func()

in pkg/controllers/controller.go [485:552]
36 lines of code
8 McCabe index (conditional complexity)

func (c *Controller) syncHandler(ctx context.Context, key string) (result syncResult) {

	klog.Infof("Sync handler: %s", key)
	// Convert the namespace/name string into a distinct namespace and name
	namespace, name, err := cache.SplitMetaNamespaceKey(key)
	if err != nil {
		utilruntime.HandleError(fmt.Errorf("invalid resource key: %s", key))
		// no need to retry as this is a permanent error
		return finishProcessing()
	}

	// Get the NdbCluster resource with this namespace/name
	ndbOrg, err := c.ndbsLister.NdbClusters(namespace).Get(name)
	if err != nil {
		if apierrors.IsNotFound(err) {
			// Stop processing if the NdbCluster resource no longer exists
			klog.Infof("NdbCluster resource %q does not exist anymore", key)
			return finishProcessing()
		}

		klog.Infof("Failed to retrieve NdbCluster resource %q", key)
		return errorWhileProcessing(err)
	}

	// Create a syncContext with a DeepCopied NdbCluster resource
	// to prevent the sync method from accidentally mutating the
	// cache object.
	nc := ndbOrg.DeepCopy()
	syncContext := c.newSyncContext(nc)

	// Run sync.
	if result = syncContext.sync(ctx); result.getError() != nil {
		// The sync step returned an error - no need to update status yet
		return result
	}

	// Update the status of the NdbCluster resource
	statusUpdated, err := syncContext.updateNdbClusterStatus(ctx)
	if err != nil {
		// Status needs to be updated, but it failed.
		// Do not record events yet.
		// TODO: Ensure that the sync doesn't get stuck
		return result
	}

	// No error returned by updateNdbClusterStatus.
	// Check status and record events if necessary.
	if nc.Status.ProcessedGeneration == nc.Generation {
		// The latest generation of the NdbCluster has been processed
		// and the MySQL Cluster is up-to-date.
		if statusUpdated {
			// The status was updated in this loop implying that this
			// sync loop marks the end of the reconciliation of
			// MySQL Cluster configuration with the latest spec.
			// Record a SyncSuccess event to notify the same.
			syncContext.recorder.Eventf(nc, nil,
				corev1.EventTypeNormal, ReasonSyncSuccess, ActionSynced, MessageSyncSuccess)
		} else {
			// No status update this loop => the MySQL Cluster
			// was already in sync with the latest NdbCluster spec.
			// Record an InSync event
			syncContext.recorder.Eventf(nc, nil,
				corev1.EventTypeNormal, ReasonInSync, ActionNone, MessageInSync)
		}
	}

	return result
}