DockerCLI/cli/command/context/export.go

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package context
import (
"bytes"
"errors"
"fmt"
"io"
"os"
"github.com/docker/cli/cli"
"github.com/docker/cli/cli/command"
"github.com/docker/cli/cli/context/kubernetes"
"github.com/docker/cli/cli/context/store"
"github.com/spf13/cobra"
"k8s.io/client-go/tools/clientcmd"
)
// ExportOptions are the options used for exporting a context
type ExportOptions struct {
Kubeconfig bool
ContextName string
Dest string
}
func newExportCommand(dockerCli command.Cli) *cobra.Command {
opts := &ExportOptions{}
cmd := &cobra.Command{
Use: "export [OPTIONS] CONTEXT [FILE|-]",
Short: "Export a context to a tar or kubeconfig file",
Args: cli.RequiresRangeArgs(1, 2),
RunE: func(cmd *cobra.Command, args []string) error {
opts.ContextName = args[0]
if len(args) == 2 {
opts.Dest = args[1]
} else {
opts.Dest = opts.ContextName
if opts.Kubeconfig {
opts.Dest += ".kubeconfig"
} else {
opts.Dest += ".dockercontext"
}
}
return RunExport(dockerCli, opts)
},
}
flags := cmd.Flags()
flags.BoolVar(&opts.Kubeconfig, "kubeconfig", false, "Export as a kubeconfig file")
return cmd
}
func writeTo(dockerCli command.Cli, reader io.Reader, dest string) error {
var writer io.Writer
var printDest bool
if dest == "-" {
if dockerCli.Out().IsTerminal() {
return errors.New("cowardly refusing to export to a terminal, please specify a file path")
}
writer = dockerCli.Out()
} else {
f, err := os.OpenFile(dest, os.O_RDWR|os.O_CREATE|os.O_EXCL, 0600)
if err != nil {
return err
}
defer f.Close()
writer = f
printDest = true
}
if _, err := io.Copy(writer, reader); err != nil {
return err
}
if printDest {
fmt.Fprintf(dockerCli.Err(), "Written file %q\n", dest)
}
return nil
}
// RunExport exports a Docker context
func RunExport(dockerCli command.Cli, opts *ExportOptions) error {
if err := validateContextName(opts.ContextName); err != nil && opts.ContextName != command.DefaultContextName {
return err
}
ctxMeta, err := dockerCli.ContextStore().GetContextMetadata(opts.ContextName)
if err != nil {
return err
}
if !opts.Kubeconfig {
reader := store.Export(opts.ContextName, dockerCli.ContextStore())
defer reader.Close()
return writeTo(dockerCli, reader, opts.Dest)
}
kubernetesEndpointMeta := kubernetes.EndpointFromContext(ctxMeta)
if kubernetesEndpointMeta == nil {
return fmt.Errorf("context %q has no kubernetes endpoint", opts.ContextName)
}
kubernetesEndpoint, err := kubernetesEndpointMeta.WithTLSData(dockerCli.ContextStore(), opts.ContextName)
if err != nil {
return err
}
kubeConfig := kubernetesEndpoint.KubernetesConfig()
rawCfg, err := kubeConfig.RawConfig()
if err != nil {
return err
}
data, err := clientcmd.Write(rawCfg)
if err != nil {
return err
}
return writeTo(dockerCli, bytes.NewBuffer(data), opts.Dest)
}