feat: add SortOptions support for kustomize resource ordering

chartify.go

@@ -108,6 +108,11 @@ type ChartifyOpts struct {
 	// and it my produce output unexpected to you.
 	KubeVersion string
 
+	// SortOptions configures kustomize's sortOptions for resource ordering.
+	// Use &SortOptions{Order: "fifo"} to preserve resource order and minimize diff noise.
+	// See https://kubectl.docs.kubernetes.io/references/kustomize/kustomization/sortoptions/
+	SortOptions *SortOptions
+
 	// ApiVersions is a string of kubernetes APIVersions and passed to helm template via --api-versions
 	// It is required if your chart contains any template that relies on Capabilities.APIVersion for rendering
 	// resources depending on the API resources and versions available in a target cluster.
@@ -163,6 +168,12 @@ func (r *Runner) Chartify(release, dirOrChart string, opts ...ChartifyOption) (s
 		}
 	}
 
+	if u.SortOptions != nil {
+		if err := u.SortOptions.validate(); err != nil {
+			return "", err
+		}
+	}
+
 	isLocal, _ := r.Exists(dirOrChart)
 
 	var isKustomization bool
@@ -267,6 +278,7 @@ func (r *Runner) Chartify(release, dirOrChart string, opts ...ChartifyOption) (s
 			EnableAlphaPlugins: u.EnableKustomizeAlphaPlugins,
 			Namespace:          u.Namespace,
 			HelmBinary:         r.helmBin(),
+			SortOptions:        u.SortOptions,
 		}
 		kustomizeFile, err := r.KustomizeBuild(dirOrChart, tempDir, kustomizeOpts)
 		if err != nil {
@@ -466,6 +478,7 @@ func (r *Runner) Chartify(release, dirOrChart string, opts ...ChartifyOption) (s
 			StrategicMergePatches: u.StrategicMergePatches,
 			Transformers:          u.Transformers,
 			EnableAlphaPlugins:    u.EnableKustomizeAlphaPlugins,
+			SortOptions:           u.SortOptions,
 		}
 		if err := r.Patch(tempDir, generatedManifestFiles, patchOpts); err != nil {
 			return "", err
@@ -684,7 +697,7 @@ func createDirForFile(f string) error {
 	dstFileDir := filepath.Dir(f)
 	if _, err := os.Lstat(dstFileDir); err == nil {
 
-	} else if err != nil && os.IsNotExist(err) {
+	} else if os.IsNotExist(err) {
 		if err := os.MkdirAll(dstFileDir, 0755); err != nil {
 			return fmt.Errorf("creating directory %s: %v", dstFileDir, err)
 		}

kustomize.go

@@ -10,11 +10,45 @@ import (
 	"gopkg.in/yaml.v3"
 )
 
+var validSortOrders = map[string]bool{
+	"legacy": true,
+	"fifo":   true,
+}
+
+type SortOptions struct {
+	Order string `yaml:"order"`
+}
+
+func (o *SortOptions) validate() error {
+	if o.Order == "" {
+		return fmt.Errorf("sortOptions.order must not be empty")
+	}
+	if !validSortOrders[o.Order] {
+		return fmt.Errorf("sortOptions.order %q is not valid; accepted values are: legacy, fifo", o.Order)
+	}
+	return nil
+}
+
+func marshalSortOptions(opts *SortOptions) ([]byte, error) {
+	if opts == nil {
+		return nil, nil
+	}
+	if err := opts.validate(); err != nil {
+		return nil, err
+	}
+	sortOptsBytes, err := yaml.Marshal(map[string]*SortOptions{"sortOptions": opts})
+	if err != nil {
+		return nil, fmt.Errorf("marshaling sortOptions: %w", err)
+	}
+	return sortOptsBytes, nil
+}
+
 type KustomizeOpts struct {
-	Images     []KustomizeImage `yaml:"images"`
-	NamePrefix string           `yaml:"namePrefix"`
-	NameSuffix string           `yaml:"nameSuffix"`
-	Namespace  string           `yaml:"namespace"`
+	Images      []KustomizeImage `yaml:"images"`
+	NamePrefix  string           `yaml:"namePrefix"`
+	NameSuffix  string           `yaml:"nameSuffix"`
+	Namespace   string           `yaml:"namespace"`
+	SortOptions *SortOptions     `yaml:"sortOptions,omitempty"`
 }
 
 type KustomizeImage struct {
@@ -45,6 +79,7 @@ type KustomizeBuildOpts struct {
 	EnableAlphaPlugins bool
 	Namespace          string
 	HelmBinary         string
+	SortOptions        *SortOptions
 }
 
 func (o *KustomizeBuildOpts) SetKustomizeBuildOption(opts *KustomizeBuildOpts) error {
@@ -80,6 +115,10 @@ func (r *Runner) KustomizeBuild(srcDir string, tempDir string, opts ...Kustomize
 		kustomizeOpts.Namespace = u.Namespace
 	}
 
+	if u.SortOptions != nil {
+		kustomizeOpts.SortOptions = u.SortOptions
+	}
+
 	if len(u.SetValues) > 0 || len(u.SetFlags) > 0 {
 		panic("--set is not yet supported for kustomize-based apps! Use -f/--values flag instead.")
 	}
@@ -139,6 +178,21 @@ func (r *Runner) KustomizeBuild(srcDir string, tempDir string, opts ...Kustomize
 			return "", err
 		}
 	}
+	// sortOptions is appended directly to kustomization.yaml because kustomize
+	// has no `edit set sortoptions` command unlike images, nameprefix, etc.
+	if kustomizeOpts.SortOptions != nil {
+		sortOptsBytes, err := marshalSortOptions(kustomizeOpts.SortOptions)
+		if err != nil {
+			return "", err
+		}
+		f, err := r.ReadFile(kustomizationPath)
+		if err != nil {
+			return "", fmt.Errorf("reading kustomization.yaml for sortOptions: %w", err)
+		}
+		if err := r.WriteFile(kustomizationPath, append(f, sortOptsBytes...), 0644); err != nil {
+			return "", err
+		}
+	}
 	outputFile := filepath.Join(tempDir, "templates", "kustomized.yaml")
 	kustomizeArgs := []string{"-o", outputFile, "build"}
 

kustomize_test.go

@@ -0,0 +1,146 @@
+package chartify
+
+import (
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	"github.com/stretchr/testify/require"
+)
+
+func TestSortOptionsValidate(t *testing.T) {
+	t.Run("empty order is invalid", func(t *testing.T) {
+		err := (&SortOptions{Order: ""}).validate()
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "must not be empty")
+	})
+
+	t.Run("invalid order is rejected", func(t *testing.T) {
+		err := (&SortOptions{Order: "unknown"}).validate()
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "is not valid")
+	})
+
+	t.Run("fifo is valid", func(t *testing.T) {
+		require.NoError(t, (&SortOptions{Order: "fifo"}).validate())
+	})
+
+	t.Run("legacy is valid", func(t *testing.T) {
+		require.NoError(t, (&SortOptions{Order: "legacy"}).validate())
+	})
+}
+
+func TestMarshalSortOptions(t *testing.T) {
+	t.Run("nil returns empty bytes", func(t *testing.T) {
+		got, err := marshalSortOptions(nil)
+		require.NoError(t, err)
+		require.Nil(t, got)
+	})
+
+	t.Run("fifo order", func(t *testing.T) {
+		got, err := marshalSortOptions(&SortOptions{Order: "fifo"})
+		require.NoError(t, err)
+		result := string(got)
+		require.Contains(t, result, "sortOptions:")
+		require.Contains(t, result, "order: fifo")
+	})
+
+	t.Run("invalid order returns error", func(t *testing.T) {
+		_, err := marshalSortOptions(&SortOptions{Order: "bogus"})
+		require.Error(t, err)
+		require.Contains(t, err.Error(), "is not valid")
+	})
+}
+
+func TestPatch_SortOptions(t *testing.T) {
+	t.Run("Patch writes sortOptions to kustomization.yaml", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		templatesDir := filepath.Join(tempDir, "templates")
+		require.NoError(t, os.MkdirAll(templatesDir, 0755))
+
+		manifest := filepath.Join(templatesDir, "deployment.yaml")
+		require.NoError(t, os.WriteFile(manifest, []byte(`apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-deployment
+spec:
+  replicas: 1
+`), 0644))
+
+		patchContent := `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-deployment
+spec:
+  replicas: 3
+`
+		patchFile := filepath.Join(tempDir, "patch.yaml")
+		require.NoError(t, os.WriteFile(patchFile, []byte(patchContent), 0644))
+
+		r := New(HelmBin(helm))
+
+		var capturedKustomization string
+		origWriteFile := r.WriteFile
+		r.WriteFile = func(filename string, data []byte, perm os.FileMode) error {
+			if strings.HasSuffix(filename, "kustomization.yaml") {
+				capturedKustomization = string(data)
+			}
+			return origWriteFile(filename, data, perm)
+		}
+
+		patchOpts := &PatchOpts{
+			StrategicMergePatches: []string{patchFile},
+			SortOptions:           &SortOptions{Order: "fifo"},
+		}
+		err := r.Patch(tempDir, []string{manifest}, patchOpts)
+		require.NoError(t, err)
+		require.Contains(t, capturedKustomization, "sortOptions:")
+		require.Contains(t, capturedKustomization, "order: fifo")
+	})
+
+	t.Run("Patch without SortOptions omits sortOptions from kustomization.yaml", func(t *testing.T) {
+		tempDir := t.TempDir()
+
+		templatesDir := filepath.Join(tempDir, "templates")
+		require.NoError(t, os.MkdirAll(templatesDir, 0755))
+
+		manifest := filepath.Join(templatesDir, "deployment.yaml")
+		require.NoError(t, os.WriteFile(manifest, []byte(`apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-deployment
+spec:
+  replicas: 1
+`), 0644))
+
+		patchContent := `apiVersion: apps/v1
+kind: Deployment
+metadata:
+  name: test-deployment
+spec:
+  replicas: 3
+`
+		patchFile := filepath.Join(tempDir, "patch.yaml")
+		require.NoError(t, os.WriteFile(patchFile, []byte(patchContent), 0644))
+
+		r := New(HelmBin(helm))
+
+		var capturedKustomization string
+		origWriteFile := r.WriteFile
+		r.WriteFile = func(filename string, data []byte, perm os.FileMode) error {
+			if strings.HasSuffix(filename, "kustomization.yaml") {
+				capturedKustomization = string(data)
+			}
+			return origWriteFile(filename, data, perm)
+		}
+
+		patchOpts := &PatchOpts{
+			StrategicMergePatches: []string{patchFile},
+		}
+		err := r.Patch(tempDir, []string{manifest}, patchOpts)
+		require.NoError(t, err)
+		require.NotContains(t, capturedKustomization, "sortOptions:")
+	})
+}

patch.go

@@ -22,6 +22,9 @@ type PatchOpts struct {
 	// Above Kustomize v3, it is `--enable-alpha-plugins`.
 	// Below Kustomize v3 (including v3), it is `--enable_alpha_plugins`.
 	EnableAlphaPlugins bool
+
+	// SortOptions configures kustomize's sortOptions for resource ordering.
+	SortOptions *SortOptions
 }
 
 func (o *PatchOpts) SetPatchOption(opts *PatchOpts) error {
@@ -173,6 +176,14 @@ resources:
 		}
 	}
 
+	if u.SortOptions != nil {
+		sortOptsBytes, err := marshalSortOptions(u.SortOptions)
+		if err != nil {
+			return err
+		}
+		kustomizationYamlContent += string(sortOptsBytes)
+	}
+
 	if err := r.WriteFile(filepath.Join(tempDir, "kustomization.yaml"), []byte(kustomizationYamlContent), 0644); err != nil {
 		return err
 	}

tempdir_test.go

@@ -35,29 +35,29 @@ func TestGenerateID(t *testing.T) {
 		release: "foo",
 		chart:   "incubator/raw",
 		opts:    ChartifyOpts{},
-		want:    "foo-57669d77b",
+		want:    "foo-5586b9d54d",
 	})
 
 	run(testcase{
 		release: "foo",
 		chart:   "stable/envoy",
 		opts:    ChartifyOpts{},
-		want:    "foo-6c769b499",
+		want:    "foo-748fb9844f",
 	})
 
 	run(testcase{
 		release: "bar",
 		chart:   "incubator/raw",
 		opts:    ChartifyOpts{},
-		want:    "bar-7d49bf498c",
+		want:    "bar-77ddc8bd65",
 	})
 
 	run(testcase{
 		release: "foo",
 		opts: ChartifyOpts{
 			Namespace: "myns",
 		},
-		want: "myns-foo-9c6f7fb79",
+		want: "myns-foo-5dbbf694b5",
 	})
 
 	for id, n := range ids {