Migrate cp command to cobra
Signed-off-by: Vincent Demeester <vincent@sbr.pm> Upstream-commit: 2e6db51de7dc293785520df81c6bb54aa96c84ca Component: engine
This commit is contained in:
Vincent Demeester
302
components/engine/api/client/container/cp.go
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302
components/engine/api/client/container/cp.go
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package container
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import (
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"fmt"
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"io"
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"os"
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"path/filepath"
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"strings"
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"golang.org/x/net/context"
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"github.com/docker/docker/api/client"
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"github.com/docker/docker/cli"
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"github.com/docker/docker/pkg/archive"
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"github.com/docker/docker/pkg/system"
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"github.com/docker/engine-api/types"
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"github.com/spf13/cobra"
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)
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type copyOptions struct {
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source string
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destination string
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followLink bool
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}
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type copyDirection int
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const (
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fromContainer copyDirection = (1 << iota)
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toContainer
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acrossContainers = fromContainer | toContainer
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)
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type cpConfig struct {
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followLink bool
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}
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// NewCopyCommand creates a new `docker cp` command
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func NewCopyCommand(dockerCli *client.DockerCli) *cobra.Command {
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var opts copyOptions
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cmd := &cobra.Command{
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Use: `cp [OPTIONS] CONTAINER:SRC_PATH DEST_PATH|-
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docker cp [OPTIONS] SRC_PATH|- CONTAINER:DEST_PATH`,
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Short: "Copy files/folders between a container and the local filesystem",
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Long: strings.Join([]string{
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"\nUse '-' as the source to read a tar archive from stdin\n",
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"and extract it to a directory destination in a container.\n",
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"Use '-' as the destination to stream a tar archive of a\n",
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"container source to stdout.",
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}, ""),
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Args: cli.ExactArgs(2),
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RunE: func(cmd *cobra.Command, args []string) error {
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if args[0] == "" {
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return fmt.Errorf("source can not be empty")
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}
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if args[1] == "" {
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return fmt.Errorf("destination can not be empty")
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}
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opts.source = args[0]
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opts.destination = args[1]
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return runCopy(dockerCli, opts)
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},
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}
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flags := cmd.Flags()
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flags.BoolVarP(&opts.followLink, "follow-link", "L", false, "Always follow symbol link in SRC_PATH")
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return cmd
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}
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func runCopy(dockerCli *client.DockerCli, opts copyOptions) error {
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srcContainer, srcPath := splitCpArg(opts.source)
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dstContainer, dstPath := splitCpArg(opts.destination)
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var direction copyDirection
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if srcContainer != "" {
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direction |= fromContainer
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}
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if dstContainer != "" {
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direction |= toContainer
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}
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cpParam := &cpConfig{
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followLink: opts.followLink,
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}
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ctx := context.Background()
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switch direction {
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case fromContainer:
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return copyFromContainer(ctx, dockerCli, srcContainer, srcPath, dstPath, cpParam)
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case toContainer:
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return copyToContainer(ctx, dockerCli, srcPath, dstContainer, dstPath, cpParam)
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case acrossContainers:
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// Copying between containers isn't supported.
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return fmt.Errorf("copying between containers is not supported")
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default:
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// User didn't specify any container.
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return fmt.Errorf("must specify at least one container source")
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}
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}
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func statContainerPath(ctx context.Context, dockerCli *client.DockerCli, containerName, path string) (types.ContainerPathStat, error) {
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return dockerCli.Client().ContainerStatPath(ctx, containerName, path)
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}
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func resolveLocalPath(localPath string) (absPath string, err error) {
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if absPath, err = filepath.Abs(localPath); err != nil {
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return
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}
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return archive.PreserveTrailingDotOrSeparator(absPath, localPath), nil
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}
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func copyFromContainer(ctx context.Context, dockerCli *client.DockerCli, srcContainer, srcPath, dstPath string, cpParam *cpConfig) (err error) {
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if dstPath != "-" {
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// Get an absolute destination path.
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dstPath, err = resolveLocalPath(dstPath)
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if err != nil {
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return err
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}
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}
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// if client requests to follow symbol link, then must decide target file to be copied
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var rebaseName string
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if cpParam.followLink {
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srcStat, err := statContainerPath(ctx, dockerCli, srcContainer, srcPath)
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// If the destination is a symbolic link, we should follow it.
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if err == nil && srcStat.Mode&os.ModeSymlink != 0 {
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linkTarget := srcStat.LinkTarget
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if !system.IsAbs(linkTarget) {
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// Join with the parent directory.
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srcParent, _ := archive.SplitPathDirEntry(srcPath)
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linkTarget = filepath.Join(srcParent, linkTarget)
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}
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linkTarget, rebaseName = archive.GetRebaseName(srcPath, linkTarget)
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srcPath = linkTarget
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}
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}
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content, stat, err := dockerCli.Client().CopyFromContainer(ctx, srcContainer, srcPath)
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if err != nil {
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return err
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}
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defer content.Close()
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if dstPath == "-" {
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// Send the response to STDOUT.
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_, err = io.Copy(os.Stdout, content)
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return err
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}
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// Prepare source copy info.
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srcInfo := archive.CopyInfo{
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Path: srcPath,
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Exists: true,
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IsDir: stat.Mode.IsDir(),
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RebaseName: rebaseName,
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}
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preArchive := content
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if len(srcInfo.RebaseName) != 0 {
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_, srcBase := archive.SplitPathDirEntry(srcInfo.Path)
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preArchive = archive.RebaseArchiveEntries(content, srcBase, srcInfo.RebaseName)
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}
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// See comments in the implementation of `archive.CopyTo` for exactly what
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// goes into deciding how and whether the source archive needs to be
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// altered for the correct copy behavior.
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return archive.CopyTo(preArchive, srcInfo, dstPath)
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}
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func copyToContainer(ctx context.Context, dockerCli *client.DockerCli, srcPath, dstContainer, dstPath string, cpParam *cpConfig) (err error) {
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if srcPath != "-" {
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// Get an absolute source path.
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srcPath, err = resolveLocalPath(srcPath)
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if err != nil {
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return err
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}
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}
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// In order to get the copy behavior right, we need to know information
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// about both the source and destination. The API is a simple tar
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// archive/extract API but we can use the stat info header about the
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// destination to be more informed about exactly what the destination is.
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// Prepare destination copy info by stat-ing the container path.
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dstInfo := archive.CopyInfo{Path: dstPath}
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dstStat, err := statContainerPath(ctx, dockerCli, dstContainer, dstPath)
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// If the destination is a symbolic link, we should evaluate it.
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if err == nil && dstStat.Mode&os.ModeSymlink != 0 {
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linkTarget := dstStat.LinkTarget
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if !system.IsAbs(linkTarget) {
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// Join with the parent directory.
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dstParent, _ := archive.SplitPathDirEntry(dstPath)
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linkTarget = filepath.Join(dstParent, linkTarget)
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}
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dstInfo.Path = linkTarget
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dstStat, err = statContainerPath(ctx, dockerCli, dstContainer, linkTarget)
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}
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// Ignore any error and assume that the parent directory of the destination
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// path exists, in which case the copy may still succeed. If there is any
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// type of conflict (e.g., non-directory overwriting an existing directory
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// or vice versa) the extraction will fail. If the destination simply did
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// not exist, but the parent directory does, the extraction will still
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// succeed.
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if err == nil {
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dstInfo.Exists, dstInfo.IsDir = true, dstStat.Mode.IsDir()
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}
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var (
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content io.Reader
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resolvedDstPath string
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)
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if srcPath == "-" {
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// Use STDIN.
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content = os.Stdin
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resolvedDstPath = dstInfo.Path
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if !dstInfo.IsDir {
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return fmt.Errorf("destination %q must be a directory", fmt.Sprintf("%s:%s", dstContainer, dstPath))
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}
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} else {
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// Prepare source copy info.
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srcInfo, err := archive.CopyInfoSourcePath(srcPath, cpParam.followLink)
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if err != nil {
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return err
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}
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srcArchive, err := archive.TarResource(srcInfo)
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if err != nil {
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return err
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}
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defer srcArchive.Close()
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// With the stat info about the local source as well as the
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// destination, we have enough information to know whether we need to
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// alter the archive that we upload so that when the server extracts
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// it to the specified directory in the container we get the desired
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// copy behavior.
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// See comments in the implementation of `archive.PrepareArchiveCopy`
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// for exactly what goes into deciding how and whether the source
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// archive needs to be altered for the correct copy behavior when it is
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// extracted. This function also infers from the source and destination
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// info which directory to extract to, which may be the parent of the
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// destination that the user specified.
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dstDir, preparedArchive, err := archive.PrepareArchiveCopy(srcArchive, srcInfo, dstInfo)
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if err != nil {
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return err
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}
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defer preparedArchive.Close()
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resolvedDstPath = dstDir
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content = preparedArchive
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}
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options := types.CopyToContainerOptions{
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AllowOverwriteDirWithFile: false,
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}
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return dockerCli.Client().CopyToContainer(ctx, dstContainer, resolvedDstPath, content, options)
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}
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// We use `:` as a delimiter between CONTAINER and PATH, but `:` could also be
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// in a valid LOCALPATH, like `file:name.txt`. We can resolve this ambiguity by
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// requiring a LOCALPATH with a `:` to be made explicit with a relative or
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// absolute path:
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// `/path/to/file:name.txt` or `./file:name.txt`
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//
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// This is apparently how `scp` handles this as well:
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// http://www.cyberciti.biz/faq/rsync-scp-file-name-with-colon-punctuation-in-it/
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//
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// We can't simply check for a filepath separator because container names may
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// have a separator, e.g., "host0/cname1" if container is in a Docker cluster,
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// so we have to check for a `/` or `.` prefix. Also, in the case of a Windows
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// client, a `:` could be part of an absolute Windows path, in which case it
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// is immediately proceeded by a backslash.
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func splitCpArg(arg string) (container, path string) {
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if system.IsAbs(arg) {
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// Explicit local absolute path, e.g., `C:\foo` or `/foo`.
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return "", arg
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}
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parts := strings.SplitN(arg, ":", 2)
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if len(parts) == 1 || strings.HasPrefix(parts[0], ".") {
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// Either there's no `:` in the arg
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// OR it's an explicit local relative path like `./file:name.txt`.
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return "", arg
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}
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return parts[0], parts[1]
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}
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