Data sync event

The data sync event is a particularly significant custom event because it is one of the most commonly registered events within the application. Handlers for this event play a crucial role in ensuring data consistency and synchronization between different databases. For example, a handler might be responsible for syncing data from DynamoDB to RDS, sending registration emails, and executing other related tasks that maintain the integrity and flow of data across the application.

To make working with the data sync event easier, we've created several helper utilities that are ready for you to use. By using these pre-built utilities, you can streamline your development process, reduce the amount of custom code needed, and ensure that your event handlers are efficient and reliable.

By convention, you create a class that implements IDataSyncHandler and then override the up and down methods as below example:

import { CommandModel, IDataSyncHandler } from "@mbc-cqrs-serverless/core";
import { Injectable, Logger } from "@nestjs/common";
import { PrismaService } from "src/prisma";

@Injectable()
export class CatDataSyncRdsHandler implements IDataSyncHandler {
  private readonly logger = new Logger(CatDataSyncRdsHandler.name);

  constructor(private readonly prismaService: PrismaService) {}

  async up(cmd: CommandModel): Promise<any> {
    this.logger.debug(cmd);
    // sync data
  }

  async down(cmd: CommandModel): Promise<any> {
    this.logger.debug(cmd);
  }
}

Then, you register this handler to CommandModule:

@Module({
  imports: [
    CommandModule.register({
      tableName: 'cat',
      dataSyncHandlers: [CatDataSyncRdsHandler],
    }),
  ],
  ...
})
export class CatModule {}