Add +optional/+required markers at package and struct level for CRD v…

…alidation

Using +kubebuilder:validation:Optional/Required at the package level sets the default value for fields in that package to that value, while using the opposite marker on fields in that package sets them as an exception

pkg/crd/markers/package.go

@@ -24,5 +24,7 @@ func init() {
 	AllDefinitions = append(AllDefinitions,
 		markers.Must(markers.MakeDefinition("groupName", markers.DescribesPackage, "")),
 		markers.Must(markers.MakeDefinition("versionName", markers.DescribesPackage, "")),
+		markers.Must(markers.MakeDefinition("kubebuilder:validation:Optional", markers.DescribesPackage, struct{}{})),
+		markers.Must(markers.MakeDefinition("kubebuilder:validation:Required", markers.DescribesPackage, struct{}{})),
 	)
 }

pkg/crd/markers/validation.go

@@ -58,6 +58,8 @@ var ValidationMarkers = mustMakeAllWithPrefix("kubebuilder:validation", markers.
 	Format(""),
 	Type(""),
 	Nullable(false),
+	Required(struct{}{}),
+	Optional(struct{}{}),
 )
 
 func init() {
@@ -88,6 +90,8 @@ type Enum []interface{}
 type Format string
 type Type string
 type Nullable bool
+type Required struct{}
+type Optional struct{}
 
 func (m Maximum) ApplyToSchema(schema *v1beta1.JSONSchemaProps) error {
 	if schema.Type != "integer" {

pkg/crd/parser.go

@@ -151,7 +151,15 @@ func (p *Parser) NeedSchemaFor(typ TypeIdent) {
 	p.Schemata[typ] = apiext.JSONSchemaProps{}
 
 	schemaCtx := newSchemaContext(typ.Package, p)
-	schema := infoToSchema(schemaCtx.ForInfo(info))
+	ctxForInfo := schemaCtx.ForInfo(info)
+
+	pkgMarkers, err := markers.PackageMarkers(p.Collector, typ.Package)
+	if err != nil {
+		typ.Package.AddError(err)
+	}
+	ctxForInfo.PackageMarkers = pkgMarkers
+
+	schema := infoToSchema(ctxForInfo)
 
 	p.Schemata[typ] = *schema
 

pkg/crd/schema.go

@@ -66,6 +66,7 @@ type schemaContext struct {
 	info *markers.TypeInfo
 
 	schemaRequester schemaRequester
+	PackageMarkers  markers.MarkerValues
 }
 
 // newSchemaContext constructs a new schemaContext for the given package and schema requester.
@@ -342,8 +343,27 @@ func structToSchema(ctx *schemaContext, structType *ast.StructType) *v1beta1.JSO
 		fieldName := jsonOpts[0]
 		inline = inline || fieldName == "" // anonymous fields are inline fields in YAML/JSON
 
-		if !inline && !omitEmpty {
-			props.Required = append(props.Required, fieldName)
+		// if no default required mode is set, default to required
+		defaultMode := "required"
+		if ctx.PackageMarkers.Get("kubebuilder:validation:Optional") != nil {
+			defaultMode = "optional"
+		}
+
+		switch defaultMode {
+		// if this package isn't set to optional default...
+		case "required":
+			// ...everything that's not inline, omitempty, or explicitly optional is required
+			// TODO(damemi): Actually add support for mythical `+optional` marker
+			if !inline && !omitEmpty && field.Markers.Get("kubebuilder:validation:Optional") == nil && field.Markers.Get("optional") == nil {
+				props.Required = append(props.Required, fieldName)
+			}
+
+		// if this package isn't set to required default...
+		case "optional":
+			// ...everything that isn't explicitly required is optional
+			if field.Markers.Get("kubebuilder:validation:Required") != nil {
+				props.Required = append(props.Required, fieldName)
+			}
 		}
 
 		propSchema := typeToSchema(ctx.ForInfo(&markers.TypeInfo{}), field.RawField.Type)