feat: support expansion in gator verify

pkg/gator/errors.go

@@ -18,6 +18,10 @@ var (
 	// ErrNotASyncSet indicates the user-indicated file does not contain a
 	// SyncSet.
 	ErrNotAGVKManifest = errors.New("not a GVKManifest")
+	// ErrNotAnExpansion indicates the user-indicated file does not contain a
+	// ErrNotAnExpansion indicates the user-indicated file does not contain an
+	// ExpansionTemplate.
+	ErrNotAnExpansion = errors.New("not an Expansion Template")
 	// ErrAddingTemplate indicates a problem instantiating a Suite's ConstraintTemplate.
 	ErrAddingTemplate = errors.New("adding template")
 	// ErrAddingConstraint indicates a problem instantiating a Suite's Constraint.

pkg/gator/fixtures/fixtures.go

@@ -158,6 +158,34 @@ spec:
         }
 `
 
+	TemplateRestrictCustomField = `
+kind: ConstraintTemplate
+apiVersion: templates.gatekeeper.sh/v1beta1
+metadata:
+  name: restrictedcustomfield
+spec:
+  crd:
+    spec:
+      names:
+        kind: RestrictedCustomField
+      validation:
+        openAPIV3Schema:
+          type: object
+          properties:
+            expectedCustomField: 
+              type: boolean
+  targets:
+    - target: admission.k8s.gatekeeper.sh
+      rego: |
+        package restrictedcustomfield
+        violation[{"msg": msg}] {
+          got := input.review.object.spec.customField
+          expected := input.parameters.expectedCustomField
+          got == expected
+          msg := sprintf("foo object has restricted custom field value of %v", [expected])
+        }
+`
+
 	ConstraintAlwaysValidate = `
 kind: AlwaysValidate
 apiVersion: constraints.gatekeeper.sh/v1beta1
@@ -262,6 +290,22 @@ metadata:
   name: other
 `
 
+	ConstraintRestrictCustomField = `
+apiVersion: constraints.gatekeeper.sh/v1beta1
+kind: RestrictedCustomField
+metadata:
+  name: restrict-foo-custom-field
+spec:
+  match:
+    kinds:
+      - apiGroups: [""]
+        kinds: ["Foo"]
+    namespaces:
+      - "default"
+  parameters:
+    expectedCustomField: true
+`
+
 	Object = `
 kind: Object
 apiVersion: group.sh/v1
@@ -328,6 +372,17 @@ apiVersion: group.sh/v1
 metadata:
   name: object`
 
+	ObjectFooTemplate = `
+apiVersion: apps/v1
+kind: FooTemplate
+metadata:
+  name: foo-template
+spec:
+  template:
+    spec:
+      customField: true
+`
+
 	NamespaceSelected = `
 kind: Namespace
 apiVersion: /v1
@@ -682,4 +737,21 @@ spec:
       - apiGroups: ["*"]
         kinds: ["*"]
 `
+
+	ExpansionRestrictCustomField = `
+apiVersion: expansion.gatekeeper.sh/v1alpha1
+kind: ExpansionTemplate
+metadata:
+  name: expand-foo
+spec:
+  applyTo:
+  - groups: [ "apps" ]
+    kinds: [ "FooTemplate" ]
+    versions: [ "v1" ]
+  templateSource: "spec.template"
+  generatedGVK:
+    kind: "Foo"
+    group: ""
+    version: "v1"
+`
 )

pkg/gator/reader/read_resources.go

@@ -243,6 +243,20 @@ func ReadConstraint(f fs.FS, path string) (*unstructured.Unstructured, error) {
 	return u, nil
 }
 
+func ReadExpansion(f fs.FS, path string) (*unstructured.Unstructured, error) {
+	u, err := ReadObject(f, path)
+	if err != nil {
+		return nil, err
+	}
+
+	gvk := u.GroupVersionKind()
+	if gvk.Group != "expansion.gatekeeper.sh" || gvk.Kind != "ExpansionTemplate" {
+		return nil, gator.ErrNotAnExpansion
+	}
+
+	return u, nil
+}
+
 // ReadK8sResources reads JSON or YAML k8s resources from an io.Reader,
 // decoding them into Unstructured objects and returning those objects as a
 // slice.

pkg/gator/verify/runner.go

@@ -12,7 +12,9 @@ import (
 	"github.com/open-policy-agent/frameworks/constraint/pkg/client/reviews"
 	"github.com/open-policy-agent/frameworks/constraint/pkg/types"
 	"github.com/open-policy-agent/gatekeeper/v3/apis"
+	"github.com/open-policy-agent/gatekeeper/v3/pkg/expansion"
 	"github.com/open-policy-agent/gatekeeper/v3/pkg/gator"
+	"github.com/open-policy-agent/gatekeeper/v3/pkg/gator/expand"
 	"github.com/open-policy-agent/gatekeeper/v3/pkg/gator/reader"
 	mutationtypes "github.com/open-policy-agent/gatekeeper/v3/pkg/mutation/types"
 	"github.com/open-policy-agent/gatekeeper/v3/pkg/target"
@@ -179,6 +181,20 @@ func (r *Runner) runCases(ctx context.Context, suiteDir string, filter Filter, t
 		return c, nil
 	}
 
+	newExpander := func() (*expand.Expander, error) {
+		e, err := r.makeTestExpander(suiteDir, t)
+		if err != nil {
+			return nil, err
+		}
+
+		return e, nil
+	}
+
+	_, err := newExpander()
+	if err != nil {
+		return nil, err
+	}
+
 	results := make([]CaseResult, len(t.Cases))
 
 	for i, c := range t.Cases {
@@ -187,7 +203,7 @@ func (r *Runner) runCases(ctx context.Context, suiteDir string, filter Filter, t
 			continue
 		}
 
-		results[i] = r.runCase(ctx, newClient, suiteDir, c)
+		results[i] = r.runCase(ctx, newClient, newExpander, suiteDir, c)
 	}
 
 	return results, nil
@@ -216,6 +232,22 @@ func (r *Runner) makeTestClient(ctx context.Context, suiteDir string, t *Test) (
 	return client, nil
 }
 
+func (r *Runner) makeTestExpander(suiteDir string, t *Test) (*expand.Expander, error) {
+	// Support Mutator logic? Then we need to add support for mutators as well or do we just ignore them?
+	expansionPath := t.Expansion
+	if expansionPath == "" {
+		return nil, nil
+	}
+
+	et, err := reader.ReadExpansion(r.filesystem, path.Join(suiteDir, expansionPath))
+	if err != nil {
+		return nil, err
+	}
+
+	er, err := expand.NewExpander([]*unstructured.Unstructured{et})
+	return er, err
+}
+
 func (r *Runner) addConstraint(ctx context.Context, suiteDir, constraintPath string, client gator.Client) error {
 	if constraintPath == "" {
 		return fmt.Errorf("%w: missing constraint", gator.ErrInvalidSuite)
@@ -252,9 +284,9 @@ func (r *Runner) addTemplate(suiteDir, templatePath string, client gator.Client)
 }
 
 // RunCase executes a Case and returns the result of the run.
-func (r *Runner) runCase(ctx context.Context, newClient func() (gator.Client, error), suiteDir string, tc *Case) CaseResult {
+func (r *Runner) runCase(ctx context.Context, newClient func() (gator.Client, error), newExpander func() (*expand.Expander, error), suiteDir string, tc *Case) CaseResult {
 	start := time.Now()
-	trace, err := r.checkCase(ctx, newClient, suiteDir, tc)
+	trace, err := r.checkCase(ctx, newClient, newExpander, suiteDir, tc)
 
 	return CaseResult{
 		Name:    tc.Name,
@@ -264,7 +296,7 @@ func (r *Runner) runCase(ctx context.Context, newClient func() (gator.Client, er
 	}
 }
 
-func (r *Runner) checkCase(ctx context.Context, newClient func() (gator.Client, error), suiteDir string, tc *Case) (trace *string, err error) {
+func (r *Runner) checkCase(ctx context.Context, newClient func() (gator.Client, error), newExpander func() (*expand.Expander, error), suiteDir string, tc *Case) (trace *string, err error) {
 	if tc.Object == "" {
 		return nil, fmt.Errorf("%w: must define object", gator.ErrInvalidCase)
 	}
@@ -274,7 +306,7 @@ func (r *Runner) checkCase(ctx context.Context, newClient func() (gator.Client,
 		return nil, fmt.Errorf("%w: assertions must be non-empty", gator.ErrInvalidCase)
 	}
 
-	review, err := r.runReview(ctx, newClient, suiteDir, tc)
+	review, err := r.runReview(ctx, newClient, newExpander, suiteDir, tc)
 	if err != nil {
 		return nil, err
 	}
@@ -293,12 +325,17 @@ func (r *Runner) checkCase(ctx context.Context, newClient func() (gator.Client,
 	return trace, nil
 }
 
-func (r *Runner) runReview(ctx context.Context, newClient func() (gator.Client, error), suiteDir string, tc *Case) (*types.Responses, error) {
+func (r *Runner) runReview(ctx context.Context, newClient func() (gator.Client, error), newExpander func() (*expand.Expander, error), suiteDir string, tc *Case) (*types.Responses, error) {
 	c, err := newClient()
 	if err != nil {
 		return nil, err
 	}
 
+	e, err := newExpander()
+	if err != nil {
+		return nil, err
+	}
+
 	toReviewPath := path.Join(suiteDir, tc.Object)
 	toReviewObjs, err := readObjects(r.filesystem, toReviewPath)
 	if err != nil {
@@ -327,7 +364,36 @@ func (r *Runner) runReview(ctx context.Context, newClient func() (gator.Client,
 		Object: *toReview,
 		Source: mutationtypes.SourceTypeOriginal,
 	}
-	return c.Review(ctx, au, reviews.EnforcementPoint(util.GatorEnforcementPoint))
+
+	review, err := c.Review(ctx, au, reviews.EnforcementPoint(util.GatorEnforcementPoint))
+	if err != nil {
+		return nil, fmt.Errorf("reviewing %v %s/%s: %w",
+			toReview.GroupVersionKind(), toReview.GetNamespace(), toReview.GetName(), err)
+	}
+
+	if e != nil {
+		resultants, err := e.Expand(toReview)
+		if err != nil {
+			return nil, fmt.Errorf("expanding resource %s: %w", toReview.GetName(), err)
+		}
+
+		for _, resultant := range resultants {
+			au := target.AugmentedUnstructured{
+				Object: *resultant.Obj,
+				Source: mutationtypes.SourceTypeGenerated,
+			}
+			resultantReview, err := c.Review(ctx, au, reviews.EnforcementPoint(util.GatorEnforcementPoint))
+			if err != nil {
+				return nil, fmt.Errorf("reviewing expanded resource %v %s/%s: %w",
+					resultant.Obj.GroupVersionKind(), resultant.Obj.GetNamespace(), resultant.Obj.GetName(), err)
+			}
+			expansion.OverrideEnforcementAction(resultant.EnforcementAction, resultantReview)
+			expansion.AggregateResponses(resultant.TemplateName, review, resultantReview)
+			expansion.AggregateStats(resultant.TemplateName, review, resultantReview)
+		}
+	}
+
+	return review, err
 }
 
 func (r *Runner) validateAndReviewAdmissionReviewRequest(ctx context.Context, c gator.Client, toReview *unstructured.Unstructured) (*types.Responses, error) {

pkg/gator/verify/runner_test.go

@@ -1170,6 +1170,68 @@ func TestRunner_Run(t *testing.T) {
 				},
 			},
 		},
+		{
+			name: "expansion system",
+			suite: Suite{
+				Tests: []Test{
+					{
+						Name:       "check custom field with expansion system",
+						Template:   "template.yaml",
+						Constraint: "constraint.yaml",
+						Expansion:  "expansion.yaml",
+						Cases: []*Case{
+							{
+								Name:       "Foo Template object",
+								Object:     "foo-template.yaml",
+								Assertions: []Assertion{{Message: ptr.To[string]("foo object has restricted custom field")}},
+							},
+						},
+					},
+					{
+						Name:       "check custom field without expansion system",
+						Template:   "template.yaml",
+						Constraint: "constraint.yaml",
+						Cases: []*Case{
+							{
+								Name:       "Foo Template object",
+								Object:     "foo-template.yaml",
+								Assertions: []Assertion{{Violations: gator.IntStrFromStr("no")}},
+							},
+						},
+					},
+				},
+			},
+			f: fstest.MapFS{
+				"template.yaml": &fstest.MapFile{
+					Data: []byte(fixtures.TemplateRestrictCustomField),
+				},
+				"constraint.yaml": &fstest.MapFile{
+					Data: []byte(fixtures.ConstraintRestrictCustomField),
+				},
+				"foo-template.yaml": &fstest.MapFile{
+					Data: []byte(fixtures.ObjectFooTemplate),
+				},
+				"expansion.yaml": &fstest.MapFile{
+					Data: []byte(fixtures.ExpansionRestrictCustomField),
+				},
+			},
+			want: SuiteResult{
+				TestResults: []TestResult{
+					{
+						Name: "check custom field with expansion system",
+						CaseResults: []CaseResult{
+							{Name: "Foo Template object"},
+						},
+					},
+					{
+						Name: "check custom field without expansion system",
+						CaseResults: []CaseResult{
+							{Name: "Foo Template object"},
+						},
+					},
+				},
+			},
+		},
 	}
 
 	for _, tc := range testCases {

pkg/gator/verify/suite.go

@@ -35,6 +35,10 @@ type Test struct {
 	// the Suite. Must be an instance of Template.
 	Constraint string `json:"constraint"`
 
+	// Expansion is the path to the Expansion, relative to the file defining
+	// the Suite.
+	Expansion string `json:"expansion"`
+
 	// Cases are the test cases to run on the instantiated Constraint.
 	// Mutually exclusive with Invalid.
 	Cases []*Case `json:"cases,omitempty"`

test/gator/verify/allow_expansion.yaml

@@ -0,0 +1,8 @@
+apiVersion: apps/v1
+kind: FooTemplate
+metadata:
+  name: foo-template
+spec:
+  template:
+    foo: bar
+

test/gator/verify/deny_expansion.yaml

@@ -0,0 +1,8 @@
+apiVersion: apps/v1
+kind: FooTemplate
+metadata:
+  name: foo-template
+spec:
+  template:
+    foo: qux
+

test/gator/verify/expansion.yaml

@@ -0,0 +1,15 @@
+apiVersion: expansion.gatekeeper.sh/v1alpha1
+kind: ExpansionTemplate
+metadata:
+  name: expand-foo
+spec:
+  applyTo:
+  - groups: [ "apps" ]
+    kinds: [ "FooTemplate" ]
+    versions: [ "v1" ]
+  templateSource: "spec.template"
+  generatedGVK:
+    kind: "FooIsBar"
+    group: ""
+    version: "v1"
+