Kotlin DSL for Kubernetes manifests

Kotlin DSL for Kubernetes generated on top of the fabric8 client.

Usage

The k8s-dsl library is published to Maven Central. Simply add the following line to your project’s dependencies block:

api("dev.forkhandles:k8s-dsl:3.5.0.0")

Using with `kubernetes-client`

Let’s check out how to create an Ingress via fabric8 client. Don’t forget to add a dependency on io.fabric8:kubernetes-client:${kubernetes_client_version}.

import dev.forkhandles.k8s.extensions.backend
import dev.forkhandles.k8s.extensions.metadata
import dev.forkhandles.k8s.extensions.newIngress
import dev.forkhandles.k8s.extensions.spec
import io.fabric8.kubernetes.api.model.IntOrString
import io.fabric8.kubernetes.client.DefaultKubernetesClient


fun main() {
    val client = KubernetesClientBuilder()
        .withConfig(ConfigBuilder().withNamespace("default").build())
        .build()

    client.extensions().ingresses().resource(
        newIngress {
            metadata {
                name = "example-ingress"
            }
            spec {
                backend {
                    serviceName = "example-service"
                    servicePort = IntOrString(8080)
                }
            }
        }
    ).serverSideApply()
}

Apply modifications

By leveraging awesomeness of Kotlin it becomes super easy to have a base service template that every microservice is created from:

val baseService = defaultServiceTemplate()
baseService.apply {
    metadata {
        name = "foo"
    }
}

Complete Deployment example

Here is an example of BaseDeployment that defines a deployment with one replica and mounts a secret that can be used by the service.

import dev.forkhandles.k8s.apps.metadata
import dev.forkhandles.k8s.apps.spec
import dev.forkhandles.k8s.apps.template
import dev.forkhandles.k8s.httpGet
import dev.forkhandles.k8s.livenessProbe
import dev.forkhandles.k8s.metadata
import dev.forkhandles.k8s.newContainer
import dev.forkhandles.k8s.newContainerPort
import dev.forkhandles.k8s.newEnvVar
import dev.forkhandles.k8s.newVolume
import dev.forkhandles.k8s.newVolumeMount
import dev.forkhandles.k8s.readinessProbe
import dev.forkhandles.k8s.secret
import dev.forkhandles.k8s.spec
import io.fabric8.kubernetes.api.model.IntOrString
import io.fabric8.kubernetes.api.model.apps.Deployment

class BaseDeployment : Deployment {
    constructor(serviceName: String) {
        metadata {
            name = "$serviceName-service-deployment"
            labels = mapOf(
                "app" to serviceName,
                "tier" to "backend"
            )
        }
        spec {
            replicas = 1
            template {
                metadata {
                    labels = mapOf(
                        "app" to serviceName,
                        "tier" to "backend"
                    )
                }
                spec {
                    containers = listOf(
                        newContainer {
                            name = "$serviceName-service"
                            image = "gcr.io/fork-handles/$serviceName-service:latest"
                            volumeMounts = listOf(
                                newVolumeMount {
                                    name = "gcp-credentials"
                                    mountPath = "/etc/credentials"
                                    readOnly = true
                                }
                            )
                            env = listOf(
                                newEnvVar {
                                    name = "GOOGLE_APPLICATION_CREDENTIALS"
                                    value = "/etc/credentials/service-account-credentials.json"
                                }
                            )
                            ports = listOf(
                                newContainerPort {
                                    containerPort = 8080
                                }
                            )
                            livenessProbe {
                                httpGet {
                                    path = "/healthz"
                                    port = IntOrString(8080)
                                }
                                periodSeconds = 60
                            }
                            readinessProbe {
                                httpGet {
                                    path = "/healthz"
                                    port = IntOrString(8080)
                                }
                                initialDelaySeconds = 10
                                periodSeconds = 60
                            }
                        }
                    )
                    volumes = listOf(
                        newVolume {
                            name = "gcp-credentials"
                            secret {
                                secretName = "gcp-credentials"
                            }
                        }
                    )
                }
            }
        }
    }
}

Contribution

Check CONTRIBUTING.md

GitHub

View Github