Helm Values - Validate with JSON Schema

Step-01: Introduction

• Helm Values - Validate with JSON Schema

Step-02: Review helmbasics Helm Chart

• Simple Helm Chart
• deployment.yaml
• Core focus will be on learning about values.schema.json

Step-03: Convert values.yaml to json

• Use website json2yaml

Step-04: Convert Json to Json Schema

• Use website

{
  "$schema": "http://json-schema.org/draft-07/schema#",
  "title": "Generated schema for Root",
  "type": "object",
  "properties": {
    "replicaCount": {
      "type": "number"
    },
    "image": {
      "type": "object",
      "properties": {
        "repository": {
          "type": "string"
        },
        "pullPolicy": {
          "type": "string"
        },
        "tag": {
          "type": "string"
        }
      },
      "required": [
        "repository",
        "pullPolicy",
        "tag"
      ]
    }
  },
  "required": [
    "replicaCount",
    "image"
  ]
}

Step-05: Create file values.schema.json on Helm Chart Root Directory

• Create file values.schema.json
• Copy JSON content from previous step

Step-06: Add Pattern for pullPolicy

        "pullPolicy": {
          "type": "string",
          "pattern": "^(Always|Never|IfNotPresent)$"
        },

Step-06: Verify values.schema.json

# Change to Chart Directory
cd helmbasics

# Helm lint
helm lint .

# Required Test: Pass null value and verify
helm template myapp1 . --set replicaCount=""

# Integer Test: Provide replicaCount as String
helm template myapp1 . --set replicaCount=kalyan

# Constraint Validation Test: Provide invalid value instead of allowed values (Allowed Values: Always, Never, IfNotPresent)
helm template myapp1 . --set image.pullPolicy=kalyan