Senior LevelExpress JS
How do you architect multi-tenant Express SaaS applications leveraging PostgreSQL Row-Level Security (RLS)?
❓ Interview Prompt: Explain multi-tenant database isolation, PostgreSQL Row-Level Security (RLS), AsyncLocalStorage, and setting tenant context in database transactions.
In multi-tenant SaaS applications, relying solely on application-level 'WHERE tenant_id = x' queries risks cross-tenant data leaks if a developer forgets a 'WHERE' clause.
PostgreSQL Row-Level Security (RLS) Architecture:
1
Extract tenant ID from JWT and store in 'AsyncLocalStorage'.
2
Before executing queries, borrow a database client and run 'SET LOCAL app.current_tenant_id = "tenant_123"'.
3
PostgreSQL RLS policies automatically filter all subsequent SELECT/UPDATE/DELETE queries at the database engine level, making data leaks impossible!
Code Implementation Example
javascript
// Multi-tenant PostgreSQL Row-Level Security (RLS) connection wrapper
export async function withTenantDb(tenantId, callback) {
const client = await pool.connect();
try {
await client.query('BEGIN');
// Set tenant context for PostgreSQL RLS policies!
await client.query('SELECT set_config($1, $2, true)', ['app.current_tenant_id', tenantId]);
const result = await callback(client);
await client.query('COMMIT');
return result;
} catch (err) {
await client.query('ROLLBACK');
throw err;
} finally {
client.release();
}
}💡Enforcing PostgreSQL Row-Level Security (RLS) tenant isolation in Express.
🎯 Interview Key Takeaway
Use PostgreSQL Row-Level Security (RLS) with SET LOCAL app.current_tenant_id to enforce multi-tenant database isolation at the engine level.
#Multi-Tenant#PostgreSQL RLS#Security#Senior
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