@kengela/adapter-expr-cel

An ExpressionEnginePort adapter that evaluates authorization conditions with CEL (Common Expression Language).

This package implements the ExpressionEnginePort contract using CEL, so declarative policy conditions (for example resource.attributes.agencyId == principal.agencyId) are evaluated safely against the expression context. It is the adapter ring, and also ships date helpers usable from CEL expressions.

Part of Kengela, a Zero Trust identity and access foundation for multi-tenant TypeScript apps (authentication + authorization + identity federation + compliance).

Install

npm install @kengela/adapter-expr-cel

Usage

import { CelExpressionEngine } from '@kengela/adapter-expr-cel';
import type { ExpressionContext } from '@kengela/contracts';

const engine = new CelExpressionEngine();

const allowed = engine.evaluateBoolean(
  'resource.attributes.agencyId == principal.agencyId',
  ctx satisfies ExpressionContext,
);

Key exports

• CelExpressionEngine - the ExpressionEnginePort implementation backed by CEL.
• CelEvaluationError - thrown on invalid or failing expression evaluation.
• toEpochMs, daysBetween, businessDaysBetween - date helpers for CEL conditions.

Documentation

Guides and recipes: https://github.com/yannds/kengela/wiki

License

Apache-2.0