How we might make devgun more generic and useful for others.

DevKube.yaml

apiVersion: v1

downloads:
    - name: "helm"
      url: "https://storage.googleapis.com/kubernetes-helm/helm-v2.2.3-{{.Local.OS}}-amd64.tar.gz"
      cmds:
          - "tar zxpf {{.SrcFile}} -C {{.TempDir}}"
          - "cp -f {{.TempDir}}/{{.Local.OS}}-amd64/helm {{.BinDir}}"
    - name: "rocker"
      url: "https://github.com/grammarly/rocker/releases/download/%s/rocker_%s_amd64.tar.gz"
      cmds:
          - "tar zxpf {{.SrcFile}} -C {{.BinDir}}"
          - "chmod +x {{.BinDir}}/rocker"

miniKube:
    memory: {{.Env.MINIKUBE_MEMORY || "6G"}}
    cpus: 2
    disk-size: 25G
    kubernetes-version: v1.6.0
    addons:
        - name: "heapster"
        - name: "ingress"

# Before executing each command the 'waitFor' rules are executed, if all waitFor rules return
# positive immediatly the 'run' command for each rule is skipped.
rules:
    - name: "External DNS"
      run: "kubectl create -f kube-dns-expose-svc.yaml"
      # Wait for directive processes each type in order
      waitFor:
          # returns true when selector correctly matchs atleast 1 service
          - type: selector
            kind: service
            selector: "k8s-app=kube-dns-external"

    - name: "Weave Scope"
      run: "kubectl apply -f https://cloud.weave.works/launch/k8s/weavescope.yaml"
      waitFor:
          # returns true if matches a regex on the pod name
          - type: pod-exists
            regex: "weave-scope*"

    - name: "Init Helm"
      run: "helm init"
      waitFor:
          # returns true when the returns status matches
          - type: return-status
            equals: 0
            cmd: "helm list"

    - name: "Etcd"
      run: "kubectl create -f etcd-service.yaml"
      waitFor:
          # returns true when selector correctly matchs atleast 1 pod
          - type: selector
            kind: pod
            selector: "app=etcd"

    - name: "Cassandra"
      run:
          - "kubectl create -f cassandra-service.yaml"
          - "kubectl create -f cassandra-statefuleset.yaml"
      waitFor:
         # Waits for 2 pods that match app=cassandra
         - type: selector
           kind: pod
           selector: "app=cassandra"
           count: 2
         # Then waits for all pods that match this selector to report ready
         - type: pod-conditions
           selector: "app=cassandra"
           type: Ready
           value: True

# Runs these subcommands after all services are succesfully up and running
runSubComands:
    - reset-db # To initialize our cassandra tables
    - env # Inform users of useful aliases


# These are additional commands for use on the command line by users
subCommands:
    # This command will run a command on the casssandra instances to wipe all
    # the data and re-create all the tables
    - cmd: "reset-db"
      rules:
          # This rule has no `waitFor` so it will succeed imediatly after executing 'run'
          - name: "Reset cassandra database"
            run: "kubectl exec --tty -i cassandra-0 -- /usr/local/bin/reset-db.sh"

    # This command restarts cassandra completely by deleting all pods, services and pvc's
    - cmd: "restart cassandra"
      # Outputs this message and asks the user for Y/N answer before running the command
      message: "This command will delete all cassandra assets and data!"
      askToContinue: true
      rules:
        - name: "Delete Cassandra"
          run: "kubectl delete statefulsets -l app=cassandra"
          waitFor:
              - type: selector
                kind: statefuleset
                # inverse true, means this will return true only when the select 
                # doesn't match a statefuleset
                inverse: true
                selector: "app=cassandra"
        - name: "Delete Pods"
          run: "kubectl delete pods -l app=cassandra"
          waitFor:
              - type: selector
                kind: pod
                inverse: true
                selector: "app=cassandra"
        - name: "Delete PVC"
          run: "kubectl delete pvc -l app=cassandra"
          waitFor:
              - type: selector
                kind: pvc
                inverse: true
                selector: "app=cassandra"
        - name: "Create Cassandra service"
          run:
              - "kubectl create -f cassandra-service.yaml"
              - "kubectl create -f cassandra-statefuleset.yaml"
          waitFor:
              - type: selector
                kind: pvc
                inverse: true
                selector: "app=cassandra"

   # devgun env
    - name: "env"
      # Perhaps commands can just have messages that are output to stdout when run?
      message: "
# Useful aliases
alias cqlsh='kubectl exec --tty -i cassandra-0 -- /usr/local/bin/cqlsh.sh'
alias etcdctl='kubectl exec etcd-0 -- /etcdctl'

# Run this command to configure your shell:
# eval $(devgun minikube env)
"