helm-parser

Helm Parser

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Template a helm chart with the Helm CLI and load the manifests into an array of JavaScript objects. Mainly intended for use within a test suite.

Helm charts can get very complicated at scale, with an infinite combination of values that can be passed to the chart by consumers. With Helm Parser, you can write comprehensive tests for your chart, using your favourite JS testing framework.

Features

• Loads the chart's manifests into an array of JavaScript objects
• Typed manifests
• You can provide a type your values (or autogenerate one from a JSON schema)
• Helper functions to easily pick out a specific manifest
• Usage with any JS test framework

Prerequisites

• Helm CLI installed on system

Installation

npm install helm-parser

Usage

import path from "path";
import { HelmParser } from "helm-parser";

const helmParser = new HelmParser({
  chartPath: path.resolve(__dirname, "./path-to/my-chart-dir");
});

const result = helmParser.template({
  chartPath,
  namespace: "my-namespace",
  releaseName: "my-release",
  values: {
    replicaCount: 3,
  },
});

const deployments = result.manifests.filter((manifest) => manifest.kind === "Deployment");

Helper functions

const deployments = result.getDeployments();
const myDeployment = result.getDeployment("my-deployment");

const services = result.getServices();
const myService = result.getService("my-service");

const ingresses = result.getIngresses();
const myIngress = result.getIngress("my-ingress");

Usage for testing

Optionally add a JSON Schema to your chart

You should place this alongside your Chart.yaml file.

This is a helm feature which will validate parameters, as well as allow you to generate a typescript definition for your values.

https://helm.sh/docs/topics/charts/#schema-files

values.schema.json

{
  "$schema": "http://json-schema.org/draft-04/schema#",
  "type": "object",
  "additionalProperties": true,
  "properties": {
    "replicaCount": {
      "type": "number"
    },
    "something": {
      "type": "string",
      "enum": ["a", "b", "c"]
    }
  }
}

Bootstrap project

npx create-helm-tests my-tests --chart-path ./path-to/my-chart-dir

Write tests

test/main.test.ts

test("can set replicas to 3", () => {
  const result = helmParser.template({
    namespace: "my-namespace",
    releaseName: "my-release",
    values: {
      replicaCount: 3,
    },
  });
  const deployment = result.getDeployment("my-deployment");
  expect(deployment.spec.replicas).to.equal(3);
});