Table of Contents
定义在/cmd/kubectl/app/kubectl.go 定义了一个cmd，然后执行cmd.Execute() 这里用到了第三方包"github.com/spf13/cobra"，这是一个功能强大的工具。 kubectl是基于其来构造生成命令行的
func Run() error {
logs.InitLogs()
defer logs.FlushLogs()
/*
构建了一个cmd，然后调用了Execute
参数除了几个标准的输入输出之外，就只有一个NewFactory
NewKubectlCommand 定义在pkg/kubectl/cmd/cmd.go
cmdutil.NewFactory(nil)
==>/pkg/kubectl/cmd/util/factory.go
*/
cmd := cmd.NewKubectlCommand(cmdutil.NewFactory(nil), os.Stdin, os.Stdout, os.Stderr)
return cmd.Execute()
}定义在/pkg/kubectl/cmd/util/factory.go
// NewFactory creates a factory with the default Kubernetes resources defined
// if optionalClientConfig is nil, then flags will be bound to a new clientcmd.ClientConfig.
// if optionalClientConfig is not nil, then this factory will make use of it.
/*
译：func NewFactory用默认kubernetes resourecs 创建一个factory。
如果入参optionalClientConfig为nil，flags会被绑定到一个新的clientcmd.ClientConfig。
如果入参optionalClientConfig非nil，该factory会使用它。
*/
func NewFactory(optionalClientConfig clientcmd.ClientConfig) Factory {
flags := pflag.NewFlagSet("", pflag.ContinueOnError)
flags.SetNormalizeFunc(utilflag.WarnWordSepNormalizeFunc) // Warn for "_" flags
clientConfig := optionalClientConfig
/*
默认情况下，/cmd/kubectl/app/kubectl.go中传递过来的入参optionalClientConfig是nil
*/
if optionalClientConfig == nil {
clientConfig = DefaultClientConfig(flags)
}
/*
获取clients,type ClientCache struct
type ClientCache struct 缓存先前加载的clients以便重用，并确保MatchServerVersion仅被调用一次
*/
clients := NewClientCache(clientConfig)
f := &factory{
flags: flags,
clientConfig: clientConfig,
clients: clients,
}
return f
}其中type ClientCache struct提供的一个方法是：
//根据指定的version初始化或者重用一个clientset
func (c *ClientCache) ClientSetForVersion(requiredVersion *unversioned.GroupVersion) (*internalclientset.Clientset, error)定义在/pkg/kubectl/cmd/cmd.go
//NewKubectlCommand创建`kubectl`命令及其嵌套子命令。
func NewKubectlCommand(f cmdutil.Factory, in io.Reader, out, err io.Writer) *cobra.Command {
/*
kubectl 命令，根命令
*/
cmds := &cobra.Command{
......
}
/*
声明了多组 命令集合
是对"github.com/spf13/cobra"的再一次封装
/pkg/kubectl/cmd/templates/command_groups.go
==>type CommandGroups []CommandGroup
所有的命令都与入参f cmdutil.Factory有关，顺着f的数据流向搞懂factory的原理
*/
groups := templates.CommandGroups{......}
/*
Add定义在/pkg/kubectl/cmd/templates/command_groups.go
==>func (g CommandGroups) Add(c *cobra.Command)
把根命令kubectl 传递进去
其完成的功能是把上面声明的所有命令(create、delete等)添加到kubectl下，成为kubectl的二级子命令
*/
groups.Add(cmds)
return cmds下面以get 命令为例子，go on！
定义在/pkg/kubectl/cmd/get.go
//从server端获取数据
func NewCmdGet(f cmdutil.Factory, out io.Writer, errOut io.Writer) *cobra.Command {
cmd := &cobra.Command{
Use: "get [(-o|--output=)json|yaml|wide|custom-columns=...|custom-columns-file=...|go-template=...|go-template-file=...|jsonpath=...|jsonpath-file=...] (TYPE [NAME | -l label] | TYPE/NAME ...) [flags]",
Run: func(cmd *cobra.Command, args []string) {
err := RunGet(f, out, errOut, cmd, args, options)
cmdutil.CheckErr(err)
},
}
/*
通过调用package cmdutil 中的函数来给一个cmd添加flag，主要用于一些公共flag
或者直接添加flag
*/
cmdutil.AddPrinterFlags(cmd)
cmd.Flags().StringP("selector", "l", "", "Selector (label query) to filter on")
.......
return cmd
}RunGet函数是kubectl get命令真正执行的实体
下面以kubectl get po --namespace=kube-system为例子，go on！
func RunGet(f cmdutil.Factory, out, errOut io.Writer, cmd *cobra.Command, args []string, options *GetOptions) error {
/*
eg: kubectl get po --namespace=kube-system
options 为空
len(options.Raw)＝0
*/
/*
f cmdutil.Factory 定义在/pkg/kubectl/cmd/util/factory.go
mappers包含了多个RESTMapper，如PriorityRESTMapper、MultiRESTMapper
typer:
map[{apps v1beta1 StatefulSet}:true {authorization.k8s.io v1beta1 SubjectAccessReview}:true
*/
mapper, typer, err := f.UnstructuredObject() [1]
//获取过滤函数集合、过滤参数opts
filterFuncs := f.DefaultResourceFilterFunc() [2]
filterOpts := f.DefaultResourceFilterOptions(cmd, allNamespaces)
/*
cmdNamespace 是cmd中指定的namespace
如果没指定，则使用default，此时enforceNamespace=false
如果指定了enforceNamespace=true
*/
cmdNamespace, enforceNamespace, err := f.DefaultNamespace()
if len(args) == 0 && cmdutil.IsFilenameEmpty(options.Filenames) {
/*
参数不对，get没有指定 the type of resource
`kubectl get` 的时候进入这部分
*/
}
/*
kubectl get all 会获取pod、rc、svc资源
此时会把printAll置为true
*/
for _, a := range args {
if a == "all" {
printAll = true
break
}
}
/*
定义在/pkg/kubectl/resource/builder.go
==>func HasNames(args []string) (bool, error)
返回true如果提供的args里面含有resource names
eg:
kubectl get po po-tomcat 的时候argsHasNames为true
kubectl get po 的时候argsHasNames为false
*/
argsHasNames, err := resource.HasNames(args)
// handle watch separately since we cannot watch multiple resource types
/*
处理watch的handle要分离，因为我们不能watch多个resource types
*/
isWatch, isWatchOnly := cmdutil.GetFlagBool(cmd, "watch"), cmdutil.GetFlagBool(cmd, "watch-only")
/*
定义在/pkg/kubectl/resource/builder.go
==>func NewBuilder
Builder大多方法支持链式调用
最后的Do()返回一个type Result struct
这里一些列链式调用大部分都在根据传入的Cmd来设置新建Builder的属性值
*/
r := resource.NewBuilder(mapper, typer, resource.ClientMapperFunc(f.UnstructuredClientForMapping), runtime.UnstructuredJSONScheme).
NamespaceParam(cmdNamespace).DefaultNamespace().AllNamespaces(allNamespaces).
FilenameParam(enforceNamespace, &options.FilenameOptions).
SelectorParam(selector).
ExportParam(export).
ResourceTypeOrNameArgs(true, args...).
ContinueOnError().
Latest().
Flatten().
Do() [3]
/*
根据cmd来获取输出的printer
==>定义在/pkg/kubectl/cmd/util/printing.go
==>func PrinterForCommand(cmd *cobra.Command) (kubectl.ResourcePrinter, bool, error)
不指定格式时，generic=false
*/
printer, generic, err := cmdutil.PrinterForCommand(cmd)
/*
/pkg/kubectl/resource/result.go
==>func (r *Result) Infos() ([]*Info, error)
以数组的形式返回所有的resource infos。
infos就是kubectl get命令查询server都后得到的结果
type Info struct包含执行REST调用的临时信息，或显示已完成的REST调用的结果。
*/
infos, err := r.Infos() [4]
/*
把infos转化为obj
objs[ix] 's type is: *runtime.Unstructured
*/
objs := make([]runtime.Object, len(infos))
for ix := range infos {
objs[ix] = infos[ix].Object [5]
}
//获取排序字段
sorting, err := cmd.Flags().GetString("sort-by")
/*
printer重新置为nil，每个object都使用默认的printer
*/
printer = nil
/*
/pkg/kubectl/resource_printer.go
==>func GetNewTabWriter(output io.Writer) *tabwriter.Writer
返回一个tabwriter，将输入中的标签列转换成正确对齐的文本。
*/
w := kubectl.GetNewTabWriter(out)
/*
pkg/kubectl/cmd/util/helpers.go
==>func MustPrintWithKinds
如果showKind = true，则
NAME CLUSTER-IP EXTERNAL-IP PORT(S) AGE
svc/kubernetes 10.10.0.1 <none> 443/TCP 1h
*/
if cmdutil.MustPrintWithKinds(objs, infos, sorter, printAll) {
showKind = true
}
/*
下面的for循环就是正常的源码编译出来的kubectl get 一个资源输出的信息
*/
for ix := range objs{
...
if printer != nil {
w.Flush()
//不指定格式 或者 kubect -o wide 的时候走此处
cmdutil.PrintFilterCount(filteredResourceCount, lastMapping.Resource, filterOpts)
}
...
}/*
func (f *factory) UnstructuredObject()
返回用于处理任意runtime.Unstructured的接口。
将执行API调用以便发现types。
非结构化对象
*/
func (f *factory) UnstructuredObject() (meta.RESTMapper, runtime.ObjectTyper, error) {
discoveryClient, err := f.DiscoveryClient()
if err != nil {
return nil, nil, err
}
groupResources, err := discovery.GetAPIGroupResources(discoveryClient)
if err != nil && !discoveryClient.Fresh() {
discoveryClient.Invalidate()
groupResources, err = discovery.GetAPIGroupResources(discoveryClient)
}
if err != nil {
return nil, nil, err
}
mapper := discovery.NewDeferredDiscoveryRESTMapper(discoveryClient, meta.InterfacesForUnstructured)
typer := discovery.NewUnstructuredObjectTyper(groupResources)
return NewShortcutExpander(mapper, discoveryClient), typer, nil
}mapper 和 typer 的输出结果如下
mapper is: {DeferredDiscoveryRESTMapper{
PriorityRESTMapper{
[{apps v1beta1 *} {authentication.k8s.io v1beta1 *} {authorization.k8s.io v1beta1 *} {autoscaling v1 *} {batch v1 *} {certificates.k8s.io v1alpha1 *} {extensions v1beta1 *} {policy v1beta1 *} {rbac.authorization.k8s.io v1alpha1 *} {storage.k8s.io v1beta1 *} { v1 *} {apps * *} {authentication.k8s.io * *} {authorization.k8s.io * *} {autoscaling * *} {batch * *} {certificates.k8s.io * *} {extensions * *} {policy * *} {rbac.authorization.k8s.io * *} {storage.k8s.io * *} { * *}]
[apps/v1beta1, Kind=* authentication.k8s.io/v1beta1, Kind=* authorization.k8s.io/v1beta1, Kind=* autoscaling/v1, Kind=* batch/v1, Kind=* certificates.k8s.io/v1alpha1, Kind=* extensions/v1beta1, Kind=* policy/v1beta1, Kind=* rbac.authorization.k8s.io/v1alpha1, Kind=* storage.k8s.io/v1beta1, Kind=* /v1, Kind=* apps/*, Kind=* authentication.k8s.io/*, Kind=* authorization.k8s.io/*, Kind=* autoscaling/*, Kind=* batch/*, Kind=* certificates.k8s.io/*, Kind=* extensions/*, Kind=* policy/*, Kind=* rbac.authorization.k8s.io/*, Kind=* storage.k8s.io/*, Kind=* /*, Kind=*]
MultiRESTMapper{
DefaultRESTMapper{kindToPluralResource=map[apps/v1beta1, Kind=StatefulSetList:{apps v1beta1 statefulsetlists} apps/v1beta1, Kind=List:{apps v1beta1 lists} apps/v1beta1, Kind=StatefulSet:{apps v1beta1 statefulsets}]}
DefaultRESTMapper{kindToPluralResource=map[authentication.k8s.io/v1beta1, Kind=List:{authentication.k8s.io v1beta1 lists} authentication.k8s.io/v1beta1, Kind=TokenReview:{authentication.k8s.io v1beta1 tokenreviews} authentication.k8s.io/v1beta1, Kind=TokenReviewList:{authentication.k8s.io v1beta1 tokenreviewlists}]}
DefaultRESTMapper{kindToPluralResource=map[authorization.k8s.io/v1beta1, Kind=SubjectAccessReview:{authorization.k8s.io v1beta1 subjectaccessreviews} authorization.k8s.io/v1beta1, Kind=SubjectAccessReviewList:{authorization.k8s.io v1beta1 subjectaccessreviewlists} authorization.k8s.io/v1beta1, Kind=List:{authorization.k8s.io v1beta1 lists} authorization.k8s.io/v1beta1, Kind=LocalSubjectAccessReview:{authorization.k8s.io v1beta1 localsubjectaccessreviews} authorization.k8s.io/v1beta1, Kind=LocalSubjectAccessReviewList:{authorization.k8s.io v1beta1 localsubjectaccessreviewlists} authorization.k8s.io/v1beta1, Kind=SelfSubjectAccessReview:{authorization.k8s.io v1beta1 selfsubjectaccessreviews} authorization.k8s.io/v1beta1, Kind=SelfSubjectAccessReviewList:{authorization.k8s.io v1beta1 selfsubjectaccessreviewlists}]}
DefaultRESTMapper{kindToPluralResource=map[autoscaling/v1, Kind=HorizontalPodAutoscaler:{autoscaling v1 horizontalpodautoscalers} autoscaling/v1, Kind=HorizontalPodAutoscalerList:{autoscaling v1 horizontalpodautoscalerlists} autoscaling/v1, Kind=List:{autoscaling v1 lists}]}
DefaultRESTMapper{kindToPluralResource=map[batch/v1, Kind=Job:{batch v1 jobs} batch/v1, Kind=JobList:{batch v1 joblists} batch/v1, Kind=List:{batch v1 lists}]}
DefaultRESTMapper{kindToPluralResource=map[certificates.k8s.io/v1alpha1, Kind=CertificateSigningRequestList:{certificates.k8s.io v1alpha1 certificatesigningrequestlists} certificates.k8s.io/v1alpha1, Kind=List:{certificates.k8s.io v1alpha1 lists} certificates.k8s.io/v1alpha1, Kind=CertificateSigningRequest:{certificates.k8s.io v1alpha1 certificatesigningrequests}]}
DefaultRESTMapper{kindToPluralResource=map[extensions/v1beta1, Kind=ReplicaSet:{extensions v1beta1 replicasets} extensions/v1beta1, Kind=ReplicationControllerDummy:{extensions v1beta1 replicationcontrollerdummies} extensions/v1beta1, Kind=List:{extensions v1beta1 lists} extensions/v1beta1, Kind=DeploymentList:{extensions v1beta1 deploymentlists} extensions/v1beta1, Kind=HorizontalPodAutoscalerList:{extensions v1beta1 horizontalpodautoscalerlists} extensions/v1beta1, Kind=NetworkPolicyList:{extensions v1beta1 networkpolicylists} extensions/v1beta1, Kind=NetworkPolicy:{extensions v1beta1 networkpolicies} extensions/v1beta1, Kind=ReplicationControllerDummyList:{extensions v1beta1 replicationcontrollerdummylists} extensions/v1beta1, Kind=ThirdPartyResourceList:{extensions v1beta1 thirdpartyresourcelists} extensions/v1beta1, Kind=Deployment:{extensions v1beta1 deployments} extensions/v1beta1, Kind=ScaleList:{extensions v1beta1 scalelists} extensions/v1beta1, Kind=HorizontalPodAutoscaler:{extensions v1beta1 horizontalpodautoscalers} extensions/v1beta1, Kind=IngressList:{extensions v1beta1 ingresslists} extensions/v1beta1, Kind=Job:{extensions v1beta1 jobs} extensions/v1beta1, Kind=JobList:{extensions v1beta1 joblists} extensions/v1beta1, Kind=ThirdPartyResource:{extensions v1beta1 thirdpartyresources} extensions/v1beta1, Kind=DaemonSetList:{extensions v1beta1 daemonsetlists} extensions/v1beta1, Kind=DeploymentRollback:{extensions v1beta1 deploymentrollbacks} extensions/v1beta1, Kind=DeploymentRollbackList:{extensions v1beta1 deploymentrollbacklists} extensions/v1beta1, Kind=ReplicaSetList:{extensions v1beta1 replicasetlists} extensions/v1beta1, Kind=DaemonSet:{extensions v1beta1 daemonsets} extensions/v1beta1, Kind=Scale:{extensions v1beta1 scales} extensions/v1beta1, Kind=Ingress:{extensions v1beta1 ingresses}]}
DefaultRESTMapper{kindToPluralResource=map[policy/v1beta1, Kind=PodDisruptionBudget:{policy v1beta1 poddisruptionbudgets} policy/v1beta1, Kind=PodDisruptionBudgetList:{policy v1beta1 poddisruptionbudgetlists} policy/v1beta1, Kind=List:{policy v1beta1 lists}]}
DefaultRESTMapper{kindToPluralResource=map[rbac.authorization.k8s.io/v1alpha1, Kind=ClusterRoleList:{rbac.authorization.k8s.io v1alpha1 clusterrolelists} rbac.authorization.k8s.io/v1alpha1, Kind=ClusterRoleBinding:{rbac.authorization.k8s.io v1alpha1 clusterrolebindings} rbac.authorization.k8s.io/v1alpha1, Kind=ClusterRole:{rbac.authorization.k8s.io v1alpha1 clusterroles} rbac.authorization.k8s.io/v1alpha1, Kind=RoleBindingList:{rbac.authorization.k8s.io v1alpha1 rolebindinglists} rbac.authorization.k8s.io/v1alpha1, Kind=Role:{rbac.authorization.k8s.io v1alpha1 roles} rbac.authorization.k8s.io/v1alpha1, Kind=RoleList:{rbac.authorization.k8s.io v1alpha1 rolelists} rbac.authorization.k8s.io/v1alpha1, Kind=List:{rbac.authorization.k8s.io v1alpha1 lists} rbac.authorization.k8s.io/v1alpha1, Kind=ClusterRoleBindingList:{rbac.authorization.k8s.io v1alpha1 clusterrolebindinglists} rbac.authorization.k8s.io/v1alpha1, Kind=RoleBinding:{rbac.authorization.k8s.io v1alpha1 rolebindings}]}
DefaultRESTMapper{kindToPluralResource=map[storage.k8s.io/v1beta1, Kind=List:{storage.k8s.io v1beta1 lists} storage.k8s.io/v1beta1, Kind=StorageClass:{storage.k8s.io v1beta1 storageclasses} storage.k8s.io/v1beta1, Kind=StorageClassList:{storage.k8s.io v1beta1 storageclasslists}]}
DefaultRESTMapper{kindToPluralResource=map[/v1, Kind=EventList:{ v1 eventlists} /v1, Kind=NamespaceList:{ v1 namespacelists} /v1, Kind=ServiceList:{ v1 servicelists} /v1, Kind=PersistentVolumeList:{ v1 persistentvolumelists} /v1, Kind=PodTemplateList:{ v1 podtemplatelists} /v1, Kind=ReplicationControllerList:{ v1 replicationcontrollerlists} /v1, Kind=ResourceQuotaList:{ v1 resourcequotalists} /v1, Kind=ServiceAccount:{ v1 serviceaccounts} /v1, Kind=EndpointsList:{ v1 endpointslists} /v1, Kind=PersistentVolume:{ v1 persistentvolumes} /v1, Kind=EvictionList:{ v1 evictionlists} /v1, Kind=ResourceQuota:{ v1 resourcequotas} /v1, Kind=List:{ v1 lists} /v1, Kind=ConfigMapList:{ v1 configmaplists} /v1, Kind=PersistentVolumeClaimList:{ v1 persistentvolumeclaimlists} /v1, Kind=Scale:{ v1 scales} /v1, Kind=SecretList:{ v1 secretlists} /v1, Kind=ScaleList:{ v1 scalelists} /v1, Kind=ComponentStatus:{ v1 componentstatuses} /v1, Kind=ConfigMap:{ v1 configmaps} /v1, Kind=Endpoints:{ v1 endpoints} /v1, Kind=LimitRange:{ v1 limitranges} /v1, Kind=Node:{ v1 nodes} /v1, Kind=PodList:{ v1 podlists} /v1, Kind=Eviction:{ v1 evictions} /v1, Kind=BindingList:{ v1 bindinglists} /v1, Kind=ComponentStatusList:{ v1 componentstatuslists} /v1, Kind=LimitRangeList:{ v1 limitrangelists} /v1, Kind=Namespace:{ v1 namespaces} /v1, Kind=PersistentVolumeClaim:{ v1 persistentvolumeclaims} /v1, Kind=PodTemplate:{ v1 podtemplates} /v1, Kind=ServiceAccountList:{ v1 serviceaccountlists} /v1, Kind=NodeList:{ v1 nodelists} /v1, Kind=ReplicationController:{ v1 replicationcontrollers} /v1, Kind=Service:{ v1 services} /v1, Kind=Binding:{ v1 bindings} /v1, Kind=Event:{ v1 events} /v1, Kind=Pod:{ v1 pods} /v1, Kind=Secret:{ v1 secrets}]}
}
}
} [{ pods} { replicationcontrollers} { services} {apps statefulsets} {autoscaling horizontalpodautoscalers} {extensions jobs} {extensions deployments} {extensions replicasets}] 0xc420552000}
typer is: &{map[{policy v1beta1 PodDisruptionBudget}:true { v1 Secret}:true {certificates.k8s.io v1alpha1 CertificateSigningRequest}:true {extensions v1beta1 DeploymentRollback}:true { v1 ConfigMap}:true { v1 Eviction}:true { v1 PodTemplate}:true {apps v1beta1 StatefulSet}:true {authorization.k8s.io v1beta1 SelfSubjectAccessReview}:true {authorization.k8s.io v1beta1 SubjectAccessReview}:true { v1 ReplicationController}:true {extensions v1beta1 Scale}:true {extensions v1beta1 Job}:true {extensions v1beta1 NetworkPolicy}:true {rbac.authorization.k8s.io v1alpha1 Role}:true { v1 LimitRange}:true { v1 PersistentVolumeClaim}:true {authentication.k8s.io v1beta1 TokenReview}:true {extensions v1beta1 Deployment}:true {rbac.authorization.k8s.io v1alpha1 RoleBinding}:true {storage.k8s.io v1beta1 StorageClass}:true { v1 Binding}:true { v1 ComponentStatus}:true { v1 Node}:true {extensions v1beta1 DaemonSet}:true {extensions v1beta1 ReplicationControllerDummy}:true {rbac.authorization.k8s.io v1alpha1 ClusterRoleBinding}:true { v1 PersistentVolume}:true { v1 Pod}:true { v1 ResourceQuota}:true {autoscaling v1 HorizontalPodAutoscaler}:true {rbac.authorization.k8s.io v1alpha1 ClusterRole}:true { v1 Endpoints}:true { v1 Service}:true {extensions v1beta1 HorizontalPodAutoscaler}:true {extensions v1beta1 ReplicaSet}:true { v1 Scale}:true {extensions v1beta1 ThirdPartyResource}:true { v1 Event}:true { v1 Namespace}:true { v1 ServiceAccount}:true {authorization.k8s.io v1beta1 LocalSubjectAccessReview}:true {batch v1 Job}:true {extensions v1beta1 Ingress}:true]}
目前只返回一个pod的过滤函数 /pkg/kubectl/resource_filter.go 中的过滤函数
/*
译：如果跳过该pod，则filterPods将返回true。
对于终止的pod，默认为true
*/
func filterPods(obj runtime.Object, options PrintOptions) bool Options 定义在/pkg/kubectl/resource_printer.go 根据输入的cmd来设置该结构体的值
type PrintOptions struct {
NoHeaders bool
WithNamespace bool
WithKind bool
Wide bool
ShowAll bool
ShowLabels bool
AbsoluteTimestamps bool
Kind string
ColumnLabels []string
}NamespaceParam、DefaultNamespace......这些函数都是对Builder的属性进行设置， 最后Do()返回一个type Result struct 该type Result struct中含有一个visitor Visitor， visitor 能访问在Builder中定义的resources。
// Infos returns an array of all of the resource infos retrieved via traversal.
// Will attempt to traverse the entire set of visitors only once, and will return
// a cached list on subsequent calls.
/*
译：func (r *Result) Infos()以数组的形式返回所有的resource infos。
尝试遍历整个visitors一次，然后在后续的调用中将返回一个cached list。
*/
func (r *Result) Infos() ([]*Info, error) {
if r.err != nil {
return nil, r.err
}
if r.info != nil {
return r.info, nil
}
infos := []*Info{}
err := r.visitor.Visit(func(info *Info, err error) error {
if err != nil {
return err
}
/*
一个个info添加到infos中
下面会展示在这个地方输出的info信息
*/
infos = append(infos, info)
return nil
})
err = utilerrors.FilterOut(err, r.ignoreErrors...)
r.info, r.err = infos, err
return infos, err
}
// Info contains temporary info to execute a REST call, or show the results
// of an already completed REST call.
/*
type Info struct包含执行REST调用的临时信息，或显示已完成的REST调用的结果。
*/
type Info struct {
Client RESTClient
Mapping *meta.RESTMapping
Namespace string
Name string
// Optional, Source is the filename or URL to template file (.json or .yaml),
// or stdin to use to handle the resource
/*
译：可选，Source是模板文件（.json或.yaml）的文件名或URL，或用于处理资源的stdin
*/
Source string
// Optional, this is the provided object in a versioned type before defaulting
// and conversions into its corresponding internal type. This is useful for
// reflecting on user intent which may be lost after defaulting and conversions.
/*
译：可选，这是一个version中的object，会有一个对应的internal type。
这将有利于在把该object转为为之后对应的internal type之后，反应出用户的意图，
*/
VersionedObject interface{}
// Optional, this is the most recent value returned by the server if available
/*
译：可选，这是服务器返回的最新值（如果可用）
*/
runtime.Object
// Optional, this is the most recent resource version the server knows about for
// this type of resource. It may not match the resource version of the object,
// but if set it should be equal to or newer than the resource version of the
// object (however the server defines resource version).
/*
译：可选，这是server端知道的此类resource的最新resource version。
它可能与该object的resource version 不匹配，
它应该等于或新于object的resource version (但服务器定义资源版本）。
简单来说，ResourceVersion的值是etcd中全局最新的Index
*/
ResourceVersion string
// Optional, should this resource be exported, stripped of cluster-specific and instance specific fields
Export bool
}一个Info的输出信息如下：
1、kubectl get node而言，
NAME STATUS AGE
fqhnode Ready 2h
a info's Name is: fqhnode
a info's Object 's type is: *runtime.Unstructured
a info's Object 's value is: &{map[metadata:map[namespace: name:fqhnode selfLink:/api/v1/nodesfqhnode uid:be2234fd-8d4f-11e7-9c42-080027e58fc6 resourceVersion:9781 creationTimestamp:2017-08-30T06:52:08Z labels:map[beta.kubernetes.io/os:linux kubernetes.io/hostname:fqhnode beta.kubernetes.io/arch:amd64] annotations:map[volumes.kubernetes.io/controller-managed-attach-detach:true]] spec:map[externalID:fqhnode] status:map[daemonEndpoints:map[kubeletEndpoint:map[Port:10250]] nodeInfo:map[systemUUID:03B30D09-EBDF-4E73-9F13-904C9BA98883 kernelVersion:3.10.0-514.6.1.el7.x86_64 kubeletVersion:v1.5.2+08e0995 operatingSystem:linux architecture:amd64 machineID:03b30d09ebdf4e739f13904c9ba98883 bootID:cf04dbc5-c529-4752-a1bf-ee3e3ab8833f osImage:CentOS Linux 7 (Core) containerRuntimeVersion:docker://1.13.1 kubeProxyVersion:v1.5.2+08e0995] images:[map[names:[hikdata.io/tomcat:7.0.78] sizeBytes:862575480] map[names:[etcd_cluster:gc4.0] sizeBytes:341890262] map[names:[redis-sentinel:v2.0] sizeBytes:289596922] map[names:[gcr.io/google_containers/redis:v1 kubernetes/redis:v1] sizeBytes:145954175] map[sizeBytes:129465861 names:[ubuntu:16.04]] map[names:[registry@sha256:28be0609f90ef53e86e1872a11d672434ce1361711760cf1fe059efd222f8d37 registry@sha256:8698d41d35eb1491822e7dbb8bfb15c74aea231c2709700b5e9a0023c3649253 registry:latest] sizeBytes:33174034] map[names:[portainer/portainer@sha256:0e7c150ad00b8c0e2a6d6a18ef7cdc349db898c8dbb850346fbed7de9ddb3772 portainer/portainer:latest] sizeBytes:9920059] map[names:[busybox:latest] sizeBytes:1109996] map[names:[gcr.io/google_containers/pause-amd64:3.0] sizeBytes:746888]] capacity:map[alpha.kubernetes.io/nvidia-gpu:0 cpu:1 memory:2048668Ki pods:110] allocatable:map[alpha.kubernetes.io/nvidia-gpu:0 cpu:1 memory:2048668Ki pods:110] conditions:[map[type:OutOfDisk status:False lastHeartbeatTime:2017-08-30T09:19:22Z lastTransitionTime:2017-08-30T06:52:08Z reason:KubeletHasSufficientDisk message:kubelet has sufficient disk space available] map[type:MemoryPressure status:False lastHeartbeatTime:2017-08-30T09:19:22Z lastTransitionTime:2017-08-30T06:52:08Z reason:KubeletHasSufficientMemory message:kubelet has sufficient memory available] map[type:DiskPressure status:False lastHeartbeatTime:2017-08-30T09:19:22Z lastTransitionTime:2017-08-30T06:52:08Z reason:KubeletHasNoDiskPressure message:kubelet has no disk pressure] map[lastTransitionTime:2017-08-30T06:52:19Z reason:KubeletReady message:kubelet is posting ready status type:Ready status:True lastHeartbeatTime:2017-08-30T09:19:22Z]] addresses:[map[type:LegacyHostIP address:10.0.2.15] map[type:InternalIP address:10.0.2.15] map[type:Hostname address:fqhnode]]] kind:Node apiVersion:v1]}
a info's Export is: false
a info's VersionedObject TypeOf is: <nil>
a info's VersionedObject ValueOf is: <invalid reflect.Value>
2、如果get一个resource，没有资源的时候，会提示No resources found.
3、kubectl get pod
NAME READY STATUS RESTARTS AGE
tomcat7-psnhd 1/1 Running 0 12s
a info's Name is: tomcat7-9r1gx
a info's Object 's type is: *runtime.Unstructured
a info's Object 's value is: &{map[metadata:map[namespace:default uid:8d06d6cb-8d62-11e7-9c42-080027e58fc6 creationTimestamp:2017-08-30T09:06:47Z labels:map[name:tomcat7] annotations:map[kubernetes.io/created-by:{"kind":"SerializedReference","apiVersion":"v1","reference":{"kind":"ReplicationController","namespace":"default","name":"tomcat7","uid":"8cfa248e-8d62-11e7-9c42-080027e58fc6","apiVersion":"v1","resourceVersion":"8929"}}
] ownerReferences:[map[name:tomcat7 uid:8cfa248e-8d62-11e7-9c42-080027e58fc6 controller:true apiVersion:v1 kind:ReplicationController]] name:tomcat7-9r1gx generateName:tomcat7- selfLink:/api/v1/namespaces/default/pods/tomcat7-9r1gx resourceVersion:8947] spec:map[terminationGracePeriodSeconds:30 dnsPolicy:ClusterFirst nodeName:fqhnode securityContext:map[] volumes:[map[hostPath:map[path:/opt/tomcat/conf] name:conf] map[name:webapps hostPath:map[path:/opt/tomcat/webapps]]] containers:[map[terminationMessagePath:/dev/termination-log imagePullPolicy:IfNotPresent name:tomcat7 image:hikdata.io/tomcat:7.0.78 resources:map[] volumeMounts:[map[name:conf mountPath:/opt/tomcat/conf] map[name:webapps mountPath:/opt/tomcat/webapps]]]] restartPolicy:Always] status:map[phase:Running conditions:[map[type:Initialized status:True lastProbeTime:<nil> lastTransitionTime:2017-08-30T09:06:47Z] map[status:True lastProbeTime:<nil> lastTransitionTime:2017-08-30T09:06:49Z type:Ready] map[type:PodScheduled status:True lastProbeTime:<nil> lastTransitionTime:2017-08-30T09:06:47Z]] hostIP:10.0.2.15 podIP:172.17.0.5 startTime:2017-08-30T09:06:47Z containerStatuses:[map[image:hikdata.io/tomcat:7.0.78 imageID:docker://sha256:5055de391846a56ad9b428ed144941cb523bb168154ca2837871ef614fd00077 containerID:docker://c9719d95fe938228b77319d05041e4557349b9857c547662e6fc33316a789d27 name:tomcat7 state:map[running:map[startedAt:2017-08-30T09:06:48Z]] lastState:map[] ready:true restartCount:0]]] kind:Pod apiVersion:v1]}
a info's ResourceVersion is: 9419
a info's Export is: false
a info's VersionedObject TypeOf is: <nil>
a info's VersionedObject ValueOf is: <invalid reflect.Value>
至此kubectl的主体流程已经结束，下一步我们将要详细分析几个核心点
- cmdutil.Factory
- mapper, typer
- Builder
- type Result struct
- type Result struct里面的visitor Visitor
- printer
我主要以func RunGet(f cmdutil.Factory, out, errOut io.Writer, cmd *cobra.Command, args []string, options *GetOptions)函数的运行过程为主线，对各个概念进行了解。