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2025-12-25 22:10:57 +00:00
commit 8adb52608f
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// Package hash provides content hashing functionality for detecting resource changes.
package hash
import (
"crypto/sha256"
"encoding/hex"
"encoding/json"
"fmt"
corev1 "k8s.io/api/core/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/runtime"
)
// ComputeContentHash computes a SHA256 hash of the resource's actual content.
// It excludes metadata fields (resourceVersion, managedFields, etc.) and status.
// This detects actual content changes vs Kubernetes metadata changes.
func ComputeContentHash(obj runtime.Object) (string, error) {
content, err := extractContent(obj)
if err != nil {
return "", fmt.Errorf("failed to extract content: %w", err)
}
// Convert to JSON for consistent hashing
jsonBytes, err := json.Marshal(content)
if err != nil {
return "", fmt.Errorf("failed to marshal content: %w", err)
}
// Compute SHA256
hash := sha256.Sum256(jsonBytes)
return hex.EncodeToString(hash[:]), nil
}
// extractContent extracts only the content fields from a resource.
// Excludes all metadata except name, namespace, labels, and annotations we care about.
func extractContent(obj runtime.Object) (interface{}, error) {
// Try typed resources first
switch resource := obj.(type) {
case *corev1.Secret:
return extractSecretContent(resource), nil
case *corev1.ConfigMap:
return extractConfigMapContent(resource), nil
default:
// Fall back to unstructured for CRDs and unknown types
return extractUnstructuredContent(obj)
}
}
// extractSecretContent extracts content from a Secret.
func extractSecretContent(secret *corev1.Secret) map[string]interface{} {
return map[string]interface{}{
"type": string(secret.Type),
"data": secret.Data,
"stringData": secret.StringData,
}
}
// extractConfigMapContent extracts content from a ConfigMap.
func extractConfigMapContent(cm *corev1.ConfigMap) map[string]interface{} {
return map[string]interface{}{
"data": cm.Data,
"binaryData": cm.BinaryData,
}
}
// extractUnstructuredContent extracts content from an unstructured resource (CRDs, etc.).
func extractUnstructuredContent(obj runtime.Object) (interface{}, error) {
// Convert to unstructured
unstructuredObj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(obj)
if err != nil {
return nil, fmt.Errorf("failed to convert to unstructured: %w", err)
}
u := &unstructured.Unstructured{Object: unstructuredObj}
// Make a deep copy to avoid race conditions when accessing nested fields
// NestedMap modifies the underlying map, so we need our own copy
uCopy := u.DeepCopy()
// Extract spec (most resources have spec)
spec, found, err := unstructured.NestedMap(uCopy.Object, "spec")
if err != nil {
return nil, fmt.Errorf("failed to extract spec: %w", err)
}
content := make(map[string]interface{})
if found {
content["spec"] = spec
}
// For resources without spec, include all fields except metadata and status
if !found {
for key, value := range uCopy.Object {
if key != "metadata" && key != "status" && key != "apiVersion" && key != "kind" {
content[key] = value
}
}
}
return content, nil
}
// NeedsSync determines if a target resource needs to be synced based on content changes.
// It uses a multi-layer strategy:
// 1. Check generation field (if available) - fastest
// 2. Check content hash - universal
func NeedsSync(source, target runtime.Object, targetAnnotations map[string]string) (bool, error) {
// Layer 1: Generation-based check (for resources that support it)
sourceGen := getGeneration(source)
if sourceGen > 0 {
targetSourceGen := targetAnnotations["source-generation"]
if fmt.Sprintf("%d", sourceGen) != targetSourceGen {
return true, nil // Generation changed
}
}
// Layer 2: Content hash check (works for all resources)
sourceHash, err := ComputeContentHash(source)
if err != nil {
return false, fmt.Errorf("failed to compute source hash: %w", err)
}
targetSourceHash := targetAnnotations["source-content-hash"]
if sourceHash != targetSourceHash {
return true, nil // Content changed
}
// No changes detected
return false, nil
}
// getGeneration extracts the generation field from a resource if it exists.
// Returns 0 if the resource doesn't have a generation field.
func getGeneration(obj runtime.Object) int64 {
// Convert to unstructured to access generation
unstructuredObj, err := runtime.DefaultUnstructuredConverter.ToUnstructured(obj)
if err != nil {
return 0
}
u := &unstructured.Unstructured{Object: unstructuredObj}
return u.GetGeneration()
}
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package hash
import (
"testing"
"github.com/stretchr/testify/assert"
"github.com/stretchr/testify/require"
corev1 "k8s.io/api/core/v1"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
"k8s.io/apimachinery/pkg/runtime"
)
func TestComputeContentHash_Secret(t *testing.T) {
tests := []struct {
secret1 *corev1.Secret
secret2 *corev1.Secret
name string
wantSame bool
wantError bool
}{
{
name: "identical secrets produce same hash",
secret1: &corev1.Secret{
Data: map[string][]byte{
"password": []byte("secret123"),
},
Type: corev1.SecretTypeOpaque,
},
secret2: &corev1.Secret{
Data: map[string][]byte{
"password": []byte("secret123"),
},
Type: corev1.SecretTypeOpaque,
},
wantSame: true,
wantError: false,
},
{
name: "different data produces different hash",
secret1: &corev1.Secret{
Data: map[string][]byte{
"password": []byte("secret123"),
},
},
secret2: &corev1.Secret{
Data: map[string][]byte{
"password": []byte("different"),
},
},
wantSame: false,
wantError: false,
},
{
name: "different type produces different hash",
secret1: &corev1.Secret{
Data: map[string][]byte{"key": []byte("value")},
Type: corev1.SecretTypeOpaque,
},
secret2: &corev1.Secret{
Data: map[string][]byte{"key": []byte("value")},
Type: corev1.SecretTypeTLS,
},
wantSame: false,
wantError: false,
},
{
name: "metadata changes don't affect hash",
secret1: &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
Name: "secret1",
Namespace: "default",
ResourceVersion: "100",
Generation: 1,
},
Data: map[string][]byte{"key": []byte("value")},
},
secret2: &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
Name: "secret2",
Namespace: "different",
ResourceVersion: "200",
Generation: 2,
},
Data: map[string][]byte{"key": []byte("value")},
},
wantSame: true,
wantError: false,
},
{
name: "stringData included in hash",
secret1: &corev1.Secret{
StringData: map[string]string{"key": "value"},
},
secret2: &corev1.Secret{
StringData: map[string]string{"key": "different"},
},
wantSame: false,
wantError: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
hash1, err1 := ComputeContentHash(tt.secret1)
hash2, err2 := ComputeContentHash(tt.secret2)
if tt.wantError {
require.Error(t, err1)
require.Error(t, err2)
return
}
require.NoError(t, err1)
require.NoError(t, err2)
assert.NotEmpty(t, hash1)
assert.NotEmpty(t, hash2)
if tt.wantSame {
assert.Equal(t, hash1, hash2, "hashes should be identical")
} else {
assert.NotEqual(t, hash1, hash2, "hashes should be different")
}
})
}
}
func TestComputeContentHash_ConfigMap(t *testing.T) {
tests := []struct {
cm1 *corev1.ConfigMap
cm2 *corev1.ConfigMap
name string
wantSame bool
wantError bool
}{
{
name: "identical configmaps produce same hash",
cm1: &corev1.ConfigMap{
Data: map[string]string{
"config.yaml": "setting: value",
},
},
cm2: &corev1.ConfigMap{
Data: map[string]string{
"config.yaml": "setting: value",
},
},
wantSame: true,
wantError: false,
},
{
name: "different data produces different hash",
cm1: &corev1.ConfigMap{
Data: map[string]string{
"key": "value1",
},
},
cm2: &corev1.ConfigMap{
Data: map[string]string{
"key": "value2",
},
},
wantSame: false,
wantError: false,
},
{
name: "binaryData included in hash",
cm1: &corev1.ConfigMap{
BinaryData: map[string][]byte{
"file": []byte{0x00, 0x01, 0x02},
},
},
cm2: &corev1.ConfigMap{
BinaryData: map[string][]byte{
"file": []byte{0x00, 0x01, 0xFF},
},
},
wantSame: false,
wantError: false,
},
{
name: "metadata changes don't affect hash",
cm1: &corev1.ConfigMap{
ObjectMeta: metav1.ObjectMeta{
ResourceVersion: "100",
Generation: 1,
},
Data: map[string]string{"key": "value"},
},
cm2: &corev1.ConfigMap{
ObjectMeta: metav1.ObjectMeta{
ResourceVersion: "200",
Generation: 5,
},
Data: map[string]string{"key": "value"},
},
wantSame: true,
wantError: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
hash1, err1 := ComputeContentHash(tt.cm1)
hash2, err2 := ComputeContentHash(tt.cm2)
if tt.wantError {
require.Error(t, err1)
require.Error(t, err2)
return
}
require.NoError(t, err1)
require.NoError(t, err2)
assert.NotEmpty(t, hash1)
assert.NotEmpty(t, hash2)
if tt.wantSame {
assert.Equal(t, hash1, hash2)
} else {
assert.NotEqual(t, hash1, hash2)
}
})
}
}
func TestComputeContentHash_Unstructured(t *testing.T) {
tests := []struct {
obj1 *unstructured.Unstructured
obj2 *unstructured.Unstructured
name string
wantSame bool
wantError bool
}{
{
name: "identical specs produce same hash",
obj1: &unstructured.Unstructured{
Object: map[string]interface{}{
"apiVersion": "v1",
"kind": "Custom",
"spec": map[string]interface{}{
"field": "value",
},
},
},
obj2: &unstructured.Unstructured{
Object: map[string]interface{}{
"apiVersion": "v1",
"kind": "Custom",
"spec": map[string]interface{}{
"field": "value",
},
},
},
wantSame: true,
wantError: false,
},
{
name: "different specs produce different hash",
obj1: &unstructured.Unstructured{
Object: map[string]interface{}{
"spec": map[string]interface{}{
"field": "value1",
},
},
},
obj2: &unstructured.Unstructured{
Object: map[string]interface{}{
"spec": map[string]interface{}{
"field": "value2",
},
},
},
wantSame: false,
wantError: false,
},
{
name: "metadata excluded from hash",
obj1: &unstructured.Unstructured{
Object: map[string]interface{}{
"metadata": map[string]interface{}{
"resourceVersion": "100",
},
"spec": map[string]interface{}{
"field": "value",
},
},
},
obj2: &unstructured.Unstructured{
Object: map[string]interface{}{
"metadata": map[string]interface{}{
"resourceVersion": "200",
},
"spec": map[string]interface{}{
"field": "value",
},
},
},
wantSame: true,
wantError: false,
},
{
name: "status excluded from hash",
obj1: &unstructured.Unstructured{
Object: map[string]interface{}{
"spec": map[string]interface{}{
"field": "value",
},
"status": map[string]interface{}{
"condition": "Ready",
},
},
},
obj2: &unstructured.Unstructured{
Object: map[string]interface{}{
"spec": map[string]interface{}{
"field": "value",
},
"status": map[string]interface{}{
"condition": "NotReady",
},
},
},
wantSame: true,
wantError: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
hash1, err1 := ComputeContentHash(tt.obj1)
hash2, err2 := ComputeContentHash(tt.obj2)
if tt.wantError {
require.Error(t, err1)
require.Error(t, err2)
return
}
require.NoError(t, err1)
require.NoError(t, err2)
assert.NotEmpty(t, hash1)
assert.NotEmpty(t, hash2)
if tt.wantSame {
assert.Equal(t, hash1, hash2)
} else {
assert.NotEqual(t, hash1, hash2)
}
})
}
}
func TestNeedsSync(t *testing.T) {
tests := []struct {
source runtime.Object
target runtime.Object
targetAnnotations map[string]string
name string
want bool
wantError bool
}{
{
name: "needs sync when generation changed",
source: &unstructured.Unstructured{
Object: map[string]interface{}{
"metadata": map[string]interface{}{
"generation": int64(5),
},
"spec": map[string]interface{}{
"field": "value",
},
},
},
target: &unstructured.Unstructured{},
targetAnnotations: map[string]string{
"source-generation": "3",
"source-content-hash": "abc123",
},
want: true,
wantError: false,
},
{
name: "doesn't need sync when generation same and hash same",
source: &corev1.Secret{
Data: map[string][]byte{"key": []byte("value")},
},
target: &corev1.Secret{},
targetAnnotations: map[string]string{
"source-generation": "0",
"source-content-hash": mustComputeHash(t, &corev1.Secret{Data: map[string][]byte{"key": []byte("value")}}),
},
want: false,
wantError: false,
},
{
name: "needs sync when content hash changed",
source: &corev1.ConfigMap{
Data: map[string]string{"key": "newvalue"},
},
target: &corev1.ConfigMap{},
targetAnnotations: map[string]string{
"source-content-hash": "oldhash",
},
want: true,
wantError: false,
},
{
name: "needs sync when no previous hash",
source: &corev1.Secret{
Data: map[string][]byte{"key": []byte("value")},
},
target: &corev1.Secret{},
targetAnnotations: map[string]string{},
want: true,
wantError: false,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got, err := NeedsSync(tt.source, tt.target, tt.targetAnnotations)
if tt.wantError {
require.Error(t, err)
return
}
require.NoError(t, err)
assert.Equal(t, tt.want, got)
})
}
}
func TestGetGeneration(t *testing.T) {
tests := []struct {
obj runtime.Object
name string
want int64
}{
{
name: "returns generation for resource with generation",
obj: &unstructured.Unstructured{
Object: map[string]interface{}{
"metadata": map[string]interface{}{
"generation": int64(42),
},
},
},
want: 42,
},
{
name: "returns 0 for resource without generation",
obj: &corev1.Secret{
ObjectMeta: metav1.ObjectMeta{
Name: "test",
},
},
want: 0,
},
{
name: "returns 0 for nil metadata",
obj: &unstructured.Unstructured{
Object: map[string]interface{}{},
},
want: 0,
},
}
for _, tt := range tests {
t.Run(tt.name, func(t *testing.T) {
got := getGeneration(tt.obj)
assert.Equal(t, tt.want, got)
})
}
}
// Helper function to compute hash for test setup
func mustComputeHash(t *testing.T, obj runtime.Object) string {
t.Helper()
hash, err := ComputeContentHash(obj)
require.NoError(t, err)
return hash
}
// Benchmark tests
func BenchmarkComputeContentHash_Secret(b *testing.B) {
secret := &corev1.Secret{
Data: map[string][]byte{
"password": []byte("secret123"),
"username": []byte("admin"),
},
Type: corev1.SecretTypeOpaque,
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
_, _ = ComputeContentHash(secret)
}
}
func BenchmarkComputeContentHash_ConfigMap(b *testing.B) {
cm := &corev1.ConfigMap{
Data: map[string]string{
"config.yaml": "setting: value\nother: data",
},
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
_, _ = ComputeContentHash(cm)
}
}
func BenchmarkNeedsSync(b *testing.B) {
source := &corev1.Secret{
Data: map[string][]byte{"key": []byte("value")},
}
target := &corev1.Secret{}
hash, _ := ComputeContentHash(source)
annotations := map[string]string{
"source-content-hash": hash,
}
b.ResetTimer()
for i := 0; i < b.N; i++ {
_, _ = NeedsSync(source, target, annotations)
}
}