nestjs-security-isolation

name	nestjs-security-isolation
description	Enforce multi-tenant isolation and PostgreSQL Row Level Security in NestJS. Use when enforcing tenant isolation or PostgreSQL RLS in NestJS multi-tenant apps.
license	MIT
version	1.0.0
author	[Filippo De Silva](https://github.com/FilippoDeSilva)
tags	["nestjs","security","isolation","rls","postgresql","multi-tenant"]
metadata	{"triggers":{"files":["src/modules/**","SECURITY.md","src/migrations/**"],"keywords":["RLS","Row Level Security","childId","isolation","access policy"]}}

Priority: P0 (CRITICAL)

Strict multi-tenant isolation. All child-centric data must secured via PostgreSQL RLS and service-level validation.

RLS Enforcement Workflow

1. Migration: Create tables with ENABLE ROW LEVEL SECURITY. Define policies using current_setting('app.current_user_id').
2. Entity Logic: Add @Security JSDoc to entity class.
3. Security Doc: Update SECURITY.md with new table and its access logic.
4. Service Validation: Call childrenService.validateChildAccess(childId, userId) before any persistence operation.

Core Guidelines

1. Mandatory RLS: Every new table linking to child or family MUST RLS enabled in its creation migration.
2. Centralized Validation: Never reimplement access logic. Use ChildrenService for child/family membership checks.
3. Traceable Security: SECURITY.md source of truth. Any change to RLS policies must reflected there immediately.
4. Nested Route Constraint: Data isolation enforced at controller level via nested routes: /children/:childId/....
5. No Direct Entity exposure: Use Response DTOs to prevent leaking internal database IDs or metadata that could bypass security filters.

Anti-Patterns

• No Public Tables: Don't create child-linked tables without RLS.
• No Manual Policy Checks: Don't write raw SQL access checks in services. Use centralized validator.
• No Stale Docs: Don't merge RLS changes without updating SECURITY.md and entity JSDoc.
• No Root IDs: Don't use /domain/:id for child data. Always scope by :childId.

References

• Implementation Patterns
• RLS Migration Patterns
• Centralized Auth Logic