Add Helm reconciler (#118)

Author: SimonBaeumer

README.md

@@ -3,4 +3,41 @@
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-Experimental refactoring of the operator-framework's 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](https://helm.sh/docs/chart_template_guide/values_files/) of a Helm chart exactly to a 
+`CustomResourceDefinition` and defining its watched resources in a `watches.yaml` 
+[configuration](https://sdk.operatorframework.io/docs/building-operators/helm/tutorial/#watch-the-nginx-cr) file.
+
+For creating a [Level II+](https://sdk.operatorframework.io/docs/advanced-topics/operator-capabilities/operator-capabilities/) operator 
+that reuses an already existing Helm chart, a [hybrid](https://github.com/operator-framework/operator-sdk/issues/670)
+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
+
+```go
+// 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))
+}
+```