MetaNamespaceKeyFunc
NamespaceIndexName: NamespaceIndexFunc, NodeNameIndexName: NodeNameIndexFunc,
cat<<EOF >informer.go package main import ( "fmt" v1 "k8s.io/api/core/v1" "k8s.io/apimachinery/pkg/api/meta" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" "k8s.io/client-go/tools/cache" ) const ( NamespaceIndexName = "namespace" NodeNameIndexName = "nodeName" ) func NamespaceIndexFunc(obj interface{}) ([]string, error) { m, err := meta.Accessor(obj) if err != nil { return []string{""}, fmt.Errorf("object has no meta: %v", err) } return []string{m.GetNamespace()}, nil } func NodeNameIndexFunc(obj interface{}) ([]string, error) { pod, ok := obj.(*v1.Pod) if !ok { return []string{}, nil } return []string{pod.Spec.NodeName}, nil } func main() { index := cache.NewIndexer(cache.MetaNamespaceKeyFunc, cache.Indexers{ NamespaceIndexName: NamespaceIndexFunc, NodeNameIndexName: NodeNameIndexFunc, }) pod1 := &v1.Pod{ ObjectMeta: metav1.ObjectMeta{ Name: "index-pod-1", Namespace: "default", }, Spec: v1.PodSpec{NodeName: "node1"}, } pod2 := &v1.Pod{ ObjectMeta: metav1.ObjectMeta{ Name: "index-pod-2", Namespace: "default", }, Spec: v1.PodSpec{NodeName: "node2"}, } pod3 := &v1.Pod{ ObjectMeta: metav1.ObjectMeta{ Name: "index-pod-3", Namespace: "kube-system", }, Spec: v1.PodSpec{NodeName: "node2"}, } _ = index.Add(pod1) _ = index.Add(pod2) _ = index.Add(pod3) // ByIndex 两个参数：IndexName（索引器名称）和 indexKey（需要检索的key） pods, err := index.ByIndex(NamespaceIndexName, "default") if err != nil { panic(err) } for _, pod := range pods { fmt.Println(pod.(*v1.Pod).Name) } fmt.Println("==========================") pods, err = index.ByIndex(NodeNameIndexName, "node2") if err != nil { panic(err) } for _, pod := range pods { fmt.Println(pod.(*v1.Pod).Name) } } EOF
root@ubuntu:~/go_learn/informer# go mod vendor root@ubuntu:~/go_learn/informer# go build -o informer . root@ubuntu:~/go_learn/informer# ./informer index-pod-1 index-pod-2 ========================== index-pod-2 index-pod-3
在上面的示例中首先通过 NewIndexer 函数实例化 Indexer 对象，第一个参数就是用于计算资源对象键的函数，这里我们使用的是 MetaNamespaceKeyFunc 这个默认的对象键函数；第二个参数是 Indexers，也就是存储索引器，上面我们知道 Indexers 的定义为 map[string]IndexFunc，为什么要定义成一个 map 呢？我们可以类比数据库中，我们要查询某项数据，索引的方式是不是多种多样啊？为了扩展，Kubernetes 中就使用一个 map 来存储各种各样的存储索引器，至于存储索引器如何生成，就使用一个 IndexFunc 暴露出去，给使用者自己实现即可。
这里我们定义的了两个索引键生成函数：NamespaceIndexFunc 与 NodeNameIndexFunc，一个根据资源对象的命名空间来进行索引，一个根据资源对象所在的节点进行索引。然后定义了3个 Pod，前两个在 default 命名空间下面，另外一个在 kube-system 命名空间下面，然后通过 index.Add 函数添加这3个 Pod 资源对象。然后通过 index.ByIndex 函数查询在名为 namespace 的索引器下面匹配索引键为 default 的 Pod 列表。也就是查询 default 这个命名空间下面的所有 Pod，这里就是前两个定义的 Pod。
对上面的示例如果我们理解了，那么就很容易理解上面定义的4个数据结构了：
- IndexFunc：索引器函数，用于计算一个资源对象的索引值列表，上面示例是指定命名空间为索引值结果，当然我们也可以根据需求定义其他的，比如根据 Label 标签、Annotation 等属性来生成索引值列表。
- Index：存储数据，对于上面的示例，我们要查找某个命名空间下面的 Pod，那就要让 Pod 按照其命名空间进行索引，对应的 Index 类型就是
map[namespace]sets.pod。 - Indexers：存储索引器，key 为索引器名称，value 为索引器的实现函数，上面的示例就是
map["namespace"]MetaNamespaceIndexFunc。 - Indices：存储缓存器，key 为索引器名称，value 为缓存的数据，对于上面的示例就是
map["namespace"]map[namespace]sets.pod。
可能最容易混淆的是 Indexers 和 Indices 这两个概念，因为平时很多时候我们没有怎么区分二者的关系，这里我们可以这样理解：Indexers 是存储索引（生成索引键）的，Indices 里面是存储的真正的数据（对象键），这样可能更好理解。
按照上面的理解我们可以得到上面示例的索引数据如下所示：
// Indexers 就是包含的所有索引器(分类)以及对应实现 Indexers: { "namespace": NamespaceIndexFunc, "nodeName": NodeNameIndexFunc, } // Indices 就是包含的所有索引分类中所有的索引数据 Indices: { "namespace": { //namespace 这个索引分类下的所有索引数据 "default": ["pod-1", "pod-2"], // Index 就是一个索引键下所有的对象键列表 "kube-system": ["pod-3"] // Index }, "nodeName": { //nodeName 这个索引分类下的所有索引数据(对象键列表) "node1": ["pod-1"], // Index "node2": ["pod-2", "pod-3"] // Index } }
root@ubuntu:~/go_learn/informer# go build -o informer . root@ubuntu:~/go_learn/informer# ./informer key is default/index-pod-1 key2 is default/index-pod-1 root@ubuntu:~/go_learn/informer# cat informer.go package main import ( "fmt" v1 "k8s.io/api/core/v1" //"k8s.io/apimachinery/pkg/api/meta" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" "k8s.io/client-go/tools/cache" "k8s.io/client-go/util/workqueue" ) func main() { queue := workqueue.NewRateLimitingQueue(workqueue.DefaultControllerRateLimiter()) pod1 := &v1.Pod{ ObjectMeta: metav1.ObjectMeta{ Name: "index-pod-1", Namespace: "default", }, Spec: v1.PodSpec{NodeName: "node1"}, } key, err := cache.MetaNamespaceKeyFunc(pod1) if err == nil { fmt.Println("key is ", key) queue.Add(key) } key2, err2 := queue.Get() if err2 { fmt.Println("quit") } else { fmt.Println("key2 is ", key2) } }
root@ubuntu:~/go_learn/informer# ./informer -kubeconfig=$HOME/.kube/config key is default/index-pod-1 key2 is default/index-pod-1
root@ubuntu:~/go_learn/informer# cat informer.go package main import ( "fmt" "flag" "time" "k8s.io/client-go/kubernetes" "k8s.io/client-go/tools/clientcmd" klog "k8s.io/klog/v2" "k8s.io/client-go/informers" v1 "k8s.io/api/core/v1" //"k8s.io/apimachinery/pkg/api/meta" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" "k8s.io/client-go/tools/cache" "k8s.io/client-go/util/workqueue" "k8s.io/kubectl/pkg/util/logs" ) var kubeconfig string func init() { flag.StringVar(&kubeconfig, "kubeconfig", "", "absolute path to the kubeconfig file") } func main() { flag.Parse() logs.InitLogs() defer logs.FlushLogs() config, err := clientcmd.BuildConfigFromFlags("", kubeconfig) if err != nil { panic(err.Error()) } clientset, err := kubernetes.NewForConfig(config) if err != nil { klog.Fatal(err) } factory := informers.NewSharedInformerFactory(clientset, time.Hour*24) queue := workqueue.NewRateLimitingQueue(workqueue.DefaultControllerRateLimiter()) pod1 := &v1.Pod{ ObjectMeta: metav1.ObjectMeta{ Name: "index-pod-1", Namespace: "default", }, Spec: v1.PodSpec{NodeName: "node1"}, } key, err := cache.MetaNamespaceKeyFunc(pod1) if err == nil { fmt.Println("key is ", key) queue.Add(key) } key2, err2 := queue.Get() if err2 { fmt.Println("quit") } else { fmt.Println("key2 is ", key2) } informer := factory.Core().V1().Pods().Informer() stop := make(chan struct{}) go informer.Run(stop) pod,_,_:= informer.GetStore().GetByKey(key2.(string)) fmt.Println(pod.(*v1.Pod).Name) }
root@ubuntu:~/go_learn/informer# ./informer -kubeconfig=$HOME/.kube/config key is default/index-pod-1 key2 is default/index-pod-1 panic: interface conversion: interface {} is nil, not *v1.Pod goroutine 1 [running]: main.main() /root/go_learn/informer/informer.go:65 +0x7e8
root@ubuntu:~/go_learn/informer# go build -o informer . root@ubuntu:~/go_learn/informer# ./informer key is default/index-pod-1 key2 is default/index-pod-1 index-pod-1 root@ubuntu:~/go_learn/informer# cat informer.go package main import ( "fmt" v1 "k8s.io/api/core/v1" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" "k8s.io/client-go/tools/cache" "k8s.io/client-go/util/workqueue" ) func main() { queue := workqueue.NewRateLimitingQueue(workqueue.DefaultControllerRateLimiter()) indexer := cache.NewIndexer(cache.MetaNamespaceKeyFunc, cache.Indexers{cache.NamespaceIndex: cache.MetaNamespaceIndexFunc}) pod1 := &v1.Pod{ ObjectMeta: metav1.ObjectMeta{ Name: "index-pod-1", Namespace: "default", }, Spec: v1.PodSpec{NodeName: "node1"}, } key, err := cache.MetaNamespaceKeyFunc(pod1) if err == nil { fmt.Println("key is ", key) queue.Add(key) _ = indexer.Add(pod1) } key2, err2 := queue.Get() if err2 { fmt.Println("quit") } else { fmt.Println("key2 is ", key2) } pod,_,_ := indexer.GetByKey(key2.(string)) fmt.Println(pod.(*v1.Pod).Name) }
DeletionHandlingMetaNamespaceKeyFunc
root@ubuntu:~/go_learn/informer# go build -o informer . informer.go:11:2: cannot find package "." in: /root/go_learn/informer/vendor/k8s.io/kubectl/pkg/util/logs root@ubuntu:~/go_learn/informer# go mod vendor go: downloading k8s.io/apimachinery v0.21.2 go: downloading k8s.io/api v0.21.2 go: downloading k8s.io/client-go v0.21.2 go: downloading k8s.io/kubectl v0.21.2 go: downloading github.com/google/go-cmp v0.5.4 go: downloading golang.org/x/net v0.0.0-20210224082022-3d97a244fca7 go: downloading sigs.k8s.io/structured-merge-diff/v4 v4.1.0 go: downloading golang.org/x/text v0.3.4 go: downloading k8s.io/utils v0.0.0-20201110183641-67b214c5f920 go: downloading google.golang.org/appengine v1.6.5 go: downloading golang.org/x/sys v0.0.0-20210426230700-d19ff857e887 go: downloading github.com/golang/protobuf v1.4.3 go: downloading google.golang.org/protobuf v1.25.0
root@ubuntu:~/go_learn/informer# cat informer.go package main import ( "fmt" v1 "k8s.io/api/core/v1" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" "k8s.io/client-go/tools/cache" "k8s.io/client-go/util/workqueue" ) func main() { queue := workqueue.NewRateLimitingQueue(workqueue.DefaultControllerRateLimiter()) indexer := cache.NewIndexer(cache.DeletionHandlingMetaNamespaceKeyFunc, cache.Indexers{cache.NamespaceIndex: cache.MetaNamespaceIndexFunc}) pod1 := &v1.Pod{ ObjectMeta: metav1.ObjectMeta{ Name: "index-pod-1", Namespace: "default", }, Spec: v1.PodSpec{NodeName: "node1"}, } key, err := cache.DeletionHandlingMetaNamespaceKeyFunc(pod1) if err == nil { fmt.Println("key is ", key) queue.Add(key) _ = indexer.Add(pod1) } key2, err2 := queue.Get() if err2 { fmt.Println("quit") } else { fmt.Println("key2 is ", key2) } pod,_,_ := indexer.GetByKey(key2.(string)) fmt.Println(pod.(*v1.Pod).Name) }
root@ubuntu:~/go_learn/informer# go build -o informer . root@ubuntu:~/go_learn/informer# ./informer key is default/index-pod-1 key2 is default/index-pod-1 index-pod-1
index.Add + cache.MetaNamespaceKeyFunc
root@ubuntu:~/go_learn/informer# cat informer.go package main import ( "fmt" v1 "k8s.io/api/core/v1" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" "k8s.io/client-go/tools/cache" ) func testIndexFunc(obj interface{}) ([]string, error) { pod := obj.(*v1.Pod) return []string{pod.Labels["foo"]}, nil } func GetIndexFuncValues() { index := cache.NewIndexer(cache.MetaNamespaceKeyFunc, cache.Indexers{"testmodes": testIndexFunc}) pod1 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "one", Labels: map[string]string{"foo": "bar"}}} pod2 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "two", Labels: map[string]string{"foo": "bar"}}} pod3 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "three", Labels: map[string]string{"foo": "biz"}}} index.Add(pod1) index.Add(pod2) index.Add(pod3) keys := index.ListIndexFuncValues("testmodes") for _, key := range keys { fmt.Println("key:", key) items, _ := index.ByIndex("testmodes", key) for _, item := range items { fmt.Println("pod", item.(*v1.Pod).ObjectMeta.Name) } } key, err := cache.MetaNamespaceKeyFunc(pod1) if err == nil { fmt.Println("key is ", key) } } func main() { GetIndexFuncValues() }
root@ubuntu:~/go_learn/informer# go build -o informer . root@ubuntu:~/go_learn/informer# ./informer key: bar pod one pod two key: biz pod three key is one
indexer.GetByKey
root@ubuntu:~/go_learn/informer# cat informer.go package main import ( "fmt" v1 "k8s.io/api/core/v1" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" "k8s.io/client-go/tools/cache" ) func testIndexFunc(obj interface{}) ([]string, error) { pod := obj.(*v1.Pod) return []string{pod.Labels["foo"]}, nil } func GetIndexFuncValues() { index := cache.NewIndexer(cache.MetaNamespaceKeyFunc, cache.Indexers{"testmodes": testIndexFunc}) pod1 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "one", Labels: map[string]string{"foo": "bar"}}} pod2 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "two", Labels: map[string]string{"foo": "bar"}}} pod3 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "three", Labels: map[string]string{"foo": "biz"}}} index.Add(pod1) index.Add(pod2) index.Add(pod3) keys := index.ListIndexFuncValues("testmodes") for _, key := range keys { fmt.Println("key:", key) items, _ := index.ByIndex("testmodes", key) for _, item := range items { fmt.Println("pod", item.(*v1.Pod).ObjectMeta.Name) } } key, err := cache.MetaNamespaceKeyFunc(pod1) if err == nil { fmt.Println("key is ", key) } pod,_,_ := index.GetByKey(key) fmt.Println(pod.(*v1.Pod).Name, pod.(*v1.Pod).Labels["foo"]) } func main() { GetIndexFuncValues() }
root@ubuntu:~/go_learn/informer# go build -o informer . root@ubuntu:~/go_learn/informer# ./informer key: bar pod one pod two key: biz pod three key is one one bar
ListIndexFuncValues
testIndexFunc()返回的是pod labels中”foo”对应的值。
在GetIndexFuncValues()中，我们先构造index，其中keyFunc为MetaNamespaceKeyFunc，就是用namespace/name作为key；IndexFunc为testIndexFunc()，名为”testmodes”。然后生成pod1, pod2, pod3。其中pod1和pod2的label “foo”的值为”bar”，pod3的label “foo”的值为”biz”。把pod1, pod2和pod3加入到index中。现在index中”testmodes” indexFunc对应的有”bar”和”biz”两个indexValue，”bar”对应pod1和pod2的key，”biz”对应pod3的key，具体的pod值可以由index的ByIndex()获取。
root@ubuntu:~/go_learn/informer# cat informer.go package main import ( "fmt" v1 "k8s.io/api/core/v1" metav1 "k8s.io/apimachinery/pkg/apis/meta/v1" "k8s.io/client-go/tools/cache" ) func testIndexFunc(obj interface{}) ([]string, error) { pod := obj.(*v1.Pod) return []string{pod.Labels["foo"]}, nil } func GetIndexFuncValues() { index := cache.NewIndexer(cache.MetaNamespaceKeyFunc, cache.Indexers{"testmodes": testIndexFunc}) pod1 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "one", Labels: map[string]string{"foo": "bar"}}} pod2 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "two", Labels: map[string]string{"foo": "bar"}}} pod3 := &v1.Pod{ObjectMeta: metav1.ObjectMeta{Name: "three", Labels: map[string]string{"foo": "biz"}}} index.Add(pod1) index.Add(pod2) index.Add(pod3) keys := index.ListIndexFuncValues("testmodes") for _, key := range keys { fmt.Println("key:", key) items, _ := index.ByIndex("testmodes", key) for _, item := range items { fmt.Println("pod", item.(*v1.Pod).ObjectMeta.Name) } } } func main() { GetIndexFuncValues() }
root@ubuntu:~/go_learn/informer# go build -o informer . root@ubuntu:~/go_learn/informer# ./informer key: bar pod two pod one key: biz pod three
sample-controller
https://gocn.vip/topics/10308
workqueue
https://github.com/kubernetes/client-go/blob/master/examples/workqueue/main.go
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