Push image tag transform code to plugin.

plugin/builtin/ImageTagTransformer.go

@@ -2,6 +2,10 @@
 package builtin
 
 import (
+	"fmt"
+	"regexp"
+	"strings"
+
 	"sigs.k8s.io/kustomize/pkg/ifc"
 	"sigs.k8s.io/kustomize/pkg/image"
 	"sigs.k8s.io/kustomize/pkg/resmap"
@@ -30,10 +34,154 @@ func (p *ImageTagTransformerPlugin) Config(
 }
 
 func (p *ImageTagTransformerPlugin) Transform(m resmap.ResMap) error {
-	t, err := transformers.NewImageTransformer(
-		[]image.Image{p.ImageTag}, p.FieldSpecs)
-	if err != nil {
-		return err
+	for _, r := range m.Resources() {
+		for _, path := range p.FieldSpecs {
+			if !r.OrgId().IsSelected(&path.Gvk) {
+				continue
+			}
+			err := transformers.MutateField(
+				r.Map(), path.PathSlice(), false, p.mutateImage)
+			if err != nil {
+				return err
+			}
+		}
+		// Kept for backward compatibility
+		if err := p.findAndReplaceImage(r.Map()); err != nil && r.OrgId().Kind != `CustomResourceDefinition` {
+			return err
+		}
 	}
-	return t.Transform(m)
+	return nil
+}
+
+func (p *ImageTagTransformerPlugin) mutateImage(in interface{}) (interface{}, error) {
+	original, ok := in.(string)
+	if !ok {
+		return nil, fmt.Errorf("image path is not of type string but %T", in)
+	}
+
+	nTag := p.ImageTag
+	if !isImageMatched(original, nTag.Name) {
+		return original, nil
+	}
+	name, tag := split(original)
+	if nTag.NewName != "" {
+		name = nTag.NewName
+	}
+	if nTag.NewTag != "" {
+		tag = ":" + nTag.NewTag
+	}
+	if nTag.Digest != "" {
+		tag = "@" + nTag.Digest
+	}
+	return name + tag, nil
+
+}
+
+/*
+ findAndReplaceImage replaces the image name and tags inside one object
+ It searches the object for container session
+ then loops though all images inside containers session,
+ finds matched ones and update the image name and tag name
+*/
+func (p *ImageTagTransformerPlugin) findAndReplaceImage(obj map[string]interface{}) error {
+	paths := []string{"containers", "initContainers"}
+	updated := false
+	for _, path := range paths {
+		containers, found := obj[path]
+		if found {
+			if _, err := p.updateContainers(containers); err != nil {
+				return err
+			}
+			updated = true
+		}
+	}
+	if !updated {
+		return p.findContainers(obj)
+	}
+	return nil
+}
+
+func (p *ImageTagTransformerPlugin) updateContainers(in interface{}) (interface{}, error) {
+	containers, ok := in.([]interface{})
+	if !ok {
+		return nil, fmt.Errorf("containers path is not of type []interface{} but %T", in)
+	}
+	for i := range containers {
+		container := containers[i].(map[string]interface{})
+		containerImage, found := container["image"]
+		if !found {
+			continue
+		}
+
+		imageName := containerImage.(string)
+		if isImageMatched(imageName, p.ImageTag.Name) {
+			newImage, err := p.mutateImage(imageName)
+			if err != nil {
+				return nil, err
+			}
+			container["image"] = newImage
+		}
+	}
+	return containers, nil
+}
+
+func (p *ImageTagTransformerPlugin) findContainers(obj map[string]interface{}) error {
+	for key := range obj {
+		switch typedV := obj[key].(type) {
+		case map[string]interface{}:
+			err := p.findAndReplaceImage(typedV)
+			if err != nil {
+				return err
+			}
+		case []interface{}:
+			for i := range typedV {
+				item := typedV[i]
+				typedItem, ok := item.(map[string]interface{})
+				if ok {
+					err := p.findAndReplaceImage(typedItem)
+					if err != nil {
+						return err
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func isImageMatched(s, t string) bool {
+	// Tag values are limited to [a-zA-Z0-9_.-].
+	pattern, _ := regexp.Compile("^" + t + "(:[a-zA-Z0-9_.-]*)?$")
+	return pattern.MatchString(s)
+}
+
+// split separates and returns the name and tag parts
+// from the image string using either colon `:` or at `@` separators.
+// Note that the returned tag keeps its separator.
+func split(imageName string) (name string, tag string) {
+	// check if image name contains a domain
+	// if domain is present, ignore domain and check for `:`
+	ic := -1
+	if slashIndex := strings.Index(imageName, "/"); slashIndex < 0 {
+		ic = strings.LastIndex(imageName, ":")
+	} else {
+		lastIc := strings.LastIndex(imageName[slashIndex:], ":")
+		// set ic only if `:` is present
+		if lastIc > 0 {
+			ic = slashIndex + lastIc
+		}
+	}
+	ia := strings.LastIndex(imageName, "@")
+	if ic < 0 && ia < 0 {
+		return imageName, ""
+	}
+
+	i := ic
+	if ic < 0 {
+		i = ia
+	}
+
+	name = imageName[:i]
+	tag = imageName[i:]
+	return
 }

plugin/builtin/imagetagtransformer/ImageTagTransformer.go

@@ -5,6 +5,10 @@
 package main
 
 import (
+	"fmt"
+	"regexp"
+	"strings"
+
 	"sigs.k8s.io/kustomize/pkg/ifc"
 	"sigs.k8s.io/kustomize/pkg/image"
 	"sigs.k8s.io/kustomize/pkg/resmap"
@@ -31,10 +35,152 @@ func (p *plugin) Config(
 }
 
 func (p *plugin) Transform(m resmap.ResMap) error {
-	t, err := transformers.NewImageTransformer(
-		[]image.Image{p.ImageTag}, p.FieldSpecs)
-	if err != nil {
-		return err
+	for _, r := range m.Resources() {
+		for _, path := range p.FieldSpecs {
+			if !r.OrgId().IsSelected(&path.Gvk) {
+				continue
+			}
+			err := transformers.MutateField(
+				r.Map(), path.PathSlice(), false, p.mutateImage)
+			if err != nil {
+				return err
+			}
+		}
+		// Kept for backward compatibility
+		if err := p.findAndReplaceImage(r.Map()); err != nil && r.OrgId().Kind != `CustomResourceDefinition` {
+			return err
+		}
 	}
-	return t.Transform(m)
+	return nil
+}
+
+func (p *plugin) mutateImage(in interface{}) (interface{}, error) {
+	original, ok := in.(string)
+	if !ok {
+		return nil, fmt.Errorf("image path is not of type string but %T", in)
+	}
+
+	if !isImageMatched(original, p.ImageTag.Name) {
+		return original, nil
+	}
+	name, tag := split(original)
+	if p.ImageTag.NewName != "" {
+		name = p.ImageTag.NewName
+	}
+	if p.ImageTag.NewTag != "" {
+		tag = ":" + p.ImageTag.NewTag
+	}
+	if p.ImageTag.Digest != "" {
+		tag = "@" + p.ImageTag.Digest
+	}
+	return name + tag, nil
+}
+
+// findAndReplaceImage replaces the image name and
+// tags inside one object.
+// It searches the object for container session
+// then loops though all images inside containers
+// session, finds matched ones and update the
+// image name and tag name
+func (p *plugin) findAndReplaceImage(obj map[string]interface{}) error {
+	paths := []string{"containers", "initContainers"}
+	updated := false
+	for _, path := range paths {
+		containers, found := obj[path]
+		if found {
+			if _, err := p.updateContainers(containers); err != nil {
+				return err
+			}
+			updated = true
+		}
+	}
+	if !updated {
+		return p.findContainers(obj)
+	}
+	return nil
+}
+
+func (p *plugin) updateContainers(in interface{}) (interface{}, error) {
+	containers, ok := in.([]interface{})
+	if !ok {
+		return nil, fmt.Errorf(
+			"containers path is not of type []interface{} but %T", in)
+	}
+	for i := range containers {
+		container := containers[i].(map[string]interface{})
+		containerImage, found := container["image"]
+		if !found {
+			continue
+		}
+		imageName := containerImage.(string)
+		if isImageMatched(imageName, p.ImageTag.Name) {
+			newImage, err := p.mutateImage(imageName)
+			if err != nil {
+				return nil, err
+			}
+			container["image"] = newImage
+		}
+	}
+	return containers, nil
+}
+
+func (p *plugin) findContainers(obj map[string]interface{}) error {
+	for key := range obj {
+		switch typedV := obj[key].(type) {
+		case map[string]interface{}:
+			err := p.findAndReplaceImage(typedV)
+			if err != nil {
+				return err
+			}
+		case []interface{}:
+			for i := range typedV {
+				item := typedV[i]
+				typedItem, ok := item.(map[string]interface{})
+				if ok {
+					err := p.findAndReplaceImage(typedItem)
+					if err != nil {
+						return err
+					}
+				}
+			}
+		}
+	}
+	return nil
+}
+
+func isImageMatched(s, t string) bool {
+	// Tag values are limited to [a-zA-Z0-9_.-].
+	pattern, _ := regexp.Compile("^" + t + "(:[a-zA-Z0-9_.-]*)?$")
+	return pattern.MatchString(s)
+}
+
+// split separates and returns the name and tag parts
+// from the image string using either colon `:` or at `@` separators.
+// Note that the returned tag keeps its separator.
+func split(imageName string) (name string, tag string) {
+	// check if image name contains a domain
+	// if domain is present, ignore domain and check for `:`
+	ic := -1
+	if slashIndex := strings.Index(imageName, "/"); slashIndex < 0 {
+		ic = strings.LastIndex(imageName, ":")
+	} else {
+		lastIc := strings.LastIndex(imageName[slashIndex:], ":")
+		// set ic only if `:` is present
+		if lastIc > 0 {
+			ic = slashIndex + lastIc
+		}
+	}
+	ia := strings.LastIndex(imageName, "@")
+	if ic < 0 && ia < 0 {
+		return imageName, ""
+	}
+
+	i := ic
+	if ic < 0 {
+		i = ia
+	}
+
+	name = imageName[:i]
+	tag = imageName[i:]
+	return
 }