Introducing Toolkit Watcher by refactoring old Observer System in new patterns.

Summary

Why Care

Implementation

Changes Made

• New Files:
  • /tidyverse/observers/watchers/toolkitWatcher.ts: Core implementation of the new watcher system
  • /tidyverse/observers/services/templateRegistry.ts: Template management service
• Modified Files:
  • /tidyverse/observers/fileSystemObserver.ts: Updated to use consistent date formatting
  • /tidyverse/observers/services/openGraphService.ts: Enhanced logging for API responses
  • /tidyverse/observers/utils/yamlFrontmatter.ts: Improved frontmatter handling
  • /tidyverse/observers/templates/tooling.ts: Updated template definitions

Technical Details

New ToolingWatcher Architecture

• Implemented a dedicated ToolingWatcher class that focuses solely on monitoring and processing files in the tooling collection
• Key features:
  typescript

  // File: /tidyverse/observers/watchers/toolkitWatcher.ts
  export class ToolingWatcher {
    private watcher: chokidar.FSWatcher | null = null;
    private toolingCollectionPath: string;
    private reportingService: ReportingService;
    private templateRegistry: TemplateRegistry;
    
    // Constructor accepts specific watch path and services
    constructor(
      specificWatchPath: string,
      reportingService: ReportingService,
      templateRegistry: TemplateRegistry
    ) {
      // Initialization code...
    }
    
    // Core file processing logic
    private async processFile(filePath: string, eventType: 'add' | 'change'): Promise<void> {
      // File processing with template validation...
    }
  }

Template Registry Service

• Created a centralized template management system that:
  1. Registers and stores metadata templates
  2. Matches files to appropriate templates based on path patterns
  3. Validates frontmatter against template rules
  4. Generates default values for required fields
  typescript

  // File: /tidyverse/observers/services/templateRegistry.ts
  export class TemplateRegistry {
    private templates: Map<string, MetadataTemplate>;
    
    // Finds the appropriate template for a file
    findTemplate(filePath: string): MetadataTemplate | null {
      // Template matching logic...
    }
    
    // Generates default values based on template rules
    generateDefaults(template: MetadataTemplate, filePath: string): Record<string, any> {
      // Default generation logic...
    }
  }

Enhanced Template Validation

• Implemented specialized inspector functions for different field types:
  typescript

  // File: /tidyverse/observers/templates/tooling.ts
  function urlInspector(fieldName: string, allowEmpty: boolean = false): (value: any) => { 
    status: InspectorStatus; 
    message: string 
  } {
    // URL validation logic...
  }
  
  function arrayInspector(fieldName: string, allowEmpty: boolean = false): (value: any) => { 
    status: InspectorStatus; 
    message: string 
  } {
    // Array validation logic...
  }

Improved Property Collection

• Implemented a property collector pattern that:
  1. Accumulates all necessary changes before writing to file
  2. Provides detailed logging of each field's validation status
  3. Only updates files when actual changes are needed
  typescript

  // File: /tidyverse/observers/watchers/toolkitWatcher.ts
  const propertyCollector: Record<string, any> = {};
  
  // Validation and collection logic
  for (const [fieldName, fieldDef] of Object.entries(templateToUse.required)) {
    // Field validation and collection...
    if (inspectionResult.status !== "ok") {
      propertyCollector[fieldName] = defaultValue;
    }
  }
  
  // Write only if changes exist
  if (Object.keys(propertyCollector).length > 0) {
    const proposedFrontmatter = { ...currentFrontmatter, ...propertyCollector };
    await writeFrontmatterToFile(filePath, proposedFrontmatter);
  }

FileSystemObserver Date Formatting Fix

• Implemented consistent date formatting in the onChange method to ensure date_modified is always written in YYYY-MM-DD format
• This prevents infinite processing loops that were occurring when full ISO timestamps were written to frontmatter and then compared with YYYY-MM-DD strings

// File: /tidyverse/observers/fileSystemObserver.ts
// Update date_modified first, ensuring YYYY-MM-DD format via formatDate
propertyCollector.results.date_modified = formatDate(new Date());

OpenGraph Service Debugging Enhancement

• Added detailed logging in the fetchOpenGraphData function to inspect:
  1. Raw API response data from OpenGraph.io
  2. Constructed pre-normalization data object

// File: /tidyverse/observers/services/openGraphService.ts
console.log(`[OpenGraph] Raw API response data.openGraph for ${url}:`, JSON.stringify(data.openGraph, null, 2));
// ...
console.log(`[OpenGraph] Constructed ogData (pre-normalization) for ${url}:`, JSON.stringify(ogData, null, 2));

• This logging revealed that the OpenGraph.io API does not return favicon or proper image data for certain URLs (like rhythms.ai)
• The system correctly handles missing fields by not including empty values in the normalized data

Integration Points

• FileSystemObserver: Integrates with the new watcher system through a common interface
• TemplateRegistry: Provides a central service for template management used by all watchers
• ReportingService: Collects validation results and errors for monitoring
• OpenGraphService: Continues to provide metadata enrichment with improved debugging

Documentation

• The new architecture follows a clear separation of concerns:
  1. Watchers: Handle file system events and basic processing
  2. Templates: Define structure and validation rules
  3. Services: Provide shared functionality (template registry, reporting, OpenGraph)
  4. Utils: Common utility functions for date formatting, UUID generation, etc.
• This modular approach makes it easier to maintain and extend the system with new content types and processing rules