kcl.md

KCL

KCL is an open-source, constraint-based record and functional programming language. It leverages mature programming language technology and practices to facilitate the writing of many complex configurations.

https://blog.devops.dev/kcl-and-kpm-the-art-of-managing-kubernetes-configurations-5a0f5b6d4198

SNIPPETS

INIT (KONFIG) KPM MODULE

INIT ENVIRONMENT (DEV)

kpm init dev && cd dev
kcl mod add konfig:0.5.0
kcl mod add k8s:1.30
kpm pull k8s:1.30
kpm pull konfig:0.5.0

cat <<EOF > main.k
import konfig.models.kube.frontend
import konfig.models.kube.templates.resource as res_tpl

# The application configuration in stack will overwrite
# the configuration with the same attribute in base.
appConfiguration: frontend.Server {
    schedulingStrategy.resource = res_tpl.tiny
}
EOF

echo '[profile]
entries = ["../base/base.k", "main.k", "${konfig:KCL_MOD}/models/kube/render/render.k"]' >> kcl.mod

CREATE BASE MODULE

mkdir ../base && cd ../base
cat <<EOF > base.k
import konfig.models.kube.frontend
import konfig.models.kube.frontend.service
import konfig.models.kube.frontend.container

# Application Configuration
appConfiguration: frontend.Server {
    # Main Container Configuration
    mainContainer = container.Main {
        ports = [
            {containerPort = 80}
        ]
        env.MY_ENV: {
            value = "MY_VALUE"
        }
    }
    image = "nginx:1.7.8"
    services = [
        service.Service {
            name = "nginx"
            type = "NodePort"
            ports = [
                {
                    nodePort = 30201
                    port = 80
                    targetPort = 80
                }
            ]
        }
    ]
}
EOF

RENDER ENVIRONMENT

kpm run dev # folder

KUBERNETES MANIFEST w/ VARIABLES

cat <<EOF > deployment.k
_project="opsat-gitlab-receiver"
_registry = "scr.cd43.sthings-pve.labul.sva.de"
_repository = "opsat"
_image = "opsat-gitlab-receiver-08556b153acb3834815dbeff6e71babf"
_tag = "5539da4ccba34231bd8518776b177985d1cb37508b0c56257f0d97fe31bc7a1e"
_label = "opsat"

apiVersion = "apps/v1"
kind = "Deployment"
metadata = {
    name = "${_project}"
    labels.app = "${_label}"
}
spec = {
    replicas = 1
    selector.matchLabels = metadata.labels
    template.metadata.labels = metadata.labels
    template.spec.containers = [
        {
            name = metadata.name
            image = "${_registry}/${_repository}/${_image}:${_tag}"
            ports = [{ containerPort = 80 }]
        }
    ]
}
EOF

CONVERT KCL

kcl deployment.k # JUST RENDER
kcl deployment.k -o deployment.yaml # OUTPUT TO FILE
kcl deployment.k | kubectl apply -f - # APPLY TO CLUSTER