Get a secret with k8s.io library

I am totally new to Go and the Kubernetes library k8s.io (https://github.com/kubernetes/client-go) and try to figure out how to get a specific secret.

I have a kind of observer which watches changes of Secrets.
I am iterating through a Secretlist within a specific namespace. That works, I also can filter them by a while loop. But I do not know how to get and search a Secret in a different namespace which should be available in this loop.

I need a secret named XXX in namespace "my-namespace"
(I know that the following line does not exist, it should only outline the idea what I am looking for) I come from Ruby, so I searched for something like this :

var myKubeSecret = kubernetes.V1().Secrets("my-namespace").Find("XXX")

Exists like the function like that one above?

This is what I have: this observes all my secrets in namespace "default". Which works. That example was taken from a Code that does something similar I was searching for, and I try to modify now.:

import (

	v1 "k8s.io/api/core/v1"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	kubeinformers "k8s.io/client-go/informers"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/cache"
	"k8s.io/client-go/tools/clientcmd"
	"sigs.k8s.io/yaml"
)
// a lot of code
// ....
// ...
// ..
// .

if data, err := ioutil.ReadFile("/var/run/secrets/kubernetes.io/serviceaccount/namespace"); err == nil {
		fmt.Println("data",data)
	}
	// listen for new secrets
	factory := kubeinformers.NewSharedInformerFactoryWithOptions(clientsetCore, 0, kubeinformers.WithNamespace(namespace()))
	informer := factory.Core().V1().Secrets().Informer()
	secrets := factory.Core().V1().Secrets().Lister()

var myKubeSecret string // will hold my secret

informer.AddEventHandler(cache.ResourceEventHandlerFuncs{
  AddFunc: func(new interface{}) {
    // get the secret
    var cpSecret = new.(*v1.Secret).DeepCopy()
     	if mySecret.GetName() == "argocd-credentials" {
				var cpData = *&cpSecret.Data
				for k, v := range cpData {
					clusterIP = kubeConfig.Clusters[0].Cluster.Server

					fmt.Println("cpData k:", k, "v:", v)
					switch k {
					case "authToken":
						fmt.Println("authToken:", v)

                    // ### HERE SHOULD BE THE VALUE OF A
                    // ### SECRET NAMED XXX in ns my-namespace 
                    myKubeSecret = // ### should a bearerToken string
					}
				}
			}
      }
}

I hope you get the idea..

Please also tell me which import libray is needed, if any.

as mentioned above, secret object resides in a namespace. They can only be referenced by pods in that same namespace.

https://stackoverflow.com/questions/46297949/sharing-secret-across-namespaces

if you want to use the secret in multiple namespaces, copy the same secret into the desired namespaces.

example case

• kubernetes secret: test-secret-1
• namespace from: testns1
• namespace to: testns2

1. Using pipe "|" operator

kubectl get secret test-secret-1 --namespace=testns1 -oyaml | grep -v ^\s*namespace:\s' |kubectl apply --namespace=testns2 -f -

2. Using sed command

kubectl get secret test-secret-1 -n testns1 -o yaml | sed s/"namespace: testns1"/"namespace: testns2"/| kubectl 
apply -n testns2 -f -

3. Export kubernetes secret to yaml and apply secret

kubectl get secret test-secret-1 -n testns1 -o yaml

apiVersion: v1
data:
  password: dGVzdFBAc3N3b3Jk
  username: dGVzdC11c2Vy
kind: Secret
metadata:
  creationTimestamp: "2021-11-11T21:21:02Z"
  name: test-secret-1
  namespace: testns1 # change namespace to testns2
  resourceVersion: "307939"
  uid: 6a8d9a6d-9648-4a39-a362-150e682c9a42
type: Opaque

https://jhooq.com/kubernetes-share-secrets-namespaces/

You can't read a secret from a different namespace from where you are making the request.

Via "k8s.io/client-go/kubernetes" you can get the secret, full example in https://github.com/minio/operator/blob/master/pkg/controller/cluster/main-controller.go something similar to:

import (
	"k8s.io/client-go/kubernetes"
)

...

type Controller struct {

	// kubeClientSet is a standard kubernetes clientset
	kubeClientSet kubernetes.Interface
}

...

// Trying to get just the csr-signer secret not the entire list from openshift-kube-controller-manager-operator namespace
secret, _ := c.kubeClientSet.CoreV1().Secrets("openshift-kube-controller-manager-operator").Get(
	ctx, "csr-signer", metav1.GetOptions{})