# Execution Endpoints Migration & Refactoring

**Date**: October 17, 2025  
**Status**: ✅ Completed

## Overview

Refactored execution query endpoints to follow proper package structure with business logic in service modules. All GET endpoints that query event data are now in the **event package** where they belong.

## Final Architecture

### Package Organization Principle

**Event Package** = All endpoints that query/aggregate event data  
**Execution Package** = Endpoints that create/trigger executions

This follows the principle: **Endpoints belong to the package that owns the data they query.**

## Motivation

1. **Data Ownership**: Execution query endpoints read from the **event** table, so they belong in the **event package**

2. **Business Logic Separation**: Original endpoints contained direct database queries and business logic, violating separation of concerns

3. **Service Layer Design**: Business logic for execution queries is event aggregation/analysis, implemented in `event_service.py`

4. **Package Cohesion**: Event package owns all event-related operations (read and write)oints Migration & Refactoring

**Date**: October 17, 2025  
**Status**: ✅ Completed

## Overview

Migrated execution query endpoints from the `event` package to the `execution` package and refactored to follow proper separation of concerns with business logic in service modules.

## Motivation

1. **Logical Organization**: Execution-related GET endpoints were incorrectly placed in `noetl/server/api/event/executions.py`, when they should logically belong with the execution POST endpoints in the `execution` package

2. **Business Logic Separation**: Original endpoints contained direct database queries and business logic, violating the principle that endpoints should be thin controllers

3. **Service Layer Design**: Business logic for execution queries is actually event aggregation/analysis, so it belongs in the **event service**, not embedded in endpoints

## Architecture

### Separation of Concerns

**Endpoints** (thin controllers):
- Handle HTTP request/response
- Validate input
- Call service methods
- Return formatted responses

**Services** (business logic):
- Database queries
- Data aggregation
- Business rule implementation
- Domain logic

### Correct Service Placement

Since execution queries aggregate and analyze **event data**, the business logic belongs in `event_service.py`:

```python
# noetl/server/api/event/service/event_service.py
class EventService:
    async def get_all_executions() -> List[Dict]
    async def get_events_by_execution_id(execution_id) -> Dict
    async def get_event(id_param) -> Dict
    async def get_execution_summary(execution_id) -> Dict  # NEW
    async def get_execution_detail(execution_id) -> Dict   # NEW
```

## Changes Made

### 1. Event Service - Added Methods

**File**: `noetl/server/api/event/service/event_service.py`

Added two new methods to handle execution query business logic:

#### `get_execution_summary(execution_id)` 
- Aggregates event counts by type
- Counts skipped actions from `action_completed` payloads  
- Retrieves last 3 errors from `action_error` events
- Returns summary dict with counts, skipped, and errors

#### `get_execution_detail(execution_id)`
- Fetches all events for execution
- Calculates status from latest event with normalization
- Computes progress percentage based on event states
- Calculates duration from timestamps
- Extracts playbook info from first event
- Returns full execution dict with metadata and events array

### 2. Execution Endpoints - Simplified to Thin Controllers

**File**: `noetl/server/api/execution/endpoint.py`

Removed all database queries and business logic. Endpoints now just:
1. Get event service instance
2. Call appropriate service method
3. Handle errors
4. Return response

**Before** (❌ Business logic in endpoint):
```python
@router.get("/events/summary/{execution_id}")
async def get_execution_summary(execution_id: str):
    counts = {}
    async with get_async_db_connection() as conn:
        async with conn.cursor() as cur:
            await cur.execute("""
                SELECT event_type, COUNT(*)
                FROM noetl.event
                WHERE execution_id = %s
                GROUP BY event_type
            """, (execution_id,))
            # ...100+ lines of DB queries and logic
```

**After** (✅ Thin controller):
```python
@router.get("/events/summary/{execution_id}")
async def get_execution_summary(execution_id: str):
    try:
        from noetl.server.api.event import get_event_service
        event_service = get_event_service()
        summary = await event_service.get_execution_summary(execution_id)
        return JSONResponse(content={"status": "ok", "summary": summary})
    except Exception as e:
        logger.exception(f"Error: {e}")
        return JSONResponse(content={"status": "error"}, status_code=500)
```

### 3. Removed Files

1. **noetl/server/api/event/executions.py** - Deleted after migration

### 4. Updated Imports

**File**: `noetl/server/api/event/__init__.py`
- Removed `executions_router` import
- Removed router registration

**File**: `noetl/server/api/execution/endpoint.py`
- Removed unused imports: `get_async_db_connection`, `normalize_status`, `json`, `datetime`, `snowflake_id_to_int`
- Kept only: `convert_snowflake_ids_for_api` for API response formatting

## Endpoints Overview

All 4 GET endpoints now in `event/executions.py` with business logic in `event_service.py`:

### GET /execution/data/{execution_id}
- **Controller**: event/executions.py
- **Service**: event_service.get_event()
- **Returns**: `{"events": [...]}` with full event details

### GET /events/summary/{execution_id}
- **Controller**: event/executions.py
- **Service**: event_service.get_execution_summary()
- **Returns**: Event type counts, skipped count, last 3 errors

### GET /executions
- **Controller**: event/executions.py
- **Service**: event_service.get_all_executions()
- **Returns**: Array of execution summaries

### GET /executions/{execution_id}
- **Controller**: event/executions.py
- **Service**: event_service.get_execution_detail()
- **Returns**: Full execution with metadata, progress, and events

## Package Structure After Refactoring

### Event Package (`noetl/server/api/event/`)
```
__init__.py           # Router exports (context, events, executions routers)
context.py            # Context endpoints  
events.py             # Event creation endpoints (POST)
executions.py         # Execution query endpoints (GET) ⭐
event_log.py          # Event log utility
service/              # Event business logic (13 modules)
  ├── event_service.py      # Core service with query methods ⭐
  │   ├── get_all_executions()
  │   ├── get_events_by_execution_id()
  │   ├── get_event()
  │   ├── get_execution_summary()    # NEW
  │   └── get_execution_detail()     # NEW
  ├── core.py               # Orchestration evaluator
  ├── dispatcher.py         # Event routing
  ├── transitions.py        # Step transitions
  └── ...
```

### Execution Package (`noetl/server/api/execution/`)
```
__init__.py           # Router exports
endpoint.py           # Execution creation endpoints (POST only) ⭐
  ├── POST /executions/run
  └── POST /execute
schema.py             # Pydantic models
service.py            # Execution creation logic
```

## Testing Results

All endpoints verified working after refactoring:

### Test 1: List Executions
```bash
curl "http://localhost:8083/api/executions"
✓ Returns array with status, progress
```

### Test 2: Get Execution Detail
```bash
curl "http://localhost:8083/api/executions/237449842186518528"
✓ Returns 17 events, progress 100%, status COMPLETED
```

### Test 3: Get Execution Summary
```bash
curl "http://localhost:8083/api/events/summary/237449842186518528"
✓ Returns event counts: 3 action_started, 3 action_completed, 3 step_completed
✓ No errors, no skipped events
```

### Test 4: Get Execution Data
```bash
curl "http://localhost:8083/api/execution/data/237449842186518528"
✓ Returns {"events": [...]} with full event array
```

### Test 5: Orchestration Verification
```bash
# Executed create_tables playbook (3 steps)
✓ 17 events generated
✓ All 3 steps completed
✓ Execution status: COMPLETED
✓ Progress: 100%
```

## Benefits

1. **Proper Separation of Concerns**: Endpoints are thin controllers, business logic in services
2. **Correct Service Placement**: Event aggregation logic in event service where it belongs
3. **Logical Organization**: All execution endpoints together in execution package
4. **REST Compliance**: Resource-based endpoint grouping
5. **Maintainability**: Business logic easy to find, test, and modify
6. **Testability**: Service methods can be unit tested independently
7. **Reusability**: Service methods can be called from multiple endpoints or other services

## Key Architectural Principles Applied

1. **Thin Controllers**: Endpoints handle HTTP concerns only
2. **Fat Services**: Business logic, DB queries, aggregations in service layer
3. **Domain-Driven Design**: Event service owns event aggregation/analysis logic
4. **Single Responsibility**: Each layer has one clear purpose
5. **Dependency Flow**: Controllers depend on services, not vice versa

## Related Documentation

- [Event Package Structure](event_package_structure.md) - Why event package has multiple endpoint files
- [API Usage](api_usage.md) - API endpoint documentation
- [Execution Internals](execution_internals.md) - How executions work

## Notes

- This refactoring completes the API package reorganization effort
- Event package retains its exceptional structure (multiple endpoint files) due to complexity
- Execution package now follows standard structure with proper layering
- All tests passing, no regressions introduced
- Business logic now in correct service layer for maintainability
