Core Hooks

Core Hooks are lifecycle callbacks that let you react to framework events. Use them for logging, monitoring, alerting, or custom error handling.

Setup

Implement the ICoreHooks interface in apps/backend/src/infrastructure/core/core-hooks.ts:

import type { ICoreHooks } from '@/core/core-injectables/core-hooks/core-hooks.interface';

export class CoreHooks implements ICoreHooks {

    public onSerializationError(context: SerializationErrorContext): void {
        // Log serialization conflicts
    }

    public onDeadlockError(context: DeadlockErrorContext): void {
        // Log database deadlocks
    }

    public onTransactionStartError(context: TransactionStartErrorContext): void {
        // Log transaction failures
    }

    public onSafeRollbackError(context: SafeRollbackErrorContext): void {
        // Log rollback failures
    }

    public onSlowUseCase(context: SlowUseCaseContext): void {
        // Alert on slow use-cases
    }

    public onSlowRepo(context: SlowRepoContext): void {
        // Alert on slow repos
    }

    public onSlowDomainService(context: SlowDomainServiceContext): void {
        // Alert on slow domain services
    }

    public onValidationError(context: ValidationErrorContext): void {
        // Log validation failures
    }
}

Available Hooks

Error Hooks

Hook	When it fires
onSerializationError	Transaction serialization conflict (retryable)
onDeadlockError	Database deadlock detected (retryable)
onTransactionStartError	Failed to start a transaction
onSafeRollbackError	Rollback failed
onValidationError	Request validation failed

Error hooks receive context including the request, error details, and retry information (attempt number, max attempts).

Performance Hooks

Hook	When it fires
onSlowUseCase	Use-case execution exceeded threshold
onSlowRepo	Repo execution exceeded threshold
onSlowDomainService	Domain service execution exceeded threshold

Performance hooks receive context including execution time and the configured threshold.

Example: Logging

public onSlowRepo(context: SlowRepoContext): void {
    console.warn(
        `Slow repo: ${context.repoName} took ${context.executionTimeMillis}ms ` +
        `(threshold: ${context.durationThresholdMillis}ms)`
    );
}

public onDeadlockError(context: DeadlockErrorContext): void {
    console.error(
        `Deadlock detected (attempt ${context.attemptNumber}/${context.maxAttempts}):`,
        context.error
    );
}