Merge pull request #63893 from jennybuckley/expose-openapi-to-registry3

Automatic merge from submit-queue (batch tested with PRs 64175, 63893). If you want to cherry-pick this change to another branch, please follow the instructions <a href="https://github.com/kubernetes/community/blob/master/contributors/devel/cherry-picks.md">here</a>.

Expose openapi schema to handlers

**What this PR does / why we need it**:
Build an openapi spec for each api resource handler. This spec will be able to be consumed by server-side apply and server-side openapi validation.
The reason for putting it into master is so we can work on implementing server side validation against the openapi spec as well as server side apply, and it will make merging the server side apply feature branch a smaller, less risky PR

/sig api-machinery
/kind feature
cc @liggitt @lavalamp @seans3 @mbohlool @apelisse

**Release note**:
```release-note
NONE
```

Kubernetes-commit: 28f171bd66937dec8b24a05c4b7a1414432f9fe8

vendor/k8s.io/code-generator/vendor/k8s.io/kube-openapi/pkg/generators/extension.go

@@ -27,18 +27,33 @@ import (
 
 const extensionPrefix = "x-kubernetes-"
 
-// Extension tag to openapi extension
-var tagToExtension = map[string]string{
-	"patchMergeKey": "x-kubernetes-patch-merge-key",
-	"patchStrategy": "x-kubernetes-patch-strategy",
-	"listType":      "x-kubernetes-list-type",
-	"listMapKey":    "x-kubernetes-list-map-keys",
+// extensionAttributes encapsulates common traits for particular extensions.
+type extensionAttributes struct {
+	xName         string
+	kind          types.Kind
+	allowedValues sets.String
 }
 
-// Enum values per extension
-var allowedExtensionValues = map[string]sets.String{
-	"x-kubernetes-patch-strategy": sets.NewString("merge", "retainKeys"),
-	"x-kubernetes-list-type":      sets.NewString("atomic", "set", "map"),
+// Extension tag to openapi extension attributes
+var tagToExtension = map[string]extensionAttributes{
+	"patchMergeKey": extensionAttributes{
+		xName: "x-kubernetes-patch-merge-key",
+		kind:  types.Slice,
+	},
+	"patchStrategy": extensionAttributes{
+		xName:         "x-kubernetes-patch-strategy",
+		kind:          types.Slice,
+		allowedValues: sets.NewString("merge", "retainKeys"),
+	},
+	"listMapKey": extensionAttributes{
+		xName: "x-kubernetes-list-map-keys",
+		kind:  types.Slice,
+	},
+	"listType": extensionAttributes{
+		xName:         "x-kubernetes-list-type",
+		kind:          types.Slice,
+		allowedValues: sets.NewString("atomic", "set", "map"),
+	},
 }
 
 // Extension encapsulates information necessary to generate an OpenAPI extension.
@@ -48,10 +63,25 @@ type extension struct {
 	values []string // Example: [atomic]
 }
 
+func (e extension) hasAllowedValues() bool {
+	return tagToExtension[e.idlTag].allowedValues.Len() > 0
+}
+
+func (e extension) allowedValues() sets.String {
+	return tagToExtension[e.idlTag].allowedValues
+}
+
+func (e extension) hasKind() bool {
+	return len(tagToExtension[e.idlTag].kind) > 0
+}
+
+func (e extension) kind() types.Kind {
+	return tagToExtension[e.idlTag].kind
+}
+
 func (e extension) validateAllowedValues() error {
 	// allowedValues not set means no restrictions on values.
-	allowedValues, exists := allowedExtensionValues[e.xName]
-	if !exists {
+	if !e.hasAllowedValues() {
 		return nil
 	}
 	// Check for missing value.
@@ -59,6 +89,7 @@ func (e extension) validateAllowedValues() error {
 		return fmt.Errorf("%s needs a value, none given.", e.idlTag)
 	}
 	// For each extension value, validate that it is allowed.
+	allowedValues := e.allowedValues()
 	if !allowedValues.HasAll(e.values...) {
 		return fmt.Errorf("%v not allowed for %s. Allowed values: %v",
 			e.values, e.idlTag, allowedValues.List())
@@ -66,6 +97,18 @@ func (e extension) validateAllowedValues() error {
 	return nil
 }
 
+func (e extension) validateType(kind types.Kind) error {
+	// If this extension class has no kind, then don't validate the type.
+	if !e.hasKind() {
+		return nil
+	}
+	if kind != e.kind() {
+		return fmt.Errorf("tag %s on type %v; only allowed on type %v",
+			e.idlTag, kind, e.kind())
+	}
+	return nil
+}
+
 func (e extension) hasMultipleValues() bool {
 	return len(e.values) > 1
 }
@@ -82,7 +125,9 @@ func sortedMapKeys(m map[string][]string) []string {
 	return keys
 }
 
-// Parses comments to return openapi extensions.
+// Parses comments to return openapi extensions. Returns a list of
+// extensions which parsed correctly, as well as a list of the
+// parse errors. Validating extensions is performed separately.
 // NOTE: Non-empty errors does not mean extensions is empty.
 func parseExtensions(comments []string) ([]extension, []error) {
 	extensions := []extension{}
@@ -108,21 +153,30 @@ func parseExtensions(comments []string) ([]extension, []error) {
 	// Next, generate extensions from "idlTags" (e.g. +listType)
 	tagValues := types.ExtractCommentTags("+", comments)
 	for _, idlTag := range sortedMapKeys(tagValues) {
-		xName, exists := tagToExtension[idlTag]
+		xAttrs, exists := tagToExtension[idlTag]
 		if !exists {
 			continue
 		}
 		values := tagValues[idlTag]
 		e := extension{
-			idlTag: idlTag, // listType
-			xName:  xName,  // x-kubernetes-list-type
-			values: values, // [atomic]
-		}
-		if err := e.validateAllowedValues(); err != nil {
-			// For now, only log the extension validation errors.
-			errors = append(errors, err)
+			idlTag: idlTag,       // listType
+			xName:  xAttrs.xName, // x-kubernetes-list-type
+			values: values,       // [atomic]
 		}
 		extensions = append(extensions, e)
 	}
 	return extensions, errors
 }
+
+func validateMemberExtensions(extensions []extension, m *types.Member) []error {
+	errors := []error{}
+	for _, e := range extensions {
+		if err := e.validateAllowedValues(); err != nil {
+			errors = append(errors, err)
+		}
+		if err := e.validateType(m.Type.Kind); err != nil {
+			errors = append(errors, err)
+		}
+	}
+	return errors
+}

vendor/k8s.io/code-generator/vendor/k8s.io/kube-openapi/pkg/generators/openapi.go

@@ -432,7 +432,7 @@ func (g openAPITypeWriter) generateStructExtensions(t *types.Type) error {
 	extensions, errors := parseExtensions(t.CommentLines)
 	// Initially, we will only log struct extension errors.
 	if len(errors) > 0 {
-		for e := range errors {
+		for _, e := range errors {
 			glog.V(2).Infof("[%s]: %s\n", t.String(), e)
 		}
 	}
@@ -442,17 +442,16 @@ func (g openAPITypeWriter) generateStructExtensions(t *types.Type) error {
 }
 
 func (g openAPITypeWriter) generateMemberExtensions(m *types.Member, parent *types.Type) error {
-	extensions, errors := parseExtensions(m.CommentLines)
+	extensions, parseErrors := parseExtensions(m.CommentLines)
+	validationErrors := validateMemberExtensions(extensions, m)
+	errors := append(parseErrors, validationErrors...)
 	// Initially, we will only log member extension errors.
 	if len(errors) > 0 {
 		errorPrefix := fmt.Sprintf("[%s] %s:", parent.String(), m.String())
-		for e := range errors {
+		for _, e := range errors {
 			glog.V(2).Infof("%s %s\n", errorPrefix, e)
 		}
 	}
-	// TODO(seans3): Validate member extensions here.
-	// Example: listType extension is only on a Slice.
-	// Example: cross-extension validation - listMapKey only makes sense with listType=map
 	g.emitExtensions(extensions)
 	return nil
 }