MCP Brain Service

# DELETE Endpoint 405 Error - Root Cause Analysis & Fix **Date**: October 4, 2025 **Issue**: DELETE /api/v1/nodes/{node_id} returning 405 Method Not Allowed **Status**: ✅ **RESOLVED** --- ## 🐛 Problem Summary The Brain API at `https://brain.ft.tc` was returning `405 Method Not Allowed` when attempting to delete nodes via the DELETE endpoint, despite the endpoint being properly implemented in the code. ### Symptoms - DELETE requests returned: `405 Method Not Allowed` - Response header showed: `allow: GET` (only GET method allowed) - GET requests to the same endpoint worked fine - Code inspection showed DELETE route was properly defined ### Test Case ```bash curl -X DELETE "https://brain.ft.tc/api/v1/nodes/68e0e835a74df94e04112dd0?project_id=68df4dab400c86a6a8cf40c6" \ -H "Authorization: Bearer YOUR_API_KEY" \ -v ``` **Expected**: 200 OK or 404 Not Found **Actual**: 405 Method Not Allowed --- ## 🔍 Root Cause Analysis ### Investigation Steps 1. **Code Verification** ✅ - Confirmed DELETE endpoint exists in `src/api_routes.py` (line 200) - Route properly decorated with `@router.delete("/nodes/{node_id}")` - Response model and authentication properly configured 2. **Route Registration** ✅ - Verified routes are registered in FastAPI app - Both DELETE and GET routes present for `/api/v1/nodes/{node_id}` - Route matching test confirmed DELETE method matches correctly 3. **Service Status** ❌ **ISSUE FOUND** - Discovered TWO Python processes running: - PID 37546: Old uvicorn process from 06:33 (running OLD code) - PID 52893: PM2 managed process from 12:27 (failing to start) 4. **Port Conflict** ❌ **ISSUE FOUND** - Old process was bound to port 8002 - New process couldn't start due to "Address already in use" - PM2 auto-reload was broken 5. **Environment Variables** ❌ **ISSUE FOUND** - PM2 configuration didn't load `.env` file - Service failed to start due to missing NEO4J_URI, JINA_API_KEY - Old process continued serving requests with outdated code ### Root Cause **The production service was running an OLD version of the code that didn't include the DELETE endpoint implementation.** The issue was caused by: 1. PM2 configuration not loading environment variables from `.env` file 2. Service failing to start properly, leaving old process running 3. Auto-reload mechanism broken due to port conflict 4. Old uvicorn process (started manually) still serving requests --- ## ✅ Solution ### Fix Applied 1. **Updated PM2 Configuration** (`ecosystem.config.js`) - Changed from direct Python execution to using `start.sh` script - `start.sh` properly loads `.env` file before starting service **Before**: ```javascript script: 'venv/bin/python', args: '-m src.main', interpreter: 'none', ``` **After**: ```javascript script: 'start.sh', interpreter: 'bash', ``` 2. **Killed Old Process** - Terminated stale uvicorn process (PID 37546) - Cleared port 8002 for proper service startup 3. **Restarted Service** ```bash pm2 delete mcp-brain-service pm2 start ecosystem.config.js pm2 save ``` ### Verification ✅ **Local Test**: ```bash curl -X DELETE "http://127.0.0.1:8002/api/v1/nodes/test-node?project_id=test-project" \ -H "Authorization: Bearer YOUR_API_KEY" ``` Response: `404 Not Found` (correct - node doesn't exist) ✅ **Production Test**: ```bash curl -X DELETE "https://brain.ft.tc/api/v1/nodes/test-node?project_id=test-project" \ -H "Authorization: Bearer YOUR_API_KEY" ``` Response: `404 Not Found` (correct - node doesn't exist) ✅ **Health Check**: ```bash curl https://brain.ft.tc/health ``` Response: `200 OK` - All components healthy --- ## 📝 Answers to Original Questions ### 1. Is the DELETE endpoint implemented? **YES** ✅ - The endpoint is fully implemented in `src/api_routes.py` (lines 200-274) ### 2. Is there an alternative bulk delete endpoint? **NO** ❌ - Currently only single node deletion is supported. For bulk operations, you need to: - Loop through nodes and delete individually - OR implement a new bulk delete endpoint (feature request) ### 3. Should we use a different endpoint? **NO** ❌ - The current endpoint is correct: `DELETE /api/v1/nodes/{node_id}?project_id={project_id}` ### 4. Authentication issue? **NO** ❌ - The 405 error was not related to authentication. It was caused by the service running old code without the DELETE endpoint. --- ## 🚀 Current Status ### Service Information - **Status**: ✅ Online and Healthy - **Port**: 8002 - **Domain**: https://brain.ft.tc - **PM2 Process**: mcp-brain-service (ID: 7) - **Environment**: Production with proper .env loading ### DELETE Endpoint - **Status**: ✅ **WORKING** - **Endpoint**: `DELETE /api/v1/nodes/{node_id}` - **Query Params**: `project_id` (required) - **Authentication**: Bearer token required - **Response Codes**: - `200 OK`: Node deleted successfully - `404 Not Found`: Node doesn't exist - `401 Unauthorized`: Invalid/missing API key - `500 Internal Server Error`: Server error ### Example Usage ```bash # Delete a node curl -X DELETE "https://brain.ft.tc/api/v1/nodes/NODE_ID?project_id=PROJECT_ID" \ -H "Authorization: Bearer YOUR_API_KEY" # Success response (200 OK) { "status": "success", "message": "Node deleted successfully", "deleted_count": 1, "node_id": "NODE_ID" } # Not found response (404) { "detail": { "error": "node_not_found", "message": "Node with ID 'NODE_ID' not found in project 'PROJECT_ID'", "details": { "node_id": "NODE_ID", "project_id": "PROJECT_ID" } } } ``` --- ## 🔧 Prevention Measures ### Recommendations 1. **Always use PM2 for process management** - Don't start services manually with uvicorn - Use `pm2 start ecosystem.config.js` - Use `pm2 restart mcp-brain-service` for updates 2. **Verify service status after deployment** ```bash pm2 list pm2 logs mcp-brain-service --lines 50 curl http://localhost:8002/health ``` 3. **Check for duplicate processes** ```bash ps aux | grep "python.*src.main" netstat -tlnp | grep 8002 ``` 4. **Monitor PM2 logs for startup errors** ```bash pm2 logs mcp-brain-service --err --lines 100 ``` 5. **Test endpoints after deployment** - Run test suite: `./test_deletion_features.sh` - Verify all HTTP methods work - Check OpenAPI docs: https://brain.ft.tc/docs --- ## 📚 Related Documentation - **API Documentation**: `docs/mcp-brain-service/how-to-use.md` - **Deletion Features**: `docs/DELETION_AND_VALIDATION.md` - **Deployment Guide**: `docs/DEPLOYMENT_GUIDE.md` - **Test Script**: `test_deletion_features.sh` --- ## ✅ Resolution Checklist - [x] Identified root cause (old process running) - [x] Fixed PM2 configuration to load .env - [x] Killed stale processes - [x] Restarted service with proper configuration - [x] Verified DELETE endpoint works locally - [x] Verified DELETE endpoint works in production - [x] Saved PM2 configuration - [x] Documented issue and resolution - [x] Tested with actual node IDs from issue report --- **Issue Status**: ✅ **RESOLVED** **Service Status**: ✅ **HEALTHY** **DELETE Endpoint**: ✅ **WORKING**