如何使用client-go在service.yaml中访问metadata.labels.{custom_field}？

huangapple
go评论112阅读模式
英文:

How to access metadata.labels.{custom_field} in service.yaml with client-go?

问题

我目前正在使用Go语言进行一个边缘项目的开发。我想要获取集群上运行的Pod的信息。

根据命名空间的值，我可以访问到Pods，但是为了访问到service.yaml文件中metadata.labels.applicationGroup值对应的工作中的Pods，我首先需要获取这个值。

我在下面添加了service.yaml文件的一部分内容。

  1. ---
  2. apiVersion: apps/v1
  3. kind: Deployment
  4. metadata:
  5.   name: metadata-name
  6.   labels:
  7.     service: service-name
  8.     applicationGroup: beta --> 这个字段
  9. spec:
  10.   replicas: 1
  11.   selector:
  12.     matchLabels:
  13.       service: service-name
  14.   template:
  15.     metadata:
  16.       labels:
  17.         service: service-name
  18.     spec:
  19.       containers:
  20.       - name: nginx
  21.         image: nginx:1.15.8
  22.         ports:
  23.         - containerPort: 80
  24. ...

目前，我可以访问"default"命名空间下的Pods信息。

  1. func getPodsInfo() (string, error) {
  3.   var kubeConfig *string
  5.   if home := homedir.HomeDir(); home != "" {
  6.     kubeConfig = flag.String("kubeConfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeConfig file")
  7.   } else {
  8.     kubeConfig = flag.String("kubeConfig", "", "absolute path to the kubeConfig file")
  9.   }
  10.   flag.Parse()
  12.   config, err := clientcmd.BuildConfigFromFlags("", *kubeConfig)
  13.   if err != nil {
  14.     err = fmt.Errorf("error occured when build config from flags: %s", err.Error())
  15.     return "", err
  16.   }
  18.   clientSet, err := kubernetes.NewForConfig(config)
  19.   if err != nil {
  20.     err = fmt.Errorf("error occured when build client set from config: %s", err.Error())
  21.     return "", err
  22.   }
  23.   /*
  24.     listOptions := meta.ListOptions{
  25.       FieldSelector: "metadata.labels.applicationGroup=alpha",
  26.     }
  27.   */
  28.   pods, err := clientSet.CoreV1().Pods("default").List(context.TODO(), metav1.ListOptions{})
  29.   if err != nil {
  30.     err = fmt.Errorf("error occured when get pods info from k8s: %s", err.Error())
  31.     return "", err
  32.   }
  34.   podsInfo, err := json.Marshal(&pods)
  35.   if err != nil {
  36.     err = fmt.Errorf("error occured when json marshal: %s", err.Error())
  37.     return "", err
  38.   }
  40.   return string(podsInfo), nil
  41. }

我尝试使用FieldSelector，但是FieldSelector只支持一些字段。

  1. listOptions := meta.ListOptions{
  2.     FieldSelector: "metadata.labels.applicationGroup=alpha",
  3. }

然后我得到了以下错误。

field label not supported: metadata.labels.applicationGroup

你可以查看这个链接来获取支持的字段列表。

对于我的问题，我该如何使用client-go来获取metadata.labels.applicationGroup的值，并且使用哪个函数来获取使用该值的Pods？

英文:

I am currently working on a side project with Go. I'm trying to get the information about the pods running on the cluster.

I can reach the pods according to the namespace value, but in order to reach the working pods with the metadata.labels.applicationGroup value in the service.yaml file, I need to obtain this value first.

I added below a part of my service.yaml file.

  1. ---
  2. apiVersion: apps/v1
  3. kind: Deployment
  4. metadata:
  5.   name: metadata-name
  6.   labels:
  7.     service: service-name
  8.     applicationGroup: beta --> this field
  9. spec:
  10.   replicas: 1
  11.   selector:
  12.     matchLabels:
  13.       service: service-name
  14.   template:
  15.     metadata:
  16.       labels:
  17.         service: service-name
  18.     spec:
  19.       containers:
  20.       - name: nginx
  21.         image: nginx:1.15.8
  22.         ports:
  23.         - containerPort: 80
  24. ...

Right now, I can access information pods with "default" namespaces.

  1. func getPodsInfo() (string, error) {
  3.   var kubeConfig *string
  5.   if home := homedir.HomeDir(); home != "" {
  6.     kubeConfig = flag.String("kubeConfig", filepath.Join(home, ".kube", "config"), "(optional) absolute path to the kubeConfig file")
  7.   } else {
  8.     kubeConfig = flag.String("kubeConfig", "", "absolute path to the kubeConfig file")
  9.   }
  10.   flag.Parse()
  12.   config, err := clientcmd.BuildConfigFromFlags("", *kubeConfig)
  13.   if err != nil {
  14.     err = fmt.Errorf("error occured when build config from flags: %s", err.Error())
  15.     return "", err
  16.   }
  18.   clientSet, err := kubernetes.NewForConfig(config)
  19.   if err != nil {
  20.     err = fmt.Errorf("error occured when build client set from config: %s", err.Error())
  21.     return "", err
  22.   }
  23.   /*
  24.     listOptions := meta.ListOptions{
  25.       FieldSelector: "metadata.labels.applicationGroup=alpha",
  26.     }
  27.   */
  28.   pods, err := clientSet.CoreV1().Pods("default").List(context.TODO(), metav1.ListOptions{})
  29.   if err != nil {
  30.     err = fmt.Errorf("error occured when get pods info from k8s: %s", err.Error())
  31.     return "", err
  32.   }
  34.   podsInfo, err := json.Marshal(&pods)
  35.   if err != nil {
  36.     err = fmt.Errorf("error occured when json marshal: %s", err.Error())
  37.     return "", err
  38.   }
  40.   return string(podsInfo), nil
  41. }

I tried to FieldSelector, but FieldSelector has supported some fields.

  1. listOptions := meta.ListOptions{
  2.     FieldSelector: "metadata.labels.applicationGroup=alpha",
  3. }

And I got the below error.

field label not supported: metadata.labels.applicationGroup

You can check this link for the supported fields.

To my question, how can I reach the metadata.labels.applicationGroup value with cilent_go, and which function should I use to reach pods working with this value?

答案1

得分: 1

只需使用LabelSelector而不是FieldSelector。

  1. listOptions := meta.ListOptions{
  2.     LabelSelector: "applicationGroup=alpha",
  3. }

更新：如果您想在Pod上使用它，您应该在Pod模板上设置applicationGroup。

  1. apiVersion: apps/v1
  2. kind: Deployment
  3. metadata:
  4.   name: metadata-name
  5.   labels:
  6.     service: service-name
  7. spec:
  8.   replicas: 1
  9.   selector:
  10.     matchLabels:
  11.       service: service-name
  12.   template:
  13.     metadata:
  14.       labels:
  15.         service: service-name
  16.         applicationGroup: beta
  17.     spec:
  18.       containers:
  19.       - name: nginx
  20.         image: nginx:1.15.8
  21.         ports:
  22.         - containerPort: 80
英文:

Just use LabelSelector instead of FieldSelector

  1. listOptions := meta.ListOptions{
  2.     LabelSelector: "applicationGroup=alpha",
  3. }

UPD: If you want to use it for pods you should set applicationGroup on pod template

  1. apiVersion: apps/v1
  2. kind: Deployment
  3. metadata:
  4.   name: metadata-name
  5.   labels:
  6.     service: service-name
  7. spec:
  8.   replicas: 1
  9.   selector:
  10.     matchLabels:
  11.       service: service-name
  12.   template:
  13.     metadata:
  14.       labels:
  15.         service: service-name
  16.         applicationGroup: beta
  17.     spec:
  18.       containers:
  19.       - name: nginx
  20.         image: nginx:1.15.8
  21.         ports:
  22.         - containerPort: 80

huangapple
  • 本文由 发表于 2022年4月13日 08:18:57
  • 转载请务必保留本文链接：https://go.coder-hub.com/71850457.html
  • devops
  • go
  • kubernetes
  • yaml
匿名

发表评论

匿名网友

:?: :razz: :sad: :evil: :!: :smile: :oops: :grin: :eek: :shock: :???: :cool: :lol: :mad: :twisted: :roll: :wink: :idea: :arrow: :neutral: :cry: :mrgreen:

确定