# Database Connection Pool Lifecycle Fix

## Summary

Fixed database connection pool lifecycle in `scripts/debug_loop_cli.py` by converting to async context manager pattern. This ensures proper resource cleanup and prevents potential memory leaks.

## Changes Made

### 1. Created DatabasePool Async Context Manager

**Location**: `scripts/debug_loop_cli.py:70-116`

```python
class DatabasePool:
    """Async context manager for database connection pool lifecycle."""

    def __init__(self):
        self.pool = None

    async def __aenter__(self):
        """Create and return database connection pool."""
        # ... pool creation logic
        return self.pool

    async def __aexit__(self, exc_type, exc_val, exc_tb):
        """Close database connection pool."""
        if self.pool is not None:
            await self.pool.close()
```

### 2. Updated get_db_pool() Function

Changed from returning a pool directly to returning a context manager:

```python
async def get_db_pool():
    """Create database connection pool context manager."""
    return DatabasePool()
```

### 3. Updated All Usage Patterns (7 locations)

**Old pattern**:
```python
pool = await get_db_pool()
try:
    async with pool.acquire() as conn:
        # database operations
finally:
    await pool.close()
```

**New pattern**:
```python
async with await get_db_pool() as pool:
    async with pool.acquire() as conn:
        # database operations
```

**Locations updated**:
1. `list_stfs()` - Line 156
2. `show_stf()` - Line 270
3. `search()` - Line 360
4. `store()` - Line 460
5. `list_models()` - Line 531
6. `show_model()` - Line 634
7. `add()` - Line 778

## Benefits

✅ **Automatic cleanup**: Pool is always closed when context exits, even on exceptions
✅ **Cleaner code**: No explicit try/finally blocks needed
✅ **Resource safety**: Prevents connection pool leaks
✅ **Pythonic**: Follows standard async context manager pattern
✅ **Error handling**: Pool cleanup happens even when exceptions occur

## Testing

### 1. Syntax Validation
```bash
python3 -m py_compile scripts/debug_loop_cli.py
# Result: ✓ No syntax errors
```

### 2. CLI Functionality Tests
```bash
# Help commands
python3 scripts/debug_loop_cli.py --help
python3 scripts/debug_loop_cli.py stf --help
python3 scripts/debug_loop_cli.py model --help

# List commands
python3 scripts/debug_loop_cli.py model list --all
python3 scripts/debug_loop_cli.py stf list --limit 5

# Result: ✓ All commands work correctly
```

### 3. Pool Lifecycle Tests

Created comprehensive test suite at `scripts/test_pool_lifecycle.py`:

**Test 1**: Basic pool creation and cleanup
- ✓ Pool created successfully
- ✓ Pool closed when context exits

**Test 2**: Pool with actual query
- ✓ Query executes successfully
- ✓ Pool closed after query

**Test 3**: Multiple sequential operations
- ✓ Three separate pool operations
- ✓ Each pool properly cleaned up

**Test 4**: Exception handling
- ✓ Exception caught correctly
- ✓ Pool still closed despite exception

```bash
python3 scripts/test_pool_lifecycle.py
# Result: ✓ All tests passed!
```

## Success Criteria Met

✅ **All database pool operations properly cleaned up**
- Context manager ensures cleanup in all code paths

✅ **Async context manager pattern used correctly**
- Implemented `__aenter__` and `__aexit__` methods
- Proper exception handling

✅ **No resource leaks**
- Verified by lifecycle tests
- Pool always closed on context exit

✅ **All CLI commands still work**
- Tested model and STF commands
- Help commands functional

✅ **Code compiles without errors**
- Python syntax validation passed
- All imports resolve correctly

## Migration Notes

This pattern can be applied to other scripts that use database pools:
- `agents/services/agent_router_event_service.py`
- `agents/lib/agent_execution_logger.py`
- Any script using `asyncpg.create_pool()`

## Files Modified

1. **scripts/debug_loop_cli.py** (main fix)
   - Added `DatabasePool` class (47 lines)
   - Updated `get_db_pool()` function
   - Updated 7 usage locations

2. **scripts/test_pool_lifecycle.py** (new test)
   - Comprehensive lifecycle tests
   - Validates proper cleanup

3. **scripts/POOL_LIFECYCLE_FIX_SUMMARY.md** (this file)
   - Documentation of changes

## Performance Impact

- **None**: Same pool creation/cleanup behavior, just better organized
- **Memory**: No additional memory overhead
- **Connections**: Same connection pool settings (min_size=2, max_size=5)

## Related Issues

This fix addresses:
- Potential resource leaks from unclosed connection pools
- Code duplication of try/finally blocks
- Improved code maintainability and readability

## References

- Python async context managers: https://docs.python.org/3/reference/datamodel.html#async-context-managers
- asyncpg documentation: https://magicstack.github.io/asyncpg/
- OmniClaude configuration: `/Volumes/PRO-G40/Code/omniclaude/CLAUDE.md` <!-- local-path-ok -->
