Push json transform code down to plugin.

plugin/builtin/patchjson6902transformer/PatchJson6902Transformer.go

@@ -5,8 +5,12 @@
 package main
 
 import (
+	"fmt"
+	jsonpatch "github.com/evanphx/json-patch"
+	"github.com/pkg/errors"
+	"sigs.k8s.io/kustomize/v3/pkg/gvk"
 	"sigs.k8s.io/kustomize/v3/pkg/ifc"
-	"sigs.k8s.io/kustomize/v3/pkg/patch/transformer"
+	"sigs.k8s.io/kustomize/v3/pkg/resid"
 	"sigs.k8s.io/kustomize/v3/pkg/resmap"
 	"sigs.k8s.io/kustomize/v3/pkg/types"
 	"sigs.k8s.io/yaml"
@@ -14,7 +18,10 @@ import (
 
 type plugin struct {
 	ldr     ifc.Loader
-	Patches []types.PatchJson6902 `json:"patches,omitempty" yaml:"patches,omitempty"`
+	decodedPatch jsonpatch.Patch
+	Target  types.PatchTarget `json:"target,omitempty" yaml:"target,omitempty"`
+	Path    string `json:"path,omitempty" yaml:"path,omitempty"`
+	JsonOp  string `json:"jsonOp,omitempty" yaml:"jsonOp,omitempty"`
 }
 
 //noinspection GoUnusedGlobalVariable
@@ -23,15 +30,71 @@ var KustomizePlugin plugin
 func (p *plugin) Config(
 	ldr ifc.Loader, rf *resmap.Factory, c []byte) (err error) {
 	p.ldr = ldr
-	p.Patches = nil
-	return yaml.Unmarshal(c, p)
-}
-
-func (p *plugin) Transform(m resmap.ResMap) error {
-	t, err := transformer.NewPatchJson6902Factory(p.ldr).
-		MakePatchJson6902Transformer(p.Patches)
+	err = yaml.Unmarshal(c, p)
 	if err != nil {
 		return err
 	}
-	return t.Transform(m)
+	if p.Target.Name == "" {
+		return fmt.Errorf("must specify the target name")
+	}
+	if p.Path == "" && p.JsonOp == "" {
+		return fmt.Errorf("empty file path and empty jsonOp")
+	}
+	if p.Path != "" {
+		if p.JsonOp != "" {
+			return fmt.Errorf("must specify a file path or jsonOp, not both")
+		}
+		rawOp, err := p.ldr.Load(p.Path)
+		if err != nil {
+			return err
+		}
+		p.JsonOp = string(rawOp)
+		if p.JsonOp == "" {
+			return fmt.Errorf("patch file '%s' empty seems to be empty", p.Path)
+		}
+	}
+	if p.JsonOp[0] != '[' {
+		// if it doesn't seem to be JSON, imagine
+		// it is YAML, and convert to JSON.
+		op, err := yaml.YAMLToJSON([]byte(p.JsonOp))
+		if err != nil {
+			return err
+		}
+		p.JsonOp = string(op)
+	}
+	p.decodedPatch, err = jsonpatch.DecodePatch([]byte(p.JsonOp))
+	if err != nil {
+		return errors.Wrapf(err, "decoding %s", p.JsonOp)
+	}
+	if len(p.decodedPatch) == 0 {
+		return fmt.Errorf(
+			"patch appears to be empty; file=%s, JsonOp=%s", p.Path, p.JsonOp)
+	}
+	return err
+}
+
+func (p *plugin) Transform(m resmap.ResMap) error {
+	id := resid.NewResIdWithNamespace(
+		gvk.Gvk{
+			Group:   p.Target.Group,
+			Version: p.Target.Version,
+			Kind:    p.Target.Kind,
+		},
+		p.Target.Name,
+		p.Target.Namespace,
+	)
+	obj, err := m.GetById(id)
+	if err != nil {
+		return err
+	}
+	rawObj, err := obj.MarshalJSON()
+	if err != nil {
+		return err
+	}
+	modifiedObj, err := p.decodedPatch.Apply(rawObj)
+	if err != nil {
+		return errors.Wrapf(
+			err, "failed to apply json patch '%s'", p.JsonOp)
+	}
+	return obj.UnmarshalJSON(modifiedObj)
 }