Kubernetes ICL Templates

While rewriting our k8s YAML files in ICL, we wanted to make it easier for everyone to write self-documented configuration files, files that exposes all the expected fields, what are they for ? and make it crystal clear for everyone what we are doing in our configuration files. Thanks to the work already done by @garethr we could write easily this simple program that generates k8s ICL templates right from kurberntes json schemas

Usage

All k8s ICL templates are written as mixins, this is for 2 main reasons :

• Readability : all the expected parameters are available and documented
• Easy to use : you just have to call the mixins and apply the necessary arguments and it's done.

Here is an example of the "Deployment" template

take deploymentstatus,
     deploymentspec,
     ../v1/objectmeta

/**Deployment enables declarative updates for Pods and ReplicaSets.*/
::orch "kubernetes" "Deployment" as Deployment {
     /**Kind is a string value representing the REST resource this object represents. Servers may
      infer this from the endpoint the client submits requests to. Cannot be updated. In CamelCase.
      More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#types-kinds*/
     kind = "Deployment",
     /**APIVersion defines the versioned schema of this representation of an object. Servers should
      convert recognized schemas to the latest internal value, and may reject unrecognized values.
      More info: https://git.k8s.io/community/contributors/devel/api-conventions.md#resources*/
     apiVersion = "v1beta1",
     /**Most recently observed status of the Deployment.*/
     DeploymentStatus "status" {}
     /**Specification of the desired behavior of the Deployment.*/
     DeploymentSpec "spec" {}
     /**Standard object metadata.*/
     ObjectMeta "metadata" {}
}

And here is how you can call it

take github.com/k8s-icl/latest/v1beta1/deployment,
	     github.com/k8s-icl/latest/v1/containerport,
	     github.com/k8s-icl/latest/v1/container

::variable "container-port" apply ContainerPort @@name="nginx", @@containerPort="8080"
::variable "container-ports" [variable.container-port]
::variable "container" apply Container @@image="nginx:1.13.0", @@name="nginx", @@ports=variable.container-ports
::variable "container-list" [variable.container]
::variable "pod-spec" apply PodSpec @@containers=variable.container-list
::variable "labels" table "app" = "nginx"
::variable "pod-metadata" apply ObjectMeta @@labels=variable.labels
::variable "template" apply PodTemplateSpec @@spec=variable.pod-spec, @@metadata=variable.pod-metadata
::variable "spec" apply DeploymentSpec @@replicas=5, @@template=variable.template
::variable "metadata" apply ObjectMeta @@name = "nginx"

_ "_" apply Deployment @@metadata=variable.metadata, @@spec=variable.spec

Generating the templates yourself

You can use the already generated templates directly, but if you want to regenerate them, you just have to perform a npm start, the program will fetch all the kubernetes schemas for the different versions and regenerate ICLs templates.