add tagsuffix to take image tag suffix (#4364)

* add tagsuffix to take image tag suffix

* add comments to warn about specifications

* add test and error handle

* fix indent

* update comment

* fix merge errors and return updates

* update image update and fix example

* fix yamls formats

remove tabs in yamls

fix space in image name

tag error in name

* fix spacing issue

format of yaml

set example as above

* spacing of spec in testing templates

* change to switch case

api/filters/imagetag/imagetag_test.go

@@ -840,6 +840,45 @@ spec:
 				},
 			},
 		},
+		"updateimagesuffix": {
+			input: `
+group: apps
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploysuffix
+spec:
+  template:
+    spec:
+      containers:
+      - image: redis:6.2.6
+        name: redis
+`,
+			expectedOutput: `
+group: apps
+apiVersion: v1
+kind: Deployment
+metadata:
+  name: deploysuffix
+spec:
+  template:
+    spec:
+      containers:
+      - image: redis:6.2.6-alpine
+        name: redis
+`,
+			filter: Filter{
+				ImageTag: types.Image{
+					Name:      "redis",
+					TagSuffix: "-alpine",
+				},
+			},
+			fsSlice: []types.FieldSpec{
+				{
+					Path: "spec/template/spec/containers[]/image",
+				},
+			},
+		},
 	}
 
 	for tn, tc := range testCases {

api/filters/imagetag/updater.go

@@ -5,6 +5,7 @@ package imagetag
 
 import (
 	"sigs.k8s.io/kustomize/api/filters/filtersutil"
+
 	"sigs.k8s.io/kustomize/api/image"
 	"sigs.k8s.io/kustomize/api/types"
 	"sigs.k8s.io/kustomize/kyaml/yaml"
@@ -46,6 +47,9 @@ func (u imageTagUpdater) SetImageValue(rn *yaml.RNode) error {
 	case u.ImageTag.Digest != "":
 		tag = ""
 		digest = u.ImageTag.Digest
+	case u.ImageTag.TagSuffix != "":
+		tag += u.ImageTag.TagSuffix
+		digest = ""
 	}
 
 	// build final image name

api/internal/builtins/AnnotationsTransformer.go

@@ -1,6 +1,8 @@
 // Code generated by pluginator on AnnotationsTransformer; DO NOT EDIT.
 // pluginator {unknown  1970-01-01T00:00:00Z  }
 
+
+
 package builtins
 
 import (
@@ -16,6 +18,7 @@ type AnnotationsTransformerPlugin struct {
 	FieldSpecs  []types.FieldSpec `json:"fieldSpecs,omitempty" yaml:"fieldSpecs,omitempty"`
 }
 
+
 func (p *AnnotationsTransformerPlugin) Config(
 	_ *resmap.PluginHelpers, c []byte) (err error) {
 	p.Annotations = nil
@@ -34,5 +37,5 @@ func (p *AnnotationsTransformerPlugin) Transform(m resmap.ResMap) error {
 }
 
 func NewAnnotationsTransformerPlugin() resmap.TransformerPlugin {
-	return &AnnotationsTransformerPlugin{}
+  return &AnnotationsTransformerPlugin{}
 }

api/types/image.go

@@ -12,6 +12,10 @@ type Image struct {
 	// NewName is the value used to replace the original name.
 	NewName string `json:"newName,omitempty" yaml:"newName,omitempty"`
 
+	// TagSuffix is the value used to suffix the original tag
+	// If Digest and NewTag is present an error is thrown
+	TagSuffix string `json:"tagSuffix,omitempty" yaml:"tagSuffix,omitempty"`
+
 	// NewTag is the value used to replace the original tag.
 	NewTag string `json:"newTag,omitempty" yaml:"newTag,omitempty"`