reconcile-pattern-1.go

func (r *ReconcileMigToken) Reconcile(request reconcile.Request) (reconcile.Result, error) {
	var err error
	log.Reset()

	token := &migapi.MigToken{}
	
	// prefer a separate function call instead of defer func() {}()
	// two advantages: 
	// 1. defers are hard(er) to debug/reason about than normal calls
	// 2. with normal function we can have a matching else condition
	err = r.syncMigToken(request)
	if err != nil {
		token.Status.DeleteCondition(migapi.Ready)
		token.Status.SetCondition(migapi.Condition{
			Type:     migapi.ReconcileFailed,
			Status:   True,
			Category: Critical,
			Message:  "Reconcile failed: []. See controller logs for details.",
			Items:    []string{err.Error()},
		})
		token.Status.EndStagingConditions()
		statusUpdateErr := r.Update(context.TODO(), token)
		if statusUpdateErr != nil {
			log.Trace(statusUpdateErr)
			return reconcile.Result{Requeue: true}, nil
		}
		return reconcile.Result{Requeue: true}, nil
	} else {
		token.Status.SetReady(true, "reconciliation succeeded")
		token.Status.SetCondition(migapi.Condition{
			Type:     migapi.ReconcileFailed,
			Status:   False,
			Category: "Info",
			Message:  fmt.Sprintf("Reconcile succeeded for %s", token.Status.ObservedDigest),
		})
		statusUpdateErr := r.Update(context.TODO(), token)
		if statusUpdateErr != nil {
			log.Trace(statusUpdateErr)
			return reconcile.Result{Requeue: true}, nil
		}
	}
	return reconcile.Result{}, nil
}

func (r *ReconcileMigToken) syncMigToken(request reconcile.Request) error {
	// Fetch the MigCluster
	token := &migapi.MigToken{}
	err := r.Get(context.TODO(), request.NamespacedName, token)
	// prefer switching rather than nested ifs
	switch {
	case errors.IsNotFound(err):
		return err
	case err != nil:
		log.Trace(err)
		return err
	default:
		// fall through on the default case
	}
	// Begin staging conditions.
	token.Status.BeginStagingConditions()

	// Validations.
	err = r.validate(token)
	if err != nil {
		log.Trace(err)
		return err
	}

	// Ready
	token.Status.SetReady(
		!token.Status.HasBlockerCondition(),
		ReadyMessage)

	// End staging conditions.
	token.Status.EndStagingConditions()

	// Apply changes.
	token.MarkReconciled()
	err = r.Update(context.TODO(), token)
	if err != nil {
		log.Trace(err)
		return err
	}

	// Done
	return nil
}