Deckhand

sbt companion for Kubernetes and OpenShift.

Status

Incubating.

Setup

For sbt 1.x add the following to project/plugins.sbt:

addSbtPlugin("com.lightbend.rp" % "sbt-deckhand" % "X.Y.Z")

See releases for the latest release.

Usage

sbt-deckhand introduces Deckhand object to your build.sbt, which is intended to drive an OpenShift cluster during integration testing.

Deckhand.kubectl

Example:

lazy val check = taskKey[Unit]("check")

check := {
  val s = streams.value
  val namespace = "somenamespace"
  val kubectl = Deckhand.kubectl(s.log)
  val yamlDir = baseDirectory.value / "kubernetes"

  try {
    kubectl.tryCreate(s"namespace $namespace")
    kubectl.setCurrentNamespace(namespace)
    kubectl.apply(yamlDir / "akka-cluster.yaml")
    kubectl.waitForPods(3)
    kubectl.describe("pods")

    // do something here...
  } finally {
    kubectl.delete(s"services,pods,deployment --all --namespace $namespace")
    kubectl.waitForPods(0)
  }
}

Deckhand.kubectl(s.log) returns Kubectrl value, which is a thin wrapper around kubectl and oc command line. It provides methods such as apply, get, and logs each corresponding to kubectl apply, kubectl get, and kubectl logs.

See Kubectl.scala for details.

waitForPods

waitForPods is a utility method to wait for the given number of pods.

kubectl.waitForPods(3)

Optionally you can also pass in String arguments to kubectl get to narrow down the pods to wait for:

kubectl.waitForPods(3, "--selector app=bootstrap-kapi-demo")

checkAkkaCluster

checkAkkaCluster is a utility method to wait for an Akka Cluster to bootstrap itself with the given number of members.

kubectl.checkAkkaCluster(3)

Deckhand.mustache

For simple templating, Deckhand provides Mustache template support, which can be used to substitute variables in the YAML files.

For example given rbac.mustache, I'd like to plugin {{namespace}} in build.sbt.

---
kind: Role
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: pod-reader
rules:
- apiGroups: [""] # "" indicates the core API group
  resources: ["pods"]
  verbs: ["get", "watch", "list"]
---
kind: RoleBinding
apiVersion: rbac.authorization.k8s.io/v1
metadata:
  name: read-pods
subjects:
- kind: User
  name: system:serviceaccount:{{namespace}}:default
roleRef:
  kind: Role
  name: pod-reader
  apiGroup: rbac.authorization.k8s.io

We can call:

val kubectl = Deckhand.kubectl(s.log)
val yamlDir = baseDirectory.value / "kubernetes"
val namespace = "somenamespace"
kubectl.apply(Deckhand.mustache(yamlDir / "rbac.mustache"),
  Map(
    "namespace"       -> namespace
  ))

Deckhand.kustomize

Alternatively, if you want to overlay specific YAML patch on top of base YAML files, Deckhand provides Kustomize integration.

For example here's a patch to patch the imagePullPolicy to Never for Minikube:

apiVersion: "apps/v1beta2"
kind: Deployment
metadata:
  name: "bootstrap-kapi-demo-v0-1-0"
spec:
  template:
    spec:
      containers:
        - name: "bootstrap-kapi-demo"
          image: "bootstrap-kapi-demo:0.1.0"
          imagePullPolicy: "Never"

In build.sbt we can apply the variant YAML file as follows:

val kubectl = Deckhand.kubectl(s.log)
kubectl.apply(Deckhand.kustomize(baseDirectory.value / "overlay" / "minikube"))

Deckhand.docker

Example:

lazy val check = taskKey[Unit]("check")

check := {
  val s = streams.value
  val nm = name.value
  val v = version.value
  val namespace = "somenamespace"
  val docker = Deckhand.docker(s.log)
  docker.tag(s"$nm:$v registry.yourcompany.com/$namespace/$nm:$v")
  docker.push(s"registry.yourcompany.com/$namespace/$nm")
}

Photo credit

Ben van Meerendonk / AHF, collectie IISG, Amsterdam

lightbend / deckhand 0.1.0