Add a rich example of fn framework for abstraction

functions/examples/fn-framework-application/pkg/dispatcher/dispatcher.go

@@ -0,0 +1,38 @@
+package dispatcher
+
+import (
+	"github.com/spf13/cobra"
+	"sigs.k8s.io/kustomize/functions/examples/fn-framework-application/pkg/exampleapp/v1alpha1"
+	"sigs.k8s.io/kustomize/kyaml/errors"
+	"sigs.k8s.io/kustomize/kyaml/fn/framework"
+	"sigs.k8s.io/kustomize/kyaml/fn/framework/command"
+	"sigs.k8s.io/kustomize/kyaml/kio"
+	"sigs.k8s.io/kustomize/kyaml/kio/filters"
+)
+
+func New() framework.ResourceListProcessor {
+	return framework.ResourceListProcessorFunc(processKnownAPIGroups)
+}
+
+func NewCommand() *cobra.Command {
+	return command.Build(New(), command.StandaloneEnabled, false)
+}
+
+func processKnownAPIGroups(rl *framework.ResourceList) error {
+	p := framework.VersionedAPIProcessor{FilterProvider: framework.GVKFilterMap{
+		"ExampleApp": map[string]kio.Filter{
+			"platform.example.com/v1alpha1": &v1alpha1.ExampleApp{},
+		},
+	}}
+	if err := p.Process(rl); err != nil {
+		return errors.Wrap(err)
+	}
+	var err error
+	// FormatFilter sorts the fields in a deterministic order, which makes the output
+	// more suitable for review in version control.
+	rl.Items, err = filters.FormatFilter{UseSchema: true}.Filter(rl.Items)
+	if err != nil {
+		return errors.WrapPrefixf(err, "formatting output")
+	}
+	return nil
+}