go基于kubernetes的二次开发(一)

文章目录

client获取资源
- 下载client-go
- - 方法一
  - 方法二
  - 方法三
- 达到kubectl效果，自定义获取的资源
- - node
  - namespace
  - service
  - deployment

client获取资源

一些概念:
1.SDK 就是 Software Development Kit 的缩写,中文意思就是【软件开发工具包】
2.client-go是kubernetes官方提供的go语言的客户端库,go应用使用该库可以访问kubernetes的API Server,这样我们就能通过编程来对kubernetes资源进行增删改查操作
3.“API（应用程序编程接口）：一套明确定义的各种软件组件之间的通信方法。
(你的开发工具比如goland要配置好GOROOT和GOPATH)

下载对应版本

下载client-go 方法一

(建议，逻辑理解更清晰，更可控)

在releaese界面进去，手动下载对应版本的包，解压到GOPATH的src下，我这里有个项目目录也在src下，所以这里我的下载的包和我的x项目目录都在src下

[root@node2 src]# ls
cl-go  client-go  hello
[root@node2 src]# pwd
/root/go/src

cl-go是我自己建立的项目目录，里面建立main.go，文件会导入client-go包下的内容的

go install相应的的包，然后就可以导入使用

[root@node2 client-go]# ls
CHANGELOG.md        discovery  go.sum      kubernetes_test  OWNERS     rest               testing      util
code-of-conduct.md  dynamic    informers   LICENSE          pkg        restmapper         third_party
CONTRIBUTING.md     examples   INSTALL.md  listers          plugin     scale              tools
deprecated          go.mod     kubernetes  metadata         README.md  SECURITY_CONTACTS  transport
[root@node2 client-go]# cd tools/
[root@node2 tools]# ls
auth   clientcmd  leaderelection  pager        record     remotecommand
cache  events     metrics         portforward  reference  watch
[root@node2 tools]# pwd
/root/go/src/client-go/tools

我们这里要用的是clientcmd包，该包下面基本是一系列的go文件
直接在这里go install clientcmd即可

下载报错就运行go env -w GOPROXY="https://goproxy.cn"，重新install

到这里就可以使用了，比如在main.go文件中

import (
  "client-go/tools/clientcmd"
)

可以使用./开头的相对路径，也可以用相对于GOPATH和GOROOT的"绝对路径"，会从这些路径下一层一层找包

如果提示报错，根据报错信息拷贝包的内容到提示的GOROOT下的路径即可(比如我这里将clientcmd下的文件全拷贝了一份到GOROOT/src/client-go/tools/clientcmd下)

在项目目录下go mod init xxx(任意名称比如项目名)
在go mod tidy即可

方法二

我这里选择了v0.19.13的分支
这些版本一般都是可以向下兼容的
(里面的example文件夹可以看一下，看这些代码案例很快能理解这个API的使用，也是学习client-go的方法)

导入client包

import下面有client各类的包

写明版本号，不用自动工具识别
这里要看你的go的版本，似乎是1.17之后弃用了go get，所以我这里改成了
你也可以直接下载整个client-go，即改成k8s.io/client-go@v0.19.13

	go install k8s.io/client-go/kubernetes@v0.19.13

如果发现下载不了，可以尝试对提示信息中的域名做个解析，这里推荐设置代理的方式

go env -w GOPROXY=https://goproxy.cn

go mod 以及包详解
(导包方式很多，只要能下载到相应的包，编译好，放在某个目录下，就能到入了)
(go get其实也没有完全弃用，install和get凭个人爱好即可，只是新版一般需要在当前项目目录下go mod init和go mod tidy，运行完之后，用get也没问题了，但是版本格式使用@）
(go install的使用有个细节，要求被install的对象底下主要是一系列的go文件的，比如装第三方包也是这样)

方法三

直接给git clone下来

达到kubectl效果，自定义获取的资源

(要使用到的包主要是client-go下的kubernetes和clientcmd)

先放一下完整的源码

package main

import (
        "client-go/tools/clientcmd"
        "context"
        "fmt"
        metaV1 "k8s.io/apimachinery/pkg/apis/meta/v1"   //重命名
        "k8s.io/client-go/kubernetes"
        "log"
)

func main() {
        //fmt.Println("client-go")
        configPath := "etc/kube.conf"   //使用API编程k8s，需要kubeconfig文件来验证
        config, err := clientcmd.BuildConfigFromFlags("", configPath)   //使用clientcmd的BuildConfigFromFlags，加载配置文件生成Config对象，该对象包含apiserver的地址和用户名和密码和token等，""那里是值masterurl，就是完整路径使用，这里将文件放到main.go同一个的cg目录下，直接空就行，然后configPath写etc/kube.conf即可，config用来变成使用api操作集群验证用
        if err != nil {
                log.Fatal(err)   //接收err这个error类型作为参数，只开启Fatal级别的日志，日志级别有LOG DEBUG INFO WARN ERROR FATAL
        }
        clientset, err := kubernetes.NewForConfig(config)   //使用kubernetes包下的NewForConfig来初始化clientset中的每个client，参数是配置文件，返回clientset对象的，是多个client的集合，就像是kubernetes的客户端
        if err != nil {
                log.Fatal(err)
        }
        nodeList, err := clientset.CoreV1().Nodes().List(context.TODO(), metaV1.ListOptions{})
        if err != nil {
                log.Fatal(err)
        }
        fmt.Println("node:")
        for _, node := range nodeList.Items {
                fmt.Printf("%st%st%st%st%st%st%st%sn",
                        node.Name,
                        node.Status.Addresses,
                        node.Status.Phase,
                        node.Status.NodeInfo.OSImage,
                        node.Status.NodeInfo.KubeletVersion,
                        node.Status.NodeInfo.OperatingSystem,
                        node.Status.NodeInfo.Architecture,
                        node.CreationTimestamp,
                )
        }
        fmt.Println("namespace")
        namespaceList, err := clientset.CoreV1().Namespaces().List(context.TODO(), metaV1.ListOptions{})
        for _, namespace := range namespaceList.Items {
                fmt.Println(namespace.Name, namespace.CreationTimestamp, namespace.Status.Phase)
        }
        serviceList, _ := clientset.CoreV1().Services("").List(context.TODO(), metaV1.ListOptions{})
        fmt.Println("services")
        for _, service := range serviceList.Items {
                fmt.Println(service.Name, service.Spec.Type, service.CreationTimestamp, service.Spec.Ports, service.Spec.ClusterIP)

        }
        deploymentList, _ := clientset.AppsV1().Deployments("default").List(context.TODO(), metaV1.ListOptions{})
        fmt.Println("deployment")
        for _, deployment := range deploymentList.Items {
                fmt.Println(deployment.Name, deployment.Namespace, deployment.CreationTimestamp, deployment.Labels, deployment.Spec.Selector.MatchLabels, deployment.Status.Replicas, deployment.Status.AvailableReplicas)

        }

}

在单当前的项目文件夹下创建etc/kube.conf，将这台节点的~/.kube/config文件内容复制进来

运行结果：

[root@node2 cg]# go run main.go 
node:
master1	[{InternalIP 192.168.23.196} {Hostname master1}]		CentOS Linux 7 (Core)	v1.19.3	linux	amd64	2022-05-28 23:50:29 +0800 CST
node1	[{InternalIP 192.168.23.197} {Hostname node1}]		CentOS Linux 7 (Core)	v1.19.3	linux	amd64	2022-05-28 23:53:14 +0800 CST
node2	[{InternalIP 192.168.23.213} {Hostname node2}]		CentOS Linux 7 (Core)	v1.19.3	linux	amd64	2022-05-28 23:53:19 +0800 CST
namespace
argocd 2022-06-11 23:59:12 +0800 CST Active
default 2022-05-28 23:50:31 +0800 CST Active
kube-node-lease 2022-05-28 23:50:29 +0800 CST Active
kube-ops 2022-06-02 15:12:40 +0800 CST Active
kube-public 2022-05-28 23:50:29 +0800 CST Active
kube-system 2022-05-28 23:50:29 +0800 CST Active
kubernetes-dashboard 2022-05-29 00:09:27 +0800 CST Active
tekton-pipelines 2022-06-04 08:48:29 +0800 CST Active
services
argocd-dex-server ClusterIP 2022-06-11 23:59:45 +0800 CST [{http TCP  5556 {0 5556 } 0} {grpc TCP  5557 {0 5557 } 0} {metrics TCP  5558 {0 5558 } 0}] 10.107.139.14
argocd-metrics ClusterIP 2022-06-11 23:59:46 +0800 CST [{metrics TCP  8082 {0 8082 } 0}] 10.97.143.188
argocd-redis ClusterIP 2022-06-11 23:59:47 +0800 CST [{tcp-redis TCP  6379 {0 6379 } 0}] 10.101.84.30
argocd-repo-server ClusterIP 2022-06-11 23:59:51 +0800 CST [{server TCP  8081 {0 8081 } 0} {metrics TCP  8084 {0 8084 } 0}] 10.109.44.72
argocd-server ClusterIP 2022-06-11 23:59:54 +0800 CST [{http TCP  80 {0 8080 } 0} {https TCP  443 {0 8080 } 0}] 10.100.53.220
argocd-server-metrics ClusterIP 2022-06-11 23:59:55 +0800 CST [{metrics TCP  8083 {0 8083 } 0}] 10.111.231.201
el-gitlab-listener ClusterIP 2022-06-05 21:02:22 +0800 CST [{http-listener TCP  8080 {0 8000 } 0}] 10.105.38.21
kubernetes ClusterIP 2022-05-28 23:50:31 +0800 CST [{https TCP  443 {0 6443 } 0}] 10.96.0.1
gitlab ClusterIP 2022-06-02 15:13:09 +0800 CST [{http TCP  80 {1 0 http} 0} {ssh TCP  22 {1 0 ssh} 0}] 10.100.191.245
harbor-harbor-chartmuseum ClusterIP 2022-06-02 21:29:19 +0800 CST [{ TCP  80 {0 9999 } 0}] 10.111.158.40
harbor-harbor-core ClusterIP 2022-06-02 21:29:19 +0800 CST [{web TCP  80 {0 8080 } 0}] 10.108.185.166
harbor-harbor-jobservice ClusterIP 2022-06-02 21:29:20 +0800 CST [{ TCP  80 {0 8080 } 0}] 10.97.108.34
harbor-harbor-notary-server ClusterIP 2022-06-02 21:29:18 +0800 CST [{ TCP  4443 {0 4443 } 0}] 10.105.81.97
harbor-harbor-notary-signer ClusterIP 2022-06-02 21:29:20 +0800 CST [{ TCP  7899 {0 7899 } 0}] 10.102.212.190
harbor-harbor-portal ClusterIP 2022-06-02 21:29:18 +0800 CST [{ TCP  80 {0 8080 } 0}] 10.110.48.37
harbor-harbor-registry ClusterIP 2022-06-02 21:29:20 +0800 CST [{registry TCP  5000 {0 5000 } 0} {controller TCP  8080 {0 8080 } 0}] 10.102.211.112
harbor-harbor-trivy ClusterIP 2022-06-02 21:29:18 +0800 CST [{api-server TCP  8080 {0 8080 } 0}] 10.98.51.223
postgresql ClusterIP 2022-06-02 15:13:09 +0800 CST [{postgres TCP  5432 {1 0 postgres} 0}] 10.105.36.95
redis ClusterIP 2022-06-02 15:13:07 +0800 CST [{redis TCP  6379 {1 0 redis} 0}] 10.105.223.133
kube-dns ClusterIP 2022-05-28 23:50:34 +0800 CST [{dns UDP  53 {0 53 } 0} {dns-tcp TCP  53 {0 53 } 0} {metrics TCP  9153 {0 9153 } 0}] 10.96.0.10
dashboard-metrics-scraper ClusterIP 2022-05-29 00:09:46 +0800 CST [{ TCP  8000 {0 8000 } 0}] 10.110.196.81
kubernetes-dashboard NodePort 2022-05-29 00:09:45 +0800 CST [{ TCP  443 {0 8443 } 30259}] 10.100.210.68
tekton-dashboard NodePort 2022-06-04 08:56:27 +0800 CST [{http TCP  9097 {0 9097 } 30308}] 10.109.124.197
tekton-pipelines-controller ClusterIP 2022-06-04 08:48:32 +0800 CST [{http-metrics TCP  9090 {0 9090 } 0}] 10.111.69.139
tekton-pipelines-webhook ClusterIP 2022-06-04 08:48:33 +0800 CST [{http-metrics TCP  9090 {0 9090 } 0} {http-profiling TCP  8008 {0 8008 } 0} {https-webhook TCP  443 {0 8443 } 0}] 10.109.245.129
tekton-triggers-controller ClusterIP 2022-06-05 20:01:15 +0800 CST [{http-metrics TCP  9000 {0 9000 } 0}] 10.107.78.209
tekton-triggers-core-interceptors ClusterIP 2022-06-05 20:01:43 +0800 CST [{http TCP  80 {0 8082 } 0}] 10.105.88.86
tekton-triggers-webhook ClusterIP 2022-06-05 20:01:15 +0800 CST [{https-webhook TCP  443 {0 8443 } 0}] 10.98.103.56
deployment
el-gitlab-listener default 2022-06-05 21:02:22 +0800 CST map[app.kubernetes.io/managed-by:EventListener app.kubernetes.io/part-of:Triggers eventlistener:gitlab-listener] map[app.kubernetes.io/managed-by:EventListener app.kubernetes.io/part-of:Triggers eventlistener:gitlab-listener] 1 0

node

查看kubernetes每种的api资源的api组

[root@node2 cg]# kubectl api-resources
NAME                              SHORTNAMES         APIGROUP                       NAMESPACED   KIND
bindings                                                                            true         Binding
componentstatuses                 cs                                                false        ComponentStatus
configmaps                        cm                                                true         ConfigMap
endpoints                         ep                                                true         Endpoints
events                            ev                                                true         Event
limitranges                       limits                                            true         LimitRange
namespaces                        ns                                                false        Namespace
nodes                             no                                                false        Node
persistentvolumeclaims            pvc                                               true         PersistentVolumeClaim
persistentvolumes                 pv                                                false        PersistentVolume
pods                              po                                                true         Pod
podtemplates                                                                        true         PodTemplate
replicationcontrollers            rc                                                true         ReplicationController
resourcequotas                    quota                                             true         ResourceQuota
secrets                                                                             true         Secret
serviceaccounts                   sa                                                true         ServiceAccount
services                          svc                                               true         Service
mutatingwebhookconfigurations                        admissionregistration.k8s.io   false        MutatingWebhookConfiguration
validatingwebhookconfigurations                      admissionregistration.k8s.io   false        ValidatingWebhookConfiguration
customresourcedefinitions         crd,crds           apiextensions.k8s.io           false        CustomResourceDefinition
apiservices                                          apiregistration.k8s.io         false        APIService
controllerrevisions                                  apps                           true         ControllerRevision
daemonsets                        ds                 apps                           true         DaemonSet
deployments                       deploy             apps                           true         Deployment
replicasets                       rs                 apps                           true         ReplicaSet
statefulsets                      sts                apps                           true         StatefulSet
applications                      app,apps           argoproj.io                    true         Application
appprojects                       appproj,appprojs   argoproj.io                    true         AppProject
tokenreviews                                         authentication.k8s.io          false        TokenReview
localsubjectaccessreviews                            authorization.k8s.io           true         LocalSubjectAccessReview
selfsubjectaccessreviews                             authorization.k8s.io           false        SelfSubjectAccessReview
selfsubjectrulesreviews                              authorization.k8s.io           false        SelfSubjectRulesReview
subjectaccessreviews                                 authorization.k8s.io           false        SubjectAccessReview
horizontalpodautoscalers          hpa                autoscaling                    true         HorizontalPodAutoscaler
cronjobs                          cj                 batch                          true         CronJob
jobs                                                 batch                          true         Job
images                            img                caching.internal.knative.dev   true         Image
certificatesigningrequests        csr                certificates.k8s.io            false        CertificateSigningRequest
leases                                               coordination.k8s.io            true         Lease
extensions                                           dashboard.tekton.dev           true         Extension
endpointslices                                       discovery.k8s.io               true         EndpointSlice
events                            ev                 events.k8s.io                  true         Event
ingresses                         ing                extensions                     true         Ingress
ingressclasses                                       networking.k8s.io              false        IngressClass
ingresses                         ing                networking.k8s.io              true         Ingress
networkpolicies                   netpol             networking.k8s.io              true         NetworkPolicy
runtimeclasses                                       node.k8s.io                    false        RuntimeClass
poddisruptionbudgets              pdb                policy                         true         PodDisruptionBudget
podsecuritypolicies               psp                policy                         false        PodSecurityPolicy
clusterrolebindings                                  rbac.authorization.k8s.io      false        ClusterRoleBinding
clusterroles                                         rbac.authorization.k8s.io      false        ClusterRole
rolebindings                                         rbac.authorization.k8s.io      true         RoleBinding
roles                                                rbac.authorization.k8s.io      true         Role
priorityclasses                   pc                 scheduling.k8s.io              false        PriorityClass
csidrivers                                           storage.k8s.io                 false        CSIDriver
csinodes                                             storage.k8s.io                 false        CSINode
storageclasses                    sc                 storage.k8s.io                 false        StorageClass
volumeattachments                                    storage.k8s.io                 false        VolumeAttachment
clustertasks                                         tekton.dev                     false        ClusterTask
conditions                                           tekton.dev                     true         Condition
pipelineresources                                    tekton.dev                     true         PipelineResource
pipelineruns                      pr,prs             tekton.dev                     true         PipelineRun
pipelines                                            tekton.dev                     true         Pipeline
taskruns                          tr,trs             tekton.dev                     true         TaskRun
tasks                                                tekton.dev                     true         Task
ingressroutes                                        traefik.containo.us            true         IngressRoute
ingressroutetcps                                     traefik.containo.us            true         IngressRouteTCP
ingressrouteudps                                     traefik.containo.us            true         IngressRouteUDP
middlewares                                          traefik.containo.us            true         Middleware
middlewaretcps                                       traefik.containo.us            true         MiddlewareTCP
serverstransports                                    traefik.containo.us            true         ServersTransport
tlsoptions                                           traefik.containo.us            true         TLSOption
tlsstores                                            traefik.containo.us            true         TLSStore
traefikservices                                      traefik.containo.us            true         TraefikService
clusterinterceptors               ci                 triggers.tekton.dev            false        ClusterInterceptor
clustertriggerbindings            ctb                triggers.tekton.dev            false        ClusterTriggerBinding
eventlisteners                    el                 triggers.tekton.dev            true         EventListener
triggerbindings                   tb                 triggers.tekton.dev            true         TriggerBinding
triggers                          tri                triggers.tekton.dev            true         Trigger
triggertemplates                  tt                 triggers.tekton.dev            true         TriggerTemplate

空就是核心组core()

要看相应的版本，比如pod

kubectl explain pod

status和spec很多信息都常用的

 nodeList, err := clientset.CoreV1().Nodes().List(context.TODO(), metaV1.ListOptions{})   //使用clientset下的方法，各方法顺序指定了CoreV1即组合版本，对node，用List获取全部的，ListOptions是标准REST列表调用的查询选项。，返回一个NodeList对象
 //context是上下文对象，这里可以不用管他,TODO()返回一个空的context
        if err != nil {
                log.Fatal(err)
        }
        fmt.Println("node:")
        for _, node := range nodeList.Items {   //NodeList是一个结构体对象，其中的Items是一个Node类型的切片，range可以逐个拿出数组切片字符串等序列数据，所以这里拿到的是一个个Node类型对象，也是一个结构体，其中每个元素有事各种类型的数据可以调用一系列的算法
                fmt.Printf("%st%st%st%st%st%st%st%sn",
                        node.Name,
                        node.Status.Addresses,
                        node.Status.Phase,
                        node.Status.NodeInfo.OSImage,
                        node.Status.NodeInfo.KubeletVersion,
                        node.Status.NodeInfo.OperatingSystem,
                        node.Status.NodeInfo.Architecture,
                        node.CreationTimestamp,
                )
        }

除了Ctrl+B能查看源码，还能查看帮助文档

复制报的路径k8s.io/apimachinery/pkg/apis/meta/v1(ListOptions包)

Ctrl+B，Ctrl+F搜索，快熟查看源码，这里面的内容都能展示

namespace

fmt.Println("namespace")
        namespaceList, err := clientset.CoreV1().Namespaces().List(context.TODO(), metaV1.ListOptions{})
        for _, namespace := range namespaceList.Items {
                fmt.Println(namespace.Name, namespace.CreationTimestamp, namespace.Status.Phase)
        }

还有一系列可以写

service

serviceList, _ := clientset.CoreV1().Services("").List(context.TODO(), metaV1.ListOptions{})
        fmt.Println("services")
        for _, service := range serviceList.Items {
                fmt.Println(service.Name, service.Spec.Type, service.CreationTimestamp, service.Spec.Ports, service.Spec.ClusterIP)

        }

deployment

deploymentList, _ := clientset.AppsV1().Deployments("default").List(context.TODO(), metaV1.ListOptions{})
        fmt.Println("deployment")
        for _, deployment := range deploymentList.Items {
                fmt.Println(deployment.Name, deployment.Namespace, deployment.CreationTimestamp, deployment.Labels, deployment.Spec.Selector.MatchLabels, deployment.Status.Replicas, deployment.Status.AvailableReplicas)

        }

go基于kubernetes的二次开发(一)

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