经过前两篇的学习与实操,也大致掌握了一个k8s资源的Controller写法了,如有不熟,可回顾
先说说CRD-controller的作用,本CR原意是记录云主机ECS及node节点映射信息,而本controller则把这个映射操作省略掉,只为所有创建成功的CR打一个Label。而本篇为达成此目的,需要执行的步骤有以下几个:
通过上述步骤,可以绕开ApiBuilder脚手架,自己手捏一个CRD-Controller出来。可以更好的理解整个Informer机制的架构
创建CRD的manifest如下所示
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
annotations:
controller-gen.kubebuilder.io/version: v0.2.5
creationTimestamp: null
name: ecsbinding.hopegi.com
spec:
group: hopegi.com #此处定义api group
names:
kind: EcsBinding #本行和下一行定义CRD的单体kind和集合类型的Kind
listKind: EcsBindingList
plural: ecsbinding #复数写法 #本行和下行仅填写CRD的小写即可
singular: ecsbinding #单数写法
shortNames:
- ecsb #
preserveUnknownFields: false #允许存储未知字段,就是下面没声明的
additionalPrinterColumns: #在kubectl显示的字段
- JSONPath: .metadata.creationTimestamp
name: Age
type: date
- JSONPath: .spec.nodename
name: NodeName
type: string
- JSONPath: .spec.innerip
name: InnerIp
type: string
scope: Cluster #资源的作用域,一般是命名空间下和集群级别,命名空间是Namespaced,集群则Cluster
validation: #本行和下行都是固定
openAPIV3Schema:
description: hopegi test crd
properties: #后面开始描述各个字段,API和metadata是固定,spec也是固定,spec往下则是自定义的字段,每个字段需要制定
#type,name属性,description可选,type有常用的string,object,bool,int等,object则会多一级properties
#用于定义下一级的子字段
apiVersion:
type: string
metadata:
type: object
spec:
properties:
id:
type: string
name:
type: string
nodename:
type: string
innerip:
type: string
type: object
status:
type: object
type: object
version: v1 #到此处往下皆固定
versions:
- name: v1
served: true
storage: true
status:
acceptedNames:
kind: ""
plural: ""
conditions: []
storedVersions: []
这里比较值得注意是ApiGroup需要定好,这个group到后续给scheme注册资源类型时用到,影响往apiserver去交互管理资源。
这个api可能容易给人造成误解,实际是定义CR的struct,包含什么字段,文件路径api/v1/ecs-bing.go
type EcsBinding struct {
metav1.TypeMeta `json:",inline"`
metav1.ObjectMeta `json:"metadata,omitempty"`
Spec EcsBindSpec `json:"spec,omitempty"`
Status EcsBindStatus `json:"status,omitempty"`
}
type EcsBindingList struct {
metav1.TypeMeta `json:",inline"`
metav1.ListMeta `json:"metadata,omitempty"`
Items []EcsBinding `json:"items"`
}
type EcsBindSpec struct {
Id string `json:"id"`
Name string `json:"name"`
NodeName string `json:"node_name"`
InnerIp string `json:"inner_ip"`
}
type EcsBindStatus struct {
}
自上而下定义EcsBinding和EcsBindingList两个struct,由于要实现runtime.Object的接口,需要实现DeepCopyObject方法,如果用脚手架生成的代码,这部分实现接口的代码就不用手敲
scheme注册这里分两部分,一部分是定义一个scheme,另一部分是在各个api里面提供AddToScheme函数,这个函数用于把各种类型各种版本的api(也就是GVK)注册到scheme
先看第一部分,文件路径client/versiond/scheme/register.go
var scheme = runtime.NewScheme()
var Codecs = serializer.NewCodecFactory(scheme)
var ParameterCodec = runtime.NewParameterCodec(scheme)
func init() {
metav1.AddToGroupVersion(scheme,schema.GroupVersion{Version:"v1"})
if err:=AddToScheme(scheme);err!=nil{
fmt.Println("error to AddToScheme ",err)
}
}
func AddToScheme(scheme *runtime.Scheme)error {
return ecsv1.AddToScheme(scheme)
}
在AddToScheme中就是调用各个kind的AddToScheme,尽管这里只有一个Kind。第二部分的又回去api/v1/ecs-bing.go
var (
// GroupVersion is group version used to register these objects
GroupVersion = schema.GroupVersion{Group: "hopegi.com", Version: "v1"}
// SchemeBuilder is used to add go types to the GroupVersionKind scheme
SchemeBuilder = &scheme.Builder{GroupVersion: GroupVersion}
//SchemeBuilder = runtime.NewSchemeBuilder(AddKnownTypes)
// AddToScheme adds the types in this group-version to the given scheme.
AddToScheme = SchemeBuilder.AddToScheme
EscBindVersionKind = schema.GroupVersionKind{Group: GroupVersion.Group, Version: GroupVersion.Version, Kind: "EcsBinding"}
)
func init() {
SchemeBuilder.Register(&EcsBinding{},&EcsBindingList{})
}
此处的Group需要和之前定义CRD时的group一致
这里实际定义了一个clientSet,clientset应该包含多个version,一个version包含多个资源类型,但是这里只有一个version,一个kind。clientSet的结构如下所示
clientSet
|---Discovery
|---EcsV1
|---RESTClient
|---EcsBindingClient
clientSet位于client/versiond/clientset.go
EcsV1位于client/versiond/typed/ecsbinding/v1/ecs_client.go中,它的RESTClient也用于传递给EcsClient,用于EcsClient对apiserver通讯的http客户端
EcsBindingClient位于client/version/typed/ecsbingding/v1/ecs-binding.go中,定义了client的各种操作方法,封装了对apiserver的各个http请求。
各个client的初始化,则是由最外层把Config一层一层的往里面具体的Client传。整套client的代码不在这里展示,仅展示一下调用链
versiond.NewForConfig->ecsbindv1.NewForConfig
创建出clientSet 创建出EcsV1
当调用EcsV1的EcsBinding方法(也就是获取EcsClient)时,才调用newEcsbindings构造函数构造一个client
ecsbindv1.NewForConfig的代码如下:
func NewForConfig(c *rest.Config)(*EcsV1Client,error) {
config:=*c
if err:=setConfigDefaults(&config);err!=nil{
return nil,err
}
client,err:=rest.RESTClientFor(&config)
if err!=nil{
return nil,err
}
return &EcsV1Client{client},nil
}
在这个函数中先给config设置默认参数,最后按照这些默认参数构造出一个RESTClient,这个RESTClient传递给EcsV1Client,一个作用是把它自己的一个成员restClient,另一个作用就是用于构造EcsClient所需的RESTClient。
setConfigDefaults函数定义如下
func setConfigDefaults(config *rest.Config) error {
gv := ecsv1.GroupVersion
config.GroupVersion = &gv
config.APIPath = "/apis"
config.NegotiatedSerializer = serializer.DirectCodecFactory{CodecFactory: scheme.Codecs}
if config.UserAgent == "" {
config.UserAgent = rest.DefaultKubernetesUserAgent()
}
return nil
}
函数给config指定了groudversion这个gv就是hopegi.com v1;api的地址固定是"/apis",通过这两句可以确定客户端跟apiserver通讯时的地址是/apis/hopegi.com/v1,后面设置scheme的序列化器,用于把apiserver响应的json数据反序列化成struct数据。
EcsBindingClient接口定义的函数如下
type EcsBindingInterface interface {
Create(*v1.EcsBinding)(*v1.EcsBinding,error)
Update(*v1.EcsBinding)(*v1.EcsBinding,error)
Delete(string,*metav1.DeleteOptions)error
DeleteCollection(options *metav1.DeleteOptions, listOptions metav1.ListOptions) error
List(metav1.ListOptions)(*v1.EcsBindingList,error)
Get(name string,options metav1.GetOptions)(*v1.EcsBinding,error)
Watch(options metav1.ListOptions)(watch.Interface,error)
Patch(name string, pt types.PatchType, data []byte, subresources ...string) (result *v1.EcsBinding, err error)
}
以List方法实现作例子
func (c *ecsBinding)List(opts metav1.ListOptions)(*v1.EcsBindingList,error){
result := &v1.EcsBindingList{}
err := c.client.Get().
Resource("ecsbinding").
VersionedParams(&opts, scheme.ParameterCodec).
Do().
Into(result)
for _,o:=range result.Items{
o.SetGroupVersionKind(v1.EscBindVersionKind)
}
return result,err
}
client成员则是先前构造时传入的RESTClient,Resource指定资源的名ecsbingding,当有CR返回时需要执行SetGroupVersionKind,否则拿到的CR结构体会丢失GroupVersion和Kind信息
在实现某个资源的Informer之前,要实现一个Informer的Factory。这个Factory的作用有几个,其一是用于构造一个Informer;另外就是在start一个Controller的时候调用它Start方法,Start方法内部就会把它管理的所有Informer Run起来。
SharedInformerFactory接口的定义如下所示,代码位于controller-demo/informers/factory.go
type SharedInformerFactory interface {
internalinterfaces.SharedInformerFactory
WaitForCacheSync(stopCh <-chan struct{}) map[reflect.Type]bool
EcsBind() ecsbind.Interface
}
这里主要是暴露一个构造并获取各个Group的Interface,Start方法的接口则来源于它继承的internalinterfaces.SharedInformerFactory接口,代码位于 controller-demo/informers/internalinterface/factory_interfaces.go
type SharedInformerFactory interface {
Start(stopCh <-chan struct{})
InformerFor(obj runtime.Object, newFunc NewInformerFunc) cache.SharedIndexInformer
}
除了Start方法,InformerFor跟构造一个Informer有关,实现Informer的时候会调用到factory的方法,后续会再介绍
EcsBind()返回的是这个Group的Interface,代码位于controller-demo/informers/ecsbind/interface.go
type Interface interface {
// V1 provides access to shared informers for resources in V1.
V1() v1.Interface
}
V1的Interface则是涵盖了这个版本下各个资源的客户端接口,代码位于controller-demo/informers/ecsbind/v1/interface.go
type Interface interface {
EcsBinding() EcsBindingInformer
}
这样也刚好跟k8s的api的层级相呼应,先是ApiGroup,再到Version,最后到Kind,就是GVK
一个Informer的最核心逻辑是List和Watch方法,不过我们实现一个Infomer时只需要给SharedIndexInformer提供这两个方法就可以,调用这两个方法的逻辑由SharedIndexInformer统一实现
func NewFilteredEcsBindingInformer(clientset *versiond.Clientset, resyncPeriod time.Duration, indexers cache.Indexers, tweakListOptions internalinterfaces.TweakListOptionsFunc) cache.SharedIndexInformer {
return cache.NewSharedIndexInformer(&cache.ListWatch{
ListFunc: func(options meta_v1.ListOptions) (object runtime.Object, e error) {
if tweakListOptions!=nil{
tweakListOptions(&options)
}
return clientset.EcsV1().EcsBinding().List(options)
},
WatchFunc: func(options meta_v1.ListOptions) (i watch.Interface, e error) {
if tweakListOptions!=nil{
tweakListOptions(&options)
}
return clientset.EcsV1().EcsBinding().Watch(options)
},
},&ecsv1.EcsBinding{},resyncPeriod,indexers)
}
实际上仅仅是调用了client而已,client则是来源于这个CR的Informer——EcsBindingInformer,看看它的接口定义和结构
type EcsBindingInformer interface {
Informer() cache.SharedIndexInformer
Lister() demov1.EcsBindingLister
}
type ecsBindingInformer struct {
factory internalinterfaces.SharedInformerFactory
tweakListOptions internalinterfaces.TweakListOptionsFunc
}
对外暴露的EcsBindingInformer仅仅是一个接口,暴露Informer和LIster两个方法,实现则交由一个内部的结构实现,纵观这个CRD的client,CR的client,clientset,Informer乃至后续的lister都是这样的模式。
EcsBindingInformer的Informer()实现如下
func (e *ecsBindingInformer) Informer() cache.SharedIndexInformer {
return e.factory.InformerFor(&ecsv1.EcsBinding{}, e.defaultInformer)
}
func (e *ecsBindingInformer) defaultInformer(client versiond.Interface, resyncPeriod time.Duration) cache.SharedIndexInformer {
return NewFilteredEcsBindingInformer(client, resyncPeriod, cache.Indexers{cache.NamespaceIndex: cache.MetaNamespaceIndexFunc}, e.tweakListOptions)
}
如前面介绍Factory的时候所介绍的,Informer创建时需要调用factory的InformerFor方法,传入资源的指针以及一个函数回调
func (e *ecsBindingInformer) Informer() cache.SharedIndexInformer {
return e.factory.InformerFor(&ecsv1.EcsBinding{}, e.defaultInformer)
}
回调的声明在internalinterface处,controller-demo/informers/internalinterface/factory_interfaces.go
type NewInformerFunc func(versiond.Interface, time.Duration) cache.SharedIndexInformer
在这里就是ecsBindingInformer.defaultInformer,调用这个方法时就会把factory的client传递到构造SharedIndexInformer函数,这样List函数和Watch函数就有client使用,相当于整个构造过程是
EcsBindingInformer接口的另一个方法就是获取Lister,仅仅需要把SharedIndexInformer的Indexer传递过去则可,Lister的缓存机构已由SharedIndexInformer实现
func (e *ecsBindingInformer) Lister() demov1.EcsBindingLister {
return demov1.NewEcsBindingLister(e.Informer().GetIndexer())
}
作为apiserver的缓存,供controller调用快速获取资源,因此它需要提供两个查询的方法,代码位于controller-demo/listers/ecsbind/v1/ecs-binding-lister.go
type EcsBindingLister interface {
List(selector labels.Selector)([]*ecsv1.EcsBinding,error)
Get(name string)(*ecsv1.EcsBinding,error)
}
func NewEcsBindingLister(indexer cache.Indexer) EcsBindingLister {
return &ecsBindingLister{
indexer:indexer,
}
}
func (e *ecsBindingLister)List(selector labels.Selector)(ret []*ecsv1.EcsBinding,err error) {
err= cache.ListAll(e.indexer,selector, func(i interface{}) {
ret= append(ret, i.(*ecsv1.EcsBinding))
})
return
}
func (e *ecsBindingLister)Get(name string)(*ecsv1.EcsBinding,error) {
obj, exists, err := e.indexer.GetByKey(name)
if err != nil {
return nil, err
}
if !exists {
return nil, errors.NewNotFound(v1.Resource("ecsbind"), name)
}
return obj.(*ecsv1.EcsBinding), nil
}
controller所依赖的各个组件都已经实现完毕,现在可以实现这个crd的controller,完整的实现不展示,大致跟上一篇NodeController类似。仅展示他的字段和构造函数
type EcsBindingController struct {
kubeClient *versiond.Clientset
clusterName string
ecsbingdingLister list_and_watch.EcsBindingLister
ecsbingdingListerSynced cache.InformerSynced
broadcaster record.EventBroadcaster
recorder record.EventRecorder
ecsQueue workqueue.DelayingInterface
lock sync.Mutex
}
func NewEcsBindingController(kubeclient *versiond.Clientset,informer list_and_watch.EcsBindingInformer,clusterName string)*EcsBindingController {
eventBroadcaster := record.NewBroadcaster()
eventBroadcaster.StartLogging(glog.Infof)
recorder := eventBroadcaster.NewRecorder(scheme.Scheme, v1.EventSource{Component: "ecsbinding_controller"})
ec:= &EcsBindingController{
kubeClient:kubeclient,
clusterName:clusterName,
ecsbingdingLister:informer.Lister(),
ecsbingdingListerSynced:informer.Informer().HasSynced,
broadcaster:eventBroadcaster,
recorder:recorder,
ecsQueue:workqueue.NewNamedDelayingQueue("EcsBinding"),
}
informer.Informer().AddEventHandler(cache.ResourceEventHandlerFuncs{
AddFunc: func(obj interface{}) {
ecsbindingg:=obj.(*ecsV1.EcsBinding)
fmt.Printf("controller: Add event, ecsbinding [%s]\n",ecsbindingg.Name)
ec.syncEcsbinding(ecsbindingg)
},
UpdateFunc: func(oldObj, newObj interface{}) {
ecs1,ok1:=oldObj.(*ecsV1.EcsBinding)
ecs2,ok2:=newObj.(*ecsV1.EcsBinding)
if ok1&&ok2 && !reflect.DeepEqual(ecs1,ecs2){
fmt.Printf("controller: Update event, ecsbinding [%s]\n",ecs1.Name)
ec.syncEcsbinding(ecs1)
}
},
DeleteFunc: func(obj interface{}) {
ecsbindingg:=obj.(*ecsV1.EcsBinding)
fmt.Printf("controller: Delete event, ecsbinding [%s]\n",ecsbindingg.Name)
ec.syncEcsbinding(ecsbindingg)
},
})
return ec
}
最后把controller加到controller的Start方法中,统一启动
demoCli, _ := versiond.NewForConfig(cfg)
ecsbindFactory := ecsbindInformer.NewSharedInformerFactory(demoCli, 0)
ecsBindingInformer := ecsbindFactory.EcsBind().V1().EcsBinding()
ec := controller.NewEcsBindingController(demoCli, ecsBindingInformer, "k8s-cluster")
go ec.Run(stopCh)
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如有侵权,请联系 cloudcommunity@tencent.com 删除。