appset-secret-plugin is an Argo CD ApplicationSet Plugin Generator (only available in Argo CD v2.8.0 or newer) to fetch variables from an existing Kubernetes Secret that is mounted as file in our plugin generator deployment.

First, install Argo CD on your cluster.

For helm, see the README for full details of the allowed values in values.yaml, but this is the gist for testing:

helm repo add appset-secret-plugin https://small-hack.github.io/appset-secret-plugin
helm install my-release-name appset-secret-plugin/appset-secret-plugin

You'll likely want to pass in a value for an existing Kubernetes Secret containing your secret keys you want to be available to the Plugin Generator. To do that, let's say the name of your Kubernetes Secret is my-secret-name, you can try this:

helm install my-release-name appset-secret-plugin/appset-secret-plugin \
   --set secretVars.existingSecret=my-secret-name

See the README in the kustomize directory.

You can create a Kubernetes Secret for your queriable variables, like this:

apiVersion: v1
kind: Secret
metadata:
  name: argocd-secret-vars
  namespace: argocd
  labels:
    app.kubernetes.io/part-of: argocd
type: stringData
data:
  secret_vars.yaml: |
    app_name: "beepboop"

Here's an example ApplicationSet, using the secret plugin generator, to apply:

apiVersion: argoproj.io/v1alpha1
kind: ApplicationSet
metadata:
  name: my-application-set
spec:
  goTemplate: true
  goTemplateOptions: ["missingkey=error"]
  generators:
    - plugin:
        configMapRef:
          name: secret-plugin-generator
        input:
          parameters:
            secret_vars: ["app_name"]
  template:
    metadata:
      name: "from-appset-{{.app_name}}"
    spec:
      project: default
      source:
        repoURL: https://github.com/argoproj/argocd-example-apps.git
        path: guestbook
      destination:
        server: https://kubernetes.default.svc
        namespace: default

You can apply the example ApplicationSet and Secret with:

kubectl apply -f example/appset_and_secret.yaml

This is an alpha project still, but I'm working on getting to beta. Please open a GitHub Issue with your method of installation, your distro of k8s and the version of your k8s tooling (kustomize, helm, etc), if you're having any trouble.