ssa: avoid potential cyclic import

This moves things into separate packages to avoid a potential cyclic
import as soon as we would like to utilize `jsondiff` in `ssa` itself.

Signed-off-by: Hidde Beydals <[email protected]>

ssa/errors.go → ssa/errors/errors.go

@@ -14,14 +14,16 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-package ssa
+package errors
 
 import (
 	"fmt"
 
 	apierrors "k8s.io/apimachinery/pkg/api/errors"
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
+
+	"github.com/fluxcd/pkg/ssa/utils"
 )
 
 // DryRunErr is an error that occurs during a server-side dry-run apply.
@@ -51,9 +53,9 @@ func (e *DryRunErr) Error() string {
 
 	if apierrors.IsNotFound(e.Unwrap()) {
 		if e.involvedObject.GetNamespace() != "" {
-			return fmt.Sprintf("%s namespace not specified: %s", FmtUnstructured(e.involvedObject), e.Unwrap().Error())
+			return fmt.Sprintf("%s namespace not specified: %s", utils.FmtUnstructured(e.involvedObject), e.Unwrap().Error())
 		}
-		return fmt.Sprintf("%s not found: %s", FmtUnstructured(e.involvedObject), e.Unwrap().Error())
+		return fmt.Sprintf("%s not found: %s", utils.FmtUnstructured(e.involvedObject), e.Unwrap().Error())
 	}
 
 	reason := string(apierrors.ReasonForError(e.Unwrap()))
@@ -67,7 +69,7 @@ func (e *DryRunErr) Error() string {
 		reason = fmt.Sprintf(" (%s)", reason)
 	}
 
-	return fmt.Sprintf("%s dry-run failed%s: %s", FmtUnstructured(e.involvedObject), reason, e.underlyingErr.Error())
+	return fmt.Sprintf("%s dry-run failed%s: %s", utils.FmtUnstructured(e.involvedObject), reason, e.underlyingErr.Error())
 }
 
 // Unwrap returns the underlying error.

ssa/errors/immutable.go

@@ -0,0 +1,48 @@
+/*
+Copyright 2023 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package errors
+
+import (
+	"regexp"
+
+	"k8s.io/apimachinery/pkg/api/errors"
+)
+
+// Match CEL immutable error variants.
+var matchImmutableFieldErrors = []*regexp.Regexp{
+	regexp.MustCompile(`.*is\simmutable.*`),
+	regexp.MustCompile(`.*immutable\sfield.*`),
+}
+
+// IsImmutableError checks if the given error is an immutable error.
+func IsImmutableError(err error) bool {
+	// Detect immutability like kubectl does
+	// https://github.com/kubernetes/kubectl/blob/8165f83007/pkg/cmd/apply/patcher.go#L201
+	if errors.IsConflict(err) || errors.IsInvalid(err) {
+		return true
+	}
+
+	// Detect immutable errors returned by custom admission webhooks and Kubernetes CEL
+	// https://kubernetes.io/blog/2022/09/29/enforce-immutability-using-cel/#immutablility-after-first-modification
+	for _, fieldError := range matchImmutableFieldErrors {
+		if fieldError.MatchString(err.Error()) {
+			return true
+		}
+	}
+
+	return false
+}

ssa/errors/immutable_test.go

@@ -0,0 +1,56 @@
+/*
+Copyright 2023 The Flux authors
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package errors
+
+import (
+	"fmt"
+	"testing"
+
+	. "github.com/onsi/gomega"
+)
+
+func TestIsImmutableError(t *testing.T) {
+	testCases := []struct {
+		name  string
+		err   error
+		match bool
+	}{
+		{
+			name:  "CEL immutable error",
+			err:   fmt.Errorf(`the ImmutableSinceFirstWrite "test1" is invalid: value: Invalid value: "string": Value is immutable`),
+			match: true,
+		},
+		{
+			name:  "Custom admission immutable error",
+			err:   fmt.Errorf(`the IAMPolicyMember's spec is immutable: admission webhook "deny-immutable-field-updates.cnrm.cloud.google.com" denied the request: the IAMPolicyMember's spec is immutable`),
+			match: true,
+		},
+		{
+			name:  "Not immutable error",
+			err:   fmt.Errorf(`is not immutable`),
+			match: false,
+		},
+	}
+
+	for _, tc := range testCases {
+		t.Run(tc.name, func(t *testing.T) {
+			g := NewWithT(t)
+
+			g.Expect(IsImmutableError(tc.err)).To(BeIdenticalTo(tc.match))
+		})
+	}
+}

ssa/jsondiff/suite_test.go

@@ -28,7 +28,7 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/envtest"
 
-	"github.com/fluxcd/pkg/ssa"
+	"github.com/fluxcd/pkg/ssa/utils"
 )
 
 var (
@@ -80,5 +80,5 @@ func LoadResource(p string) (*unstructured.Unstructured, error) {
 		return nil, err
 	}
 	defer f.Close()
-	return ssa.ReadObject(f)
+	return utils.ReadObject(f)
 }

ssa/jsondiff/unstructured.go

@@ -25,7 +25,9 @@ import (
 	"k8s.io/apimachinery/pkg/util/errors"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
-	"github.com/fluxcd/pkg/ssa"
+	ssaerrors "github.com/fluxcd/pkg/ssa/errors"
+	"github.com/fluxcd/pkg/ssa/normalize"
+	"github.com/fluxcd/pkg/ssa/utils"
 )
 
 // IgnorePathRoot ignores the root of a JSON document, i.e., the entire
@@ -118,7 +120,7 @@ func Unstructured(ctx context.Context, c client.Client, obj *unstructured.Unstru
 	o.ApplyOptions(opts)
 
 	// Check if the object should be excluded based on metadata.
-	if ssa.AnyInMetadata(obj, o.ExclusionSelector) {
+	if utils.AnyInMetadata(obj, o.ExclusionSelector) {
 		return NewDiffForUnstructured(obj, nil, DiffTypeExclude, nil), nil
 	}
 
@@ -142,14 +144,14 @@ func Unstructured(ctx context.Context, c client.Client, obj *unstructured.Unstru
 		client.FieldOwner(o.FieldManager),
 	}
 	if err := c.Patch(ctx, dryRunObj, client.Apply, patchOpts...); err != nil {
-		return nil, ssa.NewDryRunErr(err, obj)
+		return nil, ssaerrors.NewDryRunErr(err, obj)
 	}
 
 	if dryRunObj.GetResourceVersion() == "" {
 		return NewDiffForUnstructured(obj, nil, DiffTypeCreate, nil), nil
 	}
 
-	if err := ssa.NormalizeDryRunUnstructured(dryRunObj); err != nil {
+	if err := normalize.DryRunUnstructured(dryRunObj); err != nil {
 		return nil, err
 	}
 

ssa/jsondiff/unstructured_test.go

@@ -28,7 +28,7 @@ import (
 	"k8s.io/apimachinery/pkg/apis/meta/v1/unstructured"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 
-	"github.com/fluxcd/pkg/ssa"
+	"github.com/fluxcd/pkg/ssa/normalize"
 )
 
 const dummyFieldOwner = "dummy"
@@ -274,7 +274,7 @@ func TestUnstructuredList(t *testing.T) {
 			},
 			mutateDesired: func(obj *unstructured.Unstructured) {
 				_ = unstructured.SetNestedField(obj.Object, "bar", "stringData", "foo")
-				_ = ssa.NormalizeUnstructured(obj)
+				_ = normalize.Unstructured(obj)
 			},
 			opts: []ListOption{
 				MaskSecrets(true),
@@ -304,14 +304,14 @@ func TestUnstructuredList(t *testing.T) {
 					"a": "2",
 					"b": "1",
 				}, "data")
-				_ = ssa.NormalizeUnstructured(obj)
+				_ = normalize.Unstructured(obj)
 			},
 			mutateDesired: func(obj *unstructured.Unstructured) {
 				_ = unstructured.SetNestedMap(obj.Object, map[string]interface{}{
 					"a": "1",
 					"b": "2",
 				}, "data")
-				_ = ssa.NormalizeUnstructured(obj)
+				_ = normalize.Unstructured(obj)
 			},
 			opts: []ListOption{
 				Rationalize(true),
@@ -718,7 +718,7 @@ func TestUnstructured(t *testing.T) {
 			path: "testdata/empty-secret.yaml",
 			mutateDesired: func(obj *unstructured.Unstructured) {
 				_ = unstructured.SetNestedField(obj.Object, "bar", "stringData", "foo")
-				_ = ssa.NormalizeUnstructured(obj)
+				_ = normalize.Unstructured(obj)
 			},
 			opts: []ResourceOption{
 				MaskSecrets(false),
@@ -742,11 +742,11 @@ func TestUnstructured(t *testing.T) {
 			mutateCluster: func(obj *unstructured.Unstructured) {
 				_ = unstructured.SetNestedField(obj.Object, "bar", "stringData", "foo")
 				_ = unstructured.SetNestedField(obj.Object, "bar", "stringData", "bar")
-				_ = ssa.NormalizeUnstructured(obj)
+				_ = normalize.Unstructured(obj)
 			},
 			mutateDesired: func(obj *unstructured.Unstructured) {
 				_ = unstructured.SetNestedField(obj.Object, "baz", "stringData", "foo")
-				_ = ssa.NormalizeUnstructured(obj)
+				_ = normalize.Unstructured(obj)
 			},
 			opts: []ResourceOption{
 				MaskSecrets(true),
@@ -769,11 +769,11 @@ func TestUnstructured(t *testing.T) {
 			mutateCluster: func(obj *unstructured.Unstructured) {
 				_ = unstructured.SetNestedField(obj.Object, "bar", "stringData", "foo")
 				_ = unstructured.SetNestedField(obj.Object, "bar", "stringData", "bar")
-				_ = ssa.NormalizeUnstructured(obj)
+				_ = normalize.Unstructured(obj)
 			},
 			mutateDesired: func(obj *unstructured.Unstructured) {
 				_ = unstructured.SetNestedField(obj.Object, "baz", "stringData", "foo")
-				_ = ssa.NormalizeUnstructured(obj)
+				_ = normalize.Unstructured(obj)
 			},
 			opts: []ResourceOption{
 				MaskSecrets(true),

ssa/main_test.go

@@ -31,6 +31,8 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/envtest"
 
 	"github.com/fluxcd/cli-utils/pkg/kstatus/polling"
+
+	"github.com/fluxcd/pkg/ssa/utils"
 )
 
 var manager *ResourceManager
@@ -85,7 +87,7 @@ func readManifest(manifest, namespace string) ([]*unstructured.Unstructured, err
 	}
 	yml := fmt.Sprintf(string(data), namespace)
 
-	objects, err := ReadObjects(strings.NewReader(yml))
+	objects, err := utils.ReadObjects(strings.NewReader(yml))
 	if err != nil {
 		return nil, err
 	}
@@ -103,7 +105,7 @@ func generateName(prefix string) string {
 func getFirstObject(objects []*unstructured.Unstructured, kind, name string) (string, *unstructured.Unstructured) {
 	for _, object := range objects {
 		if object.GetKind() == kind && object.GetName() == name {
-			return FmtUnstructured(object), object
+			return utils.FmtUnstructured(object), object
 		}
 	}
 	return "", nil

ssa/manager.go

@@ -23,6 +23,8 @@ import (
 
 	"github.com/fluxcd/cli-utils/pkg/kstatus/polling"
 	"github.com/fluxcd/cli-utils/pkg/object"
+
+	"github.com/fluxcd/pkg/ssa/utils"
 )
 
 // ResourceManager reconciles Kubernetes resources onto the target cluster using server-side apply.
@@ -87,7 +89,7 @@ func (m *ResourceManager) changeSetEntry(o *unstructured.Unstructured, action Ac
 	return &ChangeSetEntry{
 		ObjMetadata:  object.UnstructuredToObjMetadata(o),
 		GroupVersion: o.GroupVersionKind().Version,
-		Subject:      FmtUnstructured(o),
+		Subject:      utils.FmtUnstructured(o),
 		Action:       action,
 	}
 }