Decrypt SOPS secrets for diff

Signed-off-by: Boris Kreitchman <bkreitch@gmail.com>

cmd/flux/build_kustomization_test.go

@@ -31,6 +31,7 @@ func setup(t *testing.T, tmpl map[string]string) {
 	t.Helper()
 	testEnv.CreateObjectFile("./testdata/build-kustomization/podinfo-source.yaml", tmpl, t)
 	testEnv.CreateObjectFile("./testdata/build-kustomization/podinfo-kustomization.yaml", tmpl, t)
+	testEnv.CreateObjectFile("./testdata/build-kustomization/sops-age.yaml", tmpl, t)
 }
 
 func TestBuildKustomization(t *testing.T) {

cmd/flux/diff_kustomization.go

@@ -61,6 +61,7 @@ type diffKsFlags struct {
 	progressBar       bool
 	strictSubst       bool
 	recursive         bool
+	decryptSecrets    bool
 	localSources      map[string]string
 }
 
@@ -74,6 +75,7 @@ func init() {
 	diffKsCmd.Flags().BoolVar(&diffKsArgs.strictSubst, "strict-substitute", false,
 		"When enabled, the post build substitutions will fail if a var without a default value is declared in files but is missing from the input vars.")
 	diffKsCmd.Flags().BoolVarP(&diffKsArgs.recursive, "recursive", "r", false, "Recursively diff Kustomizations")
+	diffKsCmd.Flags().BoolVar(&diffKsArgs.decryptSecrets, "decrypt-secrets", false, "Decrypt SOPS-encrypted secrets for comparison")
 	diffKsCmd.Flags().StringToStringVar(&diffKsArgs.localSources, "local-sources", nil, "Comma-separated list of repositories in format: Kind/namespace/name=path")
 	diffCmd.AddCommand(diffKsCmd)
 }
@@ -111,6 +113,7 @@ func diffKsCmdRun(cmd *cobra.Command, args []string) error {
 		build.WithIgnore(diffKsArgs.ignorePaths),
 		build.WithStrictSubstitute(diffKsArgs.strictSubst),
 		build.WithRecursive(diffKsArgs.recursive),
+		build.WithDecryptSecrets(diffKsArgs.decryptSecrets),
 		build.WithLocalSources(diffKsArgs.localSources),
 		build.WithSingleKustomization(),
 	)

cmd/flux/diff_kustomization_test.go

@@ -79,6 +79,12 @@ func TestDiffKustomization(t *testing.T) {
 			objectFile: "./testdata/diff-kustomization/value-sops-secret.yaml",
 			assert:     assertGoldenFile("./testdata/diff-kustomization/diff-with-drifted-value-sops-secret.golden"),
 		},
+		{
+			name:       "diff with a drifted value in decrypted sops secret object",
+			args:       "diff kustomization podinfo --path ./testdata/build-kustomization/decrypt-secret --progress-bar=false --decrypt-secrets",
+			objectFile: "./testdata/diff-kustomization/value-sops-secret.yaml",
+			assert:     assertGoldenFile("./testdata/diff-kustomization/diff-with-decryption.golden"),
+		},
 		{
 			name:       "diff with a sops dockerconfigjson secret object",
 			args:       "diff kustomization podinfo --path ./testdata/build-kustomization/podinfo --progress-bar=false",

cmd/flux/testdata/build-kustomization/decrypt-secret/podinfo-token-sops-secret.yaml

@@ -0,0 +1,27 @@
+apiVersion: v1
+kind: Secret
+metadata:
+    name: podinfo-token-77t89m9b67
+stringData:
+    token: ENC[AES256_GCM,data:ut7THDa7SJMTIn26orb2,iv:jBqKk4f8jzOZLpoH7pMnryHRAwwvjaycKwBryEBO3oQ=,tag:193UGSrkhQJzs4pDg5u2mQ==,type:str]
+type: Opaque
+sops:
+    kms: []
+    gcp_kms: []
+    azure_kv: []
+    hc_vault: []
+    age:
+        - recipient: age1yqval9atdcnzjwhmutcjwdukfe5pk9tsa3lqya90u08grp03zgyss93knx
+          enc: |
+            -----BEGIN AGE ENCRYPTED FILE-----
+            YWdlLWVuY3J5cHRpb24ub3JnL3YxCi0+IFgyNTUxOSBxeGdXSVAyMGUzSFpwRGNF
+            bUV5bU9scVJsRUVwbERFYWVjSVpJNFlYREJRCm5xaGxzZGRic0ZwY3hJSmJOcWk3
+            UmYzUDNIU29zd3orYlFlemNGUDhWZVEKLS0tIFJCcEsrdmlZcHBFWFE3SUlCaUNZ
+            ZkJuMm83a0VNODdXMkxUeDRmemJ2blkKebY+krevnla3Rxhrm3T4mmao8NUishwl
+            W4sV4fM2m5gjpiz72MVPjUrakqo9lA9ZLUkSue95YzFe09o7uqglRQ==
+            -----END AGE ENCRYPTED FILE-----
+    lastmodified: "2025-02-16T20:34:53Z"
+    mac: ENC[AES256_GCM,data:C6Sv7iAoMztDGMDTYEW5KFUGSdey6O9zLzNdaEHxQL1oTrQB/hSBOjA4jaEBHovdCL/58w9jDTq8G30IGqUEFEu4HM0YUrSDA1gdTrbtvOfza0hQC8CtmCBWgol3tsWBwcLAeFOlE95perdvKkJx10t/r8yb8biCpLtJcxa/WZE=,iv:2CswtWAATMPZ7BHzWSUNhvT9xfmSSGPdOMvG1jHi3Nk=,tag:FZeCX+EuAlsOGaZbErpfJQ==,type:str]
+    pgp: []
+    encrypted_regex: ^(data|stringData)$
+    version: 3.9.1

cmd/flux/testdata/build-kustomization/podinfo-kustomization.yaml

@@ -13,6 +13,10 @@ spec:
     kind: GitRepository
     name: podinfo
   targetNamespace: default
+  decryption:
+    provider: sops
+    secretRef:
+      name: sops-age
   postBuild:
     substitute:
       cluster_env: "prod"

cmd/flux/testdata/build-kustomization/sops-age.yaml

@@ -0,0 +1,10 @@
+apiVersion: v1
+kind: Secret
+metadata:
+  name: sops-age
+  namespace: {{ .fluxns }}
+type: Opaque
+stringData:
+  identity.agekey: |
+    # public key: age1yqval9atdcnzjwhmutcjwdukfe5pk9tsa3lqya90u08grp03zgyss93knx
+    AGE-SECRET-KEY-1JYSQLQ4QM6GZHDF4F5JLA3HZD2DFJFCMAA2ASCN2USTC02KC4V6SSZNLA7

cmd/flux/testdata/diff-kustomization/diff-with-decryption.golden

@@ -0,0 +1,7 @@
+► Secret/default/podinfo-token-77t89m9b67 drifted
+
+data.token
+  ± value change
+    - *** (before)
+    + *** (after)
+

internal/build/build.go

@@ -44,6 +44,7 @@ import (
 	"sigs.k8s.io/kustomize/kyaml/yaml"
 
 	kustomizev1 "github.com/fluxcd/kustomize-controller/api/v1"
+	"github.com/fluxcd/kustomize-controller/decryptor"
 	"github.com/fluxcd/pkg/kustomize"
 	runclient "github.com/fluxcd/pkg/runtime/client"
 	ssautil "github.com/fluxcd/pkg/ssa/utils"
@@ -77,15 +78,16 @@ type Builder struct {
 	kustomizationFile string
 	ignore            []string
 	// mu is used to synchronize access to the kustomization file
-	mu            sync.Mutex
+	mu             sync.Mutex
-	action        kustomize.Action
+	action         kustomize.Action
-	kustomization *kustomizev1.Kustomization
+	kustomization  *kustomizev1.Kustomization
-	timeout       time.Duration
+	timeout        time.Duration
-	spinner       *yacspin.Spinner
+	spinner        *yacspin.Spinner
-	dryRun        bool
+	dryRun         bool
-	strictSubst   bool
+	strictSubst    bool
-	recursive     bool
+	recursive      bool
-	localSources  map[string]string
+	decryptSecrets bool
+	localSources   map[string]string
 	// diff needs to handle kustomizations one by one
 	singleKustomization bool
 }
@@ -190,6 +192,14 @@ func WithRecursive(recursive bool) BuilderOptionFunc {
 	}
 }
 
+// WithDecryptSecrets sets the decrypt secrets field
+func WithDecryptSecrets(decryptSecrets bool) BuilderOptionFunc {
+	return func(b *Builder) error {
+		b.decryptSecrets = decryptSecrets
+		return nil
+	}
+}
+
 // WithLocalSources sets the local sources field
 func WithLocalSources(localSources map[string]string) BuilderOptionFunc {
 	return func(b *Builder) error {
@@ -514,7 +524,36 @@ func (b *Builder) do(ctx context.Context, kustomization kustomizev1.Kustomizatio
 		return nil, fmt.Errorf("kustomize build failed: %w", err)
 	}
 
+	var dec *decryptor.Decryptor
+	var cleanup func()
+	if b.decryptSecrets {
+		dec, cleanup, err = decryptor.NewTempDecryptor(b.resourcesPath, b.client, b.kustomization)
+		if err != nil {
+			return nil, err
+		}
+		defer cleanup()
+
+		// Import decryption keys
+		if err := dec.ImportKeys(ctx); err != nil {
+			return nil, err
+		}
+	}
+
 	for _, res := range m.Resources() {
+		if res.GetKind() == "Secret" && b.decryptSecrets {
+			outRes, err := dec.DecryptResource(res)
+			if err != nil {
+				return nil, fmt.Errorf("decryption failed for '%s': %w", res.GetName(), err)
+			}
+
+			if outRes != nil {
+				_, err = m.Replace(res)
+				if err != nil {
+					return nil, err
+				}
+			}
+		}
+
 		// run variable substitutions
 		if kustomization.Spec.PostBuild != nil {
 			data, err := runtime.DefaultUnstructuredConverter.ToUnstructured(&kustomization)

internal/build/diff.go

@@ -221,6 +221,7 @@ func (b *Builder) kustomizationDiff(kustomization *kustomizev1.Kustomization) (s
 		WithIgnore(b.ignore),
 		WithStrictSubstitute(b.strictSubst),
 		WithRecursive(b.recursive),
+		WithDecryptSecrets(b.decryptSecrets),
 		WithLocalSources(b.localSources),
 		WithSingleKustomization(),
 	)