🌱 new tag symmetry and required validations

hack/tools/crd-generator/README.md

@@ -33,6 +33,14 @@ A semi-colon separated list of enumerations, similar to the `+kubebuilder:valida
 
 An XValidation scheme, similar to the `+kubebuilder:validation:XValidation` scheme, but more limited.
 
+* `Optional`
+
+Indicating that this field should not be listed as required in its parent.
+
+* `Required`
+
+Indicating that this field should be listed as required in its parent.
+
 ## Experimental Description
 
 * Start Tag: `<opcon:experimental:description>`
@@ -44,6 +52,18 @@ All text between the tags is included in the experimental CRD, but removed from
 This is only useful if the field is included in the standard CRD, but there's additional meaning in
 the experimental CRD when feature gates are enabled.
 
+## Standard Description
+
+* Start Tag: `<opcon:standard:description>`
+* End Tag: `</opcon:standard:description>`
+
+Descriptive text that is only included as part of the field description within the standard CRD.
+All text between the tags is included in the standard CRD, but removed from the experimental CRD.
+
+This is useful if the field is included in the standard CRD and has differing meaning than when the
+field is used in the experimental CRD when feature gates are enabled.
+
+
 ## Exclude from CRD Description
 
 * Start Tag: `<opcon:util:excludeFromCRD>`

hack/tools/crd-generator/main.go

@@ -23,6 +23,7 @@ import (
 	"log"
 	"os"
 	"regexp"
+	"slices"
 	"strings"
 
 	apiextensionsv1 "k8s.io/apiextensions-apiserver/pkg/apis/apiextensions/v1"
@@ -136,7 +137,7 @@ func runGenerator(args ...string) {
 				if channel == StandardChannel && strings.Contains(version.Name, "alpha") {
 					channelCrd.Spec.Versions[i].Served = false
 				}
-				version.Schema.OpenAPIV3Schema.Properties = opconTweaksMap(channel, version.Schema.OpenAPIV3Schema.Properties)
+				channelCrd.Spec.Versions[i].Schema.OpenAPIV3Schema.Properties = opconTweaksMap(channel, channelCrd.Spec.Versions[i].Schema.OpenAPIV3Schema)
 			}
 
 			conv, err := crd.AsVersion(*channelCrd, apiextensionsv1.SchemeGroupVersion)
@@ -179,25 +180,51 @@ func runGenerator(args ...string) {
 	}
 }
 
-func opconTweaksMap(channel string, props map[string]apiextensionsv1.JSONSchemaProps) map[string]apiextensionsv1.JSONSchemaProps {
+// Apply Opcon specific tweaks to all properties in a map, and update the parent schema's required list according to opcon tags.
+// For opcon validation optional/required tags, the parent schema's required list is mutated directly.
+// TODO: if we need to support other conditions from opconTweaks, it will likely be preferable to convey the parent schema to facilitate direct alteration.
+func opconTweaksMap(channel string, parentSchema *apiextensionsv1.JSONSchemaProps) map[string]apiextensionsv1.JSONSchemaProps {
+	props := parentSchema.Properties
+
 	for name := range props {
 		jsonProps := props[name]
-		p := opconTweaks(channel, name, jsonProps)
+		p, reqStatus := opconTweaks(channel, name, jsonProps)
 		if p == nil {
 			delete(props, name)
 		} else {
 			props[name] = *p
+			// Update required list based on tag
+			switch reqStatus {
+			case statusRequired:
+				if !slices.Contains(parentSchema.Required, name) {
+					parentSchema.Required = append(parentSchema.Required, name)
+				}
+			case statusOptional:
+				parentSchema.Required = slices.DeleteFunc(parentSchema.Required, func(s string) bool { return s == name })
+			default:
+				// "" (unspecified) means keep existing status
+			}
 		}
 	}
 	return props
 }
 
+const (
+	statusRequired  = "required"
+	statusOptional  = "optional"
+	statusNoOpinion = ""
+)
+
 // Custom Opcon API Tweaks for tags prefixed with `<opcon:` that get past
 // the limitations of Kubebuilder annotations.
-func opconTweaks(channel string, name string, jsonProps apiextensionsv1.JSONSchemaProps) *apiextensionsv1.JSONSchemaProps {
+// Returns the modified schema and a string indicating required status where indicated by opcon tags:
+// "required", "optional", or "" (no decision -- preserve any non-opcon required status).
+func opconTweaks(channel string, name string, jsonProps apiextensionsv1.JSONSchemaProps) (*apiextensionsv1.JSONSchemaProps, string) {
+	requiredStatus := statusNoOpinion
+
 	if channel == StandardChannel {
 		if strings.Contains(jsonProps.Description, "<opcon:experimental>") {
-			return nil
+			return nil, statusNoOpinion
 		}
 	}
 
@@ -219,7 +246,7 @@ func opconTweaks(channel string, name string, jsonProps apiextensionsv1.JSONSche
 
 			numValid++
 			jsonProps.Enum = []apiextensionsv1.JSON{}
-			for _, val := range strings.Split(enumMatch[1], ";") {
+			for val := range strings.SplitSeq(enumMatch[1], ";") {
 				jsonProps.Enum = append(jsonProps.Enum, apiextensionsv1.JSON{Raw: []byte("\"" + val + "\"")})
 			}
 		}
@@ -237,6 +264,28 @@ func opconTweaks(channel string, name string, jsonProps apiextensionsv1.JSONSche
 				Rule:    celMatch[2],
 			})
 		}
+		optReqRe := regexp.MustCompile(validationPrefix + "(Optional|Required)>")
+		optReqMatches := optReqRe.FindAllStringSubmatch(jsonProps.Description, 64)
+		hasOptional := false
+		hasRequired := false
+		for _, optReqMatch := range optReqMatches {
+			if len(optReqMatch) != 2 {
+				log.Fatalf("Invalid %s Optional/Required tag for %s", validationPrefix, name)
+			}
+
+			numValid++
+			switch optReqMatch[1] {
+			case "Optional":
+				hasOptional = true
+				requiredStatus = statusOptional
+			case "Required":
+				hasRequired = true
+				requiredStatus = statusRequired
+			}
+		}
+		if hasOptional && hasRequired {
+			log.Fatalf("Field %s has both Optional and Required validation tags for channel %s", name, channel)
+		}
 	}
 
 	if numValid < numExpressions {
@@ -246,34 +295,43 @@ func opconTweaks(channel string, name string, jsonProps apiextensionsv1.JSONSche
 	jsonProps.Description = formatDescription(jsonProps.Description, channel, name)
 
 	if len(jsonProps.Properties) > 0 {
-		jsonProps.Properties = opconTweaksMap(channel, jsonProps.Properties)
+		jsonProps.Properties = opconTweaksMap(channel, &jsonProps)
 	} else if jsonProps.Items != nil && jsonProps.Items.Schema != nil {
-		jsonProps.Items.Schema = opconTweaks(channel, name, *jsonProps.Items.Schema)
+		jsonProps.Items.Schema, _ = opconTweaks(channel, name, *jsonProps.Items.Schema)
 	}
 
-	return &jsonProps
+	return &jsonProps, requiredStatus
 }
 
 func formatDescription(description string, channel string, name string) string {
-	startTag := "<opcon:experimental:description>"
-	endTag := "</opcon:experimental:description>"
-	if channel == StandardChannel && strings.Contains(description, startTag) {
-		regexPattern := `\n*` + regexp.QuoteMeta(startTag) + `(?s:(.*?))` + regexp.QuoteMeta(endTag) + `\n*`
-		re := regexp.MustCompile(regexPattern)
-		match := re.FindStringSubmatch(description)
-		if len(match) != 2 {
-			log.Fatalf("Invalid <opcon:experimental:description> tag for %s", name)
+	tagset := []struct {
+		channel string
+		tag     string
+	}{
+		{channel: ExperimentalChannel, tag: "opcon:standard:description"},
+		{channel: StandardChannel, tag: "opcon:experimental:description"},
+	}
+	for _, ts := range tagset {
+		startTag := fmt.Sprintf("<%s>", ts.tag)
+		endTag := fmt.Sprintf("</%s>", ts.tag)
+		if channel == ts.channel && strings.Contains(description, ts.tag) {
+			regexPattern := `\n*` + regexp.QuoteMeta(startTag) + `(?s:(.*?))` + regexp.QuoteMeta(endTag) + `\n*`
+			re := regexp.MustCompile(regexPattern)
+			match := re.FindStringSubmatch(description)
+			if len(match) != 2 {
+				log.Fatalf("Invalid %s tag for %s", startTag, name)
+			}
+			description = re.ReplaceAllString(description, "\n\n")
+		} else {
+			description = strings.ReplaceAll(description, startTag, "")
+			description = strings.ReplaceAll(description, endTag, "")
 		}
-		description = re.ReplaceAllString(description, "\n\n")
-	} else {
-		description = strings.ReplaceAll(description, startTag, "")
-		description = strings.ReplaceAll(description, endTag, "")
 	}
 
 	// Comments within "opcon:util:excludeFromCRD" tag are not included in the generated CRD and all trailing \n operators before
 	// and after the tags are removed and replaced with three \n operators.
-	startTag = "<opcon:util:excludeFromCRD>"
-	endTag = "</opcon:util:excludeFromCRD>"
+	startTag := "<opcon:util:excludeFromCRD>"
+	endTag := "</opcon:util:excludeFromCRD>"
 	if strings.Contains(description, startTag) {
 		regexPattern := `\n*` + regexp.QuoteMeta(startTag) + `(?s:(.*?))` + regexp.QuoteMeta(endTag) + `\n*`
 		re := regexp.MustCompile(regexPattern)