Validation

When you run kosko generate or kosko validate, Kosko will run validate() method of every exported manifests.

Error

For example, when a manifest is invalid.

TypeScript

import { Deployment } from "kubernetes-models/apps/v1/Deployment";

const deployment = new Deployment({
  metadata: {
    name: "nginx",
    namespace: "dev"
  },
  spec: {
    replicas: "INVALID" // This should be a number
  }
});

export default [deployment];

JavaScript (ESM)

import { Deployment } from "kubernetes-models/apps/v1/Deployment";

const deployment = new Deployment({
  metadata: {
    name: "nginx",
    namespace: "dev"
  },
  spec: {
    replicas: "INVALID" // This should be a number
  }
});

export default [deployment];

JavaScript (CJS)

const { Deployment } = require("kubernetes-models/apps/v1/Deployment");

const deployment = new Deployment({
  metadata: {
    name: "nginx",
    namespace: "dev"
  },
  spec: {
    replicas: "INVALID" // This should be a number
  }
});

module.exports = [deployment];

Kosko will throw an error as below, which includes error details and location of invalid manifests.

components/nginx.js - 1 error

  ✖ ResolveError: Validation error
    Index: [0]
    Kind: apps/v1/Deployment
    Namespace: dev
    Name: nginx

      /spec/replicas must be integer

error - Generate failed (Total 1 error)

Below are description of each field.

• Index: Location of manifest in a component. In this example, [0] means it is the first manifest in the component.
• Kind: apiVersion and kind of manifest.
• Namespace: metadata.namespace of manifest.
• Name: metadata.name of manifest.

Built-in Validation

All classes in kubernetes-models package support validate() method, so you don't need to implement it manually.

Custom Validation

Create a class with validate() method and throws an error when the validation failed.

TypeScript

class Pod {
  validate() {
    if (!this.metadata.name) {
      throw new Error("metadata.name is required");
    }
  }
}

JavaScript (ESM)

class Pod {
  validate() {
    if (!this.metadata.name) {
      throw new Error("metadata.name is required");
    }
  }
}

JavaScript (CJS)

class Pod {
  validate() {
    if (!this.metadata.name) {
      throw new Error("metadata.name is required");
    }
  }
}

You can also override validate() method of existing classes.

TypeScript

import { Deployment } from "kubernetes-models/apps/v1/Deployment";

class MyDeployment extends Deployment {
  validate() {
    super.validate();

    if (this.spec.replicas < 1) {
      throw new Error("replicas must be at least 1");
    }
  }
}

JavaScript (ESM)

import { Deployment } from "kubernetes-models/apps/v1/Deployment";

class MyDeployment extends Deployment {
  validate() {
    super.validate();

    if (this.spec.replicas < 1) {
      throw new Error("replicas must be at least 1");
    }
  }
}

JavaScript (CJS)

const { Deployment } = require("kubernetes-models/apps/v1/Deployment");

class MyDeployment extends Deployment {
  validate() {
    super.validate();

    if (this.spec.replicas < 1) {
      throw new Error("replicas must be at least 1");
    }
  }
}

Disable Validation

To disable validation on certain manifests, you can call toJSON() method to convert a manifest into a plain object, or just create a plain object instead.

// Use toJSON method,
new Pod().toJSON();

// or just create a plain object.
{
  "apiVerison": "v1",
  "kind": "Pod"
}

To disable validation on all manifests, run kosko generate with --validate=false option.

kosko generate --validate=false