helm-operator

Reimplementation of the helm operator to enrich the Helm operator's reconciliation with custom Go code to create a hybrid operator.

Introduction

The Helm operator type automates Helm chart operations by mapping the values of a Helm chart exactly to a CustomResourceDefinition and defining its watched resources in a watches.yaml configuration file.

For creating a Level II+ operator that reuses an already existing Helm chart, a hybrid between the Go and Helm operator types is necessary.

The hybrid approach allows adding customizations to the Helm operator, such as:

value mapping based on cluster state, or
executing code in specific events.

Quick start

Creating a Helm reconciler

// Operator's main.go
chart, err := loader.Load("path/to/chart")
if err != nil {
 panic(err)
}

reconciler := reconciler.New(
 reconciler.WithChart(*chart),
 reconciler.WithGroupVersionKind(gvk),
)

if err := reconciler.SetupWithManager(mgr); err != nil {
 panic(fmt.Sprintf("unable to create reconciler: %s", err))
}

Creating a Helm reconciler with multiple namespace installation

Add the WATCH_NAMESPACE to the manager files to restrict the namespace to observe where the operator is installed

name: manager
env:
  - name: WATCH_NAMESPACE
        valueFrom:
          fieldRef:
            fieldPath: metadata.namespace

Filter the events to the namespace where the operator is installed

// Operator's main.go
watchNamespace = os.Getenv("WATCH_NAMESPACE")

var cacheOpts cache.Options
if watchNamespace != "" {
	setupLog.Info("Watching specific namespace", "namespace", watchNamespace)
	cacheOpts = cache.Options{
		DefaultNamespaces: map[string]cache.Config{
			watchNamespace: {},
		},
	}
} else {
	setupLog.Info("Watching all namespaces")
}

mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
        ...
		Cache:                  cacheOpts,
})

...
chart, err := loader.Load("path/to/chart")
if err != nil {
 panic(err)
}

reconciler := reconciler.New(
 reconciler.WithChart(*chart),
 reconciler.WithGroupVersionKind(gvk),
)

if err := reconciler.SetupWithManager(mgr); err != nil {
 panic(fmt.Sprintf("unable to create reconciler: %s", err))
}

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