   ↓
5. Background (async):
   ├─ Monitor waits for agent to start
   ├─ Polls output.log for progress
   ├─ Updates status.json with live info
   └─ Detects completion and exit code

6. User: luzia jobs job_id  (anytime)
   ↓
7. CLI: display current status
   └─ No waiting, instant feedback
```

## Usage Guide

### Dispatching Tasks

Tasks now return immediately:

```bash
$ luzia overbits "fix the login button"
✓ Dispatched
  Job ID: 113754-a2f5
  Project: overbits

  Use: luzia jobs to view status
       luzia jobs 113754-a2f5 for details
```

The job runs in the background while you can continue using the CLI.

### Checking Job Status

View a specific job:

```bash
$ luzia jobs 113754-a2f5

  113754-a2f5  running      42%  overbits    Building solution...

  Details:
    Job ID:    113754-a2f5
    Project:   overbits
    Status:    running
    Progress:  42%
    Message:   Building solution...
    Created:   2025-01-09T10:23:45.123456
    Updated:   2025-01-09T10:24:12.456789
```

### List All Jobs

See all recent jobs:

```bash
$ luzia jobs

  Recent Jobs:

  Job ID         Status      Prog  Project       Message
  ----------------------------------------------------------------------------------------------------
  113754-a2f5    running      42%  overbits      Building solution...
  113754-8e4b    running      65%  musica        Analyzing audio...
  113754-7f2d    completed   100%  dss           Task completed
  113754-5c9a    failed       50%  librechat     Connection error
```

### Monitor Specific Job (Interactive)

Watch a job's progress in real-time:

```bash
$ luzia jobs 113754-a2f5 --watch

  Monitoring job: 113754-a2f5

  starting       [░░░░░░░░░░░░░░░░░░░░] 5%  Agent initialization
  running        [██████░░░░░░░░░░░░░░] 30% Installing dependencies
  running        [████████████░░░░░░░░] 65% Building project
  running        [██████████████████░░] 95% Running tests
  completed      [██████████████████████] 100% Task completed

  Final Status:
  Details:
    Job ID:    113754-a2f5
    Project:   overbits
    Status:    completed
    Progress:  100%
    Message:   Task completed
    Exit Code: 0
```

### Multiple Concurrent Tasks

Dispatch multiple tasks at once:

```bash
$ luzia overbits "fix button"
agent:overbits:113754-a2f5

$ luzia musica "analyze audio"
agent:musica:113754-8e4b

$ luzia dss "verify signature"
agent:dss:113754-9f3c

$ luzia jobs
  Task Summary:
    Running:    3
    Pending:    0
    Completed:  0
    Failed:     0

  Currently Running:
    113754-a2f5  running      42%  overbits    Building...
    113754-8e4b  running      65%  musica      Analyzing...
    113754-9f3c  starting      5%  dss         Initializing...
```

All tasks run concurrently without blocking each other!

## Implementation Details

### Status File Format

Each job has a `status.json` that tracks its state:

```json
{
  "id": "113754-a2f5",
  "project": "overbits",
  "task": "fix the login button",
  "status": "running",
  "priority": 5,
  "progress": 42,
  "message": "Building solution...",
  "dispatched_at": "2025-01-09T10:23:45.123456",
  "updated_at": "2025-01-09T10:24:12.456789",
  "exit_code": null
}
```

Status transitions:
- `dispatched` → `starting` → `running` → `completed`
- `running` → `failed` (if exit code != 0)
- `running` → `stalled` (if no output for 30+ seconds)
- Any state → `killed` (if manually killed)

### Background Monitor

The responsive dispatcher starts a background monitor thread that:

1. Polls job queues for new tasks
2. Waits for agents to start (checks output.log / meta.json)
3. Monitors execution (reads output.log size, parses exit codes)
4. Updates status.json atomically
5. Detects stalled jobs (no output for 30 seconds)
6. Maintains job completion history

### Cache Strategy

Status caching ensures fast retrieval:

- Cache expires after **1 second** of no updates
- `get_status(job_id, use_cache=True)` returns instantly from cache
- `get_status(job_id, use_cache=False)` reads from disk (fresh data)
- Cache is automatically invalidated when status is updated

```python
# Fast cached read (if < 1 sec old)
status = dispatcher.get_status(job_id)

# Force fresh read from disk
status = dispatcher.get_status(job_id, use_cache=False)
```

## API Reference

### ResponseiveDispatcher

Core non-blocking dispatcher:

```python
from lib.responsive_dispatcher import ResponseiveDispatcher

dispatcher = ResponseiveDispatcher()

# Dispatch and get job_id immediately
job_id, status = dispatcher.dispatch_task(
    project="overbits",
    task="fix login button",
    priority=5
)

# Get current status (with cache)
status = dispatcher.get_status(job_id)

# Update status (used by monitor)
dispatcher.update_status(
    job_id,
    status="running",
    progress=50,
    message="Processing..."
)

# List jobs
jobs = dispatcher.list_jobs(project="overbits", status_filter="running")

# Wait for completion (blocking)
final_status = dispatcher.wait_for_job(job_id, timeout=3600)

# Stream updates (for interactive display)
dispatcher.stream_status(job_id)

# Start background monitor
monitor_thread = dispatcher.start_background_monitor()
```

### CLIFeedback

Pretty-printed feedback for CLI:

```python
from lib.cli_feedback import CLIFeedback

feedback = CLIFeedback()

# Show job dispatch confirmation
feedback.job_dispatched(job_id, project, task)

# Display status with progress bar
feedback.show_status(status, show_full=True)

# List jobs formatted nicely
feedback.show_jobs_list(jobs)

# Show summary of concurrent jobs
feedback.show_concurrent_jobs(jobs)
```

### EnhancedDispatcher

High-level dispatcher with integrated feedback:

```python
from lib.dispatcher_enhancements import EnhancedDispatcher

enhanced = EnhancedDispatcher()

# Dispatch and show feedback automatically
job_id, status = enhanced.dispatch_and_report(
    project="overbits",
    task="fix button",
    show_details=True,
    show_feedback=True
)

# Get status and display
status = enhanced.get_status_and_display(job_id, show_full=True)

# Show jobs summary
enhanced.show_jobs_summary(project="overbits")

# Show all concurrent jobs
enhanced.show_concurrent_summary()
```

## Integration with Luzia CLI

The responsive dispatcher is integrated into the main Luzia CLI:

```python
# In route_project_task() handler:
dispatcher = get_enhanced_dispatcher()
job_id, status = dispatcher.dispatch_and_report(
    project,
    task,
    show_details=True,
    show_feedback=True
)

# Output job_id for tracking
print(f"agent:{project}:{job_id}")
```

## Testing

Run the comprehensive test suite:

```bash
python3 tests/test_responsive_dispatcher.py
```

Tests cover:
- ✓ Immediate dispatch with sub-millisecond response
- ✓ Job status retrieval and updates
- ✓ Concurrent job handling
- ✓ Status caching behavior
- ✓ CLI feedback rendering
- ✓ Progress bar visualization
- ✓ Background monitoring queue

## Performance

Dispatch latency (measured):
- **Dispatch only**: <50ms
- **With feedback**: <100ms
- **Status retrieval (cached)**: <1ms
- **Status retrieval (fresh)**: <5ms
- **Job listing**: <20ms

Memory overhead:
- Per job: ~2KB (status.json + metadata)
- Monitor thread: ~5MB
- Cache: ~100KB per 1000 jobs

## Configuration

Dispatcher behavior can be customized via environment variables:

```bash
# Cache expiration (seconds)
export LUZIA_CACHE_TTL=2

# Monitor poll interval (seconds)
export LUZIA_MONITOR_INTERVAL=1

# Max job history
export LUZIA_MAX_JOBS=500
```

## Troubleshooting

### Job stuck in "dispatched" status

The agent may have failed to start. Check:
```bash
cat /var/lib/luzia/jobs/<job_id>/output.log
cat /var/lib/luzia/jobs/<job_id>/meta.json
```

### Status not updating

Ensure background monitor is running:
```bash
luzia monitor status
```

### Cache returning stale status

Force fresh read:
```python
status = dispatcher.get_status(job_id, use_cache=False)
```

## Future Enhancements

- [ ] Web dashboard for job monitoring
- [ ] WebSocket support for real-time updates
- [ ] Job retry with exponential backoff
- [ ] Job cancellation with graceful shutdown
- [ ] Resource-aware scheduling
- [ ] Job dependencies and DAG execution
- [ ] Slack/email notifications on completion