stock-bot/DATA-INGESTION-REFACTOR-SUMMARY.md

Data-Ingestion Service Refactor Summary

What Was Done

Successfully refactored the data-ingestion service to use the new connection pool pattern, completely removing dependencies on the singleton anti-pattern.

Key Changes

1. Service Container Setup

   • Created database-setup.ts with proper connection factory configuration
   • Configured appropriate pool sizes for data ingestion workloads
   • Added optional dynamic pool sizing for production environments

2. Main Service Refactor (index.ts)

   • Removed connectMongoDB() and connectPostgreSQL() singleton calls
   • Replaced with setupServiceContainer() initialization
   • Updated shutdown handlers to dispose container properly
   • Routes now have access to the service container

3. Handler Updates

   • All handlers now accept ServiceContainer parameter
   • QM handler operations use container-based OperationContext
   • IB, Proxy, and WebShare handlers updated to accept container
   • Added proper resource disposal with ctx.dispose()

4. Route Refactoring

   • Created create-routes.ts factory function
   • Routes can access container through Hono context
   • Maintains backward compatibility for simple routes

5. Migration Helper

   • Created temporary migration helper for legacy operations
   • Provides getMongoDBClient() for IB operations still being migrated
   • Includes cleanup in shutdown sequence

Configuration Changes

• Added @stock-bot/connection-factory dependency
• Updated tsconfig.json with proper references
• Pool sizes optimized for data ingestion:
  • MongoDB: 50 connections (batch imports)
  • PostgreSQL: 30 connections
  • Cache: 20 connections

Benefits Achieved

1. No More Global State: Each service manages its own connections
2. Better Resource Management: Proper cleanup on shutdown
3. Scalability: Dynamic pool sizing for production workloads
4. Monitoring: Pool metrics available for observability
5. Testing: Easier to test with mock containers
6. Gradual Migration: Legacy operations still work during transition

Next Steps

1. Complete Operation Migration: Update IB operations to use container
2. Remove Migration Helper: Once all operations are migrated
3. Add Monitoring: Set up dashboards for pool metrics
4. Performance Testing: Validate pool sizes under load
5. Replicate Pattern: Apply same refactor to other services

Example Usage

// Handler with container
export function initializeHandler(container: ServiceContainer) {
  const config = {
    operations: {
      'my-operation': createJobHandler(async (payload) => {
        // Operation uses container
        const ctx = OperationContext.create('handler', 'operation', { container });
        try {
          // Use databases through context
          await ctx.mongodb.insertOne(data);
          await ctx.postgres.query('...');
          return { success: true };
        } finally {
          await ctx.dispose(); // Clean up resources
        }
      })
    }
  };
}

Migration Checklist

• Remove singleton imports from index.ts
• Create service container setup
• Update all handlers to accept container
• Create route factory with container access
• Add migration helper for legacy code
• Update shutdown handlers
• Test build successfully
• Migrate remaining operations
• Remove migration helper
• Deploy and monitor