From e24394f32991daa0fae2a995c1aba53b3c775d15 Mon Sep 17 00:00:00 2001
From: Dario Tranchitella <dario@tranchitella.eu>
Date: Sat, 31 Jul 2021 17:22:35 +0200
Subject: [PATCH] refactor: avoiding init functions for direct registration

---
 pkg/indexer/add_ingress.go      | 26 --------------------------
 pkg/indexer/add_namespace.go    | 12 ------------
 pkg/indexer/add_tenant.go       | 12 ------------
 pkg/indexer/indexer.go          | 26 +++++++++++++++++++++++---
 pkg/indexer/ingress/hostname.go | 11 ++++++-----
 5 files changed, 29 insertions(+), 58 deletions(-)
 delete mode 100644 pkg/indexer/add_ingress.go
 delete mode 100644 pkg/indexer/add_namespace.go
 delete mode 100644 pkg/indexer/add_tenant.go

diff --git a/pkg/indexer/add_ingress.go b/pkg/indexer/add_ingress.go
deleted file mode 100644
index 6248b521..00000000
--- a/pkg/indexer/add_ingress.go
+++ /dev/null
@@ -1,26 +0,0 @@
-// Copyright 2020-2021 Clastix Labs
-// SPDX-License-Identifier: Apache-2.0
-
-package indexer
-
-import (
-	extensionsv1beta1 "k8s.io/api/extensions/v1beta1"
-	networkingv1 "k8s.io/api/networking/v1"
-	networkingv1beta1 "k8s.io/api/networking/v1beta1"
-
-	"github.com/clastix/capsule/pkg/indexer/ingress"
-	"github.com/clastix/capsule/pkg/webhook/utils"
-)
-
-func init() {
-	majorVer, minorVer, _, _ := utils.GetK8sVersion()
-
-	switch {
-	case majorVer == 1 && minorVer >= 19:
-		AddToIndexerFuncs = append(AddToIndexerFuncs, ingress.Hostname{Obj: &networkingv1.Ingress{}})
-	case majorVer == 1 && (minorVer >= 19 && minorVer < 22):
-		AddToIndexerFuncs = append(AddToIndexerFuncs, ingress.Hostname{Obj: &networkingv1beta1.Ingress{}})
-	case majorVer == 1 && minorVer < 22:
-		AddToIndexerFuncs = append(AddToIndexerFuncs, ingress.Hostname{Obj: &extensionsv1beta1.Ingress{}})
-	}
-}
diff --git a/pkg/indexer/add_namespace.go b/pkg/indexer/add_namespace.go
deleted file mode 100644
index 772fcfff..00000000
--- a/pkg/indexer/add_namespace.go
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright 2020-2021 Clastix Labs
-// SPDX-License-Identifier: Apache-2.0
-
-package indexer
-
-import (
-	"github.com/clastix/capsule/pkg/indexer/namespace"
-)
-
-func init() {
-	AddToIndexerFuncs = append(AddToIndexerFuncs, namespace.OwnerReference{})
-}
diff --git a/pkg/indexer/add_tenant.go b/pkg/indexer/add_tenant.go
deleted file mode 100644
index a269a016..00000000
--- a/pkg/indexer/add_tenant.go
+++ /dev/null
@@ -1,12 +0,0 @@
-// Copyright 2020-2021 Clastix Labs
-// SPDX-License-Identifier: Apache-2.0
-
-package indexer
-
-import "github.com/clastix/capsule/pkg/indexer/tenant"
-
-func init() {
-	AddToIndexerFuncs = append(AddToIndexerFuncs, tenant.IngressHostnames{})
-	AddToIndexerFuncs = append(AddToIndexerFuncs, tenant.NamespacesReference{})
-	AddToIndexerFuncs = append(AddToIndexerFuncs, tenant.OwnerReference{})
-}
diff --git a/pkg/indexer/indexer.go b/pkg/indexer/indexer.go
index 205c5002..9e6aa36b 100644
--- a/pkg/indexer/indexer.go
+++ b/pkg/indexer/indexer.go
@@ -6,6 +6,13 @@ package indexer
 import (
 	"context"
 
+	"github.com/clastix/capsule/pkg/indexer/ingress"
+	"github.com/clastix/capsule/pkg/indexer/namespace"
+	"github.com/clastix/capsule/pkg/indexer/tenant"
+	"github.com/clastix/capsule/pkg/webhook/utils"
+	extensionsv1beta1 "k8s.io/api/extensions/v1beta1"
+	networkingv1 "k8s.io/api/networking/v1"
+	networkingv1beta1 "k8s.io/api/networking/v1beta1"
 	"sigs.k8s.io/controller-runtime/pkg/client"
 	"sigs.k8s.io/controller-runtime/pkg/manager"
 )
@@ -16,13 +23,26 @@ type CustomIndexer interface {
 	Func() client.IndexerFunc
 }
 
-var AddToIndexerFuncs []CustomIndexer
-
 func AddToManager(m manager.Manager) error {
-	for _, f := range AddToIndexerFuncs {
+	indexers := append([]CustomIndexer{},
+		tenant.IngressHostnames{},
+		tenant.NamespacesReference{},
+		tenant.OwnerReference{},
+		namespace.OwnerReference{},
+		ingress.Hostname{Obj: &extensionsv1beta1.Ingress{}},
+		ingress.Hostname{Obj: &networkingv1beta1.Ingress{}},
+	)
+
+	majorVer, minorVer, _, _ := utils.GetK8sVersion()
+	if majorVer == 1 && minorVer >= 19 {
+		indexers = append(indexers, ingress.Hostname{Obj: &networkingv1.Ingress{}})
+	}
+
+	for _, f := range indexers {
 		if err := m.GetFieldIndexer().IndexField(context.TODO(), f.Object(), f.Field(), f.Func()); err != nil {
 			return err
 		}
 	}
+
 	return nil
 }
diff --git a/pkg/indexer/ingress/hostname.go b/pkg/indexer/ingress/hostname.go
index 299ffd89..11bd22c2 100644
--- a/pkg/indexer/ingress/hostname.go
+++ b/pkg/indexer/ingress/hostname.go
@@ -11,6 +11,10 @@ import (
 	"sigs.k8s.io/controller-runtime/pkg/client"
 )
 
+const (
+	HostnameFieldSelector = "host"
+)
+
 type Hostname struct {
 	Obj metav1.Object
 }
@@ -20,26 +24,23 @@ func (h Hostname) Object() client.Object {
 }
 
 func (h Hostname) Field() string {
-	return ".spec.rules[*].host"
+	return HostnameFieldSelector
 }
 
 func (h Hostname) Func() client.IndexerFunc {
 	return func(object client.Object) (hostnames []string) {
-		switch h.Obj.(type) {
+		switch ing := h.Obj.(type) {
 		case *networkingv1.Ingress:
-			ing := object.(*networkingv1.Ingress)
 			for _, r := range ing.Spec.Rules {
 				hostnames = append(hostnames, r.Host)
 			}
 			return
 		case *networkingv1beta1.Ingress:
-			ing := object.(*networkingv1beta1.Ingress)
 			for _, r := range ing.Spec.Rules {
 				hostnames = append(hostnames, r.Host)
 			}
 			return
 		case *extensionsv1beta1.Ingress:
-			ing := object.(*extensionsv1beta1.Ingress)
 			for _, r := range ing.Spec.Rules {
 				hostnames = append(hostnames, r.Host)
 			}