From 62ddccd3bbe349f8b97a9925eeaa3a70cdff5235 Mon Sep 17 00:00:00 2001
From: James Munnelly <james.munnelly@jetstack.io>
Date: Fri, 8 Sep 2017 21:41:40 +0100
Subject: [PATCH] Add custom SharedInformerFactory

---
 pkg/kube/factory.go | 87 +++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 87 insertions(+)
 create mode 100644 pkg/kube/factory.go

diff --git a/pkg/kube/factory.go b/pkg/kube/factory.go
new file mode 100644
index 000000000..df89d52e8
--- /dev/null
+++ b/pkg/kube/factory.go
@@ -0,0 +1,87 @@
+/*
+Copyright 2017 Jetstack Ltd.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+    http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License.
+*/
+
+package kube
+
+import (
+	sync "sync"
+
+	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
+	cache "k8s.io/client-go/tools/cache"
+)
+
+type SharedInformerFactory interface {
+	InformerFor(string, metav1.GroupVersionKind, cache.SharedIndexInformer) cache.SharedIndexInformer
+	Start(<-chan struct{})
+}
+
+var DefaultSharedInformerFactory = NewSharedInformerFactory()
+
+type sharedInformerFactory struct {
+	lock             sync.Mutex
+	informers        map[string]map[metav1.GroupVersionKind]cache.SharedIndexInformer
+	startedInformers map[string]map[metav1.GroupVersionKind]bool
+}
+
+var _ SharedInformerFactory = &sharedInformerFactory{}
+
+func NewSharedInformerFactory() SharedInformerFactory {
+	return &sharedInformerFactory{
+		informers:        make(map[string]map[metav1.GroupVersionKind]cache.SharedIndexInformer),
+		startedInformers: make(map[string]map[metav1.GroupVersionKind]bool),
+	}
+}
+
+func (s *sharedInformerFactory) InformerFor(namespace string, gvk metav1.GroupVersionKind, i cache.SharedIndexInformer) cache.SharedIndexInformer {
+	s.lock.Lock()
+	defer s.lock.Unlock()
+	if s.informers == nil {
+		s.informers = make(map[string]map[metav1.GroupVersionKind]cache.SharedIndexInformer)
+	}
+	informerMap, nsExists := s.informers[namespace]
+	if !nsExists {
+		s.informers[namespace] = map[metav1.GroupVersionKind]cache.SharedIndexInformer{
+			gvk: i,
+		}
+		return i
+	}
+	informer, exists := informerMap[gvk]
+	if !exists {
+		informerMap[gvk] = i
+		return i
+	}
+	return informer
+}
+
+// Start initializes all requested informers.
+func (f *sharedInformerFactory) Start(stopCh <-chan struct{}) {
+	f.lock.Lock()
+	defer f.lock.Unlock()
+
+	for namespace, informerMap := range f.informers {
+		startedMap, exists := f.startedInformers[namespace]
+		if !exists {
+			startedMap = make(map[metav1.GroupVersionKind]bool)
+			f.startedInformers[namespace] = startedMap
+		}
+		for informerType, informer := range informerMap {
+			if !startedMap[informerType] {
+				go informer.Run(stopCh)
+				startedMap[informerType] = true
+			}
+		}
+	}
+}