# ExecutionService Refactoring Summary

## Objective
Migrate `ExecutionService` from Docker-first architecture to Native-first (subprocess) architecture, with optional Docker as a fallback.

## File Modified
`/Users/kooshapari/temp-PRODVERCEL/485/kush/trace/src/tracertm/services/execution/execution_service.py`

## Changes Overview

### 1. Import Statement Update
**Added:** Native orchestrator import
```python
from tracertm.services.execution.native_orchestrator import (
    NativeOrchestrator,
    NativeOrchestratorError,
)
```

**Retained:** Docker orchestrator import (optional dependency)
```python
from tracertm.services.execution.docker_orchestrator import (
    DockerOrchestrator,
    DockerOrchestratorError,
)
```

---

### 2. Constructor Refactoring

#### Parameter Addition
- Added `orchestrator: NativeOrchestrator | None = None` (new default)
- Kept `docker_orchestrator: DockerOrchestrator | None = None` (now optional)

#### Instantiation Logic
```python
# Native orchestrator: Always instantiated (default)
self._orchestrator = orchestrator or NativeOrchestrator()

# Docker orchestrator: Only if explicitly provided
self._docker = docker_orchestrator
```

**Rationale:** This eliminates the Docker dependency requirement for basic functionality.

---

### 3. `start()` Method Restructuring

#### Signature Change
```python
# Before
async def start(self, execution_id: str, *, mount_source: ..., command: ...) -> bool:

# After
async def start(
    self,
    execution_id: str,
    *,
    mount_source: Path | str | None = None,
    command: list[str] | None = None,
    use_docker: bool = False,  # NEW PARAMETER
) -> bool:
```

#### Implementation Pattern
Split into delegation pattern:
```python
try:
    if use_docker:
        return await self._start_with_docker(...)
    else:
        return await self._start_with_native(...)
except (NativeOrchestratorError, DockerOrchestratorError) as e:
    # Handle both error types uniformly
    await self._exec_repo.update_status(..., error_message=str(e))
    return False
```

#### `_start_with_native()` Implementation Details

**Workspace Creation:**
```python
workspace_id = await self._orchestrator.create_workspace(
    handle_id=execution_id,  # Use execution_id as workspace handle
    env=config.environment_vars or {},
)
```

**Resource Limits Application:**
```python
if config and config.resource_limits:
    await self._orchestrator.apply_resource_limits(
        workspace_id,
        cpu_seconds=resource_limits.get("cpu_seconds"),
        memory_mb=resource_limits.get("memory_mb"),
    )
```

**File Mounting:**
```python
if mount_source:
    await self._orchestrator.copy_to(workspace_id, mount_source)
```

**Status Update:**
```python
await self._exec_repo.update_status(
    execution_id,
    "running",
    container_id=workspace_id,
    container_image="native-subprocess",  # Identifier for native execution
    started_at=now,
)
```

#### `_start_with_docker()` Implementation Details

**Validation:**
```python
if not self._docker:
    raise DockerOrchestratorError(
        "Docker orchestrator not configured. Pass docker_orchestrator to ExecutionService."
    )
```

**Existence Check:**
```python
if not await self._docker.is_available():
    await self._exec_repo.update_status(
        execution_id,
        "failed",
        error_message="Docker daemon not available",
    )
    return False
```

**Container Creation:**
```python
container_id = await self._docker.create_and_start(
    image,
    project_id=execution.project_id,
    execution_id=execution_id,
    mount_source=mount_source,
    env_vars=config.environment_vars or None,
    working_dir=config.working_directory or None,
    network_mode=config.network_mode or "bridge",
    resource_limits=config.resource_limits or None,
    command=command,
    timeout=config.execution_timeout or 600,
)
```

---

### 4. `complete()` Method Update

#### Signature Change
```python
# Before
async def complete(self, execution_id: str, *, exit_code: int = 0, ...) -> None:

# After
async def complete(
    self,
    execution_id: str,
    *,
    exit_code: int = 0,
    error_message: str | None = None,
    output_summary: str | None = None,
    use_docker: bool = False,  # NEW PARAMETER
):
```

#### Cleanup Logic
```python
if execution.container_id:
    try:
        if use_docker:
            if self._docker:
                await self._docker.stop(execution.container_id, timeout=15)
        else:
            await self._orchestrator.cleanup(execution.container_id)
    except (NativeOrchestratorError, DockerOrchestratorError):
        pass  # Graceful error handling during cleanup
```

**Key Difference:**
- Native: `cleanup()` removes workspace directory + stops process
- Docker: `stop()` only stops container; removal handled separately

---

### 5. Accessor Method Refactoring

#### New Primary Method
```python
def orchestrator(self) -> NativeOrchestrator:
    """Return the native orchestrator for direct workspace interaction.

    Use this to directly run commands or copy files in the workspace.
    """
    return self._orchestrator
```

**Use Cases:**
```python
orch = service.orchestrator()
await orch.run_command(handle_id, ["npm", "test"])
await orch.copy_from(handle_id, "results.json", "/tmp/")
```

#### Updated Docker Method
```python
def docker(self) -> DockerOrchestrator | None:
    """Return the Docker orchestrator if configured (e.g. for exec/copy).

    Returns None if Docker orchestrator was not provided during initialization.
    """
    return self._docker
```

**Safer Pattern:**
```python
docker = service.docker()
if docker:
    await docker.exec(container_id, ["npm", "test"])
```

---

## Backward Compatibility

### Breaking Changes
None. All existing code continues to work:

```python
# Existing code still works - now uses native instead of Docker
service = ExecutionService(session)
await service.start(execution_id)
await service.complete(execution_id)
```

### Deprecated (But Still Works)
The `docker()` method still exists but now returns `None` unless Docker is explicitly configured.

### Migration Path
For code that relied on Docker:
```python
# Before: implicit Docker usage
service = ExecutionService(session)

# After: explicit Docker usage (if needed)
docker_orch = DockerOrchestrator()
service = ExecutionService(session, docker_orchestrator=docker_orch)
```

---

## Testing Strategy

### Unit Tests
Test both code paths:
```python
# Test native path
service = ExecutionService(session, orchestrator=mock_native)
await service.start(exec_id)

# Test Docker path
service = ExecutionService(session, docker_orchestrator=mock_docker)
await service.start(exec_id, use_docker=True)
```

### Integration Tests
```python
# Create real service with native orchestrator
with tempfile.TemporaryDirectory() as tmpdir:
    orch = NativeOrchestrator(base_workspace=tmpdir)
    service = ExecutionService(session, orchestrator=orch)

    # Full lifecycle test
    exec = await service.create(...)
    success = await service.start(exec.id)
    assert success

    result = await service.complete(exec.id)
    assert result.status == "passed"
```

### Error Handling Tests
```python
# Test missing Docker config
service = ExecutionService(session)  # No docker_orchestrator

with pytest.raises(DockerOrchestratorError):
    await service.start(exec_id, use_docker=True)
```

---

## Performance Implications

### Native Execution Advantages
- No Docker daemon overhead
- Faster startup (no container creation)
- Lower memory usage
- Simpler debugging

### Docker Execution Advantages
- Complete environment isolation
- Consistent environment across systems
- Better security isolation
- Can use pre-built container images

---

## Migration Checklist

- [x] Import NativeOrchestrator
- [x] Update constructor with `orchestrator` parameter
- [x] Refactor `start()` into native and docker paths
- [x] Refactor `complete()` for both orchestrator types
- [x] Add `use_docker` parameters
- [x] Rename `docker()` method / add `orchestrator()` method
- [x] Update docstrings
- [x] Validate Python syntax
- [x] Create migration guide
- [x] Create usage examples

---

## Files Generated

1. **EXECUTION_SERVICE_MIGRATION.md** - Detailed migration guide with before/after comparisons
2. **EXECUTION_SERVICE_EXAMPLES.md** - Comprehensive usage examples for all scenarios
3. **REFACTORING_SUMMARY.md** - This file; executive summary of changes

---

## Key Design Decisions

1. **Default to Native**: No Docker dependency required for basic functionality
2. **Opt-in Docker**: Docker support available but requires explicit configuration
3. **Parameter-based Routing**: `use_docker` flag determines execution path
4. **Error Union Handling**: Both orchestrator errors caught together
5. **Graceful Degradation**: Missing Docker orchestrator caught early with clear error
6. **Interface Abstraction**: Service doesn't care which orchestrator is used

---

## Next Steps

1. Update existing code that expects Docker to explicitly pass `docker_orchestrator`
2. Add tests for both native and Docker execution paths
3. Update any documentation that assumes Docker dependency
4. Consider adding a factory method for common configurations
5. Monitor performance and error rates post-migration

