dra api: implement semver attribute value type

This adds support for semantic version comparison to the CEL support in the
"named resources" structured parameter model. For example, it can be used to
check that an instance supports a certain API level.

To minimize the risk, the new "semver" type is only defined in the CEL
environment for DRA expressions, not in the base library. See
kubernetes/kubernetes#123664 for a PR which
adds it to the base library.

Validation of semver strings is done with the regular expression from
semver.org. The actual evaluation at runtime then uses semver/v4.

Kubernetes-commit: 42ee56f093133402ed860d4c5f54b049041386c9

Author: pohly

resource/v1alpha2/generated.pb.go

@@ -70,7 +70,8 @@ type NamedResourcesAttributeValue struct {
 	StringValue *string `json:"string,omitempty" protobuf:"bytes,5,opt,name=string"`
 	// StringSliceValue is an array of strings.
 	StringSliceValue *NamedResourcesStringSlice `json:"stringSlice,omitempty" protobuf:"bytes,9,rep,name=stringSlice"`
-	// TODO: VersionValue     *SemVersion        `json:"version,omitempty" protobuf:"bytes,7,opt,name=version"`
+	// VersionValue is a semantic version according to semver.org spec 2.0.0.
+	VersionValue *string `json:"version,omitempty" protobuf:"bytes,10,opt,name=version"`
 }
 
 // NamedResourcesIntSlice contains a slice of 64-bit integers.
@@ -89,17 +90,6 @@ type NamedResourcesStringSlice struct {
 	Strings []string `json:"strings" protobuf:"bytes,1,opt,name=strings"`
 }
 
-// TODO
-//
-// A wrapper around https://pkg.go.dev/github.com/blang/semver/v4#Version which
-// is encoded as a string. During decoding, it validates that the string
-// can be parsed using tolerant parsing (currently trims spaces, removes a "v" prefix,
-// adds a 0 patch number to versions with only major and minor components specified,
-// and removes leading 0s).
-// type NamedResourcesSemVersion struct {
-//	semver.Version
-//}
-
 // NamedResourcesRequest is used in ResourceRequestModel.
 type NamedResourcesRequest struct {
 	// Selector is a CEL expression which must evaluate to true if a

resource/v1alpha2/generated.proto

@@ -65,7 +65,8 @@
               "strings": [
                 "stringsValue"
               ]
-            }
+            },
+            "version": "versionValue"
           }
         ]
       }

resource/v1alpha2/namedresources.go

@@ -47,5 +47,6 @@ namedResources:
       stringSlice:
         strings:
         - stringsValue
+      version: versionValue
     name: nameValue
 nodeName: nodeNameValue