Add 'kpod import' command

Imports a tarball and saves it as a filesystem image

Signed-off-by: Urvashi Mohnani <umohnani@redhat.com>

Closes: #12
Approved by: rhatdan

1 files changed, 190 insertions, 0 deletions

diff --git a/cmd/kpod/import.go b/cmd/kpod/import.go
new file mode 100644
index 000000000..2e8702c3d
--- /dev/null
+++ b/cmd/kpod/import.go
@@ -0,0 +1,190 @@
+package main
+
+import (
+	"fmt"
+	"io"
+	"io/ioutil"
+	"net/http"
+	"net/url"
+	"os"
+	"strings"
+
+	"github.com/opencontainers/image-spec/specs-go/v1"
+	"github.com/pkg/errors"
+	"github.com/projectatomic/libpod/libpod"
+	"github.com/urfave/cli"
+)
+
+var (
+	importFlags = []cli.Flag{
+		cli.StringSliceFlag{
+			Name:  "change, c",
+			Usage: "Apply the following possible instructions to the created image (default []): CMD | ENTRYPOINT | ENV | EXPOSE | LABEL | STOPSIGNAL | USER | VOLUME | WORKDIR",
+		},
+		cli.StringFlag{
+			Name:  "message, m",
+			Usage: "Set commit message for imported image",
+		},
+	}
+	importDescription = `Create a container image from the contents of the specified tarball (.tar, .tar.gz, .tgz, .bzip, .tar.xz, .txz).
+	 Note remote tar balls can be specified, via web address.
+	 Optionally tag the image. You can specify the Dockerfile instructions using the --change option.
+	`
+	importCommand = cli.Command{
+		Name:        "import",
+		Usage:       "Import a tarball to create a filesystem image",
+		Description: importDescription,
+		Flags:       importFlags,
+		Action:      importCmd,
+		ArgsUsage:   "TARBALL [REFERENCE]",
+	}
+)
+
+func importCmd(c *cli.Context) error {
+	if err := validateFlags(c, importFlags); err != nil {
+		return err
+	}
+
+	runtime, err := getRuntime(c)
+	if err != nil {
+		return errors.Wrapf(err, "could not get runtime")
+	}
+	defer runtime.Shutdown(false)
+
+	var opts libpod.CopyOptions
+	var source string
+	args := c.Args()
+	switch len(args) {
+	case 0:
+		return errors.Errorf("need to give the path to the tarball, or must specify a tarball of '-' for stdin")
+	case 1:
+		source = args[0]
+	case 2:
+		source = args[0]
+		opts.Reference = args[1]
+	default:
+		return errors.Errorf("too many arguments. Usage TARBALL [REFERENCE]")
+	}
+
+	changes := v1.ImageConfig{}
+	if c.IsSet("change") {
+		changes, err = getImageConfig(c.StringSlice("change"))
+		if err != nil {
+			return errors.Wrapf(err, "error adding config changes to image %q", source)
+		}
+	}
+
+	history := []v1.History{
+		{Comment: c.String("message")},
+	}
+
+	config := v1.Image{
+		Config:  changes,
+		History: history,
+	}
+
+	opts.ImageConfig = config
+
+	// if source is a url, download it and save to a temp file
+	u, err := url.ParseRequestURI(source)
+	if err == nil && u.Scheme != "" {
+		file, err := downloadFromURL(source)
+		if err != nil {
+			return err
+		}
+		defer os.Remove(file)
+		source = file
+	}
+
+	return runtime.ImportImage(source, opts)
+}
+
+// donwloadFromURL downloads an image in the format "https:/example.com/myimage.tar"
+// and tempoarily saves in it /var/tmp/importxyz, which is deleted after the image is imported
+func downloadFromURL(source string) (string, error) {
+	fmt.Printf("Downloading from %q\n", source)
+
+	outFile, err := ioutil.TempFile("/var/tmp", "import")
+	if err != nil {
+		return "", errors.Wrap(err, "error creating file")
+	}
+	defer outFile.Close()
+
+	response, err := http.Get(source)
+	if err != nil {
+		return "", errors.Wrapf(err, "error downloading %q", source)
+	}
+	defer response.Body.Close()
+
+	_, err = io.Copy(outFile, response.Body)
+	if err != nil {
+		return "", errors.Wrapf(err, "error saving %q to %q", source, outFile)
+	}
+
+	return outFile.Name(), nil
+}
+
+// getImageConfig converts the --change flag values in the format "CMD=/bin/bash USER=example"
+// to a type v1.ImageConfig
+func getImageConfig(changes []string) (v1.ImageConfig, error) {
+	// USER=value | EXPOSE=value | ENV=value | ENTRYPOINT=value |
+	// CMD=value | VOLUME=value | WORKDIR=value | LABEL=key=value | STOPSIGNAL=value
+
+	var (
+		user       string
+		env        []string
+		entrypoint []string
+		cmd        []string
+		workingDir string
+		stopSignal string
+	)
+
+	exposedPorts := make(map[string]struct{})
+	volumes := make(map[string]struct{})
+	labels := make(map[string]string)
+
+	for _, ch := range changes {
+		pair := strings.Split(ch, "=")
+		if len(pair) == 1 {
+			return v1.ImageConfig{}, errors.Errorf("no value given for instruction %q", ch)
+		}
+		switch pair[0] {
+		case "USER":
+			user = pair[1]
+		case "EXPOSE":
+			var st struct{}
+			exposedPorts[pair[1]] = st
+		case "ENV":
+			env = append(env, pair[1])
+		case "ENTRYPOINT":
+			entrypoint = append(entrypoint, pair[1])
+		case "CMD":
+			cmd = append(cmd, pair[1])
+		case "VOLUME":
+			var st struct{}
+			volumes[pair[1]] = st
+		case "WORKDIR":
+			workingDir = pair[1]
+		case "LABEL":
+			if len(pair) == 3 {
+				labels[pair[1]] = pair[2]
+			} else {
+				labels[pair[1]] = ""
+			}
+		case "STOPSIGNAL":
+			stopSignal = pair[1]
+		}
+	}
+
+	return v1.ImageConfig{
+		User:         user,
+		ExposedPorts: exposedPorts,
+		Env:          env,
+		Entrypoint:   entrypoint,
+		Cmd:          cmd,
+		Volumes:      volumes,
+		WorkingDir:   workingDir,
+		Labels:       labels,
+		StopSignal:   stopSignal,
+	}, nil
+}