Persona MCP

# Engineering Experts - Deep Knowledge Base ## Fullstack Developer (101) ### Core Competencies - End-to-end application development - Frontend: React, Vue, Angular, Next.js - Backend: Node.js, Python, Go, Java - Databases: PostgreSQL, MongoDB, Redis - APIs: REST, GraphQL, gRPC - Cloud: Major cloud platforms ### Architecture Patterns **Monolith to Microservices Decision Matrix:** | Factor | Monolith | Microservices | |--------|----------|---------------| | Team size | <10 | 10+ | | Deployment freq | Monthly | Daily/hourly | | Scaling needs | Uniform | Independent | | Tech diversity | Single stack | Polyglot | **Recommended Pattern by Stage:** - MVP: Modular Monolith - Growth: Service-Oriented Architecture - Scale: Microservices with Service Mesh ### Code Example: Express API with Auth ```javascript // server.js - Production-ready Express API const express = require('express'); const helmet = require('helmet'); const cors = require('cors'); const rateLimit = require('express-rate-limit'); const { body, validationResult } = require('express-validator'); const app = express(); // Security middleware app.use(helmet()); app.use(cors({ origin: process.env.ALLOWED_ORIGINS?.split(',') })); app.use(express.json({ limit: '10kb' })); // Rate limiting const limiter = rateLimit({ windowMs: 15 * 60 * 1000, // 15 minutes max: 100, standardHeaders: true, legacyHeaders: false, }); app.use('/api/', limiter); // Authentication middleware const authenticate = async (req, res, next) => { const token = req.headers.authorization?.split(' ')[1]; if (!token) { return res.status(401).json({ error: 'Authentication required' }); } try { const decoded = await verifyToken(token); req.user = decoded; next(); } catch (error) { return res.status(401).json({ error: 'Invalid token' }); } }; // Route with validation app.post('/api/users', authenticate, [ body('email').isEmail().normalizeEmail(), body('name').trim().isLength({ min: 2, max: 100 }), ], async (req, res) => { const errors = validationResult(req); if (!errors.isEmpty()) { return res.status(400).json({ errors: errors.array() }); } // ... create user logic } ); // Global error handler app.use((err, req, res, next) => { console.error(err.stack); res.status(500).json({ error: 'Internal server error' }); }); module.exports = app; ``` --- ## DevOps Engineer (110) ### CI/CD Pipeline Best Practices **Pipeline Stages:** ``` Build → Test → Security Scan → Deploy Staging → Integration Test → Deploy Prod ``` **Deployment Strategies:** | Strategy | Zero Downtime | Rollback Speed | Resource Cost | |----------|---------------|----------------|---------------| | Rolling | Yes | Medium | Low | | Blue/Green | Yes | Instant | 2x | | Canary | Yes | Fast | Low | | A/B Testing | Yes | Fast | Low | ### Kubernetes Deployment Example ```yaml # deployment.yaml apiVersion: apps/v1 kind: Deployment metadata: name: api-server labels: app: api-server spec: replicas: 3 strategy: type: RollingUpdate rollingUpdate: maxSurge: 1 maxUnavailable: 0 selector: matchLabels: app: api-server template: metadata: labels: app: api-server spec: containers: - name: api image: myapp/api:v1.2.3 ports: - containerPort: 3000 resources: requests: memory: "256Mi" cpu: "250m" limits: memory: "512Mi" cpu: "500m" livenessProbe: httpGet: path: /health port: 3000 initialDelaySeconds: 10 periodSeconds: 10 readinessProbe: httpGet: path: /ready port: 3000 initialDelaySeconds: 5 periodSeconds: 5 env: - name: NODE_ENV value: "production" - name: DATABASE_URL valueFrom: secretKeyRef: name: api-secrets key: database-url ``` ### CI/CD Workflow Example ```yaml # .ci/workflows/deploy.yml name: CI/CD Pipeline on: push: branches: [main] pull_request: branches: [main] jobs: test: runs-on: ubuntu-latest steps: - uses: actions/checkout@v4 - uses: actions/setup-node@v4 with: node-version: '20' cache: 'npm' - run: npm ci - run: npm test - run: npm run lint security: runs-on: ubuntu-latest needs: test steps: - uses: actions/checkout@v4 - name: Run Snyk uses: snyk/actions/node@master env: SNYK_TOKEN: ${{ secrets.SNYK_TOKEN }} deploy: runs-on: ubuntu-latest needs: [test, security] if: github.ref == 'refs/heads/main' steps: - uses: actions/checkout@v4 - name: Deploy to production run: | # Deploy logic here ``` --- ## Security Engineer (113) ### OWASP Top 10 Prevention | Vulnerability | Prevention | |---------------|------------| | Injection | Parameterized queries, input validation | | Broken Auth | MFA, secure session management | | Sensitive Data Exposure | Encryption at rest/transit | | XXE | Disable DTDs, use JSON | | Broken Access Control | RBAC, deny by default | | Security Misconfiguration | Hardening, patch management | | XSS | Output encoding, CSP headers | | Insecure Deserialization | Validate before deserialize | | Vulnerable Components | Dependency scanning, updates | | Insufficient Logging | Centralized logging, alerting | ### Security Headers Configuration ```javascript // Express security headers const helmet = require('helmet'); app.use(helmet({ contentSecurityPolicy: { directives: { defaultSrc: ["'self'"], scriptSrc: ["'self'", "'unsafe-inline'"], styleSrc: ["'self'", "'unsafe-inline'"], imgSrc: ["'self'", "data:", "https:"], connectSrc: ["'self'", "https://api.example.com"], fontSrc: ["'self'"], objectSrc: ["'none'"], mediaSrc: ["'self'"], frameSrc: ["'none'"], }, }, hsts: { maxAge: 31536000, includeSubDomains: true, preload: true }, referrerPolicy: { policy: 'strict-origin-when-cross-origin' } })); ``` --- ## Database Engineer (114) ### Query Optimization Patterns **Index Strategy:** ```sql -- Composite index for common query patterns CREATE INDEX idx_orders_user_date ON orders(user_id, created_at DESC); -- Partial index for filtered queries CREATE INDEX idx_active_users ON users(email) WHERE status = 'active'; -- Include columns to avoid table lookup CREATE INDEX idx_orders_covering ON orders(user_id) INCLUDE (total, status); ``` **Query Optimization Checklist:** 1. [ ] EXPLAIN ANALYZE the query 2. [ ] Check index usage 3. [ ] Avoid SELECT * 4. [ ] Use appropriate JOINs 5. [ ] Consider query caching 6. [ ] Partition large tables 7. [ ] Use connection pooling ### PostgreSQL Performance Tuning ```sql -- Configuration for 16GB RAM server ALTER SYSTEM SET shared_buffers = '4GB'; ALTER SYSTEM SET effective_cache_size = '12GB'; ALTER SYSTEM SET maintenance_work_mem = '1GB'; ALTER SYSTEM SET work_mem = '256MB'; ALTER SYSTEM SET random_page_cost = 1.1; -- SSD ALTER SYSTEM SET effective_io_concurrency = 200; -- SSD ALTER SYSTEM SET max_connections = 200; ALTER SYSTEM SET max_parallel_workers_per_gather = 4; ``` --- ## Expert Activation ``` @fullstack-developer @devops-engineer @security-engineer @database-engineer ``` or describe your technical challenge