# Introduction

Sunstone is a simple, open source templating engine built with Go for Kubernetes and beyond.

# Templating

Sunstone, just like helm, mostly uses https://masterminds.github.io/sprig/ templates with several notable additions.

In addition to standard helm/sprig templating options, Sunstone enables retrieving data from remote registries (such as DockerHub, Quay.io, etcd.). To use this functionality, see example template here.

In this case we are setting default tag to be latest semver tag from keelhq/push-workflow-example registry:

apiVersion: apps/v1
kind: Deployment
metadata: 
  name: pushwf  
  labels: 
    name: "pushwf"
spec:
  replicas: 1
  revisionHistoryLimit: 5
  selector:
    matchLabels:
      app: pushwf
  template:
    metadata:
      name: pushwf
      labels:
        app: pushwf
    spec:     
      containers:                    
        - image: keelhq/push-workflow-example:{{ .version | latestRegistrySemver "keelhq/push-workflow-example" }}
          imagePullPolicy: Always
          name: pushwf
          ports:
            - containerPort: {{ .port | default 8500 }}
          livenessProbe:
            httpGet:
              path: /
              port: {{ .port | default 8500 }}
            initialDelaySeconds: 10
            timeoutSeconds: 5    

# Using templates

To use a template, it has to be publicly accessible when using with a public Sunstone instance (sunstone.dev). Remove the https:// part from your template and supply it as a link to the service:

curl https://sunstone.dev/raw.githubusercontent.com/sunstone-dev/example/master/deployment.yaml

Fortunately, Kubernetes can consume HTTP URLs as well, this allows you to use templates directly:

kubectl apply -f https://sunstone.dev/raw.githubusercontent.com/sunstone-dev/example/master/deployment.yaml

# Aliases

Aliases work like a URL shorteners, creating an easy to remember links for any resource. All these aliases are defined in the https://github.com/sunstone-dev/hub/blob/master/repositories.yaml file (repository address: https://github.com/sunstone-dev/hub)

# Understanding aliases file

Looking at the alias file, we can see that it contains both the alias and url:

repositories:
  - alias: keel
    url: https://gist.githubusercontent.com/rusenask/9ed5c505e31a9b9c89b8591b5ca660e3/raw/3ce05d722ee02c5fbdd3d52c3ac5b04a5bba1de2/sunstone_test.yaml
    maintainers:
      - name: Karolis Rusenas
        email: [email protected]

This means, that instead of calling https://sunstone.dev/gist.githubusercontent.com/rusenask/9ed5c505e31a9b9c89b8591b5ca660e3/raw/3ce05d722ee02c5fbdd3d52c3ac5b04a5bba1de2/sunstone_test.yaml, user can just call https://sunstone.dev/keel to get the same resource.

# Adding your own alias

To add your own alias to this list:

1. Fork https://github.com/sunstone-dev/hub repository
2. Add your own alias entry that includes unique alias name, url and one or more maintainers.
3. Submit a pull request

# Hosting Sunstone on your own infrastructure

Coming soon...