Created scp.go image_scp_test.go and podman-image-scp.1.md

added functionality for image secure copying from local to remote.
Also moved system connection add code around a bit so functions within that file
can be used by scp.

Signed-off-by: cdoern <cdoern@redhat.com>

1 files changed, 348 insertions, 0 deletions

diff --git a/cmd/podman/images/scp.go b/cmd/podman/images/scp.go
new file mode 100644
index 000000000..71399e0b7
--- /dev/null
+++ b/cmd/podman/images/scp.go
@@ -0,0 +1,348 @@
+package images
+
+import (
+	"context"
+	"fmt"
+	"io/ioutil"
+	urlP "net/url"
+	"os"
+	"strconv"
+	"strings"
+
+	"github.com/containers/common/pkg/config"
+	"github.com/containers/podman/v3/cmd/podman/common"
+	"github.com/containers/podman/v3/cmd/podman/parse"
+	"github.com/containers/podman/v3/cmd/podman/registry"
+	"github.com/containers/podman/v3/cmd/podman/system/connection"
+	"github.com/containers/podman/v3/libpod/define"
+	"github.com/containers/podman/v3/pkg/domain/entities"
+	"github.com/docker/distribution/reference"
+	scpD "github.com/dtylman/scp"
+	"github.com/pkg/errors"
+	"github.com/sirupsen/logrus"
+	"github.com/spf13/cobra"
+	"golang.org/x/crypto/ssh"
+)
+
+var (
+	saveScpDescription = `Securely copy an image from one host to another.`
+	imageScpCommand    = &cobra.Command{
+		Use:               "scp [options] IMAGE [HOST::]",
+		Annotations:       map[string]string{registry.EngineMode: registry.ABIMode},
+		Long:              saveScpDescription,
+		Short:             "securely copy images",
+		RunE:              scp,
+		Args:              cobra.RangeArgs(1, 2),
+		ValidArgsFunction: common.AutocompleteImages,
+		Example:           `podman image scp myimage:latest otherhost::`,
+	}
+)
+
+var (
+	scpOpts entities.ImageScpOptions
+)
+
+func init() {
+	registry.Commands = append(registry.Commands, registry.CliCommand{
+		Command: imageScpCommand,
+		Parent:  imageCmd,
+	})
+	scpFlags(imageScpCommand)
+}
+
+func scpFlags(cmd *cobra.Command) {
+	flags := cmd.Flags()
+	flags.BoolVarP(&scpOpts.Save.Quiet, "quiet", "q", false, "Suppress the output")
+}
+
+func scp(cmd *cobra.Command, args []string) (finalErr error) {
+	var (
+		// TODO add tag support for images
+		err error
+	)
+	if scpOpts.Save.Quiet { // set quiet for both load and save
+		scpOpts.Load.Quiet = true
+	}
+	f, err := ioutil.TempFile("", "podman") // open temp file for load/save output
+	if err != nil {
+		return err
+	}
+	defer os.Remove(f.Name())
+
+	scpOpts.Save.Output = f.Name()
+	scpOpts.Load.Input = scpOpts.Save.Output
+	if err := parse.ValidateFileName(saveOpts.Output); err != nil {
+		return err
+	}
+	confR, err := config.NewConfig("") // create a hand made config for the remote engine since we might use remote and native at once
+	if err != nil {
+		return errors.Wrapf(err, "could not make config")
+	}
+	abiEng, err := registry.NewImageEngine(cmd, args) // abi native engine
+	if err != nil {
+		return err
+	}
+
+	cfg, err := config.ReadCustomConfig() // get ready to set ssh destination if necessary
+	if err != nil {
+		return err
+	}
+	serv, err := parseArgs(args, cfg) // parses connection data and "which way" we are loading and saving
+	if err != nil {
+		return err
+	}
+	// TODO: Add podman remote support
+	confR.Engine = config.EngineConfig{Remote: true, CgroupManager: "cgroupfs", ServiceDestinations: serv} // pass the service dest (either remote or something else) to engine
+	switch {
+	case scpOpts.FromRemote: // if we want to load FROM the remote
+		err = saveToRemote(scpOpts.SourceImageName, scpOpts.Save.Output, "", scpOpts.URI[0], scpOpts.Iden[0])
+		if err != nil {
+			return err
+		}
+		if scpOpts.ToRemote { // we want to load remote -> remote
+			rep, err := loadToRemote(scpOpts.Save.Output, "", scpOpts.URI[1], scpOpts.Iden[1])
+			if err != nil {
+				return err
+			}
+			fmt.Println(rep)
+			break
+		}
+		report, err := abiEng.Load(context.Background(), scpOpts.Load)
+		if err != nil {
+			return err
+		}
+		fmt.Println("Loaded images(s): " + strings.Join(report.Names, ","))
+	case scpOpts.ToRemote: // remote host load
+		scpOpts.Save.Format = "oci-archive"
+		abiErr := abiEng.Save(context.Background(), scpOpts.SourceImageName, []string{}, scpOpts.Save) // save the image locally before loading it on remote, local, or ssh
+		if abiErr != nil {
+			errors.Wrapf(abiErr, "could not save image as specified")
+		}
+		rep, err := loadToRemote(scpOpts.Save.Output, "", scpOpts.URI[0], scpOpts.Iden[0])
+		if err != nil {
+			return err
+		}
+		fmt.Println(rep)
+	// TODO: Add podman remote support
+	default: // else native load
+		if scpOpts.Tag != "" {
+			return errors.Wrapf(define.ErrInvalidArg, "Renaming of an image is currently not supported")
+		}
+		scpOpts.Save.Format = "oci-archive"
+		abiErr := abiEng.Save(context.Background(), scpOpts.SourceImageName, []string{}, scpOpts.Save) // save the image locally before loading it on remote, local, or ssh
+		if abiErr != nil {
+			errors.Wrapf(abiErr, "could not save image as specified")
+		}
+		rep, err := abiEng.Load(context.Background(), scpOpts.Load)
+		if err != nil {
+			return err
+		}
+		fmt.Println("Loaded images(s): " + strings.Join(rep.Names, ","))
+	}
+	return nil
+}
+
+// loadToRemote takes image and remote connection information. it connects to the specified client
+// and copies the saved image dir over to the remote host and then loads it onto the machine
+// returns a string containing output or an error
+func loadToRemote(localFile string, tag string, url *urlP.URL, iden string) (string, error) {
+	dial, remoteFile, err := createConnection(url, iden)
+	if err != nil {
+		return "", err
+	}
+	defer dial.Close()
+
+	n, err := scpD.CopyTo(dial, localFile, remoteFile)
+	if err != nil {
+		errOut := (strconv.Itoa(int(n)) + " Bytes copied before error")
+		return " ", errors.Wrapf(err, errOut)
+	}
+	run := ""
+	if tag != "" {
+		return "", errors.Wrapf(define.ErrInvalidArg, "Renaming of an image is currently not supported")
+	}
+	podman := os.Args[0]
+	run = podman + " image load --input=" + remoteFile + ";rm " + remoteFile // run ssh image load of the file copied via scp
+	out, err := connection.ExecRemoteCommand(dial, run)
+	if err != nil {
+		return "", err
+	}
+	return strings.TrimSuffix(out, "\n"), nil
+}
+
+// saveToRemote takes image information and remote connection information. it connects to the specified client
+// and saves the specified image on the remote machine and then copies it to the specified local location
+// returns an error if one occurs.
+func saveToRemote(image, localFile string, tag string, uri *urlP.URL, iden string) error {
+	dial, remoteFile, err := createConnection(uri, iden)
+
+	if err != nil {
+		return err
+	}
+	defer dial.Close()
+
+	if tag != "" {
+		return errors.Wrapf(define.ErrInvalidArg, "Renaming of an image is currently not supported")
+	}
+	podman := os.Args[0]
+	run := podman + " image save " + image + " --format=oci-archive --output=" + remoteFile // run ssh image load of the file copied via scp. Files are reverse in thie case...
+	_, err = connection.ExecRemoteCommand(dial, run)
+	if err != nil {
+		return nil
+	}
+	n, err := scpD.CopyFrom(dial, remoteFile, localFile)
+	connection.ExecRemoteCommand(dial, "rm "+remoteFile)
+	if err != nil {
+		errOut := (strconv.Itoa(int(n)) + " Bytes copied before error")
+		return errors.Wrapf(err, errOut)
+	}
+	return nil
+}
+
+// makeRemoteFile creates the necessary remote file on the host to
+// save or load the image to. returns a string with the file name or an error
+func makeRemoteFile(dial *ssh.Client) (string, error) {
+	run := "mktemp"
+	remoteFile, err := connection.ExecRemoteCommand(dial, run)
+	if err != nil {
+		return "", err
+	}
+	remoteFile = strings.TrimSuffix(remoteFile, "\n")
+	if err != nil {
+		return "", err
+	}
+	return remoteFile, nil
+}
+
+// createConnections takes a boolean determining which ssh client to dial
+// and returns the dials client, its newly opened remote file, and an error if applicable.
+func createConnection(url *urlP.URL, iden string) (*ssh.Client, string, error) {
+	cfg, err := connection.ValidateAndConfigure(url, iden)
+	if err != nil {
+		return nil, "", err
+	}
+	dialAdd, err := ssh.Dial("tcp", url.Host, cfg) // dial the client
+	if err != nil {
+		return nil, "", errors.Wrapf(err, "failed to connect")
+	}
+	file, err := makeRemoteFile(dialAdd)
+	if err != nil {
+		return nil, "", err
+	}
+
+	return dialAdd, file, nil
+}
+
+// validateImageName makes sure that the image given is valid and no injections are occurring
+// we simply use this for error checking, bot setting the image
+func validateImageName(input string) error {
+	// ParseNormalizedNamed transforms a shortname image into its
+	// full name reference so busybox => docker.io/library/busybox
+	// we want to keep our shortnames, so only return an error if
+	// we cannot parse what th euser has given us
+	_, err := reference.ParseNormalizedNamed(input)
+	return err
+}
+
+// remoteArgLength is a helper function to simplify the extracting of host argument data
+// returns an int which contains the length of a specified index in a host::image string
+func remoteArgLength(input string, side int) int {
+	return len((strings.Split(input, "::"))[side])
+}
+
+// parseArgs returns the valid connection data based off of the information provided by the user
+// args is an array of the command arguments and cfg is tooling configuration used to get service destinations
+// returned is serv and an error if applicable. serv is a map of service destinations with the connection name as the index
+// this connection name is intended to be used as EngineConfig.ServiceDestinations
+// this function modifies the global scpOpt entities: FromRemote, ToRemote, Connections, and SourceImageName
+func parseArgs(args []string, cfg *config.Config) (map[string]config.Destination, error) {
+	serv := map[string]config.Destination{}
+	cliConnections := []string{}
+	switch len(args) {
+	case 1:
+		if strings.Contains(args[0], "::") {
+			scpOpts.FromRemote = true
+			cliConnections = append(cliConnections, args[0])
+		} else {
+			err := validateImageName(args[0])
+			if err != nil {
+				return nil, err
+			}
+			scpOpts.SourceImageName = args[0]
+		}
+	case 2:
+		if strings.Contains(args[0], "::") {
+			if !(strings.Contains(args[1], "::")) && remoteArgLength(args[0], 1) == 0 { // if an image is specified, this mean we are loading to our client
+				cliConnections = append(cliConnections, args[0])
+				scpOpts.ToRemote = true
+				scpOpts.SourceImageName = args[1]
+			} else if strings.Contains(args[1], "::") { // both remote clients
+				scpOpts.FromRemote = true
+				scpOpts.ToRemote = true
+				if remoteArgLength(args[0], 1) == 0 { // is save->load w/ one image name
+					cliConnections = append(cliConnections, args[0])
+					cliConnections = append(cliConnections, args[1])
+				} else if remoteArgLength(args[0], 1) > 0 && remoteArgLength(args[1], 1) > 0 {
+					//in the future, this function could, instead of rejecting renames, also set a DestImageName field
+					return nil, errors.Wrapf(define.ErrInvalidArg, "cannot specify an image rename")
+				} else { // else its a load save (order of args)
+					cliConnections = append(cliConnections, args[1])
+					cliConnections = append(cliConnections, args[0])
+				}
+			} else {
+				//in the future, this function could, instead of rejecting renames, also set a DestImageName field
+				return nil, errors.Wrapf(define.ErrInvalidArg, "cannot specify an image rename")
+			}
+		} else if strings.Contains(args[1], "::") { // if we are given image host::
+			if remoteArgLength(args[1], 1) > 0 {
+				//in the future, this function could, instead of rejecting renames, also set a DestImageName field
+				return nil, errors.Wrapf(define.ErrInvalidArg, "cannot specify an image rename")
+			}
+			err := validateImageName(args[0])
+			if err != nil {
+				return nil, err
+			}
+			scpOpts.SourceImageName = args[0]
+			scpOpts.ToRemote = true
+			cliConnections = append(cliConnections, args[1])
+		} else {
+			//in the future, this function could, instead of rejecting renames, also set a DestImageName field
+			return nil, errors.Wrapf(define.ErrInvalidArg, "cannot specify an image rename")
+		}
+	}
+	var url string
+	var iden string
+	for i, val := range cliConnections {
+		splitEnv := strings.SplitN(val, "::", 2)
+		scpOpts.Connections = append(scpOpts.Connections, splitEnv[0])
+		if len(splitEnv[1]) != 0 {
+			err := validateImageName(splitEnv[1])
+			if err != nil {
+				return nil, err
+			}
+			scpOpts.SourceImageName = splitEnv[1]
+			//TODO: actually use the new name given by the user
+		}
+		conn, found := cfg.Engine.ServiceDestinations[scpOpts.Connections[i]]
+		if found {
+			url = conn.URI
+			iden = conn.Identity
+		} else { // no match, warn user and do a manual connection.
+			url = "ssh://" + scpOpts.Connections[i]
+			iden = ""
+			logrus.Warnf("Unknown connection name given. Please use system connection add to specify the default remote socket location")
+		}
+		urlT, err := urlP.Parse(url) // create an actual url to pass to exec command
+		if err != nil {
+			return nil, err
+		}
+		if urlT.User.Username() == "" {
+			if urlT.User, err = connection.GetUserInfo(urlT); err != nil {
+				return nil, err
+			}
+		}
+		scpOpts.URI = append(scpOpts.URI, urlT)
+		scpOpts.Iden = append(scpOpts.Iden, iden)
+	}
+	return serv, nil
+}