From 8d30f365e93dd92a6d744d1007a589c6e7578a40 Mon Sep 17 00:00:00 2001
From: Timofei Larkin <lllamnyp@gmail.com>
Date: Tue, 30 Jul 2024 23:21:27 +0300
Subject: [PATCH] outline some of the subroutines of the non-happy path for
 cluster reconciliation

---
 internal/controller/etcdcluster_controller.go | 49 +++++++++++++++----
 internal/controller/factory/configmap.go      | 31 ++----------
 internal/controller/factory/statefulset.go    |  5 ++
 3 files changed, 49 insertions(+), 36 deletions(-)

diff --git a/internal/controller/etcdcluster_controller.go b/internal/controller/etcdcluster_controller.go
index 2cb13a8..156cd25 100644
--- a/internal/controller/etcdcluster_controller.go
+++ b/internal/controller/etcdcluster_controller.go
@@ -125,16 +125,28 @@ func (r *EtcdClusterReconciler) Reconcile(ctx context.Context, req ctrl.Request)
 
 	if !state.endpointsFound {
 		if !state.stsExists {
-			cm := factory.TemplateClusterStateConfigMap(instance, "new", state.desiredReplicas())
-			err := ctrl.SetControllerReference(instance, cm, r.Scheme)
-			if err != nil {
-				return ctrl.Result{}, err
-			}
-			err = r.patchOrCreateObject(ctx, cm)
-			if err != nil {
-				return ctrl.Result{}, err
-			}
+			return r.createClusterFromScratch(ctx, &state) // TODO: needs implementing
+		}
+		// else try reconciling the sts
+		existingSts := state.statefulSet.DeepCopy()
+		desiredSts := factory.TemplateStatefulSet() // TODO: needs implementing
+		existingSts.Spec.Template.Spec = desiredSts.Spec.Template.Spec
+		err := r.patchOrCreateObject(ctx, existingSts)
+		if err != nil {
+			return ctrl.Result{}, err
+		}
+		state.statefulSet = *existingSts
+		if existingSts.Status.ReadyReplicas != *existingSts.Spec.Replicas { // TODO: this check might not be the best to check for a ready sts
+			return ctrl.Result{}, fmt.Errorf("waiting for statefulset to become ready")
+		}
+		if *existingSts.Spec.Replicas > 0 {
+			return ctrl.Result{}, fmt.Errorf("reached an impossible state (no endpoints, but active pods)")
+		}
+		if *instance.Spec.Replicas == 0 {
+			// cluster successfully scaled down to zero
+			return ctrl.Result{}, nil
 		}
+		return r.scaleUpFromZero(ctx, &state) // TODO: needs implementing
 	}
 
 	// get status of every endpoint and member list from every endpoint
@@ -690,3 +702,22 @@ func (r *EtcdClusterReconciler) patchOrCreateObject(ctx context.Context, obj cli
 	}
 	return err
 }
+
+// TODO!
+func (r *EtcdClusterReconciler) createClusterFromScratch(ctx context.Context, state *observables) (ctrl.Result, error) {
+	cm := factory.TemplateClusterStateConfigMap(state.instance, "new", state.desiredReplicas())
+	err := ctrl.SetControllerReference(state.instance, cm, r.Scheme)
+	if err != nil {
+		return ctrl.Result{}, err
+	}
+	err = r.patchOrCreateObject(ctx, cm)
+	if err != nil {
+		return ctrl.Result{}, err
+	}
+	panic("not yet implemented")
+}
+
+// TODO!
+func (r *EtcdClusterReconciler) scaleUpFromZero(ctx context.Context, state *observables) (ctrl.Result, error) {
+	panic("not yet implemented")
+}
diff --git a/internal/controller/factory/configmap.go b/internal/controller/factory/configmap.go
index 7a06e47..7081b06 100644
--- a/internal/controller/factory/configmap.go
+++ b/internal/controller/factory/configmap.go
@@ -70,39 +70,16 @@ func CreateOrUpdateClusterStateConfigMap(
 	rclient client.Client,
 ) error {
 	var err error
-	initialCluster := ""
-	clusterService := fmt.Sprintf("%s.%s.svc:2380", GetHeadlessServiceName(cluster), cluster.Namespace)
-	for i := int32(0); i < *cluster.Spec.Replicas; i++ {
-		if i > 0 {
-			initialCluster += ","
-		}
-		podName := fmt.Sprintf("%s-%d", cluster.Name, i)
-		initialCluster += fmt.Sprintf("%s=https://%s.%s",
-			podName, podName, clusterService,
-		)
-	}
-
-	configMap := &corev1.ConfigMap{
-		ObjectMeta: metav1.ObjectMeta{
-			Namespace: cluster.Namespace,
-			Name:      GetClusterStateConfigMapName(cluster),
-		},
-		Data: map[string]string{
-			"ETCD_INITIAL_CLUSTER_STATE": "new",
-			"ETCD_INITIAL_CLUSTER":       initialCluster,
-			"ETCD_INITIAL_CLUSTER_TOKEN": cluster.Name + "-" + cluster.Namespace,
-		},
+	state := "new"
+	if isEtcdClusterReady(cluster) {
+		state = "existing"
 	}
+	configMap := TemplateClusterStateConfigMap(cluster, state, int(*cluster.Spec.Replicas))
 	ctx, err = contextWithGVK(ctx, configMap, rclient.Scheme())
 	if err != nil {
 		return err
 	}
 
-	if isEtcdClusterReady(cluster) {
-		// update cluster state to existing
-		log.Debug(ctx, "updating cluster state")
-		configMap.Data["ETCD_INITIAL_CLUSTER_STATE"] = "existing"
-	}
 	log.Debug(ctx, "configmap data generated", "data", configMap.Data)
 
 	if err := ctrl.SetControllerReference(cluster, configMap, rclient.Scheme()); err != nil {
diff --git a/internal/controller/factory/statefulset.go b/internal/controller/factory/statefulset.go
index 859fd80..93e1266 100644
--- a/internal/controller/factory/statefulset.go
+++ b/internal/controller/factory/statefulset.go
@@ -41,6 +41,11 @@ const (
 	defaultBackendQuotaBytesFraction = 0.95
 )
 
+// TODO!
+func TemplateStatefulSet() *appsv1.StatefulSet {
+	panic("not yet implemented")
+}
+
 func PodLabels(cluster *etcdaenixiov1alpha1.EtcdCluster) map[string]string {
 	labels := NewLabelsBuilder().WithName().WithInstance(cluster.Name).WithManagedBy()