/
generic_spec_to_db_reconciler.go
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/
generic_spec_to_db_reconciler.go
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// Copyright (c) 2020 Red Hat, Inc.
// Copyright Contributors to the Open Cluster Management project
package controller
import (
"context"
"errors"
"fmt"
"time"
"github.com/go-logr/logr"
pgx "github.com/jackc/pgx/v4"
"github.com/jackc/pgx/v4/pgxpool"
apierrors "k8s.io/apimachinery/pkg/api/errors"
ctrl "sigs.k8s.io/controller-runtime"
"sigs.k8s.io/controller-runtime/pkg/client"
"sigs.k8s.io/controller-runtime/pkg/controller/controllerutil"
)
type genericSpecToDBReconciler struct {
client client.Client
log logr.Logger
databaseConnectionPool *pgxpool.Pool
tableName string
finalizerName string
createInstance func() client.Object
cleanStatus func(client.Object)
areEqual func(client.Object, client.Object) bool
}
const requeuePeriodSeconds = 5
func (r *genericSpecToDBReconciler) Reconcile(ctx context.Context, request ctrl.Request) (ctrl.Result, error) {
reqLogger := r.log.WithValues("Request.Namespace", request.Namespace, "Request.Name", request.Name)
reqLogger.Info(fmt.Sprintf("Reconciling %s ...", r.tableName))
instanceUID, instance, err := r.processCR(ctx, request, reqLogger)
if err != nil {
reqLogger.Error(err, "Reconciliation failed")
return ctrl.Result{Requeue: true, RequeueAfter: requeuePeriodSeconds * time.Second}, err
}
if instance == nil {
reqLogger.Info("Reconciliation complete.")
return ctrl.Result{}, nil
}
instanceInTheDatabase, err := r.processInstanceInTheDatabase(ctx, instance, instanceUID, reqLogger)
if err != nil {
reqLogger.Error(err, "Reconciliation failed")
return ctrl.Result{Requeue: true, RequeueAfter: requeuePeriodSeconds * time.Second}, err
}
if !r.areEqual(instance, instanceInTheDatabase) {
reqLogger.Info("Mismatch between hub and the database, updating the database")
_, err := r.databaseConnectionPool.Exec(ctx,
fmt.Sprintf("UPDATE spec.%s SET payload = $1 WHERE id = $2", r.tableName),
&instance, instanceUID)
if err != nil {
// wrap the error from an external package, see https://github.com/tomarrell/wrapcheck
err = fmt.Errorf("failed to update the database with new value: %w", err)
reqLogger.Error(err, "Reconciliation failed")
return ctrl.Result{}, err
}
}
reqLogger.Info("Reconciliation complete.")
return ctrl.Result{}, err
}
func (r *genericSpecToDBReconciler) processCR(ctx context.Context, request ctrl.Request,
log logr.Logger) (string, client.Object, error) {
instance := r.createInstance()
err := r.client.Get(ctx, request.NamespacedName, instance)
if apierrors.IsNotFound(err) {
// the instance on hub was deleted, update all the matching instances in the database as deleted
return "", nil, r.deleteFromTheDatabase(ctx, request.Name, request.Namespace, log)
}
if err != nil {
return "", nil, fmt.Errorf("failed to get the instance from hub: %w", err)
}
if isInstanceBeingDeleted(instance) {
return "", nil, r.removeFinalizerAndDelete(ctx, instance, log)
}
err = r.addFinalizer(ctx, instance, log)
return string(instance.GetUID()), r.cleanInstance(instance), err
}
func isInstanceBeingDeleted(instance client.Object) bool {
return !instance.GetDeletionTimestamp().IsZero()
}
func (r *genericSpecToDBReconciler) removeFinalizerAndDelete(ctx context.Context, instance client.Object,
log logr.Logger) error {
if !controllerutil.ContainsFinalizer(instance, r.finalizerName) {
return nil
}
log.Info("Removing an instance from the database")
// the policy is being deleted, update all the matching policies in the database as deleted
if err := r.deleteFromTheDatabase(ctx, instance.GetName(), instance.GetNamespace(), log); err != nil {
return fmt.Errorf("failed to delete an instance from the database: %w", err)
}
log.Info("Removing finalizer")
controllerutil.RemoveFinalizer(instance, r.finalizerName)
if err := r.client.Update(ctx, instance); err != nil {
return fmt.Errorf("failed to remove a finalizer: %w", err)
}
return nil
}
func (r *genericSpecToDBReconciler) addFinalizer(ctx context.Context, instance client.Object, log logr.Logger) error {
if controllerutil.ContainsFinalizer(instance, r.finalizerName) {
return nil
}
log.Info("Adding finalizer")
controllerutil.AddFinalizer(instance, r.finalizerName)
if err := r.client.Update(ctx, instance); err != nil {
return fmt.Errorf("failed to add a finalizer: %w", err)
}
return nil
}
func (r *genericSpecToDBReconciler) processInstanceInTheDatabase(ctx context.Context, instance client.Object,
instanceUID string, log logr.Logger) (client.Object, error) {
instanceInTheDatabase := r.createInstance()
err := r.databaseConnectionPool.QueryRow(ctx,
fmt.Sprintf("SELECT payload FROM spec.%s WHERE id = $1", r.tableName),
instanceUID).Scan(&instanceInTheDatabase)
if errors.Is(err, pgx.ErrNoRows) {
log.Info("The instance with the current UID does not exist in the database, inserting...")
_, err := r.databaseConnectionPool.Exec(ctx,
fmt.Sprintf("INSERT INTO spec.%s (id,payload) values($1, $2::jsonb)", r.tableName),
instanceUID, &instance)
if err != nil {
return nil, fmt.Errorf("insert into database failed: %w", err)
}
log.Info("The instance has been inserted into the database")
return instance, nil // the instance in the database is identical to the instance we just inserted
}
if err != nil {
return nil, fmt.Errorf("failed to get the instance in the database: %w", err)
}
return instanceInTheDatabase, nil
}
func (r *genericSpecToDBReconciler) cleanInstance(instance client.Object) client.Object {
instance.SetUID("")
instance.SetResourceVersion("")
instance.SetManagedFields(nil)
instance.SetFinalizers(nil)
instance.SetGeneration(0)
instance.SetOwnerReferences(nil)
instance.SetClusterName("")
delete(instance.GetAnnotations(), "kubectl.kubernetes.io/last-applied-configuration")
r.cleanStatus(instance)
return instance
}
func (r *genericSpecToDBReconciler) deleteFromTheDatabase(ctx context.Context, name, namespace string,
log logr.Logger) error {
log.Info("Instance was deleted, update the deleted field in the database")
_, err := r.databaseConnectionPool.Exec(ctx,
fmt.Sprintf(`UPDATE spec.%s SET deleted = true WHERE payload -> 'metadata' ->> 'name' = $1 AND
payload -> 'metadata' ->> 'namespace' = $2 AND deleted = false`, r.tableName), name, namespace)
if err != nil {
return fmt.Errorf("failed to delete instance from the database: %w", err)
}
log.Info("Instance has been updated as deleted in the database")
return nil
}