init

Author: markwallsgrove

.gitignore

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+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+env/
+venv/
+node_modules/
+.env
+.venv
+*.log
+.DS_Store
+dist/
+build/
+*.egg-info/
+.pytest_cache/
+.coverage
+htmlcov/
+frontend/build/

README.md

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+# Lab Automation System - Technical Exercise
+
+## Overview
+
+Welcome to the Lab Automation System technical exercise! This is a microservice-based application for managing laboratory workflows and devices. Your task is to debug existing issues and implement a new feature.
+
+**Time allocation: 60-90 minutes**
+
+## System Architecture
+
+The system consists of:
+
+- **Frontend**: React application (port 3000)
+- **Backend Microservices**:
+  - `workflow-service`: Manages automation workflows (port 5003)
+  - `device-service`: Controls lab equipment (port 5001)
+  - `sample-service`: Tracks samples (port 5002)
+- **Infrastructure**: Redis for caching and state management
+
+## Getting Started
+
+### Prerequisites
+
+- Docker and Docker Compose
+- Git
+
+### Setup
+
+1. Clone this repository (if not already done)
+2. Navigate to the project directory
+3. Start the system:
+
+```bash
+docker-compose up --build
+```
+
+4. Access the application:
+   - Frontend: http://localhost:3000
+   - Workflow Service: http://localhost:5003
+   - Device Service: http://localhost:5001
+   - Sample Service: http://localhost:5002
+
+## Exercise Structure
+
+This exercise is divided into two phases:
+
+### Phase 1: Debugging (30-40 minutes)
+
+The system currently has several bugs that prevent it from working correctly. Your task is to identify and fix them.
+
+**Scenario**: A lab technician reports that they cannot start workflows. The system appears to have multiple issues.
+
+**Known Issues**:
+1. One or more services fail to start
+2. Workflows cannot be started successfully
+3. Device status display is incorrect
+4. System has race conditions under concurrent load
+
+**Your Tasks**:
+- Get all services running correctly
+- Enable workflows to be created and started successfully
+- Ensure device status updates correctly in the UI
+- Identify and fix the race condition in device booking
+
+**Tips**:
+- Check service logs: `docker-compose logs [service-name]`
+- Use browser DevTools to inspect API calls
+- Test the system end-to-end after each fix
+
+### Phase 2: Feature Implementation (30-50 minutes)
+
+Implement a **Workflow Pause/Resume** feature that allows users to pause running workflows and resume them later.
+
+**Requirements**:
+
+**Backend** (`workflow-service`):
+- Add `POST /workflows/<workflow_id>/pause` endpoint
+  - Should release the device (but mark it as resumable)
+  - Update workflow status to "paused"
+  - Store any necessary state for resuming
+- Add `POST /workflows/<workflow_id>/resume` endpoint
+  - Should re-book the device
+  - Update workflow status back to "running"
+  - Handle errors gracefully (e.g., device no longer available)
+
+**Frontend**:
+- Add "Pause" button for workflows with status "running"
+- Add "Resume" button for workflows with status "paused"
+- Handle loading and error states appropriately
+- Update the UI to distinguish paused workflows visually
+
+**Integration**:
+- Ensure device status updates correctly when paused/resumed
+- Test the complete flow: create → start → pause → resume → complete
+
+## Evaluation Criteria
+
+We're looking for:
+
+✅ **System Understanding**: Can you trace requests across services? Do you understand the architecture?
+
+✅ **Debugging Skills**: Do you use a methodical approach? Check logs? Use appropriate debugging tools?
+
+✅ **Full-Stack Competency**: Are you comfortable working across React and Python? Can you switch contexts effectively?
+
+✅ **Problem-Solving**: When you don't know something, do you know how to find the answer?
+
+✅ **Code Quality**: Is your implementation clean, well-structured, and maintainable?
+
+✅ **Communication**: Do you explain your thought process? Ask clarifying questions?
+
+## Useful Commands
+
+```bash
+# View logs for all services
+docker-compose logs -f
+
+# View logs for specific service
+docker-compose logs -f workflow-service
+
+# Restart a specific service
+docker-compose restart workflow-service
+
+# Rebuild and restart
+docker-compose up --build
+
+# Stop all services
+docker-compose down
+
+# Check if services are healthy
+curl http://localhost:5001/health
+curl http://localhost:5002/health
+curl http://localhost:5003/health
+```
+
+## API Documentation
+
+### Workflow Service
+
+- `GET /workflows` - List all workflows
+- `POST /workflows` - Create workflow
+  ```json
+  {
+    "name": "PCR Setup",
+    "device_id": "liquid-handler-1",
+    "sample_barcodes": ["SAMPLE001"],
+    "steps": ["Aspirate 10uL", "Dispense to A1"]
+  }
+  ```
+- `POST /workflows/<id>/start` - Start workflow
+- `POST /workflows/<id>/complete` - Complete workflow
+
+### Device Service
+
+- `GET /devices` - List all devices
+- `GET /devices/<id>` - Get device details
+- `POST /devices/<id>/book` - Book device for workflow
+- `POST /devices/<id>/release` - Release device
+
+### Sample Service
+
+- `GET /samples` - List all samples
+- `GET /samples/<barcode>` - Get sample details
+- `POST /samples/validate` - Validate sample barcodes
+
+## Questions?
+
+Feel free to ask questions at any time! We're interested in how you approach problems and work through challenges, not just whether you can find all the bugs immediately.
+
+Good luck! 🚀