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/
sync.go
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/
sync.go
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//
// Copyright (c) 2019-2020 Red Hat, Inc.
// This program and the accompanying materials are made
// available under the terms of the Eclipse Public License 2.0
// which is available at https://www.eclipse.org/legal/epl-2.0/
//
// SPDX-License-Identifier: EPL-2.0
//
// Contributors:
// Red Hat, Inc. - initial API and implementation
//
package sync
import (
"context"
"fmt"
"github.com/google/go-cmp/cmp"
"k8s.io/apimachinery/pkg/api/errors"
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/client"
"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
)
var (
log = ctrl.Log.WithName("sync")
)
// Syncer synchronized K8s objects with the cluster
type Syncer struct {
client client.Client
scheme *runtime.Scheme
}
func New(client client.Client, scheme *runtime.Scheme) Syncer {
return Syncer{client: client, scheme: scheme}
}
// Sync syncs the blueprint to the cluster in a generic (as much as Go allows) manner.
// Returns true if the object was created or updated, false if there was no change detected.
func (s *Syncer) Sync(ctx context.Context, owner metav1.Object, blueprint metav1.Object, diffOpts cmp.Option) (bool, runtime.Object, error) {
blueprintObject, ok := blueprint.(runtime.Object)
if !ok {
return false, nil, fmt.Errorf("object %T is not a runtime.Object. Cannot sync it", blueprint)
}
key := client.ObjectKey{Name: blueprint.GetName(), Namespace: blueprint.GetNamespace()}
actual := blueprintObject.DeepCopyObject()
if getErr := s.client.Get(context.TODO(), key, actual); getErr != nil {
if statusErr, ok := getErr.(*errors.StatusError); !ok || statusErr.Status().Reason != metav1.StatusReasonNotFound {
return false, nil, getErr
}
actual = nil
}
if actual == nil {
actual, err := s.create(ctx, owner, key, blueprint)
if err != nil {
return false, actual, err
}
return true, actual, nil
}
return s.update(ctx, owner, actual, blueprint, diffOpts)
}
// Delete deletes the supplied object from the cluster.
func (s *Syncer) Delete(ctx context.Context, object metav1.Object) error {
key := client.ObjectKey{Name: object.GetName(), Namespace: object.GetNamespace()}
var err error
ro, ok := object.(runtime.Object)
if !ok {
return fmt.Errorf("Could not use the supplied object as kubernetes runtime object. That's unexpected: %s", object)
}
if err = s.client.Get(ctx, key, ro); err == nil {
err = s.client.Delete(ctx, ro)
}
if err != nil && !errors.IsNotFound(err) {
return err
}
return nil
}
func (s *Syncer) create(ctx context.Context, owner metav1.Object, key client.ObjectKey, blueprint metav1.Object) (runtime.Object, error) {
blueprintObject, ok := blueprint.(runtime.Object)
kind := blueprintObject.GetObjectKind().GroupVersionKind().Kind
if !ok {
return nil, fmt.Errorf("object %T is not a runtime.Object. Cannot sync it", blueprint)
}
actual := blueprintObject.DeepCopyObject()
log.Info("Creating a new object", "kind", kind, "name", blueprint.GetName(), "namespace", blueprint.GetNamespace())
obj, err := s.setOwnerReferenceAndConvertToRuntime(owner, blueprint)
if err != nil {
return nil, err
}
err = s.client.Create(ctx, obj)
if err != nil {
if !errors.IsAlreadyExists(err) {
return nil, err
}
// ok, we got an already-exists error. So let's try to load the object into "actual".
// if we fail this retry for whatever reason, just give up rather than retrying this in a loop...
// the reconciliation loop will lead us here again in the next round.
if err = s.client.Get(ctx, key, actual); err != nil {
return nil, err
}
}
return actual, nil
}
func (s *Syncer) update(ctx context.Context, owner metav1.Object, actual runtime.Object, blueprint metav1.Object, diffOpts cmp.Option) (bool, runtime.Object, error) {
actualMeta := actual.(metav1.Object)
diff := cmp.Diff(actual, blueprint, diffOpts)
if len(diff) > 0 {
kind := actual.GetObjectKind().GroupVersionKind().Kind
log.Info("Updating existing object", "kind", kind, "name", actualMeta.GetName(), "namespace", actualMeta.GetNamespace())
// we need to handle labels and annotations specially in case the cluster admin has modified them.
// if the current object in the cluster has the same annos/labels, they get overwritten with what's
// in the blueprint. Any additional labels/annos on the object are kept though.
targetLabels := map[string]string{}
targetAnnos := map[string]string{}
for k, v := range actualMeta.GetAnnotations() {
targetAnnos[k] = v
}
for k, v := range actualMeta.GetLabels() {
targetLabels[k] = v
}
for k, v := range blueprint.GetAnnotations() {
targetAnnos[k] = v
}
for k, v := range blueprint.GetLabels() {
targetLabels[k] = v
}
blueprint.SetAnnotations(targetAnnos)
blueprint.SetLabels(targetLabels)
if isUpdateUsingDeleteCreate(actual.GetObjectKind().GroupVersionKind().Kind) {
err := s.client.Delete(ctx, actual)
if err != nil {
return false, actual, err
}
key := client.ObjectKey{Name: actualMeta.GetName(), Namespace: actualMeta.GetNamespace()}
obj, err := s.create(ctx, owner, key, blueprint)
return false, obj, err
} else {
obj, err := s.setOwnerReferenceAndConvertToRuntime(owner, blueprint)
if err != nil {
return false, actual, err
}
// to be able to update, we need to set the resource version of the object that we know of
obj.(metav1.Object).SetResourceVersion(actualMeta.GetResourceVersion())
err = s.client.Update(ctx, obj)
if err != nil {
return false, obj, err
}
return true, obj, nil
}
}
return false, actual, nil
}
func isUpdateUsingDeleteCreate(kind string) bool {
// Routes are not able to update the host, so we just need to re-create them...
// ingresses and services have been identified to needs this, too, for reasons that I don't know..
return "Service" == kind || "Ingress" == kind || "Route" == kind
}
func (s *Syncer) setOwnerReferenceAndConvertToRuntime(owner metav1.Object, obj metav1.Object) (runtime.Object, error) {
robj, ok := obj.(runtime.Object)
if !ok {
return nil, fmt.Errorf("object %T is not a runtime.Object. Cannot sync it", obj)
}
if owner == nil {
return robj, nil
}
err := controllerutil.SetControllerReference(owner, obj, s.scheme)
if err != nil {
return nil, err
}
return robj, nil
}