nats-k8s

Nats.java

package io.grhk.infra;

import io.k8s.api.core.v1.Namespace;
import io.k8s.api.core.v1.volumeresourcerequirements.Requests;
import io.vacco.beleth.rt.BlKubeRt;
import java.util.List;

import static io.k8s.api.apps.v1.StatefulSet.statefulSet;
import static io.k8s.api.apps.v1.StatefulSetSpec.statefulSetSpec;

import static io.k8s.api.core.v1.ConfigMap.configMap;
import static io.k8s.api.core.v1.ConfigMapVolumeSource.configMapVolumeSource;
import static io.k8s.api.core.v1.Container.container;
import static io.k8s.api.core.v1.ContainerPort.containerPort;
import static io.k8s.api.core.v1.PersistentVolumeClaim.persistentVolumeClaim;
import static io.k8s.api.core.v1.PersistentVolumeClaimSpec.persistentVolumeClaimSpec;
import static io.k8s.api.core.v1.PodSpec.podSpec;
import static io.k8s.api.core.v1.PodTemplateSpec.podTemplateSpec;
import static io.k8s.api.core.v1.ResourceRequirements.resourceRequirements;
import static io.k8s.api.core.v1.Service.service;
import static io.k8s.api.core.v1.ServicePort.servicePort;
import static io.k8s.api.core.v1.ServiceSpec.serviceSpec;
import static io.k8s.api.core.v1.Volume.volume;
import static io.k8s.api.core.v1.VolumeMount.volumeMount;
import static io.k8s.api.core.v1.VolumeResourceRequirements.volumeResourceRequirements;
import static io.k8s.api.core.v1.configmap.Data.data;
import static io.k8s.api.core.v1.resourcerequirements.Limits.limits;
import static io.k8s.api.core.v1.resourcerequirements.Requests.requests;
import static io.k8s.api.core.v1.servicespec.Selector.selector;

import static io.k8s.apimachinery.pkg.apis.meta.v1.LabelSelector.labelSelector;
import static io.k8s.apimachinery.pkg.apis.meta.v1.ObjectMeta.objectMeta;
import static io.k8s.apimachinery.pkg.apis.meta.v1.labelselector.MatchLabels.matchLabels;
import static io.k8s.apimachinery.pkg.apis.meta.v1.objectmeta.Labels.labels;

public class Nats {

  public static void apply(BlKubeRt k, Namespace ns, String memoryMi, String cpuM) {

    var configMap = configMap()
      .apiVersion("v1")
      .kind("ConfigMap")
      .metadata(
        objectMeta()
          .name("nats-config")
          .namespace(ns.metadata.name)
      )
      .data(
        data().kv("nats.conf", String.join("\n",
          "server_name: $HOSTNAME",
          "listen: 0.0.0.0:4222",
          "http: 0.0.0.0:8222",
          "jetstream: { store_dir: \"/data\" }",
          "cluster: {",
          "  name: \"c1\"",
          "  listen: 0.0.0.0:6222",
          "  routes: [\"nats://nats-0.nats:6222\", \"nats://nats-1.nats:6222\", \"nats://nats-2.nats:6222\"]",
          "  cluster_advertise: \"$HOSTNAME:6222\"",
          "}"
        ))
      );

    var statefulSet = statefulSet()
      .apiVersion("apps/v1")
      .kind("StatefulSet")
      .metadata(
        objectMeta()
          .name("nats")
          .namespace(ns.metadata.name)
          .labels(labels().kv("app", "nats"))
      )
      .spec(
        statefulSetSpec()
          .serviceName("nats")
          .replicas(3L)
          .selector(labelSelector().matchLabels(matchLabels().kv("app", "nats")))
          .template(
            podTemplateSpec()
              .metadata(objectMeta().labels(labels().kv("app", "nats")))
              .spec(
                podSpec()
                  .containers(List.of(
                    container()
                      .name("nats")
                      .image("docker.io/nats:2.10")
                      .command(List.of("/nats-server"))
                      .args(List.of("-c", "/etc/nats-config/nats.conf"))
                      .ports(List.of(
                        containerPort().name("nats-client").containerPort(4222L),
                        containerPort().name("nats-cluster").containerPort(6222L),
                        containerPort().name("nats-http").containerPort(8222L)
                      ))
                      .volumeMounts(List.of(
                        volumeMount().name("data").mountPath("/data"),
                        volumeMount().name("nats-config").mountPath("/etc/nats-config")
                      ))
                      .resources(
                        resourceRequirements()
                          .requests(requests().kv("memory", memoryMi).kv("cpu", cpuM))
                          .limits(limits().kv("memory", memoryMi).kv("cpu", cpuM))
                      )
                  ))
                  .volumes(List.of(
                    volume()
                      .configMap(configMapVolumeSource().name("nats-config"))
                      .name("nats-config")
                  ))
              )
          )
          .volumeClaimTemplates(List.of(
            persistentVolumeClaim()
              .metadata(objectMeta().name("data").labels(labels().kv("app", "nats")))
              .spec(
                persistentVolumeClaimSpec()
                  .accessModes(List.of("ReadWriteOnce"))
                  .resources(volumeResourceRequirements().requests(new Requests().kv("storage", "8Gi")))
                  .storageClassName("local-nats")
              )
          ))
      );

    var service = service()
      .apiVersion("v1")
      .kind("Service")
      .metadata(
        objectMeta()
          .name("nats")
          .namespace(ns.metadata.name)
          .labels(labels().kv("app", "nats"))
      )
      .spec(
        serviceSpec()
          .type("NodePort")
          .externalTrafficPolicy("Local")
          .selector(selector().kv("app", "nats"))
          .ports(List.of(
            servicePort().name("nats-client").port(4222L).targetPort("nats-client").nodePort(30422L),
            servicePort().name("nats-http").port(8222L).targetPort("nats-http").nodePort(30081L)
          ))
      );

    k
      .add(configMap)
      .add(statefulSet)
      .add(service)
    ;
  }

}