https://github.com/losisin/helm-values-schema-json
Helm plugin for generating values.schema.json from multiple values files
https://github.com/losisin/helm-values-schema-json
helm helm-chart helm-charts helm-plugin helm-plugins json-schema json-schema-generator schema-json
Last synced: 3 days ago
JSON representation
Helm plugin for generating values.schema.json from multiple values files
- Host: GitHub
- URL: https://github.com/losisin/helm-values-schema-json
- Owner: losisin
- License: mit
- Created: 2023-10-24T09:13:41.000Z (almost 2 years ago)
- Default Branch: main
- Last Pushed: 2025-09-29T04:24:06.000Z (16 days ago)
- Last Synced: 2025-09-30T02:46:57.424Z (15 days ago)
- Topics: helm, helm-chart, helm-charts, helm-plugin, helm-plugins, json-schema, json-schema-generator, schema-json
- Language: Go
- Homepage:
- Size: 875 KB
- Stars: 158
- Watchers: 4
- Forks: 15
- Open Issues: 20
-
Metadata Files:
- Readme: README.md
- Funding: .github/FUNDING.yml
- License: LICENSE
- Codeowners: CODEOWNERS
Awesome Lists containing this project
README
# helm values schema json plugin
[](https://github.com/losisin/helm-values-schema-json/actions/workflows/ci.yaml)
[](https://codecov.io/gh/losisin/helm-values-schema-json)
[](https://goreportcard.com/report/github.com/losisin/helm-values-schema-json)
[](https://github.com/losisin/helm-values-schema-json/blob/main/LICENSE)
[](https://github.com/losisin/helm-values-schema-json/releases)
Helm plugin for generating `values.schema.json` from single or multiple values files. Schema can be enriched by reading annotations from comments. Works only with Helm3 charts.
## Installation
```bash
helm plugin install https://github.com/losisin/helm-values-schema-json.git
```
## Upgrading
```bash
helm plugin update schema
```
See changelogs:
- [Breaking changes](./docs/upgrading.md)
- [Full release notes in GitHub Releases](https://github.com/losisin/helm-values-schema-json/releases)
## Features
- Add multiple values files and merge them together - default is `values.yaml` in the current working directory
- Save output with custom name and location - default is `values.schema.json` in current working directory
- Use preferred schema draft version - default is draft 2020
- Read annotations from comments.
- Read description from [helm-docs](https://github.com/norwoodj/helm-docs)
- Bundling subschemas referenced in `$ref`
See [docs](./docs/README.md) for more info or checkout example yaml files
in [testdata](./testdata).
## Integrations
There are several ways to automate schema generation with this plugin. Main reason is that the json schema file can be hard to follow and we as humans tend to forget and update routine tasks. So why not automate it?
### GitHub actions
There is GitHub action that I've build using typescript and published on marketplace. You can find it [here](https://github.com/marketplace/actions/helm-values-schema-json-action). Basic usage is as follows:
```yaml
name: Generate values schema json
on:
- pull_request
jobs:
generate:
runs-on: ubuntu-latest
steps:
- uses: actions/checkout@v4
with:
ref: ${{ github.event.pull_request.head.ref }}
- name: Generate values schema json
uses: losisin/helm-values-schema-json-action@v1
with:
input: values.yaml
```
### pre-commit hook
With pre-commit, you can ensure your JSON schema is kept up-to-date each time you make a commit.
First [install pre-commit](https://pre-commit.com/#install) and then create or update a `.pre-commit-config.yaml` in the root of your Git repo with at least the following content:
```yaml
repos:
- repo: https://github.com/losisin/helm-values-schema-json
rev: v1.7.2
hooks:
- id: helm-schema
args: ["--values", "values.yaml"]
```
Then run:
```bash
pre-commit install
pre-commit install-hooks
```
Further changes to your chart files will cause an update to json schema when you make a commit.
### Husky
This is a great tool for adding git hooks to your project. You can find it's documentation [here](https://typicode.github.io/husky/). Here is how you can use it:
```json
"husky": {
"hooks": {
"pre-commit": "helm schema --values values.yaml"
}
},
```
### CI/CD fail-on-diff
You can use this plugin in your CI/CD pipeline to ensure that the schema is always up-to-date. Here is an example for GitLab [#82](https://github.com/losisin/helm-values-schema-json/issues/82):
```yaml
schema-check:
script:
- cd path/to/helm/chart
- helm schema -output generated-schema.json
- CURRENT_SCHEMA=$(cat values.schema.json)
- GENERATED_SCHEMA=$(cat generated-schema.json)
- |
if [ "$CURRENT_SCHEMA" != "$GENERATED_SCHEMA" ]; then
echo "Schema must be re-generated! Run 'helm schema' in the helm-chart directory" 1>&2
exit 1
fi
```
## Usage
```bash
$ helm schema -help
Usage:
helm schema [flags]
Flags:
--bundle Bundle referenced ($ref) subschemas into a single file inside $defs
--bundle-root string Root directory to allow local referenced files to be loaded from (default current working directory)
--bundle-without-id Bundle without using $id to reference bundled schemas, which improves compatibility with e.g the VS Code JSON extension
--config string Config file for setting defaults. (default ".schema.yaml")
--draft int Draft version (4, 6, 7, 2019, or 2020) (default 2020)
-h, --help help for helm schema
--indent int Indentation spaces (even number) (default 4)
--k8s-schema-url string URL template used in $ref: $k8s/... alias (default "https://raw.githubusercontent.com/yannh/kubernetes-json-schema/master/{{ .K8sSchemaVersion }}/")
--k8s-schema-version string Version used in the --k8s-schema-url template for $ref: $k8s/... alias
--no-additional-properties Default additionalProperties to false for all objects in the schema
--no-default-global Disable automatic injection of 'global' property when schema root does not allow it
-o, --output string Output file path (default "values.schema.json")
--schema-root.additional-properties Allow additional properties
--schema-root.description string JSON schema description
--schema-root.id string JSON schema ID
--schema-root.ref string JSON schema URI reference. Relative to current working directory when using "-bundle true".
--schema-root.title string JSON schema title
--use-helm-docs Read description from https://github.com/norwoodj/helm-docs comments
-f, --values strings One or more YAML files as inputs. Use comma-separated list or supply flag multiple times (default [values.yaml])
-v, --version version for helm schema
```
### Configuration file
Uses `.schema.yaml` in the current working directory.
Example:
```yaml
# .schema.yaml
# yaml-language-server: $schema=https://github.com/losisin/helm-values-schema-json/raw/refs/heads/main/config.schema.json
values:
- values.yaml
draft: 2020
indent: 4
output: values.schema.json
bundle: false
bundleRoot: ""
bundleWithoutID: false
k8sSchemaURL: https://raw.githubusercontent.com/yannh/kubernetes-json-schema/refs/heads/master/{{ .K8sSchemaVersion }}/
k8sSchemaVersion: "v1.33.1"
useHelmDocs: false
noAdditionalProperties: false
noDefaultGlobal: false
schemaRoot:
id: https://example.com/schema
title: Helm Values Schema
description: Schema for Helm values
additionalProperties: true
```
All options available from CLI can be set in this file.
However, do note that the file uses camelCase, while the flags uses kebab-case.
Then, just run the plugin without any arguments:
```bash
helm schema
```
You can override which config file to use with the `--config` flag:
```bash
helm schema --config ./my-helm-schema-config.yaml
```
### CLI
#### Basic
In most cases you will want to run the plugin with default options:
```bash
$ helm schema
```
This will read `values.yaml`, set draft version to `2020-12` and save output to `values.schema.json`.
#### Extended
##### Multiple values files
Merge multiple values files, set json-schema draft version explicitly and save output to `my.schema.json`:
`values_1.yaml`
```yaml
nodeSelector:
kubernetes.io/hostname: ""
dummyList:
- "a"
- "b"
- "c"
key1: "asd"
key2: 42
key3: {}
key4: []
```
`custom/path/values_2.yaml`
```yaml
nodeSelector:
kubernetes.io/hostname: "node1"
deep:
deep1:
deep2:
deep3:
deep4: "asdf"
```
Run the following command to merge the yaml files and output json schema:
```bash
helm schema --values values_1.yaml,custom/path/values_2.yaml --draft 7 --output my.schema.json
```
Output will be something like this:
```json
{
"$schema": "http://json-schema.org/draft-07/schema#",
"type": "object",
"properties": {
"deep": {
"type": "object",
"properties": {
"deep1": {
"type": "object",
"properties": {
"deep2": {
"type": "object",
"properties": {
"deep3": {
"type": "object",
"properties": {
"deep4": {
"type": "string"
}
}
}
}
}
}
}
}
},
"dummyList": {
"type": "array",
"items": {
"type": "string"
}
},
"key1": {
"type": "string"
},
"key2": {
"type": "integer"
},
"key3": {
"type": "object"
},
"key4": {
"type": "array"
},
"nodeSelector": {
"type": "object",
"properties": {
"kubernetes.io/hostname": {
"type": "string"
}
}
}
}
}
```
> [!NOTE]
> When using multiple values files as input, the plugin follows Helm's behavior. This means that if the same yaml keys are present in multiple files, the latter file will take precedence over the former. The same applies to annotations in comments. Therefore, the order of the input files is important.
##### Root JSON object properties
Adding ID, title and description to the schema:
`basic.yaml`
```yaml
image:
repository: nginx
tag: latest
pullPolicy: Always
```
```bash
helm schema --values values.yaml --schema-root.id "https://example.com/schema" --schema-root.ref "schema/product.json" -schema-root.title "My schema" --schema-root.description "This is my schema"
```
Generated schema will be:
```json
{
"$id": "https://example.com/schema",
"$ref": "schema/product.json",
"$schema": "https://json-schema.org/draft/2020-12/schema",
"additionalProperties": true,
"description": "This is my schema",
"properties": {
"image": {
"properties": {
"pullPolicy": {
"type": "string"
},
"repository": {
"type": "string"
},
"tag": {
"type": "string"
}
},
"type": "object"
}
},
"title": "My schema",
"type": "object"
}
```
## Issues, Features, Feedback
Your input matters. Feel free to open [issues](https://github.com/losisin/helm-values-schema-json/issues) for bugs, feature requests, or any feedback you may have. Check if a similar issue exists before creating a new one, and please use clear titles and explanations to help understand your point better. Your thoughts help me improve this project!
### How to Contribute
🌟 Thank you for considering contributing to my project! Your efforts are incredibly valuable. To get started:
1. Fork the repository.
2. Create your feature branch: `git checkout -b feature/YourFeature`
3. Commit your changes: `git commit -am 'Add: YourFeature'`
4. Push to the branch: `git push origin feature/YourFeature`
5. Submit a pull request! 🚀