参考项目: kubernetes/sample-controller
编程环境：
- Go v1.13.8
- MacOS 10.15.8
- Kubernetes v1.17.0
注意，由于后期使用 code-generator 时，code-generator 不支持 go module 模式，所以项目虽然依然可以使用 go module ，但是目录需要建成 GOPATH 的样式，例如如下
go mod init github.com/schwarzeni/k8s-sample-controller-doc-demo此时项目 k8s-sample-controller-doc-demo 父文件夹路径应该为 github.com/schwarzeni/
安装相关的依赖，对于 1.17 版本的 Kubernetes ，下载 0.17.0 版本的相关客户端，下载 code-generator 时可能会报错，这个不用管
go get -u k8s.io/code-generator@v0.17.0
go get -u k8s.io/client-go@v0.17.0
go get -u k8s.io/apimachinery@v0.17.0
go get -u k8s.io/api@v0.17.0建立 hack/tools.go 并写入如下内容，便于之后使用 go mod vendor
// +build tools
// This package imports things required by build scripts, to force `go mod` to see them as dependencies
package tools
import _ "k8s.io/code-generator"之后执行命令：
go mod vendor此时项目结构如下：
.
├── go.mod
├── go.sum
├── vendor
└── ...
├── hack
└── tools.go文件 vendor/k8s.io/code-generator/generate-groups.sh 就是用来生成代码的脚本
首先先定义相关的 K8S 资源，然后使用 K8S 提供的工具生成相关的访问代码。这里的代码全部参照 kubernetes/sample-controller 中的相关代码。
在根目录下新建文件夹 pkg/apis/samplecontroller 作为定义资源的目录，在此目录下新建四个文件并填入相应的内容，IDE 可能会报错，这个不用管
pkg/apis/samplecontroller
├── register.go
└── v1alpha1
├── doc.go
├── register.go
└── types.goregister.go
package samplecontroller
// GroupName is the group name used in this package
const GroupName = "samplecontroller.k8s.io"v1alpha1/doc.go
// +k8s:deepcopy-gen=package
// +groupName=samplecontroller.k8s.io
// Package v1alpha1 is the v1alpha1 version of the API.
package v1alpha1v1alpha1/types.go
package v1alpha1
import (
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
)
// +genclient
// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
// Foo is a specification for a Foo resource
type Foo struct {
metav1.TypeMeta `json:",inline"`
metav1.ObjectMeta `json:"metadata,omitempty"`
Spec FooSpec `json:"spec"`
Status FooStatus `json:"status"`
}
// FooSpec is the spec for a Foo resource
type FooSpec struct {
DeploymentName string `json:"deploymentName"`
Replicas *int32 `json:"replicas"`
}
// FooStatus is the status for a Foo resource
type FooStatus struct {
AvailableReplicas int32 `json:"availableReplicas"`
}
// +k8s:deepcopy-gen:interfaces=k8s.io/apimachinery/pkg/runtime.Object
// FooList is a list of Foo resources
type FooList struct {
metav1.TypeMeta `json:",inline"`
metav1.ListMeta `json:"metadata"`
Items []Foo `json:"items"`
}v1alpha1/register.go
package v1alpha1
import (
metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
"k8s.io/apimachinery/pkg/runtime"
"k8s.io/apimachinery/pkg/runtime/schema"
samplecontroller "github.com/schwarzeni/k8s-sample-controller-doc-demo/pkg/apis/samplecontroller"
)
// SchemeGroupVersion is group version used to register these objects
var SchemeGroupVersion = schema.GroupVersion{Group: samplecontroller.GroupName, Version: "v1alpha1"}
// Kind takes an unqualified kind and returns back a Group qualified GroupKind
func Kind(kind string) schema.GroupKind {
return SchemeGroupVersion.WithKind(kind).GroupKind()
}
// Resource takes an unqualified resource and returns a Group qualified GroupResource
func Resource(resource string) schema.GroupResource {
return SchemeGroupVersion.WithResource(resource).GroupResource()
}
var (
// SchemeBuilder initializes a scheme builder
SchemeBuilder = runtime.NewSchemeBuilder(addKnownTypes)
// AddToScheme is a global function that registers this API group & version to a scheme
AddToScheme = SchemeBuilder.AddToScheme
)
// Adds the list of known types to Scheme.
func addKnownTypes(scheme *runtime.Scheme) error {
scheme.AddKnownTypes(SchemeGroupVersion,
&Foo{},
&FooList{},
)
metav1.AddToGroupVersion(scheme, SchemeGroupVersion)
return nil
}再执行一次 go mod vendor
为自动生成的文件准备一个 header
hack/boilerplate.go.txt
/*
this is a header file
*/执行如下命令生成代码：（我在 Goland 的终端中执行此命令会报错，但是在普通终端中执行就没问题了，目前还不太清楚原因）
bash vendor/k8s.io/code-generator/generate-groups.sh all \
github.com/schwarzeni/k8s-sample-controller-doc-demo/pkg/generated github.com/schwarzeni/k8s-sample-controller-doc-demo/pkg/apis \
samplecontroller:v1alpha1 \
--go-header-file hack/boilerplate.go.txt \
--output-base /Users/nizhenyang/my-project/cloud/src对于 --output-base ，假如你的项目绝对路径为 /Users/nizhenyang/my-project/cloud/src/github.com/schwarzeni/k8s-sample-controller-doc-demo ，将后半段 github.com/schwarzeni/k8s-sample-controller-doc-demo 视为 GOPATH，则这个参数的值就是前半段路径。
执行完代码之后，在 pkg/ 下会出现新生成的 generated 文件夹， 大致的结构如下
pkg/generated
├── clientset
│ └── versioned
│ ├── clientset.go
│ ├── doc.go
│ ├── fake
│ ├── scheme
│ └── typed
├── informers
│ └── externalversions
│ ├── factory.go
│ ├── generic.go
│ ├── internalinterfaces
│ └── samplecontroller
└── listers
└── samplecontroller
└── v1alpha1在pkg/apis/samplecontroller/v1alpha1/ 下新生成了 zz_generated.deepcopy.go 文件。
生成代码任务完成，再执行一次 go mod vendor
这里写一个测试程序来验证我们生产代码的可用性，首先，根据自定义资源的格式准备两份 yaml 配置文件：
crd.yaml
apiVersion: apiextensions.k8s.io/v1beta1
kind: CustomResourceDefinition
metadata:
name: foos.samplecontroller.k8s.io
spec:
group: samplecontroller.k8s.io
version: v1alpha1
names:
kind: Foo
plural: foos
scope: Namespacedexample-foo.yaml
apiVersion: samplecontroller.k8s.io/v1alpha1
kind: Foo
metadata:
name: example-foo
spec:
deploymentName: example-foo
replicas: 1执行命令 kubectl apply -f crd.yaml 创建资源定义
删除 vendor 目录，在项目根目录新建 main.go ，内容如下
package main
import (
"log"
"time"
"github.com/schwarzeni/k8s-sample-controller-doc-demo/pkg/apis/samplecontroller/v1alpha1"
"k8s.io/client-go/tools/cache"
clientset "github.com/schwarzeni/k8s-sample-controller-doc-demo/pkg/generated/clientset/versioned"
informers "github.com/schwarzeni/k8s-sample-controller-doc-demo/pkg/generated/informers/externalversions"
"k8s.io/client-go/tools/clientcmd"
)
func main() {
// 你的Kubernetes配置文件路径，一般为 ~/.kube/config
config, err := clientcmd.BuildConfigFromFlags("", "config/config")
if err != nil {
panic(err)
}
exampleClient, err := clientset.NewForConfig(config)
sharedInformers := informers.NewSharedInformerFactory(exampleClient, time.Second*2)
informer := sharedInformers.Samplecontroller().V1alpha1().Foos().Informer()
informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
AddFunc: func(obj interface{}) {
mObj := obj.(*v1alpha1.Foo)
log.Printf("New Foo Added: %s", mObj.GetName())
},
DeleteFunc: func(obj interface{}) {
mObj := obj.(*v1alpha1.Foo)
log.Printf("Delete Foo : %s", mObj.GetName())
},
})
stopCh := make(chan struct{})
defer close(stopCh)
informer.Run(stopCh)
}执行该程序
执行 kubectl apply -f foo-example.yaml ，发现程序输出了 “New Foo Added: example-foo”
执行 kubectl delete -f foo-example.yaml ，发现程序输出了 “Delete Foo : example-foo”