Kubernetes Client-Go で Kubectl コンテキストを指定する方法

<code class="go">import (
    "fmt"

    "k8s.io/client-go/kubernetes"
    "k8s.io/client-go/rest"
    "k8s.io/client-go/tools/clientcmd"
)

// GetKubeClient creates a Kubernetes config and client for a given kubeconfig context.
func GetKubeClient(context string) (*rest.Config, kubernetes.Interface, error) {
    config, err := configForContext(context)
    if err != nil {
        return nil, nil, err
    }
    client, err := kubernetes.NewForConfig(config)
    if err != nil {
        return nil, nil, fmt.Errorf("could not get Kubernetes client: %s", err)
    }
    return config, client, nil
}</code>

<code class="go">func configForContext(context string) (*rest.Config, error) {
    config, err := getConfig(context).ClientConfig()
    if err != nil {
        return nil, fmt.Errorf("could not get Kubernetes config for context %q: %s", context, err)
    }
    return config, nil
}</code>

<code class="go">func getConfig(context string) clientcmd.ClientConfig {
    rules := clientcmd.NewDefaultClientConfigLoadingRules()

    var configOverrides *clientcmd.ConfigOverrides
    if context != "" {
        configOverrides = &clientcmd.ConfigOverrides{
            ClusterDefaults: clientcmd.ClusterDefaults,
            CurrentContext:  context,
        }
    }

    return clientcmd.NewNonInteractiveDeferredLoadingClientConfig(rules, configOverrides)
}</code>

<code class="go">import (
    "context"
    "fmt"

    "k8s.io/client-go/kubernetes"
    kubeInitializer "k8s.io/client-go/tools/clientcmd/api"
)

func main() {
    // Load the kubeconfig file.
    kubeconfig := "/path/to/my/.kube/config"
    config, err := clientcmd.LoadFromFile(kubeconfig)
    if err != nil {
        fmt.Println("Error loading kubeconfig:", err)
        return
    }

    // Create a Kubernetes config for the specified context.
    clientConfig, err := configForContext(config, "context-name")
    if err != nil {
        fmt.Println("Error creating Kubernetes config:", err)
        return
    }

    // Create a Kubernetes client.
    client, err := kubernetes.NewForConfig(clientConfig)
    if err != nil {
        fmt.Println("Error creating Kubernetes client:", err)
        return
    }

    // Perform operations using the Kubernetes client.
    ctx := context.Background()
    nodes, err := client.CoreV1().Nodes().List(ctx, metav1.ListOptions{})
    if err != nil {
        fmt.Println("Error listing nodes:", err)
        return
    }
    fmt.Println("Nodes:", nodes)
}</code>