Maintenance and Updates

Comprehensive guide for maintaining mini programs, including update strategies, version management, performance optimization, and long-term sustainability practices.

Maintenance Strategy

Maintenance Planning

• Preventive Maintenance: Proactive measures to prevent issues
• Corrective Maintenance: Fixing identified problems and bugs
• Adaptive Maintenance: Updates for changing requirements
• Perfective Maintenance: Performance and feature improvements

Maintenance Schedule

• Daily: Monitoring, log review, critical issue response
• Weekly: Performance analysis, security updates, minor fixes
• Monthly: Feature updates, dependency updates, comprehensive testing
• Quarterly: Major updates, architecture review, capacity planning

Version Management

Semantic Versioning

// Version management implementation
class VersionManager {
  constructor() {
    this.currentVersion = this.getCurrentVersion();
    this.versionHistory = new Map();
    this.updateStrategies = new Map();
  }
  
  createVersion(type, changes = []) {
    const currentVersion = this.parseVersion(this.currentVersion);
    let newVersion;
    
    switch (type) {
      case 'major':
        newVersion = `${currentVersion.major + 1}.0.0`;
        break;
      case 'minor':
        newVersion = `${currentVersion.major}.${currentVersion.minor + 1}.0`;
        break;
      case 'patch':
        newVersion = `${currentVersion.major}.${currentVersion.minor}.${currentVersion.patch + 1}`;
        break;
      default:
        throw new Error('Invalid version type');
    }
    
    const versionInfo = {
      version: newVersion,
      type: type,
      changes: changes,
      releaseDate: new Date().toISOString(),
      previousVersion: this.currentVersion,
      compatibility: this.checkCompatibility(type),
      rollbackPlan: this.createRollbackPlan()
    };
    
    this.versionHistory.set(newVersion, versionInfo);
    return versionInfo;
  }
  
  checkCompatibility(versionType) {
    return {
      backwardCompatible: versionType !== 'major',
      forwardCompatible: false,
      migrationRequired: versionType === 'major',
      deprecatedFeatures: this.getDeprecatedFeatures()
    };
  }
  
  planUpdate(targetVersion, strategy = 'gradual') {
    const updatePlan = {
      targetVersion: targetVersion,
      strategy: strategy,
      phases: this.createUpdatePhases(strategy),
      rollbackTriggers: this.defineRollbackTriggers(),
      successCriteria: this.defineSuccessCriteria(),
      timeline: this.calculateTimeline(strategy)
    };
    
    this.updateStrategies.set(targetVersion, updatePlan);
    return updatePlan;
  }
}

Update Strategies

// Different update deployment strategies
class UpdateDeployment {
  constructor() {
    this.deploymentStrategies = {
      'blue-green': this.blueGreenDeployment,
      'canary': this.canaryDeployment,
      'rolling': this.rollingDeployment,
      'feature-flag': this.featureFlagDeployment
    };
  }
  
  async blueGreenDeployment(updateConfig) {
    const deployment = {
      id: this.generateDeploymentId(),
      strategy: 'blue-green',
      status: 'preparing',
      startTime: Date.now()
    };
    
    try {
      // Prepare green environment
      deployment.status = 'preparing_green';
      await this.prepareGreenEnvironment(updateConfig);
      
      // Deploy to green
      deployment.status = 'deploying_green';
      await this.deployToGreen(updateConfig);
      
      // Run health checks
      deployment.status = 'health_checking';
      const healthCheck = await this.runHealthChecks('green');
      
      if (!healthCheck.passed) {
        throw new Error('Health checks failed');
      }
      
      // Switch traffic
      deployment.status = 'switching_traffic';
      await this.switchTrafficToGreen();
      
      // Monitor for issues
      deployment.status = 'monitoring';
      await this.monitorDeployment(deployment.id, 300000); // 5 minutes
      
      // Cleanup blue environment
      deployment.status = 'cleanup';
      await this.cleanupBlueEnvironment();
      
      deployment.status = 'completed';
      deployment.endTime = Date.now();
      
      return deployment;
    } catch (error) {
      deployment.status = 'failed';
      deployment.error = error.message;
      
      // Rollback if necessary
      await this.rollbackDeployment(deployment.id);
      
      throw error;
    }
  }
  
  async canaryDeployment(updateConfig) {
    const deployment = {
      id: this.generateDeploymentId(),
      strategy: 'canary',
      status: 'preparing',
      phases: [
        { percentage: 5, duration: 600000 },   // 10 minutes
        { percentage: 25, duration: 1800000 },  // 30 minutes
        { percentage: 50, duration: 3600000 },  // 1 hour
        { percentage: 100, duration: 0 }
      ],
      currentPhase: 0
    };
    
    try {
      for (let i = 0; i < deployment.phases.length; i++) {
        const phase = deployment.phases[i];
        deployment.currentPhase = i;
        deployment.status = `phase_${i + 1}`;
        
        // Deploy to percentage of users
        await this.deployToPercentage(updateConfig, phase.percentage);
        
        // Monitor metrics
        const metrics = await this.monitorPhase(phase.duration);
        
        // Check success criteria
        if (!this.evaluatePhaseSuccess(metrics)) {
          throw new Error(`Phase ${i + 1} failed success criteria`);
        }
        
        // Wait for phase duration (except last phase)
        if (phase.duration > 0) {
          await this.wait(phase.duration);
        }
      }
      
      deployment.status = 'completed';
      deployment.endTime = Date.now();
      
      return deployment;
    } catch (error) {
      deployment.status = 'failed';
      deployment.error = error.message;
      
      await this.rollbackCanaryDeployment(deployment.id);
      throw error;
    }
  }
}

Performance Optimization

Performance Monitoring

// Continuous performance monitoring and optimization
class PerformanceOptimizer {
  constructor() {
    this.performanceBaseline = new Map();
    this.optimizationRules = new Map();
    this.performanceHistory = [];
  }
  
  establishBaseline() {
    const baseline = {
      timestamp: Date.now(),
      metrics: {
        pageLoadTime: this.measurePageLoadTime(),
        apiResponseTime: this.measureAPIResponseTime(),
        memoryUsage: this.measureMemoryUsage(),
        cpuUsage: this.measureCPUUsage(),
        networkLatency: this.measureNetworkLatency()
      },
      userExperience: {
        firstContentfulPaint: this.measureFCP(),
        largestContentfulPaint: this.measureLCP(),
        cumulativeLayoutShift: this.measureCLS(),
        firstInputDelay: this.measureFID()
      }
    };
    
    this.performanceBaseline.set('current', baseline);
    return baseline;
  }
  
  analyzePerformance() {
    const currentMetrics = this.getCurrentMetrics();
    const baseline = this.performanceBaseline.get('current');
    
    const analysis = {
      timestamp: Date.now(),
      comparison: this.compareMetrics(currentMetrics, baseline),
      trends: this.analyzeTrends(),
      bottlenecks: this.identifyBottlenecks(currentMetrics),
      recommendations: this.generateRecommendations(currentMetrics)
    };
    
    this.performanceHistory.push(analysis);
    return analysis;
  }
  
  optimizeAutomatically() {
    const analysis = this.analyzePerformance();
    const optimizations = [];
    
    // Apply automatic optimizations
    analysis.recommendations.forEach(recommendation => {
      if (recommendation.autoApplicable) {
        const optimization = this.applyOptimization(recommendation);
        optimizations.push(optimization);
      }
    });
    
    return {
      applied: optimizations,
      manual: analysis.recommendations.filter(r => !r.autoApplicable)
    };
  }
  
  applyOptimization(recommendation) {
    const optimization = {
      id: this.generateOptimizationId(),
      type: recommendation.type,
      description: recommendation.description,
      appliedAt: Date.now(),
      expectedImprovement: recommendation.expectedImprovement
    };
    
    switch (recommendation.type) {
      case 'cache_optimization':
        this.optimizeCache(recommendation.parameters);
        break;
      case 'image_compression':
        this.optimizeImages(recommendation.parameters);
        break;
      case 'code_splitting':
        this.implementCodeSplitting(recommendation.parameters);
        break;
      case 'lazy_loading':
        this.implementLazyLoading(recommendation.parameters);
        break;
      default:
        throw new Error(`Unknown optimization type: ${recommendation.type}`);
    }
    
    return optimization;
  }
}

Resource Optimization

// Resource management and optimization
class ResourceOptimizer {
  constructor() {
    this.resourceCache = new Map();
    this.compressionStrategies = new Map();
    this.loadingStrategies = new Map();
  }
  
  optimizeImages() {
    const imageOptimizations = {
      webpConversion: this.convertToWebP(),
      responsiveImages: this.generateResponsiveImages(),
      lazyLoading: this.implementImageLazyLoading(),
      compression: this.compressImages()
    };
    
    return imageOptimizations;
  }
  
  optimizeJavaScript() {
    const jsOptimizations = {
      minification: this.minifyJavaScript(),
      treeshaking: this.removeUnusedCode(),
      codeSplitting: this.splitCodeByRoute(),
      bundleAnalysis: this.analyzeBundleSize()
    };
    
    return jsOptimizations;
  }
  
  optimizeCSS() {
    const cssOptimizations = {
      minification: this.minifyCSS(),
      unusedCSS: this.removeUnusedCSS(),
      criticalCSS: this.extractCriticalCSS(),
      cssModules: this.implementCSSModules()
    };
    
    return cssOptimizations;
  }
  
  implementCaching() {
    const cachingStrategy = {
      staticAssets: {
        strategy: 'cache-first',
        maxAge: 31536000, // 1 year
        versioning: true
      },
      apiResponses: {
        strategy: 'network-first',
        maxAge: 300, // 5 minutes
        staleWhileRevalidate: true
      },
      userContent: {
        strategy: 'network-only',
        maxAge: 0
      }
    };
    
    this.applyCachingStrategy(cachingStrategy);
    return cachingStrategy;
  }
}

Security Maintenance

Security Updates

// Security maintenance and vulnerability management
class SecurityMaintenance {
  constructor() {
    this.vulnerabilityScanner = new VulnerabilityScanner();
    this.securityPatches = new Map();
    this.securityBaseline = new Map();
  }
  
  async performSecurityAudit() {
    const audit = {
      timestamp: Date.now(),
      vulnerabilities: await this.scanVulnerabilities(),
      dependencies: await this.auditDependencies(),
      configurations: await this.auditConfigurations(),
      permissions: await this.auditPermissions()
    };
    
    // Generate security report
    const report = this.generateSecurityReport(audit);
    
    // Create remediation plan
    const remediationPlan = this.createRemediationPlan(audit);
    
    return {
      audit: audit,
      report: report,
      remediationPlan: remediationPlan
    };
  }
  
  async updateDependencies() {
    const dependencies = await this.getDependencies();
    const updates = [];
    
    for (const dependency of dependencies) {
      const latestVersion = await this.getLatestVersion(dependency.name);
      
      if (this.hasSecurityUpdate(dependency, latestVersion)) {
        const update = await this.updateDependency(dependency, latestVersion);
        updates.push(update);
      }
    }
    
    // Test after updates
    await this.runSecurityTests();
    
    return updates;
  }
  
  async applySecurityPatch(patchId) {
    const patch = this.securityPatches.get(patchId);
    
    if (!patch) {
      throw new Error(`Security patch ${patchId} not found`);
    }
    
    const application = {
      patchId: patchId,
      appliedAt: Date.now(),
      backupCreated: await this.createBackup(),
      testResults: null,
      rollbackPlan: this.createRollbackPlan()
    };
    
    try {
      // Apply patch
      await this.executePatch(patch);
      
      // Run tests
      application.testResults = await this.runSecurityTests();
      
      if (!application.testResults.passed) {
        throw new Error('Security tests failed after patch application');
      }
      
      application.status = 'success';
      return application;
    } catch (error) {
      application.status = 'failed';
      application.error = error.message;
      
      // Rollback
      await this.rollbackPatch(application);
      
      throw error;
    }
  }
}

Database Maintenance

Database Optimization

// Database maintenance and optimization
class DatabaseMaintenance {
  constructor() {
    this.optimizationSchedule = new Map();
    this.performanceMetrics = new Map();
    this.maintenanceHistory = [];
  }
  
  async performRoutineMaintenance() {
    const maintenance = {
      id: this.generateMaintenanceId(),
      startTime: Date.now(),
      tasks: []
    };
    
    try {
      // Index optimization
      const indexOptimization = await this.optimizeIndexes();
      maintenance.tasks.push(indexOptimization);
      
      // Query optimization
      const queryOptimization = await this.optimizeQueries();
      maintenance.tasks.push(queryOptimization);
      
      // Data cleanup
      const dataCleanup = await this.cleanupOldData();
      maintenance.tasks.push(dataCleanup);
      
      // Statistics update
      const statisticsUpdate = await this.updateStatistics();
      maintenance.tasks.push(statisticsUpdate);
      
      // Backup verification
      const backupVerification = await this.verifyBackups();
      maintenance.tasks.push(backupVerification);
      
      maintenance.endTime = Date.now();
      maintenance.status = 'completed';
      
      this.maintenanceHistory.push(maintenance);
      return maintenance;
    } catch (error) {
      maintenance.status = 'failed';
      maintenance.error = error.message;
      maintenance.endTime = Date.now();
      
      throw error;
    }
  }
  
  async optimizeIndexes() {
    const indexes = await this.analyzeIndexUsage();
    const optimizations = [];
    
    for (const index of indexes) {
      if (index.usage < 0.1) {
        // Remove unused index
        await this.dropIndex(index.name);
        optimizations.push({
          type: 'drop',
          index: index.name,
          reason: 'unused'
        });
      } else if (index.fragmentationLevel > 0.3) {
        // Rebuild fragmented index
        await this.rebuildIndex(index.name);
        optimizations.push({
          type: 'rebuild',
          index: index.name,
          reason: 'fragmentation'
        });
      }
    }
    
    // Suggest new indexes
    const suggestions = await this.suggestNewIndexes();
    optimizations.push(...suggestions);
    
    return {
      task: 'index_optimization',
      optimizations: optimizations,
      duration: Date.now() - startTime
    };
  }
  
  async cleanupOldData() {
    const cleanupRules = this.getDataRetentionRules();
    const cleanupResults = [];
    
    for (const rule of cleanupRules) {
      const cutoffDate = new Date(Date.now() - rule.retentionPeriod);
      
      const result = await this.deleteOldRecords(
        rule.table,
        rule.dateColumn,
        cutoffDate
      );
      
      cleanupResults.push({
        table: rule.table,
        deletedRecords: result.deletedCount,
        freedSpace: result.freedSpace
      });
    }
    
    return {
      task: 'data_cleanup',
      results: cleanupResults
    };
  }
}

Backup and Recovery

Backup Management

// Comprehensive backup and recovery system
class BackupManager {
  constructor() {
    this.backupSchedule = new Map();
    this.backupHistory = [];
    this.recoveryPlans = new Map();
  }
  
  async createBackup(type = 'full') {
    const backup = {
      id: this.generateBackupId(),
      type: type,
      startTime: Date.now(),
      status: 'in_progress'
    };
    
    try {
      switch (type) {
        case 'full':
          backup.data = await this.createFullBackup();
          break;
        case 'incremental':
          backup.data = await this.createIncrementalBackup();
          break;
        case 'differential':
          backup.data = await this.createDifferentialBackup();
          break;
        default:
          throw new Error(`Unknown backup type: ${type}`);
      }
      
      // Verify backup integrity
      const verification = await this.verifyBackup(backup);
      backup.verification = verification;
      
      if (!verification.valid) {
        throw new Error('Backup verification failed');
      }
      
      // Store backup metadata
      backup.endTime = Date.now();
      backup.status = 'completed';
      backup.size = this.calculateBackupSize(backup.data);
      backup.location = await this.storeBackup(backup);
      
      this.backupHistory.push(backup);
      return backup;
    } catch (error) {
      backup.status = 'failed';
      backup.error = error.message;
      backup.endTime = Date.now();
      
      throw error;
    }
  }
  
  async restoreFromBackup(backupId, options = {}) {
    const backup = this.getBackup(backupId);
    
    if (!backup) {
      throw new Error(`Backup ${backupId} not found`);
    }
    
    const restoration = {
      id: this.generateRestorationId(),
      backupId: backupId,
      startTime: Date.now(),
      options: options,
      status: 'in_progress'
    };
    
    try {
      // Create pre-restoration backup
      if (options.createBackup !== false) {
        restoration.preRestorationBackup = await this.createBackup('full');
      }
      
      // Restore data
      await this.executeRestore(backup, options);
      
      // Verify restoration
      const verification = await this.verifyRestoration(backup, options);
      restoration.verification = verification;
      
      if (!verification.valid) {
        throw new Error('Restoration verification failed');
      }
      
      restoration.endTime = Date.now();
      restoration.status = 'completed';
      
      return restoration;
    } catch (error) {
      restoration.status = 'failed';
      restoration.error = error.message;
      restoration.endTime = Date.now();
      
      // Attempt rollback if pre-restoration backup exists
      if (restoration.preRestorationBackup) {
        await this.rollbackRestoration(restoration);
      }
      
      throw error;
    }
  }
}

Maintenance Automation

Automated Maintenance Tasks

// Automated maintenance scheduling and execution
class MaintenanceAutomation {
  constructor() {
    this.scheduledTasks = new Map();
    this.taskHistory = [];
    this.maintenanceWindows = new Map();
  }
  
  scheduleTask(taskConfig) {
    const task = {
      id: this.generateTaskId(),
      name: taskConfig.name,
      type: taskConfig.type,
      schedule: taskConfig.schedule, // cron expression
      priority: taskConfig.priority || 'normal',
      maxDuration: taskConfig.maxDuration,
      dependencies: taskConfig.dependencies || [],
      notifications: taskConfig.notifications || [],
      enabled: true,
      lastRun: null,
      nextRun: this.calculateNextRun(taskConfig.schedule)
    };
    
    this.scheduledTasks.set(task.id, task);
    return task;
  }
  
  async executeMaintenanceWindow(windowId) {
    const window = this.maintenanceWindows.get(windowId);
    
    if (!window) {
      throw new Error(`Maintenance window ${windowId} not found`);
    }
    
    const execution = {
      windowId: windowId,
      startTime: Date.now(),
      tasks: [],
      status: 'running'
    };
    
    try {
      // Sort tasks by priority and dependencies
      const sortedTasks = this.sortTasksByPriority(window.tasks);
      
      for (const taskId of sortedTasks) {
        const task = this.scheduledTasks.get(taskId);
        
        if (!task || !task.enabled) continue;
        
        const taskExecution = await this.executeTask(task);
        execution.tasks.push(taskExecution);
        
        // Check if we're running out of time
        if (this.isMaintenanceWindowExpiring(window, execution.startTime)) {
          break;
        }
      }
      
      execution.endTime = Date.now();
      execution.status = 'completed';
      
      return execution;
    } catch (error) {
      execution.status = 'failed';
      execution.error = error.message;
      execution.endTime = Date.now();
      
      throw error;
    }
  }
  
  async executeTask(task) {
    const execution = {
      taskId: task.id,
      startTime: Date.now(),
      status: 'running'
    };
    
    try {
      // Check dependencies
      await this.checkTaskDependencies(task);
      
      // Execute task based on type
      switch (task.type) {
        case 'backup':
          execution.result = await this.executeBackupTask(task);
          break;
        case 'cleanup':
          execution.result = await this.executeCleanupTask(task);
          break;
        case 'optimization':
          execution.result = await this.executeOptimizationTask(task);
          break;
        case 'security_scan':
          execution.result = await this.executeSecurityScanTask(task);
          break;
        default:
          throw new Error(`Unknown task type: ${task.type}`);
      }
      
      execution.endTime = Date.now();
      execution.status = 'completed';
      
      // Update task metadata
      task.lastRun = execution.endTime;
      task.nextRun = this.calculateNextRun(task.schedule);
      
      // Send notifications
      await this.sendTaskNotifications(task, execution);
      
      return execution;
    } catch (error) {
      execution.status = 'failed';
      execution.error = error.message;
      execution.endTime = Date.now();
      
      // Send error notifications
      await this.sendErrorNotifications(task, execution);
      
      throw error;
    }
  }
}

Maintenance Best Practices

Maintenance Checklist

• [ ] Regular Monitoring: Continuous system health monitoring
• [ ] Automated Backups: Scheduled and verified backup procedures
• [ ] Security Updates: Regular security patches and vulnerability scans
• [ ] Performance Optimization: Ongoing performance monitoring and tuning
• [ ] Dependency Updates: Regular updates of libraries and frameworks
• [ ] Database Maintenance: Index optimization and data cleanup
• [ ] Log Management: Log rotation and analysis
• [ ] Capacity Planning: Resource usage monitoring and scaling

Emergency Procedures

• [ ] Incident Response Plan: Clear procedures for handling emergencies
• [ ] Rollback Procedures: Quick rollback mechanisms for failed updates
• [ ] Communication Plan: Stakeholder notification procedures
• [ ] Recovery Testing: Regular testing of backup and recovery procedures
• [ ] Documentation: Up-to-date maintenance documentation
• [ ] Team Training: Regular training on maintenance procedures

Long-term Sustainability

• [ ] Technical Debt Management: Regular assessment and reduction
• [ ] Architecture Evolution: Planned architecture improvements
• [ ] Technology Upgrades: Strategic technology stack updates
• [ ] Knowledge Management: Documentation and knowledge sharing
• [ ] Team Development: Continuous learning and skill development
• [ ] Process Improvement: Regular review and optimization of procedures

This comprehensive maintenance guide ensures the long-term health, security, and performance of mini programs through systematic maintenance practices and automated procedures.