Kubernetes (k8s)

A framework for synthesizing Kubernetes manifests using Winglang.

Installation

Install the Wing CLI:

npm i -g winglang

Create a new project and install this library:

mkdir wing-loves-k8s
cd wing-loves-k8s
npm i @winglibs/k8s

Usage

Let's define an app with a simple Kubernetes object:

// main.w
bring k8s;

new k8s.ApiObject(
  apiVersion: "v1",
  kind: "ConfigMap",
  spec: {
    data: {
      key: "value",
    },
  }
);

Now, compile it to YAML:

$ wing compile -t @winglibs/k8s ubuntu.main.w
target/ubuntu.main.k8s

You

The output is a valid K8S YAML is in target/ubuntu.main.k8s:

$ ls target/ubuntu.main.k8s
chart-c86185a7.k8s.yaml

Creating Helm charts

You can set WING_K8S_OUTPUT to helm in order to produce a helm chart instead of simple manifest. This requires a Chart.yaml file next in the current directory.

Default labels and namespace

You can use the WING_K8S_LABELS environment variable to apply labels to all resources in an app. The value is a JSON-encoded map.

The WING_K8S_NAMESPACE variable can be used to specify the default namespace.

export WING_K8S_LABELS='{ "my-label": "123", "your-label": "444" }'
export WING_K8S_NAMESPACE='my-namespace'
wing compile -t @winglibs/k8s main.w

CDK8s Support

This library supports cdk8s and cdk8s-plus, so you can do stuff like this:

npm i cdk8s-plus-27

And then:

bring "cdk8s-plus-27" as k8s;

// lets create a volume that contains our app.
let appData = new k8s.ConfigMap();
appData.addDirectory("./nodejs-app");

let appVolume = k8s.Volume.fromConfigMap(this, "App", appData);

// lets create a deployment to run a few instances of a pod
let deployment = new k8s.Deployment(
  replicas: 3,
);

// now we create a container that runs our app
let appPath = "/var/lib/app";
let port = 80;
let container = deployment.addContainer({
  image: "node:14.4.0-alpine3.12",
  command: ["node", "index.js", "{port}"],
  port: port,
  workingDir: appPath,
});

// make the app accessible to the container
container.mount(appPath, appVolume);

// finally, we expose the deployment as a load balancer service and make it run
deployment.exposeViaService(serviceType: k8s.ServiceType.LOAD_BALANCER);

Roadmap

• Support generating Wing bindings from K8S API specifications and CRDs (cdk8s import).

Maintainers

• Elad Ben-Israel

License

This library is licensed under the MIT License.

API Reference

Table of Contents

• Classes
  • ApiObject
• Structs
  • ApiObjectProps

ApiObject (preflight class)

No description

Constructor

new(props: ApiObjectProps): ApiObject

Properties

Name	Type	Description
apiGroup	str	The group portion of the API version (e.g. authorization.k8s.io).
apiVersion	str	The object's API version (e.g. authorization.k8s.io/v1).
chart	Chart	The chart in which this object is defined.
kind	str	The object kind.
metadata	ApiObjectMetadataDefinition	Metadata associated with this API object.
name	str	The name of the API object.

Methods

Signature	Description
addDependency(dependencies: Array): void	Create a dependency between this ApiObject and other constructs.
addJsonPatch(ops: Array): void	Applies a set of RFC-6902 JSON-Patch operations to the manifest synthesized for this API object.
static isApiObject(o: any): bool	Return whether the given object is an ApiObject.
static of(c: IConstruct): ApiObject	Returns the ApiObject named Resource which is a child of the given construct.
toJson(): any	Renders the object to Kubernetes JSON.

ApiObjectProps (struct)

No description

Properties

Name	Type	Description
apiVersion	str	API version.
kind	str	Resource kind.
metadata	ApiObjectMetadata?	Object metadata.
spec	Json?	No description