create_or_update.go

// Copyright 2023 Google LLC
//
// 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 controllers

import (
	"context"
	"fmt"

	"k8s.io/apimachinery/pkg/api/equality"
	apierrors "k8s.io/apimachinery/pkg/api/errors"
	"sigs.k8s.io/controller-runtime/pkg/client"
	"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
)

// CreateOrUpdate creates or updates the given object in the Kubernetes
// cluster. The object's desired state must be reconciled with the existing
// state inside the passed in callback MutateFn.
//
// The MutateFn is called regardless of creating or updating an object.
//
// Returns the executed operation and an error.
//
// Similar to controllerutil.CreateOrUpdate, except it returns
// ObjectOperationError when possible, with added context for error handling.
func CreateOrUpdate(ctx context.Context, c client.Client, obj client.Object, f controllerutil.MutateFn) (controllerutil.OperationResult, error) {
	key := client.ObjectKeyFromObject(obj)
	if err := c.Get(ctx, key, obj); err != nil {
		if !apierrors.IsNotFound(err) {
			return controllerutil.OperationResultNone, NewObjectOperationErrorWithKey(err, obj, OperationGet, key)
		}
		if err := mutateWrapper(f, key, obj); err != nil {
			return controllerutil.OperationResultNone, err
		}
		if err := c.Create(ctx, obj); err != nil {
			return controllerutil.OperationResultNone, NewObjectOperationErrorWithKey(err, obj, OperationCreate, key)
		}
		return controllerutil.OperationResultCreated, nil
	}

	existing := obj.DeepCopyObject() //nolint
	if err := mutateWrapper(f, key, obj); err != nil {
		return controllerutil.OperationResultNone, err
	}

	if equality.Semantic.DeepEqual(existing, obj) {
		return controllerutil.OperationResultNone, nil
	}

	if err := c.Update(ctx, obj); err != nil {
		return controllerutil.OperationResultNone, NewObjectOperationErrorWithKey(err, obj, OperationUpdate, key)
	}
	return controllerutil.OperationResultUpdated, nil
}

// mutateWrapper wraps a MutateFn and applies validation to its result.
func mutateWrapper(f controllerutil.MutateFn, key client.ObjectKey, obj client.Object) error {
	if err := f(); err != nil {
		return err
	}
	if newKey := client.ObjectKeyFromObject(obj); key != newKey {
		return fmt.Errorf("MutateFn cannot mutate object name or namespace (before: %q, after: %q)",
			key, newKey)
	}
	return nil
}