Add -w to acorn kube to write kubeconfig to a file

Signed-off-by: Darren Shepherd <[email protected]>

pkg/cli/kube.go

@@ -14,7 +14,6 @@ import (
 func NewKubectl(c CommandContext) *cobra.Command {
 	cmd := cli.Command(&Kube{client: c.ClientFactory}, cobra.Command{
 		Use:          "kube [flags]",
-		Args:         cobra.MinimumNArgs(1),
 		Hidden:       true,
 		SilenceUsage: true,
 		Short:        "Run command with KUBECONFIG env set to a generated kubeconfig of the current project",
@@ -26,8 +25,9 @@ acorn -j acorn kube k9s
 }
 
 type Kube struct {
-	client ClientFactory
-	Region string `usage:"Get access to the cluster supporting that specific region"`
+	client    ClientFactory
+	Region    string `usage:"Get access to the cluster supporting that specific region"`
+	WriteFile string `usage:"Write kubeconfig to file" short:"w"`
 }
 
 func (s *Kube) Run(cmd *cobra.Command, args []string) error {
@@ -36,6 +36,16 @@ func (s *Kube) Run(cmd *cobra.Command, args []string) error {
 		return err
 	}
 
+	if s.WriteFile != "" {
+		data, err := c.KubeConfig(cmd.Context(), &client.KubeProxyAddressOptions{
+			Region: s.Region,
+		})
+		if err != nil {
+			return err
+		}
+		return os.WriteFile(s.WriteFile, data, 0644)
+	}
+
 	ctx, cancel := context.WithCancel(cmd.Context())
 	defer cancel()
 
@@ -78,6 +88,10 @@ users:
 		return err
 	}
 
+	if len(args) == 0 {
+		args = []string{os.Getenv("SHELL")}
+	}
+
 	k := exec.Command(args[0], args[1:]...)
 	k.Env = append(os.Environ(), fmt.Sprintf("KUBECONFIG=%s", f.Name()))
 	k.Stdin = os.Stdin

pkg/cli/testdata/MockClient.go

@@ -119,6 +119,11 @@ type MockClient struct {
 	EventItem        *apiv1.Event
 }
 
+func (m *MockClient) KubeConfig(ctx context.Context, opts *client.KubeProxyAddressOptions) ([]byte, error) {
+	//TODO implement me
+	panic("implement me")
+}
+
 func (m *MockClient) KubeProxyAddress(ctx context.Context, opts *client.KubeProxyAddressOptions) (string, error) {
 	//TODO implement me
 	panic("implement me")

pkg/client/client.go

@@ -25,6 +25,7 @@ import (
 	"k8s.io/apimachinery/pkg/fields"
 	"k8s.io/client-go/rest"
 	"k8s.io/client-go/tools/clientcmd"
+	clientcmdapi "k8s.io/client-go/tools/clientcmd/api"
 	kclient "sigs.k8s.io/controller-runtime/pkg/client"
 )
 
@@ -282,7 +283,9 @@ type Client interface {
 	GetProject() string
 	GetNamespace() string
 	GetClient() (kclient.WithWatch, error)
+
 	KubeProxyAddress(ctx context.Context, opts *KubeProxyAddressOptions) (string, error)
+	KubeConfig(ctx context.Context, opts *KubeProxyAddressOptions) ([]byte, error)
 }
 
 type CredentialLookup func(ctx context.Context, serverAddress string) (*apiv1.RegistryAuth, bool, error)
@@ -408,6 +411,31 @@ type DefaultClient struct {
 	Dialer     *k8schannel.Dialer
 }
 
+func generateKubeConfig(restConfig *rest.Config) ([]byte, error) {
+	config := &clientcmdapi.Config{
+		Clusters: map[string]*clientcmdapi.Cluster{
+			"acorn": {
+				Server:                   restConfig.Host,
+				CertificateAuthorityData: restConfig.TLSClientConfig.CAData,
+			},
+		},
+		AuthInfos: map[string]*clientcmdapi.AuthInfo{
+			"auth": {
+				Token: restConfig.BearerToken,
+			},
+		},
+		Contexts: map[string]*clientcmdapi.Context{
+			"default": {
+				Cluster:  "acorn",
+				AuthInfo: "auth",
+			},
+		},
+		CurrentContext: "default",
+	}
+
+	return clientcmd.Write(*config)
+}
+
 func (c *DefaultClient) getRESTConfig(ctx context.Context, opts *KubeProxyAddressOptions) (*rest.Config, error) {
 	if opts == nil || opts.Region == "" {
 		return c.RESTConfig, nil
@@ -453,6 +481,14 @@ func (c *DefaultClient) getRESTConfig(ctx context.Context, opts *KubeProxyAddres
 	return clientcmd.RESTConfigFromKubeConfig(parsed.Config)
 }
 
+func (c *DefaultClient) KubeConfig(ctx context.Context, opts *KubeProxyAddressOptions) ([]byte, error) {
+	restConfig, err := c.getRESTConfig(ctx, opts)
+	if err != nil {
+		return nil, err
+	}
+	return generateKubeConfig(restConfig)
+}
+
 func (c *DefaultClient) KubeProxyAddress(ctx context.Context, opts *KubeProxyAddressOptions) (string, error) {
 	restConfig, err := c.getRESTConfig(ctx, opts)
 	if err != nil {

pkg/client/deferred.go

@@ -459,6 +459,13 @@ func (d *DeferredClient) GetClient() (client.WithWatch, error) {
 	return d.Client.GetClient()
 }
 
+func (d *DeferredClient) KubeConfig(ctx context.Context, opts *KubeProxyAddressOptions) ([]byte, error) {
+	if err := d.create(); err != nil {
+		return nil, err
+	}
+	return d.Client.KubeConfig(ctx, opts)
+}
+
 func (d *DeferredClient) KubeProxyAddress(ctx context.Context, opts *KubeProxyAddressOptions) (string, error) {
 	if err := d.create(); err != nil {
 		return "", err

pkg/client/multi.go

@@ -656,6 +656,14 @@ func (m *MultiClient) GetClient() (kclient.WithWatch, error) {
 	return c.GetClient()
 }
 
+func (m *MultiClient) KubeConfig(ctx context.Context, opts *KubeProxyAddressOptions) ([]byte, error) {
+	c, err := m.Factory.ForProject(context.Background(), m.Factory.DefaultProject())
+	if err != nil {
+		panic(err)
+	}
+	return c.KubeConfig(ctx, opts)
+}
+
 func (m *MultiClient) KubeProxyAddress(ctx context.Context, opts *KubeProxyAddressOptions) (string, error) {
 	c, err := m.Factory.ForProject(context.Background(), m.Factory.DefaultProject())
 	if err != nil {