Add validators: optional/required/forbidden

Co-authored-by: Tim Hockin <[email protected]>
Co-authored-by: Aaron Prindle <[email protected]>
Co-authored-by: Yongrui Lin <[email protected]>

Author: 4 people

staging/src/k8s.io/apimachinery/pkg/api/validate/required.go

@@ -0,0 +1,133 @@
+/*
+Copyright 2024 The Kubernetes Authors.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package validate
+
+import (
+	"context"
+
+	"k8s.io/apimachinery/pkg/api/operation"
+	"k8s.io/apimachinery/pkg/util/validation/field"
+)
+
+// RequiredValue verifies that the specified value is not the zero-value for
+// its type.
+func RequiredValue[T comparable](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ *T) field.ErrorList {
+	var zero T
+	if *value != zero {
+		return nil
+	}
+	return field.ErrorList{field.Required(fldPath, "")}
+}
+
+// RequiredPointer verifies that the specified pointer is not nil.
+func RequiredPointer[T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ *T) field.ErrorList {
+	if value != nil {
+		return nil
+	}
+	return field.ErrorList{field.Required(fldPath, "")}
+}
+
+// RequiredSlice verifies that the specified slice is not empty.
+func RequiredSlice[T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ []T) field.ErrorList {
+	if len(value) > 0 {
+		return nil
+	}
+	return field.ErrorList{field.Required(fldPath, "")}
+}
+
+// RequiredMap verifies that the specified map is not empty.
+func RequiredMap[K comparable, T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ map[K]T) field.ErrorList {
+	if len(value) > 0 {
+		return nil
+	}
+	return field.ErrorList{field.Required(fldPath, "")}
+}
+
+// ForbiddenValue verifies that the specified value is the zero-value for its
+// type.
+func ForbiddenValue[T comparable](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ *T) field.ErrorList {
+	var zero T
+	if *value == zero {
+		return nil
+	}
+	return field.ErrorList{field.Forbidden(fldPath, "")}
+}
+
+// ForbiddenPointer verifies that the specified pointer is nil.
+func ForbiddenPointer[T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ *T) field.ErrorList {
+	if value == nil {
+		return nil
+	}
+	return field.ErrorList{field.Forbidden(fldPath, "")}
+}
+
+// ForbiddenSlice verifies that the specified slice is empty.
+func ForbiddenSlice[T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ []T) field.ErrorList {
+	if len(value) == 0 {
+		return nil
+	}
+	return field.ErrorList{field.Forbidden(fldPath, "")}
+}
+
+// RequiredMap verifies that the specified map is empty.
+func ForbiddenMap[K comparable, T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ map[K]T) field.ErrorList {
+	if len(value) == 0 {
+		return nil
+	}
+	return field.ErrorList{field.Forbidden(fldPath, "")}
+}
+
+// OptionalValue verifies that the specified value is not the zero-value for
+// its type. This is identical to RequiredValue, but the caller should treat an
+// error here as an indication that the optional value was not specified.
+func OptionalValue[T comparable](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ *T) field.ErrorList {
+	var zero T
+	if *value != zero {
+		return nil
+	}
+	return field.ErrorList{field.Required(fldPath, "optional value was not specified")}
+}
+
+// OptionalPointer verifies that the specified pointer is not nil. This is
+// identical to RequiredPointer, but the caller should treat an error here as an
+// indication that the optional value was not specified.
+func OptionalPointer[T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ *T) field.ErrorList {
+	if value != nil {
+		return nil
+	}
+	return field.ErrorList{field.Required(fldPath, "optional value was not specified")}
+}
+
+// OptionalSlice verifies that the specified slice is not empty. This is
+// identical to RequiredSlice, but the caller should treat an error here as an
+// indication that the optional value was not specified.
+func OptionalSlice[T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ []T) field.ErrorList {
+	if len(value) > 0 {
+		return nil
+	}
+	return field.ErrorList{field.Required(fldPath, "optional value was not specified")}
+}
+
+// OptionalMap verifies that the specified map is not empty. This is identical
+// to RequiredMap, but the caller should treat an error here as an indication that
+// the optional value was not specified.
+func OptionalMap[K comparable, T any](_ context.Context, _ operation.Operation, fldPath *field.Path, value, _ map[K]T) field.ErrorList {
+	if len(value) > 0 {
+		return nil
+	}
+	return field.ErrorList{field.Required(fldPath, "optional value was not specified")}
+}