LabelSelector for Secrets List in k8s

Question

I want to get Secret object from k8s cluster using go-client API

I have function that looks like that

func GetSecret( version string) (retVal interface{}, err error){
    clientset := GetClientOutOfCluster()
    labelSelector := metav1.LabelSelector{MatchLabels: map[string]string{"version":version}}

    listOptions := metav1.ListOptions{
        LabelSelector: labelSelector.String(),
        Limit:         100,
    }
    secretList, err := clientset.CoreV1().Secrets("namespace").List( listOptions )
    retVal = secretList.Items[0]
    return retVal, err
}

GetClientOutOfCluster is basically retrieves configuration from cluster or from local ~/.kube/config

I used metav1.LabelSelector just like i do when i generate new Deployment object.So i thought i was cool. But ListOptions.LabelSelector is a string. When i run my function it fails.

unable to parse requirement: invalid label key "&LabelSelector{MatchLabels:map[string]string{version:": name part must consist of alphanumeric characters, '-', '_' or '.', and must start and end with an alphanumeric character (e.g. 'MyName',  or 'my.name',  or '123-abc', regex used for validation is '([A-Za-z0-9][-A-Za-z0-9_.]*)?[A-Za-z0-9]')

I cannot find example of usage of this function anywhere. Documentation assumes that you know what is LabelSelector.

What is format of LabelSelector for ListOptions?

Thanks

Solution 1

You can use the k8s provided function to do the toString operation

import "k8s.io/apimachinery/pkg/labels"
...

func GetSecret(version string) (retVal interface{}, err error){
  clientset := GetClientOutOfCluster()
  labelSelector := metav1.LabelSelector{MatchLabels: map[string]string{"version":version}}

  listOptions := metav1.ListOptions{
    LabelSelector: labels.Set(labelSelector.MatchLabels).String(),
    Limit:         100,
  }
  secretList, err := clientset.CoreV1().Secrets("namespace").List(listOptions)
  retVal = secretList.Items[0]
  return retVal, err
}

Solution 2

func GetSecret( version string, param2 string) (retVal interface{}, err error){
    clientset := GetClientOutOfCluster()
    labelSelector := fmt.Sprintf("version=%s, param2=%s", version, param2)

    listOptions := metav1.ListOptions{
        LabelSelector: labelSelector,
        Limit:         100,
    }
    secretList, err := clientset.CoreV1().Secrets("namespace").List( listOptions )
    retVal = secretList.Items[0]
    return retVal, err
}

Comments

[mdaniel]

I would assume it's the same syntax as kubectl's --selector argument: some-key=some-value,other-key=something-else; have you already tried that? In your specific case, I would think: labelSelector: fmt.Sprintf("version=%s", version),

[Daniel Schütte]

Please try to make this a complete answer to help others who read the question to understand your solution.