Module Metadata Seeder Events

SolidX core emits two lifecycle events from ModuleMetadataSeederService:

• module-metadata-seeder.started
• module-metadata-seeder.finished

This lets a consuming project attach project-specific behavior around metadata seeding without modifying core seeding logic.

Typical uses:

• log seed lifecycle to an external system
• trigger cache warmup after seeding completes
• notify internal tooling that a seed run started or finished
• capture timing and failure details for CI or operational dashboards

Event Payload

Both events are emitted as EventDetails<ModuleMetadataSeederEventPayload>.

The payload includes:

• seedRunId - stable id shared by the started and finished events
• options - normalized seed options used for the run
• startedAt - ISO timestamp when the seed run began
• finishedAt - ISO timestamp when the run ended (finished event only)
• durationMs - total runtime in milliseconds (finished event only)
• success - true or false on the finished event
• seededModuleNames - modules actually processed during the run
• currentStep - last active seed step when the event was emitted
• errorMessage - failure message when the run ends unsuccessfully

options currently contains:

• modulesToSeed
• pruneMetadata
• seedGlobalMetadata

Consuming From Your App

Import EventEmitterModule.forRoot() once in your application's root module, then register any listeners you need.

Create a listener:

import { Injectable, Logger } from '@nestjs/common';
import { OnEvent } from '@nestjs/event-emitter';
import {
  EventDetails,
  EventType,
  ModuleMetadataSeederEventPayload,
} from '@solidxai/core';

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

  @OnEvent(EventType.MODULE_METADATA_SEEDER_STARTED)
  handleStarted(event: EventDetails<ModuleMetadataSeederEventPayload>) {
    this.logger.log(
      `Seed started: runId=${event.payload.seedRunId}, modules=${event.payload.options.modulesToSeed?.join(',') ?? 'ALL'}`
    );
  }

  @OnEvent(EventType.MODULE_METADATA_SEEDER_FINISHED)
  handleFinished(event: EventDetails<ModuleMetadataSeederEventPayload>) {
    this.logger.log(
      `Seed finished: runId=${event.payload.seedRunId}, success=${event.payload.success}, durationMs=${event.payload.durationMs}`
    );
  }
}

Register the listener in the consuming module:

import { ModuleMetadataSeederListener } from './listeners/module-metadata-seeder.listener';

@Module({
  providers: [
    AppService,
    ModuleMetadataSeederListener,
  ],
})
export class AppModule {}

Notes

• Import EventEmitterModule.forRoot() once in the consuming app's root module.
• Listener registration is optional. If no listener is registered, seeding behavior is unchanged.
• The finished event is emitted for both successful and failed runs. Check payload.success.
• The payload exposes normalized seed options, which is a better contract than raw CLI argv because the seeder can also be invoked from code, not only from solidctl.
• These events are meant for integration hooks and telemetry, not for replacing core seeding behavior.

References

• NestJS Events technique
• Custom Seeders