Cross-Policy is a TypeScript library designed to simplify policy evaluation by providing a unified interface for multiple policy target runtimes. With support for defining policies in Open Policy Agent (OPA), Common Expression Language (CEL), and more, Cross-Policy streamlines policy evaluation and decision-making in applications.
Key Features:
- Single Interface: Interact with different policy engines through one consistent API.
- Flexible and Extensible: Add support for additional policy targets or customize behavior as needed.
cross-policy is split into several packages, but to get started, you only need
to install the @cross-policy/core package.
To install the library, run the following command:
yarn add cross-policyFor our usage examples, we will use the OPA WASM policy target. To install the OPA WASM target, run the following command:
yarn add @cross-policy/target-opa-wasmTo create a callable policy, you need to create a CrossPolicy instance.
This instance provides a evaluate method that takes an input and returns a
promise that resolves to a boolean indicating whether the policy is allowed or
not.
import { createCrossPolicy } from "@cross-policy/core";
import { opaWasmPolicyTarget } from "@cross-policy/target-opa-wasm";
const crossPolicy = createCrossPolicy({
target: opaWasmPolicyTarget({
// The path to the WASM policy file.
policyPath: "path/to/policy.wasm",
}),
schema: z.object({ input: z.string() }),
});
const result = await crossPolicy.evaluate({ input: "test" });This example demonstrates how to create a callable policy using the OPA WASM policy target. The policy is defined in a WASM file and loaded at runtime.
This is just a collection of policy targets which are included in this repository:
- Open Policy Agent (OPA) with WASM: Evaluate policies using the OPA WASM runtime.
- Open Policy Agent (OPA) with REST API: Evaluate policies using the OPA REST API.
- Common Expression Language (CEL): Evaluate policies using the CEL (cel-js) library.