Function framework support for patching containers

kyaml/fn/framework/containers.go

@@ -0,0 +1,60 @@
+// Copyright 2019 The Kubernetes Authors.
+// SPDX-License-Identifier: Apache-2.0
+
+package framework
+
+import (
+	"bytes"
+	"text/template"
+
+	"sigs.k8s.io/kustomize/kyaml/errors"
+	"sigs.k8s.io/kustomize/kyaml/sets"
+	"sigs.k8s.io/kustomize/kyaml/yaml"
+	"sigs.k8s.io/kustomize/kyaml/yaml/merge2"
+)
+
+// PatchTemplateContainers executes t as a template and patches each container in each resource
+// with the result.
+func PatchTemplateContainers(resources []*yaml.RNode, t string, input interface{}, containers ...string) error {
+	resourcePatch := template.Must(template.New("containers").Parse(t))
+	var b bytes.Buffer
+	if err := resourcePatch.Execute(&b, input); err != nil {
+		return errors.Wrap(err)
+	}
+	patch, err := yaml.Parse(b.String())
+	if err != nil {
+		return errors.WrapPrefixf(err, b.String())
+	}
+	return PatchContainers(resources, patch, containers...)
+}
+
+// PatchContainers applies patch to each container in each resource.
+func PatchContainers(resources []*yaml.RNode, patch *yaml.RNode, containers ...string) error {
+	names := sets.String{}
+	names.Insert(containers...)
+
+	for i := range resources {
+		containers, err := resources[i].Pipe(yaml.Lookup("spec", "template", "spec", "containers"))
+		if err != nil {
+			return errors.Wrap(err)
+		}
+		if containers == nil {
+			continue
+		}
+		err = containers.VisitElements(func(node *yaml.RNode) error {
+			f := node.Field("name")
+			if f == nil {
+				return nil
+			}
+			if names.Len() > 0 && !names.Has(yaml.GetValue(f.Value)) {
+				return nil
+			}
+			_, err := merge2.Merge(patch, node, yaml.MergeOptions{})
+			return errors.Wrap(err)
+		})
+		if err != nil {
+			return errors.Wrap(err)
+		}
+	}
+	return nil
+}