kubectl源码分析之set selector

喜欢ヅ旅行 2023-02-11 15:27 89阅读 0赞

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目前刚开始写一个月，一共写了18篇原创文章，文章目录如下：

[istio多集群探秘，部署了50次多集群后我得出的结论][istio_50]

[istio多集群链路追踪，附实操视频][istio]

[istio防故障利器，你知道几个,istio新手不要读，太难！][istio_istio]

[istio业务权限控制，原来可以这么玩][istio 1]

[istio实现非侵入压缩，微服务之间如何实现压缩][istio 2]

[不懂envoyfilter也敢说精通istio系列-http-rbac-不要只会用AuthorizationPolicy配置权限][envoyfilter_istio_-http-rbac-_AuthorizationPolicy]

[不懂envoyfilter也敢说精通istio系列-02-http-corsFilter-不要只会vs][envoyfilter_istio_-02-http-corsFilter-_vs]

[不懂envoyfilter也敢说精通istio系列-03-http-csrf filter-再也不用再代码里写csrf逻辑了][envoyfilter_istio_-03-http-csrf filter-_csrf]

[不懂envoyfilter也敢说精通istio系列http-jwt\_authn-不要只会RequestAuthorization][envoyfilter_istio_http-jwt_authn-_RequestAuthorization]

[不懂envoyfilter也敢说精通istio系列-05-fault-filter-故障注入不止是vs][envoyfilter_istio_-05-fault-filter-_vs]

[不懂envoyfilter也敢说精通istio系列-06-http-match-配置路由不只是vs][envoyfilter_istio_-06-http-match-_vs]

[不懂envoyfilter也敢说精通istio系列-07-负载均衡配置不止是dr][envoyfilter_istio_-07-_dr]

[不懂envoyfilter也敢说精通istio系列-08-连接池和断路器][envoyfilter_istio_-08-]

[不懂envoyfilter也敢说精通istio系列-09-http-route filter][envoyfilter_istio_-09-http-route filter]

[不懂envoyfilter也敢说精通istio系列-network filter-redis proxy][envoyfilter_istio_-network filter-redis proxy]

[不懂envoyfilter也敢说精通istio系列-network filter-HttpConnectionManager][envoyfilter_istio_-network filter-HttpConnectionManager]

[不懂envoyfilter也敢说精通istio系列-ratelimit-istio ratelimit完全手册][envoyfilter_istio_-ratelimit-istio ratelimit]

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type SetSelectorOptions struct {//set selector结构体
    	// Bound
    	ResourceBuilderFlags *genericclioptions.ResourceBuilderFlags
    	PrintFlags           *genericclioptions.PrintFlags
    	RecordFlags          *genericclioptions.RecordFlags
    	dryrun               bool
    
    	// set by args
    	resources []string
    	selector  *metav1.LabelSelector
    
    	// computed
    	WriteToServer  bool
    	PrintObj       printers.ResourcePrinterFunc
    	Recorder       genericclioptions.Recorder
    	ResourceFinder genericclioptions.ResourceFinder
    
    	// set at initialization
    	genericclioptions.IOStreams
    }

func NewSelectorOptions(streams genericclioptions.IOStreams) *SetSelectorOptions {
    	return &SetSelectorOptions{//初始化结构体
    		ResourceBuilderFlags: genericclioptions.NewResourceBuilderFlags().
    			WithScheme(scheme.Scheme).
    			WithAll(false).
    			WithLocal(false).
    			WithLatest(),
    		PrintFlags:  genericclioptions.NewPrintFlags("selector updated").WithTypeSetter(scheme.Scheme),
    		RecordFlags: genericclioptions.NewRecordFlags(),
    
    		Recorder: genericclioptions.NoopRecorder{},
    
    		IOStreams: streams,
    	}
    }

//创建set selector命令
    func NewCmdSelector(f cmdutil.Factory, streams genericclioptions.IOStreams) *cobra.Command {
    	o := NewSelectorOptions(streams)//初始化结构体
    
    	cmd := &cobra.Command{//创建cobra命令
    		Use:                   "selector (-f FILENAME | TYPE NAME) EXPRESSIONS [--resource-version=version]",
    		DisableFlagsInUseLine: true,
    		Short:                 i18n.T("Set the selector on a resource"),
    		Long:                  fmt.Sprintf(selectorLong, validation.LabelValueMaxLength),
    		Example:               selectorExample,
    		Run: func(cmd *cobra.Command, args []string) {
    			cmdutil.CheckErr(o.Complete(f, cmd, args))//准备
    			cmdutil.CheckErr(o.Validate())//校验
    			cmdutil.CheckErr(o.RunSelector())//运行
    		},
    	}
    
    	o.ResourceBuilderFlags.AddFlags(cmd.Flags())//构造资源flag
    	o.PrintFlags.AddFlags(cmd)//设置打印flag
    	o.RecordFlags.AddFlags(cmd)//设置record选项
    
    	cmd.Flags().String("resource-version", "", "If non-empty, the selectors update will only succeed if this is the current resource-version for the object. Only valid when specifying a single resource.")//设置resource version选项
    	cmdutil.AddDryRunFlag(cmd)//设置干跑选项
    
    	return cmd
    }

//准备函数
    func (o *SetSelectorOptions) Complete(f cmdutil.Factory, cmd *cobra.Command, args []string) error {
    	var err error
    
    	o.RecordFlags.Complete(cmd)//record flag complete
    	o.Recorder, err = o.RecordFlags.ToRecorder()//record flag转recorder
    	if err != nil {
    		return err
    	}
    
    	o.dryrun = cmdutil.GetDryRunFlag(cmd)//设置干跑
    
    	o.resources, o.selector, err = getResourcesAndSelector(args)//设置resource和selector
    	if err != nil {
    		return err
    	}
    
    	o.ResourceFinder = o.ResourceBuilderFlags.ToBuilder(f, o.resources)//设置resorucebuilder
    	o.WriteToServer = !(*o.ResourceBuilderFlags.Local || o.dryrun)//判断是否写到服务器
    
    	if o.dryrun {
    		o.PrintFlags.Complete("%s (dry run)")
    	}
    	printer, err := o.PrintFlags.ToPrinter()//打印选项转printer
    	if err != nil {
    		return err
    	}
    	o.PrintObj = printer.PrintObj//设置printObj函数
    
    	return err
    }

func (o *SetSelectorOptions) Validate() error {
    	if o.selector == nil {//selector不能为空
    		return fmt.Errorf("one selector is required")
    	}
    	return nil
    }

//运行
    func (o *SetSelectorOptions) RunSelector() error {
    	r := o.ResourceFinder.Do()//从builder获取result
    
    	return r.Visit(func(info *resource.Info, err error) error {//访问result
    		patch := &Patch{Info: info}//构造patch
    		CalculatePatch(patch, scheme.DefaultJSONEncoder(), func(obj runtime.Object) ([]byte, error) {//计算patch
    			selectErr := updateSelectorForObject(info.Object, *o.selector)//更新对象selector
    			if selectErr != nil {
    				return nil, selectErr
    			}
    
    			// record this change (for rollout history)
    			if err := o.Recorder.Record(patch.Info.Object); err != nil {//判断是否更新change-cause注解
    				klog.V(4).Infof("error recording current command: %v", err)
    			}
    
    			return runtime.Encode(scheme.DefaultJSONEncoder(), info.Object)//obj转json
    		})
    
    		if patch.Err != nil {
    			return patch.Err
    		}
    		if !o.WriteToServer {//如果不写到服务器则打印
    			return o.PrintObj(info.Object, o.Out)
    		}
    
    		actual, err := resource.NewHelper(info.Client, info.Mapping).Patch(info.Namespace, info.Name, types.StrategicMergePatchType, patch.Patch, nil)//应用patch到服务器
    		if err != nil {
    			return err
    		}
    
    		return o.PrintObj(actual, o.Out)//打印对象
    	})
    }

//更新对象selector
    func updateSelectorForObject(obj runtime.Object, selector metav1.LabelSelector) error {
    	copyOldSelector := func() (map[string]string, error) {//获取selector
    		if len(selector.MatchExpressions) > 0 {//不支持matchExpression
    			return nil, fmt.Errorf("match expression %v not supported on this object", selector.MatchExpressions)
    		}
    		dst := make(map[string]string)
    		for label, value := range selector.MatchLabels {//遍历matchLabels
    			dst[label] = value//设置labels map
    		}
    		return dst, nil//返回labels map
    	}
    	var err error
    	switch t := obj.(type) {//判断对象
    	case *v1.Service://如果是service
    		t.Spec.Selector, err = copyOldSelector()//设置selector
    	default:
    		err = fmt.Errorf("setting a selector is only supported for Services")
    	}
    	return err
    }

[watermark_type_ZHJvaWRzYW5zZmFsbGJhY2s_shadow_50_text_Q1NETiBAaHhwamF2YTE_size_8_color_FFFFFF_t_70_g_se_x_16]: https://img-blog.csdnimg.cn/20211007094240106.jpg?x-oss-process=image/watermark,type_ZHJvaWRzYW5zZmFsbGJhY2s,shadow_50,text_Q1NETiBAaHhwamF2YTE=,size_8,color_FFFFFF,t_70,g_se,x_16
[istio_50]: https://mp.weixin.qq.com/s/_OPMjmWCDSTlmbAxytg33A
[istio]: https://mp.weixin.qq.com/s/kjvtno_UzJAGr1joxm3tvw
[istio_istio]: https://mp.weixin.qq.com/s/e2-p_NY31Mc5y07S4Bb1JQ
[istio 1]: https://mp.weixin.qq.com/s/iTV0SCQLhSOTYncp3PxoHQ
[istio 2]: https://mp.weixin.qq.com/s/eINlrT242RlAwfuZu1_PcA
[envoyfilter_istio_-http-rbac-_AuthorizationPolicy]: https://mp.weixin.qq.com/s/Q-yTGBNqkjOov49LTXPrPA
[envoyfilter_istio_-02-http-corsFilter-_vs]: https://mp.weixin.qq.com/s/bFMdrT7OKSqoWv8pDXOIqQ
[envoyfilter_istio_-03-http-csrf filter-_csrf]: https://mp.weixin.qq.com/s/dlG9phV-kMMxs4UPzuRNYg
[envoyfilter_istio_http-jwt_authn-_RequestAuthorization]: https://mp.weixin.qq.com/s/IfrJ-FdLYsdhPkDrcO_YXA
[envoyfilter_istio_-05-fault-filter-_vs]: https://mp.weixin.qq.com/s/a4gDXqD8uswgglMwkUph2Q
[envoyfilter_istio_-06-http-match-_vs]: https://mp.weixin.qq.com/s/TpS3DHdcaJiPivIS_jsIGw
[envoyfilter_istio_-07-_dr]: https://mp.weixin.qq.com/s/k-zJm7n7OOKg6MotQJYPAA
[envoyfilter_istio_-08-]: https://mp.weixin.qq.com/s/n_bJ3saNeTtXRprIymhwzg
[envoyfilter_istio_-09-http-route filter]: https://mp.weixin.qq.com/s/JAeZr0BMVQxIrB3S_7Ru0A
[envoyfilter_istio_-network filter-redis proxy]: https://mp.weixin.qq.com/s/B9IPTI8F3q42nVkqbQRlPw
[envoyfilter_istio_-network filter-HttpConnectionManager]: https://mp.weixin.qq.com/s/W3OPQWkCVvuHGS49cTNhlg
[envoyfilter_istio_-ratelimit-istio ratelimit]: https://mp.weixin.qq.com/s/KgiDsELNol27mgZvDbFsqw
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h4cGphdmEx_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20200524125723190.jpg?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2h4cGphdmEx,size_16,color_FFFFFF,t_70