init get kubeconfig

cmd/get/getKubeconfig.go

@@ -22,6 +22,8 @@ THE SOFTWARE.
 package get
 
 import (
+	"fmt"
+
 	"github.com/rancher/k3d/pkg/cluster"
 	"github.com/rancher/k3d/pkg/runtimes"
 	k3d "github.com/rancher/k3d/pkg/types"
@@ -40,18 +42,27 @@ func NewCmdGetKubeconfig() *cobra.Command {
 		Long:  `Get kubeconfig.`,
 		Run: func(cmd *cobra.Command, args []string) {
 			log.Debugln("get kubeconfig called")
-			rt, c := parseGetKubeconfigCmd(cmd, args)
-			cluster.GetKubeconfig(rt, c)
+			rt, c, path := parseGetKubeconfigCmd(cmd, args)
+			kubeconfigpath, err := cluster.GetKubeconfigPath(rt, c, path)
+			if err != nil {
+				log.Fatalln(err)
+			}
+
+			// only print kubeconfig file path if output is not stdout ("-")
+			if path != "-" {
+				fmt.Println(kubeconfigpath)
+			}
 		},
 	}
 
-	// add subcommands
+	// add flags
+	cmd.Flags().StringP("output", "o", "", "Define output.")
 
 	// done
 	return cmd
 }
 
-func parseGetKubeconfigCmd(cmd *cobra.Command, args []string) (runtimes.Runtime, *k3d.Cluster) {
+func parseGetKubeconfigCmd(cmd *cobra.Command, args []string) (runtimes.Runtime, *k3d.Cluster, string) {
 	// --runtime
 	rt, err := cmd.Flags().GetString("runtime")
 	if err != nil {
@@ -61,5 +72,12 @@ func parseGetKubeconfigCmd(cmd *cobra.Command, args []string) (runtimes.Runtime,
 	if err != nil {
 		log.Fatalln(err)
 	}
-	return runtime, &k3d.Cluster{Name: args[0]} // TODO: validate first?
+
+	// --output
+	output, err := cmd.Flags().GetString("output")
+	if err != nil {
+		log.Fatalln("No output specified")
+	}
+
+	return runtime, &k3d.Cluster{Name: args[0]}, output // TODO: validate first
 }

go.mod

@@ -1,6 +1,6 @@
 module github.com/rancher/k3d
 
-go 1.12
+go 1.13
 
 require (
 	github.com/Azure/go-ansiterm v0.0.0-20170929234023-d6e3b3328b78 // indirect

pkg/cluster/kubeconfig.go

@@ -22,21 +22,73 @@ THE SOFTWARE.
 package cluster
 
 import (
+	"bytes"
+	"io/ioutil"
+	"os"
+
 	"github.com/rancher/k3d/pkg/runtimes"
 	k3d "github.com/rancher/k3d/pkg/types"
 	log "github.com/sirupsen/logrus"
 )
 
 // GetKubeconfig grabs the kubeconfig file from /output from a master node container and puts it into a local directory
-func GetKubeconfig(runtime runtimes.Runtime, cluster *k3d.Cluster) error {
+func GetKubeconfig(runtime runtimes.Runtime, cluster *k3d.Cluster) ([]byte, error) {
 	masterNodes, err := runtime.GetNodesByLabel(map[string]string{"k3d.cluster": cluster.Name, "k3d.role": string(k3d.MasterRole)})
 	if err != nil {
 		log.Errorln("Failed to get masternodes")
-		return err
+		return nil, err
 	}
-	if err := runtime.GetKubeconfig(masterNodes[0]); err != nil {
+	reader, err := runtime.GetKubeconfig(masterNodes[0])
+	if err != nil {
 		log.Errorf("Failed to get kubeconfig from node '%s'", masterNodes[0].Name)
-		return err
+		return nil, err
+	}
+	defer reader.Close()
+
+	readBytes, err := ioutil.ReadAll(reader)
+	if err != nil {
+		log.Errorln("Couldn't read kubeconfig file")
+		return nil, err
 	}
-	return nil
+
+	// write to file, skipping the first 512 bytes which contain file metadata
+	// and trimming any NULL characters
+	trimBytes := bytes.Trim(readBytes[512:], "\x00")
+
+	return trimBytes, nil
+}
+
+// GetKubeconfigPath uses GetKubeConfig to grab the kubeconfig from the cluster master node, writes it to a file and outputs the path
+func GetKubeconfigPath(runtime runtimes.Runtime, cluster *k3d.Cluster, path string) (string, error) {
+	var output *os.File
+	defer output.Close()
+	var err error
+
+	kubeconfigBytes, err := GetKubeconfig(runtime, cluster)
+	if err != nil {
+		log.Errorln("Failed to get kubeconfig")
+		return "", err
+	}
+
+	if path == "-" {
+		output = os.Stdout
+	} else {
+		if path == "" {
+			path = "/tmp/test.yaml" // TODO: set proper default
+		}
+		output, err = os.Create(path)
+		if err != nil {
+			log.Errorf("Failed to create file '%s'", path)
+			return "", err
+		}
+	}
+
+	_, err = output.Write(kubeconfigBytes)
+	if err != nil {
+		log.Errorf("Failed to write to file '%s'", output.Name())
+		return "", err
+	}
+
+	return output.Name(), nil
+
 }

pkg/runtimes/containerd/kubeconfig.go

@@ -23,10 +23,12 @@ THE SOFTWARE.
 package containerd
 
 import (
+	"io"
+
 	k3d "github.com/rancher/k3d/pkg/types"
 )
 
 // GetKubeconfig grabs the kubeconfig from inside a k3d node
-func (d Containerd) GetKubeconfig(node *k3d.Node) error {
-	return nil
+func (d Containerd) GetKubeconfig(node *k3d.Node) (io.ReadCloser, error) {
+	return nil, nil
 }

pkg/runtimes/docker/kubeconfig.go

@@ -23,25 +23,35 @@ THE SOFTWARE.
 package docker
 
 import (
+	"context"
+	"io"
+
+	"github.com/docker/docker/client"
 	k3d "github.com/rancher/k3d/pkg/types"
 	log "github.com/sirupsen/logrus"
 )
 
 // GetKubeconfig grabs the kubeconfig from inside a k3d node
-func (d Docker) GetKubeconfig(node *k3d.Node) error {
-	/*ctx := context.Background
+func (d Docker) GetKubeconfig(node *k3d.Node) (io.ReadCloser, error) {
+	ctx := context.Background()
 	docker, err := client.NewClientWithOpts(client.FromEnv, client.WithAPIVersionNegotiation())
 	if err != nil {
 		log.Errorln("Failed to create docker client")
-		return err
-	}*/
+		return nil, err
+	}
 
 	container, err := getNodeContainer(node)
 	if err != nil {
-		return err
+		return nil, err
 	}
 
 	log.Debugf("Container: %+v", container)
 
-	return nil
+	reader, _, err := docker.CopyFromContainer(ctx, container.ID, "/output/kubeconfig.yaml")
+	if err != nil {
+		log.Errorf("Failed to copy from container '%s'", container.ID)
+		return nil, err
+	}
+
+	return reader, nil
 }

pkg/runtimes/runtime.go

@@ -23,6 +23,7 @@ package runtimes
 
 import (
 	"fmt"
+	"io"
 
 	"github.com/rancher/k3d/pkg/runtimes/containerd"
 	"github.com/rancher/k3d/pkg/runtimes/docker"
@@ -41,7 +42,7 @@ type Runtime interface {
 	DeleteNode(*k3d.Node) error
 	GetNodesByLabel(map[string]string) ([]*k3d.Node, error)
 	CreateNetworkIfNotPresent(name string) (string, error)
-	GetKubeconfig(*k3d.Node) error
+	GetKubeconfig(*k3d.Node) (io.ReadCloser, error)
 	// StartContainer() error
 	// ExecContainer() error
 	// StopContainer() error