cmd-eks.go

package main

import (
	"context"
	b64 "encoding/base64"
	"fmt"

	awsconfig "github.com/aws/aws-sdk-go-v2/config"
	"github.com/aws/aws-sdk-go-v2/service/eks"
	"github.com/aws/aws-sdk-go-v2/service/sts"
	smithyhttp "github.com/aws/smithy-go/transport/http"
	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
	"k8s.io/client-go/kubernetes"
	"k8s.io/client-go/tools/clientcmd"
	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
)

const (
	clusterIDHeader = "x-k8s-aws-id"
	v1Prefix        = "k8s-aws-v1."
)

func getClusterInfo(clusterName string) clientcmdapi.Cluster {
	////////////////// EKS stuff
	cfg, _ := awsconfig.LoadDefaultConfig(context.TODO())
	eksClient := eks.NewFromConfig(cfg)
	clusterInfo, _ := eksClient.DescribeCluster(context.TODO(), &eks.DescribeClusterInput{
		Name: &clusterName,
	})
	cert, _ := b64.RawStdEncoding.DecodeString(*clusterInfo.Cluster.CertificateAuthority.Data)
	return clientcmdapi.Cluster{
		Server:                   *clusterInfo.Cluster.Endpoint,
		CertificateAuthorityData: cert,
	}
}

func getAuthToken(clusterName string) string {
	///////////////// STS STUFF
	cfg, _ := awsconfig.LoadDefaultConfig(context.TODO())
	stsClient := sts.NewFromConfig(cfg)
	stsSigner := sts.NewPresignClient(stsClient)
	presignedURLRequest, _ := stsSigner.PresignGetCallerIdentity(context.TODO(), &sts.GetCallerIdentityInput{}, func(presignOptions *sts.PresignOptions) {
		presignOptions.ClientOptions = append(presignOptions.ClientOptions, func(stsOptions *sts.Options) {
			// Add clusterId Header
			stsOptions.APIOptions = append(stsOptions.APIOptions, smithyhttp.SetHeaderValue(clusterIDHeader, clusterName))
			// Add X-Amz-Expires query param
			stsOptions.APIOptions = append(stsOptions.APIOptions, smithyhttp.SetHeaderValue("X-Amz-Expires", "60"))
		})
	})
	return v1Prefix + b64.RawURLEncoding.EncodeToString([]byte(presignedURLRequest.URL))
}

func main() {
	clusterName := "russ-cluster"
	cluster := getClusterInfo(clusterName)

	/// configure kubernetes client
	config := clientcmdapi.Config{
		Clusters: map[string]*clientcmdapi.Cluster{
			"cluster1": &cluster,
		},
		Contexts: map[string]*clientcmdapi.Context{
			"context1": {
				Cluster:  "cluster1",
				AuthInfo: "context1",
			},
		},
		AuthInfos: map[string]*clientcmdapi.AuthInfo{
			"context1": {},
		},
		CurrentContext: "context1",
	}
	config.AuthInfos[config.CurrentContext].Token = getAuthToken(clusterName)

	// create the clientset
	rawConfig, _ := clientcmd.NewDefaultClientConfig(config, &clientcmd.ConfigOverrides{}).ClientConfig()
	clientset, _ := kubernetes.NewForConfig(rawConfig)

	// get the list of pods
	pods, _ := clientset.CoreV1().Pods("").List(context.TODO(), metav1.ListOptions{})
	fmt.Printf("There are %d pods in the cluster\n", len(pods.Items))
}