jsPolicy SDK

While there are many ways to write policies, you can use the jsPolicy SDK to get up and running faster and build on best practices. The jsPolicy SDK provides a project structure, some development and testing tools as well as some guidance on how to efficiently write, test and publish policies using TypeScript (or JavaScript).

Using jsPolicy SDK

The jsPolicy SDK project on GitHub is desined as a template for you to get started with.

1. Clone Template Project

So, to use jsPolicy SDK, clone the project:

git clone https://github.com/loft-sh/jspolicy-sdk mypolicies

cd mypolicies

2. Install Dev Dependencies

This project has several devDependencies defined in the package.json, so let's install them:

npm install

3. Write & Compile Policies

The project is structured like this:

|- src/ # Source Code

| |--- lib/ # Shared policy logic for common things (e.g. validateImages is used for pod and deployment validation policies)

| |--- policies/ # Contains folders that represent one policy each (1x policy.yaml + 1x index.yaml as entrypoint)

| |--- util/ # Shared utility functions (not policy specific, small helpers)

| |--- index.ts # Specifies all functions that are exported and are intended to be reused by others that use this package after you publish this project to npmjs.com for example

|

|- tests/ # Contains tests (this project uses Jest by default)

|- lib/ # Temporary folder that the project uses to output the JavaScript code that has been generated from the TypeScript files

|- policies/ # The SDK will output your policies as yaml files in this folder, so you can apply them with `kubectl apply -f policies/`

To compile the policies defined in src/policies to ready-to-use JsPolicy + JsPolicyBundle combos, run:

npm run compile # will compile policies and output them to `policies/`

For a more efficient hot reloading workflow, run:

npm run watch # watches for file changes in src/ and compiles policies iteratively

To also apply the policies after each iterative compile process, run:

npm run watch-apply # think: npm run watch && kubectl apply -f policies/

4. Test Policies

The project is configured to use Jest and execute all files in tests/ as test suites. You can run the tests with this command:

npm run test

5. Publish Policy Logic

If you want to share policy logic from your lib/ folder, make sure you export the functions you want to make available by adding these functions in src/index.ts and then publish the project:

npm publish